HEATING SYSTEM PRODUCING ELECTRICITY

Abstract

A heating system for a property has a thermal interconnection (5) between a thermal heat generator (1), in particular a conventional heating system (2), and a plurality of heat consumers (7) for simultaneous production of heat and electricity, the thermal interconnection (5) being controlled by a control unit (12). One of the heat consumers (7) includes a conversion system (11) based on a thermodynamic cycle (10), in particular a water vapor or an ORC or Kalina process, and provided for the conversion of thermodynamic energy into electrical energy. The condensation heat occurring in the thermodynamic cycle (10) is transferred to further heat consumers (7). The heating system is operable in at least one of two modes of operation, wherein in the first mode of operation the heat generated is supplied to the thermodynamic cycle (10) for producing electricity and the residual heat resulting from the thermodynamic cycle (10) is used for heating, and in the second mode of operation electricity is produced independently of the heating demand in that a heat sink (6) absorbs the condensation heat of the thermodynamic cycle (10).

Description

The present invention relates to a heating system for a property, including a thermal interconnection between a thermal heat generator, in particular a conventional heating system, and a plurality of heat consumers for simultaneous production of heat and electricity, the thermal interconnection being controlled by a control unit, one of the heat consumers including a conversion system based on a thermodynamic cycle, in particular a water vapor or an ORC or Kalina process, and provided for the conversion of thermodynamic energy into electrical energy, and the condensation heat occurring in the thermodynamic cycle being transferred to further heat consumers.

As regards the following description, reference is made to the attached “List of terms used and their meanings” and the “List of abbreviations”.

The brochure “Kurzinfo: Lion® Powerblock” (as at October 2007) of OTAG Vertriebs GmbH & Co. KG, Olsberg, Germany (http://www.otag.de/download/071007_Lion_Kurzinfo_—2007_D.pdf) presents a heating system for residential properties according to the prior art. Essential components of this system are a gas burner, a steam-based thermodynamic circuit consisting of a tube evaporator and a heat exchanger for condensation of the water vapor and for transferring the condensation heat to the heating circuit. The steam pressure energy generated is first converted into linear kinetic energy by means of a double free-piston uniflow steam engine and then into electric power with the aid of a linear generator coupled thereto. The supply of steam into the working chamber of the free piston is controlled mechanically by way of slide valves which are firmly connected with the piston rod and, depending on the piston position and piston velocity, open and close the inlet for a specific time that can not be controlled further. As a result of this, the piston path in which the inlet is open is always fixed and is therefore optimally designed for one working pressure only. The lower working pressures occurring, e.g., during start-up or switch-off can therefore not be optimally exploited since this requires a relatively longer opening of the inlet to ensure a full utilization of the expansion chamber.

After the piston has performed its expansion work, it travels over an opening in the cylinder wall which serves as an outlet for the expanded water vapor until such time as the piston closes the opening again in its return movement, which, for one thing, results in that compression work is to be performed on the steam remaining in the cylinder in order to push the piston to its initial position again. This compression work is carried out by the contradirectional working cycle of the double free piston, accompanied by the losses in the energy conversion which inevitably appear in the process. For another thing, the piston is unable to perform the maximum possible expansion work since at the moment when the piston travels over the outlet opening, an overpressure must still be present in the working chamber for the remaining water vapor to flow into the condensation chamber at all, something which leads to further conversion losses.

A further drawback of this known mini CHP (combined heat and power) unit results from the use of water as the medium for the thermodynamic cycle since water will only condense at 100° C. at normal pressure. But since the domestic heat consumers often require only distinctly lower temperature levels, such as, e.g., in the operation of a floor heating system with a flow temperature of 50° C. max., the maximum possible efficiency of electric power generation, which is based on the spread between vaporization temperature and condensation temperature, is not exhausted thereby. While a cycle using water vapor as the medium and involving condensation temperatures of below 100° C. is also conceivable, the negative pressure resulting therefrom is difficult to maintain in the long run due to leakages that can be hardly avoided for technical reasons.

For a more economic way to generate electricity by means of a mini CHP unit, the following characteristics would additionally be worthwhile:

• • An efficient generation of electricity should be possible also at times when there is no heating demand, in order to ensure a higher utilization of the unit;
  • the heating system should be able to effectively utilize the thermal energy from thermal solar collectors, which is excessively available in summer, for generating electricity;
  • the heating system should be able to automatically adjust the condensation temperature of the thermodynamic cycle to the variable low temperature level provided, such as, e.g., heating return temperatures, in order to achieve a maximum temperature spread; and
  • the electricity generation unit should not be bound to a particular type of combustion plant (gas, oil, pellets, etc.).

The current state of the art relating to heating systems with a simultaneous thermal heat production and an electricity production based on a thermodynamic process is characterized by the following features:

• • (a) only one single heat generator: a conventional heating system which is configured as a gas heating in order to reach the high temperatures required in the thermodynamic process;
  • (b) the heating system is combined with a thermally coupled heat accumulator in which the thermal heat produced by the heating system can be temporarily accumulated and be passed on to a heat consumer offset in time. The equilibrium between the thermal energy generation and the thermal energy demand results according to the following formula:

E_Heiz(t)+E_{Sp OUT}(t)=E_WW(t)+E_HW(t)+E_THDY(t)+E_{Sp IN}(t)

• •  where: E_{Sp OUT}(t)=E_WW(t)+E_HW(t)
  •  and thus the following applies: E_Heiz(t)=E_THDY(t) E_{Sp IN}(t);
  • (c) the system has only one mode of operation, in which, by means of a system of converting thermodynamic to electrical energy, electricity is produced and the condensation heat arising in the thermodynamic process fills the heat accumulator at the same time;
  • (d) there exists no thermal interconnection to a thermal heat sink provided at the property and which is exploited in an efficiency-increasing manner in the production of electricity;
  • (e) there exists no thermal interconnection to thermal solar collectors provided at the property and which are exploited for solar electricity production;
  • (f) there exists no thermal interconnection to a waste gas heat recovery system provided at the property and which is exploited in an efficiency-increasing manner in the production of electricity;
  • (g) the thermodynamic cycle is based on a single-stage water-steam circuit;
  • (h) the conversion of thermodynamic to electrical energy is effected either by means of a combination of a uniflow steam engine with a linear generator of a type having two contradirectional pressure cylinders as are used in conventional free piston systems, with one working chamber always remaining unutilized and only one pressure cylinder carrying out the working cycle at a time alternately. In principle, the capacity (power) of the conversion system is adjustable through the repetition frequency of the working cycles, with the conversion system being however realizable only based on a constant ratio of inlet pressure to outlet pressure due to an absence of a possibility of a closed-loop control of the inlet volume per working cycle, which in turn leads to the fact that the condensation temperature, which is dependent on the outlet pressure, of the thermodynamic cycle is not adjustable;
  • (i) an equalization of the inconstant consumption of energy of the heat consumers is effected by means of the heat accumulator filling level. The operating mode is active until the heat accumulator filling level has exceeded an upper limit, and becomes active again as soon as the filling level has fallen below a lower limit. The following applies here:

P_Heiz(t)=P_THDY(t)+P_{Sp IN}(t)

• •  where: P_THDY(t)=f (input temperature T_TNDY-In)

Generally, the following boundary conditions and requirements are to be taken into account for an economic electricity generation by a thermodynamic process by means of a mini CHP unit:

• • A high efficiency in electricity generation is achievable only when great temperature differences are involved, i.e. an output temperature of the heating system that is as high as possible (>300° C.) is required and, in particular in the generation of electricity when there is no heating demand, a condensation temperature that is as low as possible (<20° C.) is required;
  • at present, no working medium is known which can be used for technically implementing a thermodynamic process in this temperature range demanded and which has thermodynamic properties which, in addition, allow a high efficiency in the generation of electricity. In addition to the high boiling point, which is a disadvantage, water further has the characteristic that a high superheating of the steam is required to allow an expansion with dry steam, which has a negative effect on the thermodynamic efficiency;
  • in a mode of operation “generation of electricity when there is no heating demand”, a very high cooling capacity at as low a temperature level as possible (<20° C.) is required for the condensation heat arising, but such cooling capacity is realizable from the environment only with high prime costs involved (e.g., water cooling circuit with geothermal probe) or by a high expenditure of energy (e.g., by a heat exchanger having ventilators); and
  • for residential properties, only a low noise emission caused by the conversion system is acceptable.

Furthermore, the problem has to be solved of how the various heat generators, heat accumulators and heat consumers can be thermally coupled to each other in the most favorable way.

According to the invention, provision is made in a heating system of the type initially mentioned that the heating system is operable in at least one of two modes of operation, wherein in the first mode of operation the heat generated is supplied to the thermodynamic cycle for producing electricity and the residual heat resulting from the thermodynamic cycle is used for heating, and in the second mode of operation electricity is produced independently of the heating demand in that a heat sink absorbs the condensation heat of the thermodynamic process. Advantageous and expedient configurations of the heating system according to the invention will be apparent from the dependent claims.

The invention is primarily geared to a heating system for residential properties, which is used to heat the rooms of a property and/or the domestic service water of the property (heat consumers). For the first time, a system is proposed in which a conventional heating system is combined with a thermodynamic circuit, for instance with an ORC circuit (Organic Rankine Cycle) “on a small scale” (i.e. not in industrial plant engineering or power plant construction) to provide in this way an efficient option for generating electrical power. Until now, ORC installations have been rarely made use of in the low load range since the efficiency of conventional ORC installations in this range is generally considered to be too low.

The invention provides a heating system which avoids the above-mentioned disadvantages of the prior art by one or more preferred measures and meets the additional requirements. These preferred measures relate both to improvements in the basic system structure and improvements in respect of a demand-oriented efficiency- and cost-optimized design of each individual component, and also to an optimized overall system structure resulting from the additional requirements. A special overall system consisting of a combination of the advantageous measures listed below leads to a preferred technical realization of the heating system which, based on the thermodynamic system design, results in a maximum energy efficiency in the conversion of thermodynamic to electrical energy:

• • (a) a thermal interconnection to a thermal heat sink provided at the property for increasing the efficiency in the production of electricity and for realizing a further mode of operation, “Production of electricity only”;
  • (b) a thermal interconnection to thermal solar collectors for generating solar electricity by means of a thermodynamic process in the low temperature range and for realizing a further mode of operation, “Production of solar electricity”, in which electricity is produced with the aid of the thermal solar collectors;
  • (c) a thermal interconnection to a waste gas heat recovery system which is provided at the property and is exploited by means of a thermodynamic process in the low temperature range for increasing the efficiency in the production of electricity;
  • (d) a technical realization of a combined heat and power generation having a very wide temperature spread beneficial to the Carnot efficiency, of from approx. 20 to 300° C. using a medium which is suitable for the extended temperature range for a single-stage thermodynamic cycle, in particular thermal oils or silicates, having a critical temperature above the exit temperature of approx. 300° C. and which ideally does not create a negative pressure relative to the ambient pressure, also in the low condensation temperature range at the level of the heat sink;
  • (e) the use of a very efficient multistage thermodynamic cycle having a high temperature circuit and a low temperature circuit, preferably both being ORC circuits, electricity being generated from both circuits;
  • (f) the use of a valve-controlled, possibly double-acting pressure cylinder/linear generator system which is optimally suited for this application and is adjustable in respect of both the transfer capacity and the inlet pressure/outlet pressure ratio by the closed-loop control of the inlet volume or of the expansion path per working cycle;
  • (g) or, as an alternative to (f), the use of a suitable a rotational conversion system for converting thermodynamic energy into mechanical rotational energy, in particular using a DiPietro engine;
  • (h) as a further improvement regarding (g): the rotational system includes a rotational generator, in particular an RMT generator;
  • (i) the control unit controls a capacity (power) adaptation required owing to the additional heat generators in the different modes of operation, it being prevented that the heating system needs an adjustable capacity, and the thermal equilibrium in the different modes of operation being balanced either by a power regulation in the conversion system for converting thermodynamic into electrical energy or by means of closed-loop control of an accumulator inflow P_{Sp IN}(t) and thus by way of the accumulator filling level of the heat accumulator;
  • (j) the use of a high temperature heating system, in particular a high temperature biomass combustion plant, as the heat generator.

Generally, the thermal coupling according to the invention, of a heat sink provided at the property, configured as, e.g., an air moisture heat exchanger, a geothermal collector, a geothermal probe, a body of water, an air cooling system or a cold reservoir, allows an additional mode of operation in which electricity can also be produced at a time when there is no heating demand, by the heat sink absorbing the condensation heat of the thermodynamic cycle. By the thermal coupling of a heat sink provided at the property to the thermodynamic cycle, a maximum temperature spread is reached between the temperature level of the medium prior to expansion (T_THDY-In) and the temperature level of a heat sink (T_Ws) provided at the property.

The theoretically possible Carnot efficiency in the conversion of the thermal energy thus results from the formula:

η_CARNOT=1−T_Ws/T_THDY-In

Especially advantageous with respect to the maximum possible Carnot efficiency is the use of a special high temperature heating system, in particular a biomass combustion plant configured in this way, such as, e.g., a wooden pellets heating system allowing medium outlet temperatures T_{H Out} of above the boiling point of water, in particular with outlet temperatures of greater than 300° C.

In order to be able to exploit the high outlet temperatures of the high temperature heating system, a thermodynamic circuit medium (e.g., thermal oils) suitable for this temperature range and having a critical temperature above the outlet temperature of the high temperature heating system is required.

The generation of electricity with the aid of the thermodynamic cycle is effected in that the working medium, preferably a cooling agent having a low boiling point, is vaporized, a high pressure being produced by the vaporization. This pressure can be extracted as mechanical kinetic energy in the form of volume change work during the expansion of the gas and be converted into electrical energy in the process.

Preferred is a medium which is suitable for the thermodynamic cycle, e.g. thermal oils, or an ORC medium which is specially developed for this application and which, in addition to the good heat transfer characteristics required, also distinguishes itself in that no negative pressure relative to the ambient pressure arises in the medium in the required low condensation temperature range since the efficiency of the thermodynamic cycle is reduced by an ingress of air during negative pressure conditions, which is difficult to avoid in the long term for technical reasons. Furthermore, the superheating of the vaporized gas required prior to expansion should be as small as possible since the energy added during superheating does not increase the energy yield of the thermodynamic cycle.

The control unit manages the energy distribution and, based on periodically determined measured data, adjusts an equilibrium between thermal energy generation and thermal energy demand according to the formula

E_Heiz(t)=E_WW(t)+E_HW(t)+E_THDY(t)+E_Rest(t).

According to a special embodiment of the invention, a valve-controlled piston engine is provided which can be used for separately and variable setting the inlet and outlets periods of each working cycle. For one thing, this results in that under the given conditions, each expansion proceeds under optimum pressure conditions. For another thing, based on the inlet period the inlet volume is controlled and thus the outlet pressure of the medium after expansion has been effected, which in turn allows the temperature of the medium after the expansion of the thermodynamic cycle to be able to be variably adjusted to maximum temperature required at the moment of conversion, of one of the heat consumers. Ideally, the condensation of the medium then also takes place at this temperature level. Therefore the maximum possible portion—under the given circumstances—out of the thermal energy available is used for electricity generation. The equilibrium between the thermal energy generation and thermal energy demand is periodically determined and adjusted by the control unit here preferably according to following formula:

E_Heiz(t)=E_WW(t)+E_HW(t)+E_THDY(t)

A further improvement in the energy utilization is achieved by a thermally coupled heat accumulator in which the thermal heat produced by the heating system can be temporarily accumulated and be passed on to at least one heat consumer offset in time. Owing to this thermal interconnection, the heating system always only needs to be put into operation for a short time for heating purposes. Furthermore, as will be described below, the heat accumulator also allows the solar energy to be utilized both for heating purposes and for solar electricity generation. The heat accumulator preferably is a heat accumulator of an additive configuration having different temperature levels (stratified storage tank), in which a heat exchange takes place both in the flow line and in the return flow in each case at a selectable, best possible temperature level available in the heat accumulator. In addition to the extensively used buffer vessels, other types of accumulator are also conceivable, such as, e.g., space-saving latent heat accumulators with an accumulator medium which performs a phase change, preferably from solid to liquid, in the required accumulator temperature range, or a thermochemical heat accumulator. The equilibrium between thermal energy generation and thermal energy demand is periodically determined and adjusted here by the control unit preferably according to the following formula:

E_Heiz(t)+E_{Sp OUT}(t)=E_WW(t)+E_HW(t)+E_THDY(t)+E_{Sp IN}(t)

Based on data from sensors for detecting process-influencing parameters, the control unit automatically adjusts the most favorable operation at and for each particular point in time by changes in the process control variables (such as, e.g., flow velocity of the circuits, etc.). On the basis of sensor data, each heat exchange between individual components of the heating system is adjusted by a closed-loop control of the heat flows occurring, such that the transfer of the thermal energy of the respectively warmer medium to the respectively colder medium is as effective and complete as possible. The control unit can also include information from an electricity supplier of the property into the process of controlling the heating system to allow a production of electricity in particularly profitable periods of time.

The equilibrium between thermal energy generation and thermal energy demand is periodically determined and adjusted by the control unit preferably according to the following formula:

E_Heiz(t)+E_{Sp OUT}(t)=E_WW(t)+E_HW(t)+E_THDY(t)+E_{Sp IN}(t)+E_Rest(t)

By means of sensors for detecting process-influencing parameters, the control unit independently sets one or more of the modes of operation characterized below:

• • (a) Mode of operation “Heating, WW and production of electricity”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
Heating, WW heating,	EHeiz + ESp OUT =	TH Out = TTHDY-In > 300° C.
and THDY production of	ETHDY + EHW + ESp IN + EWW	THK VL = TSp In = TTHDY-Out = TWW =
electricity		TKond = TH In = 45 . . . 85° C.
FIG. 5		THK RL = TSP Out = 20 . . . 70° C.

• • (b) Mode of operation “Exclusive production of electricity from thermal heat”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
THDY production of	EHeiz = ETHDY + ERest	TH Out = TTHDY-In > 300° C.
electricity from thermal	ERest = EWs	TTHDY-Out = TKond = TWs In = 15 . . . 25° C.
heat		TWs Out = < 20° C.
FIG. 6

• • (c) Mode of operation “Standstill”.

In connection with the temperatures indicated above, an ideal situation without losses in the thermal transmission is assumed in which the control unit adjusts the operation at the respectively most favorable temperature spreads.

One difficulty in the technical realization of the thermal equilibrium between thermal energy generation and thermal energy demand in a plurality of modes of operation is constituted by the required load distribution between the individual components, which need to have a power throughput dependent on the mode of operation and on the condensation temperature. The following must always apply:

P_Heiz(t)+P_{Sp OUT}(t)=P_WW(t)+P_HW(t)+P_THDY(t)+P_{Sp IN}(t)+P_Ws(t)

The generator side of the equation can always be equalized for all modes of operation by the use of a heating system which is controllable in terms of the power P_Heiz(t) and which generates a constantly high output temperature T_{H Out} at a constant thermal transfer efficiency, independently of the power required. The consumer side of the equation can always be equalized by a variable power throughput of the thermodynamic conversion system P_THDY(t), which, however, additionally requires a closed-loop control for the condensation temperature. An additional option resides in regulating the heat accumulator input power P_{Sp IN}(t).

The technical realization of a heating system having a controllable heating power P_Heiz(t) at the required high output temperatures T_{H Out}>300° C. is difficult. It is therefore of advantage if the heating system can be operated at a constant heating power P_Heiz, irrespectively of the mode of operation, by the required load distribution being effected either by means of the variable accumulator inflow P_{Sp IN}(t) or by means of an adjustable power throughput P_THDY(t) of the thermodynamic conversion system.

The dynamic load distribution required has the following effect on the relevant modes of operation:

• • (a) Mode of operation “Heating, WW and production of electricity”

The thermal equilibrium of this mode of operation reads as follows:

E_Heiz(t)+E_{Sp OUT}(t)=E_THDY(t)+E_HW(t)+E_{Sp IN}(t)+E_WW(t)

The heat accumulator absorbs the condensation heat of the thermodynamic process and, at the same time, the heat consumers are supplied from the heat accumulator. Thus the following applies:

E_{Sp OUT}(t)=E_WW(t)+E_HW(t)

E_Heiz(t)=E_THDY(t)+E_{Sp IN}(t)

E_{Sp IN}(t)=E_Heiz(t)−E_THDY(t)

On the power level this means:

P_{Sp IN}(t)=P_Heiz(t)−P_THDY(t)

At a constant heating power:

P_Heiz(t)=P_Heiz=constant

While this mode of operation is active, the power throughput P_THDY(t) of the of the thermodynamic conversion system is constant:

P_THDY-Heizk at T_Kond=T_{Heizk RL}

This results in a constant accumulator inflow:

P_{Sp IN}=P_Heiz−P_THDY-Heizk

An equalization of the inconstant energy consumption of the heat consumers is effected by means of the heat accumulator filling level. The operating mode is active until the heat accumulator filling level has exceeded an upper limit, and becomes active again as soon as the filling level has fallen below a lower limit.

• • (b) Mode of operation “Exclusive production of electricity from thermal heat”

No regulation by means of the accumulator inflow takes place here. The thermal equilibrium of this mode of operation reads as follows:

E_Heiz(t)=E_THDY(t)+E_Rest(t)

and, hence:

P_THDY(t)=P_Heiz−P_Ws(t)

When the temperature level T_Ws is sufficiently low, a constant cooling capacity P_Ws can be taken from the heat sink. Thus, the following applies:

P_THDY(t)=P_THDY=constant at T_Kond=T_Ws

While this mode of operation is active, the power throughput P_THDY(t) of the thermodynamic conversion system is constant:

P_THDY-Stromp=P_Heiz−P_Ws

When it is intended to operate the heating system at an equally high heating power P_Heiz irrespectively of the mode of operation, this means:

P_Heiz-Stromp=P_Heiz-Heizk=P_{Heiz-Heiz Solar}=P_Heiz-Solar

This results in a separate power level for P_THDY for each mode of operation:

Mode of operation (a) P_THDY-Heizk=P_Heiz−P_{Sp IN}

Mode of operation (b) P_THDY-Stromp=P_Heiz−P_Ws

Due to the lower temperature of the heat sink, P_THDY-Stromp is higher than P_THDY-Heizk. When the temperature levels of T_Ws and T_{Heizk RL} are unequal, the following applies:

P_THDY-Stromp≠P_THDY-Heizk

One option to realize a heating system with only two modes of operation, (a) and (b), and a constant conversion power P_THDY and a constant heating power P_Heiz is obtained when the temperature level of the heat sink equals the return temperature of the radiators T_{Heizk RL}.

When T_Kond=T_{Heizk RL}=T_Ws

then P_Heiz=P_THDY-Stromp=P_THDY-Heizk applies.

The maximum Carnot efficiency reduced thereby for this system thus results from:

η_CARNOT=1−T_{Heizk RL}/T_Heiz

A further option to realize a heating system having a constant heating power P_Heiz is obtained when the outlet pressure constantly corresponds to the temperature level of the heat sink T_Ws. The mode of operation (a), which, as a result, is no longer applicable, must therefore be replaced by a mode of operation in which the heating system 2 produces thermal energy exclusively for use as thermal heat and for WW heating, with the appropriate heat circuits needing to be integrated for this purpose, of course. While this requires a conversion system having a variable conversion power P_THDY(t), an advantage of this application resides in that the conversion system only needs to implement a constant ratio of the inlet pressure to the outlet pressure and the power can be controlled by means of the repetition frequency f_cyc. Realization is possible using a turbine or a uniflow steam engine, for example.

• • Here the following applies: P_THDY(t)=f(f_cyc)

The maximum Carnot efficiency of this application results from the following formula:

η_CARNOT=1−T_{Heizk RL}/T_Heiz

A preferred option for producing electricity is a linear conversion system for converting thermodynamic energy into electrical energy, which is coupled to the thermodynamic cycle and includes one or more pressure cylinders, a linear generator, and a filter and rectifier unit. The linear conversion system provides for a piston/cylinder unit which is coupled to the thermodynamic cycle and specifically matched therewith, for initially converting the thermodynamic energy into kinetic energy from which electrical energy is then produced by means of a linear generator that is likewise specifically matched with this application, and the electrical energy is converted by means of a grid-based frequency converter into an AC voltage suitable for being fed to the grid. A suitable pressure cylinder/linear generator arrangement distinguishes itself by a high overall conversion efficiency, low prime costs, quiet operation as well as by a long service life as there are no transverse or rotational forces.

A special aspect of the conversion system consists in that by means of a valve-controlled piston engine, the inlet and outlet times of each working cycle can be adjusted separately and variably. This results, for one thing, in that under the given conditions, each expansion proceeds under optimum pressure conditions. For another thing, based on the inlet time the inlet volume is controlled and, hence, the outlet pressure of the medium after the expansion is completed, which in turn allows the temperature of the medium after the expansion of the thermodynamic cycle to be variably adapted to the temperature required at a maximum at the moment of conversion, of one of the heat consumers. Ideally, the condensation of the medium likewise takes place at this temperature level. As a result, the highest possible amount—under the given circumstances—of the thermal energy available is used for generating electricity.

To prevent the piston from striking against the cylinder head or cover, it is possible, in principle, to limit the piston stroke in that the piston rod is coupled to an idling crankshaft, for example.

A further possibility of avoiding a hard strike consists in that the expansion stroke available is not completely utilized for decompression and the remaining piston travel is realized by way of a magnet snapping. Here, the induction force that guides the piston up to the stop is adjusted such that only small forces act upon impact, thus allowing long-lasting operation.

In a thermodynamic pressure cylinder conversion system having a variable conversion power P_THDY(t), the conversion power is obtained from the product of the number of working cycles (stroke1 and stroke2) and the work performed by one piston stroke W_THDY and the cycle frequency f_Cyc:

P_THDY(t)=2*W_THDY*f_Cyc(t)

The work W_THDY performed is a function of the constant cylinder dimensions and the variable parameters:

W_THDY=(t)(T_VaporizV_Einl,T_Kond)

• • T_Vaporiz: temperature of medium→inlet pressure of medium
  • V_Einl: inlet volume per stroke
  • T_Kond: condensation temperature→outlet pressure of medium

At constant, high T_Vaporiz and in conversion systems having a constant inlet volume per stroke V_Einl, the outlet pressure of the medium can not be closed-loop controlled. This means that in these systems only one condensation temperature level is possible for all modes of operation:

W_THDY=constant

The conversion power P_THDY(t) in this thermodynamic pressure cylinder conversion system can be varied by changes in the cycle frequency:

P_THDY(t)=2*W_THDY*f_Cyc(t)

One possibility of making the cycle frequency f_cyc to be variable consists in varying the expansion velocity and, hence, the expansion duration t_Exp of a piston stroke by making the induction force F_ind to be variable through electrically variable parameters of the linear generator.

The cycle frequency f_cyc is dependent on the expansion duration t_Exp. When a working cycle is immediately (without dead time) followed by the contradirectional working cycle, then the following applies:

f_cyc=1/(2*t_Exp)

The expansion duration t_Exp is dependent on the stroke length, which however is constant, and on the expansion velocity of the piston, which, in turn, is the result of the equilibrium of forces between the mechanical thrust F_stroke of the pressure cylinder during expansion and the opposed induction force F_Ind of the linear generator.

t_Exp=f(F_Ind)

and, hence: f_Cyc(t)=f(F_Ind)

An electrically adjustable parameter of the linear generator is the coil inductance, which can be varied, for example, through an electrically selectable wiring of coil pairs.

Another way of configuring the induction force F_Ind of the linear generator to be variable consists in a closed-loop control of the load current of the inverter by the input resistance of the inverter, for example. The special advantage of this configuration resides in that this interface, for example in the form of a semiconductor junction, allows a very rapid and precise closed-loop control of the induction force F_Ind also during the expansion phase. This, in turn, results in that the combination of pressure cylinder and linear generator can be optimized in the design of the dimensions since this allows an optimum operation to be realized under the limiting factors of maximum acceleration and maximum piston velocity. The highest power throughput is produced when the piston is initially constantly accelerated at maximum acceleration during expansion. Once the maximum permissible velocity of the piston is reached, the piston is moved at this maximum velocity until it is necessary to decelerate the piston again at a negative and constant maximum acceleration.

In this way, it is possible to provide a heating system having a variable conversion power P_THDY(t) for all modes of operation; however, since it is not possible to adjust the outlet pressure, the following applies here, too:

T_kond=T_{Heizk RL}=T_Ws

η_CARNOT=1−T_{Heizk RL}/T_Heiz

The technical implementation of such a conversion system, such as, for example, a pressure cylinder, a uniflow steam engine, or a Corliss engine, is effected by means of a periodic valve timing. Each individual inlet valve and outlet valve is opened and closed periodically at the cycle frequency f_Cyc for a time period as determined by the valve timing settings, as illustrated in FIG. 10, the cycle duration t_Cyc corresponding to the sum of the duration of one working cycle t_Ausl1 and one contradirectional working cycle t_Ausl2:

t_Einl1=t_Einl2=constant

t_Cyc=t_Ausl1+t_Ausl2

f_Cyc=1/t_Cyc

t_Exp=1/(2*f_cyc)

All of the valves are synchronized in time in that in its expansion phase, the pressure cylinder periodically changes the valve position by the mechanical motion of the pressure cylinder or a synchronized motion derived therefrom, such as a rotary motion, and in this way directly mechanically controls the closed periods of each individual valve. The open periods for each valve are defined by the dimensions of a piston valve, for example, which opens and closes a valve by a linear motion. One example of a linear design of a periodically operating conversion system having a double-acting pressure cylinder is the known steam engine by James Watt.

A rotary type of this periodic pressure cylinder conversion system includes separate rotary valves which are opened and closed synchronously with the cycle frequency f_Cyc for defined periods of time as illustrated in FIG. 10. The open periods t_Einl of the separate valves result from the angular dimensions of the rotating valve segment in which a flow through the valve is possible. In purely mechanical systems, the cycle frequency f_Cyc is derived from the mechanical motion of the pressure cylinder, which is converted to a rotary motion, such as; e.g., in the known Corliss engine. Another way of implementation is produced by obtaining the cycle frequency by means of an external control, e.g. using an electric motor which rotates synchronously with the piston position. The rotary valves are synchronized in time in that, for example, all valves are connected with each other by a rotary spindle which rotates at the cycle frequency f_Cyc.

In order to realize a dynamic closed-loop control of the outlet pressure of the medium and, thus, of the condensation temperature T_Kond, the inlet volume per stroke V_Einl needs to be adjustable, which is possible by way of a variable open period of the inlet valves t_Einl. Ideally, the inlet valves are externally controlled, i.e. a control unit sets the inlet volume V_Einl(t) by means of the inlet period t_Einl such that the desired pressure of the medium is reached over the full piston stroke upon completion of the expansion. The condensation temperature of the medium is thereby set such that it corresponds to the maximum required temperature of the heat consumers coupled.

Preferably, inlet valves that can be electrically driven are employed for this purpose. In principle, the valve can also be driven pneumatically or hydraulically. Further conceivable is a solution in which the inlet valves are realized with a piston valve which opens and closes the inlet valves by its linear motion, the linear motion of the piston valve being externally controlled, i.e. not being derived from the motion of the pressure cylinder. A controlled linear motion of the piston valve can be realized using a linear motor, for example.

One way of implementation is constituted by the valve-controlled double-acting pressure cylinder illustrated in FIG. 11, in which the piston of the piston/cylinder unit is moved by the working medium flowing into a working chamber of the pressure cylinder. Following an evaluation of sensor data, the control unit automatically determines the inflow duration. The inlet volume to be controlled is therefore a function of the medium pressure available on the input side, which, however, can be considered to be constant, and the temperature desired on the output side during condensation.

Since it is always the full piston stroke that is used for expansion, a direct interrelation exists between the inlet period t_Einl and the desired condensation temperature T_Kond, i.e. for each adjustable condensation temperature T_Kond there exists a corresponding inlet period t_Einl and thus a constant value for the work performed by a piston stroke W_THDY. As a result, the following applies:

W_THDY=f(T_Kond)

This means that the inlet period t_Einl can not be made use of for controlling work performed by a piston stroke W_THDY. The inlet period t_Einl can be exclusively used for adjusting the outlet pressure of the medium after the expansion. The conversion power P_THDY(t) in a thermodynamic pressure cylinder conversion system can therefore be exclusively varied by varying the cycle frequency. The conversion power P_THDY results from the product of the number of working cycles (stroke 1 and stroke 2) and the work performed by one piston stroke W_THDY and the cycle frequency f_Cyc:

P_THDY(t)=2*W_THDY(T_Kond)*f_Cyc(t)

This principle is, of course, also applicable when using two contradirectional pressure cylinders, as are made use of in conventional free piston systems, with one working chamber always remaining unutilized and only one pressure cylinder carrying out the working cycle at a time alternately, while the other one is currently in the outlet phase.

Based on a conversion system implemented in this way, the cycle frequency f_Cyc thus controls the conversion power P_THDY, while the condensation temperature T_Kond is adjusted on the basis of the inlet period t_Einl.

The following results from this for the different modes of operation:

Mode of operation (a) P_THDY-Heizk=2*W_THDY-Heizk*f_Cyc-Heizk=P_Heiz−P_{Sp IN}

• • when T_Kond=T_{Heizk RL}
    Mode of operation (b) P_THDY-Stromp=2*W_THDY-Stromp*f_Cyc-stromp=P_Heiz−P_Ws
  • when T_Kond=T_Ws

It is, however, technically complicated to configure the induction force of a linear generator to be adjustable in order to use it for regulating the conversion power. A further advantage of the valve-controlled double-acting pressure cylinder consists in that it is not necessary to immediately start with the execution of the next working cycle once a working cycle has been executed. By a variable dead time t_tot inserted between execution of the working cycles, the repetition frequency and thus the conversion power P_THDY can be controlled. The cycle frequency f_Cyc is dependent on the expansion duration t_Exp and the dead time t_tot:

f_cyc=1/(2*(t_Exp+t_tot))

For the required capacity (power) adaptation, the control unit determines the appropriate cycle frequency f_Cyc in the different modes of operation:

f_Cyc=P_THDY/2*W_THDY

Here, the control unit waits between execution of one working cycle and execution of the contradirectional working cycle until half the period duration T_Cyc has elapsed. A power-modulated valve control takes place here, as illustrated in FIG. 12. The dead times are compensated by the filter and rectifier unit almost without loss.

In the process, the outlet valves are alternately opened and closed after half the period duration T_Cyc, that is, synchronously with the cycle frequency f_Cyc. It is therefore feasible to design the outlet valves to be externally controlled, such as, e.g., by electrically drivable valves, and also by a control derived from the linear motion of the pressure cylinder, such as, e.g., by means of a rotary valve control that is synchronous with the piston position.

Basically, however, a generation of electricity is also possible using a valve-controlled rotational conversion system coupled to the thermodynamic cycle, such as a compressed air motor specially matched therewith, in which the linear piston movement is first converted to rotational energy by means of a crankshaft, the rotational energy then being converted to electrical energy by means of a generator likewise specially adapted to this application.

A further preferred option is offered by the use of a rotary piston machine, in particular a DiPietro engine as such, in which the inlet volume per working cycle can be likewise controlled. An RMT generator, primarily designed for wind power plants, presents itself for use as a rotational generator. Both components distinguish themselves by a high efficiency in conversion as well as by very low start-up and switch-off losses in the required capacity range, even at low rotational speeds.

The electrical voltage produced in the generator in all of the systems described may, of course, also be used for other purposes. Instead of generating a line voltage, it is possible to generate battery charging voltages using a suitable converter, e.g. for lithium ion batteries for electric vehicles, or voltages suitable to be used for obtaining hydrogen through electrolysis. The kinetic energy produced by the conversion system may also be used for other purposes, e.g. for cooling indoor air by means of a refrigerating machine.

In a combustion plant involving output temperatures of T_{H Out}>300° C., it is technically difficult to reach the low waste gas temperatures required for an efficient operation. A marked improvement according to the invention in the efficiency of the combustion system is achieved by the thermal interconnection of a waste gas heat recovery system in a function as a separate heat generator for the thermal heat energy E_Rück(t) recovered having the temperature level T_Rück.

The equilibrium between thermal energy generation and thermal energy demand is periodically determined and adjusted here by the control unit preferably according to the following formula:

E_Heiz(t)+E_{Sp OUT}(t)+E_Rück(t)=E_WW(t)+E_HWE_THDY(t)+E_{SP IN}(t)+E_Rest(t)

For one thing, the waste gas residual heat can be made use of for meeting the heating and WW demand, the following applying:

E_Rück(t)=E_WW(t)+E_HW(t)

FIG. 8 illustrates one possible technical realization of this thermal interconnection by means of the heat accumulator. The disadvantage of this arrangement resides in that E_WW(t)+E_HW(t) are variable, whereas the quantity of heat recovered is always obtained constantly as soon as the heating system is in operation. The thermal equalization can only be effected when there is a heating demand.

Therefore, a further improvement in accordance with the invention is the use of the waste gas residual heat for producing electricity in the thermodynamic cycle, that is, in the modes of operation (a) and (b), the following applying:

E_THDY(t)=E_Rück(t)+E_Heiz(t)

By a thermal coupling of thermal solar collectors either directly to a heat consumer or preferably to the heat accumulator, the annual heating costs may be reduced. The equilibrium between thermal energy generation and thermal energy demand is periodically determined and adjusted here by the control unit preferably according to the following formula:

E_Heiz(t)+Es_Sol(t)+E_{Sp OUT}(t)+E_Rück(t)=E_WW(t)+E_HWE_THDY(t)+E_{Sp IN}(t)+E_Rest(t)

An optimum energy utilization is obtained by a thermal interconnection, according to the invention, of the individual components of the heating system, which ensures that each heat generator is in a heat exchanging relationship with each heat consumer, the heat accumulator, or with any other heat generator, with provision being preferably made for a contradirectional heat transfer when different heat transfer media are involved, and preferably for an exchange of medium when identical heat transfer media are involved.

Furthermore, the heating system according to the invention may be selectively operated in a plurality of modes of operation. In a first mode of operation, the heat generated or accumulated by one or more heat generators is used for heating or for filling the heat accumulators. In a second mode of operation, the heat generated is supplied to the thermodynamic cycle for the production of electricity, the residual heat arising from the thermodynamic cycle being transferred to the heat sink. In a third mode of operation, the heat generated is supplied to the thermodynamic cycle for the production of electricity, the residual heat arising from the thermodynamic cycle being used for heating or for filling the heat accumulators. On the basis of predefined criteria, the control unit automatically determines in which one of the modes of operation the heating system is operated and, to this end, can optionally obtain information from an electricity supplier of the property to allow a production of electricity in especially profitable periods of time.

This heating system is able to effectively exploit solar energy, both for the production of electricity and for obtaining thermal heat, by further raising the low temperature level prevailing in the heat accumulator or in the solar collector, which must only be higher than the temperature of the heat sink (T_Ws), by the remaining temperature range up to a consumption-dependent target temperature.

Further advantages arise in that, in one mode of operation of the heating system, in particular during the night or in winter, the solar collectors are made use of as a heat sink which absorbs the residual heat of the thermodynamic cycle. A multistage solar collector structure is of advantage here, which includes a series connection of different types of collectors consisting, on the one hand, of cost-effective collectors having a lower thermal insulation and, on the other hand, of higher-quality collectors having a high thermal insulation. For the purpose of energy optimization, it is further of advantage in some modes of operation that the individual collector types can also be bypassed, i.e. the solar medium does not flow through them. Based on predefined criteria, such as, e.g., the outside temperature, the control unit here determines whether the solar medium flows through only one of the collector types or through both in series.

In addition, radiators or a floor heating system provided in the property may be utilized as a permanent heat sink for the thermodynamic cycle, even when there is no heating demand. A special radiator in the laundry room, which is heated with residual heat whenever the latter develops during the exclusive production of electricity, could at the same time be utilized for laundry drying, for example.

As a rule, a solar-assisted heating system shows an inverse ratio between the availability of solar primary energy and the heating demand, i.e. while a large amount of primary energy is available in summer, there is hardly any or only little heating demand, whereas the opposite applies in winter. The invention makes use of exactly this inverse ratio, to the effect that the surplus of primary energy is converted into electrical energy. Due to a multiple dual use of the resources of the components which are already present in the solar-assisted heating system, of the solar collectors, heat accumulators, heating system and radiators, only the prime costs of the conversion system plus worthwhile add-ons such as additional collector surfaces and additional accumulator volume have to be incurred for solar electricity production. A high overall system utilization of the cost-intensive collector surface is advantageously achieved as there is no excess supply of solar heat energy in summer any more and in winter the solar supply is utilized via the heating system.

Due to the weak points as initially described of the circuit media currently available, the system presented so far, which is based on a thermodynamic process for electricity generation, is however not able to cover the desirable high temperature range which is given, on the one hand, by the high flash point of a heating system (>1000° C.) and, on the other hand, by the ambient temperature (<0° C.) of theoretically available temperature potentials.

A marked improvement according to the invention is therefore constituted by the combination of two thermodynamic cycles (partial processes) for successive temperature ranges, each partial process being a separate independent thermodynamic process and each partial process having a conversion system of its own for the conversion of pressure to electrical energy, and the condensation heat of the partial process for the higher temperature range being used as vaporization heat for the partial process of the lower temperature range by means of an interconnection via a heat exchanger. For example, a steam, butyl benzene, propyl benzene, ethyl benzene, toluene or OMTS cycle may be used for the temperature range of from 300 to 150° C. and an ORC cycle using the R245fa medium may be used for the low temperature range of from 150 to 15° C. The resultant addition of the temperature ranges results in a theoretical Carnot efficiency of 50% in this example.

The equilibrium between thermal energy generation and thermal energy demand is periodically determined and adjusted here by the control unit preferably according to the following formula:

E_Heiz(t)+E_Sol(t)+E_{Sp OUT}(t)=E_WW(t)+E_HW(t)+E_THDY1(t)+E_THDY2(t)+E_{Sp IN}(t)+E_Rest(t)

A further improvement according to the invention appears if the necessary capacity compensation between the partial processes occurs in that the control unit controls the transition temperature between the condensation of the medium of the first partial process and the vaporization of the medium of the second partial process and the capacity ratio of the two partial processes and adjusts it in accordance with the requirements.

A further aspect according to the invention is a cost-effective coupling of individual components of the two conversion systems for the conversion of pressure into electrical energy, so that it is not required to provide all individual components twice, by means of a mechanical coupling of the conversion systems which is configured such that the mechanical forces add, so that only one generator and one grid-based frequency converter are required, each of which transfers the sum of the energy of the partial processes.

A further possible cost-effective coupling of individual components of the two conversion systems for the conversion of pressure into electrical energy, so that it is not necessary to provide all individual components twice, can be implemented by means of an electrical coupling of the generator outputs; as a result, only one grid-based frequency converter is required, which transfers the sum of the energy of the partial processes.

In principle, it is also possible to couple the pressure cylinders of the two conversion systems for the partial processes by means of a crankshaft, the generation of electricity being effected by way of a rotational generator.

Of particular advantage here is the coupling of a waste gas heat recovery system and a thermal solar plant to the low temperature circuit of the two-stage thermodynamic process. The energy supply E_THDY is effected here in two stages at different temperature levels. In the low temperature stage (stage 2), the thermal energy E_Rück recovered is made use of for heating or partial vaporization of the thermodynamic medium up to the temperature level T_Rück, the following applying:

E_THDY2(t)=E_sol(t)+E_Rück(t)+E_Rest1(t)

This means that owing to the different temperature levels, the amount of energy for conversion into electrical energy E_THDY-stage2 and thus E_THDY additively increases by the value of the waste gas heat E_Rück(t) recovered and the solar energy E_Sol(t).

In the first stage of the thermodynamic process, the thermal energy E_Heiz recovered is made use of only for residual vaporization of the thermodynamic medium from the temperature level T_Rück up to the temperature level T_Heiz, the following applying:

E_THDY1(t)=E_Heiz(t)−E_Rest1(t)

By means of sensors for detecting process-influencing parameters, the control unit independently sets one or more of the modes of operation characterized below:

• • (a) Mode of operation “Heating, WW and production of electricity”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
Heating, WW heating,	EHeiz = ETHDY1 + ERest1	TBren = TTHDY1-In = 300° C.
and THDY production of	ETHDY2 = ERück + ERest1	TTHDY1-Out = TTHDY2-In = 150° C.
electricity	ESp IN = ERest2	THK VL = TSp In = TTHDY2-Out = TWW =
FIG. 19	ESp OUT = EHW + EWW	TKond = TH In = 45 . . . 85° C.
		THK RL = TSP Out = THeiz Ab = 20 . . . 60° C.
		THeiz Rück = THeiz Mit = 100 . . . 140° C.

• • (b) Mode of operation “Exclusive production of electricity from thermal heat”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
THDY production of	EHeiz = ETHDY1 + ERest1	TBren = TTHDY1-In = 300° C.
electricity from thermal	ETHDY2 = ERück + ERest1	TTHDY1-Out = TTHDY2-In = 150° C.
heat	ERest2 = EWs	TTHDY2-Out = TWs = THeiz Ab = 15 . . . 25° C.
FIG. 20		THeiz Rück = THeiz Mit = 100 . . . 140° C.

• • (c) Mode of operation “Exclusive production of electricity from thermal heat and accumulated or direct solar energy”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
THDY production of	EHeiz = ETHDY1 + ERest1	TSP Out =TH In = 20 . . . 60° C.
electricity from thermal	ETHDY2 =	TBren = TTHDY1-In = 300° C.
heat and heat	ESp Out + ERück + ERest1	TTHDY1-Out = TTHDY2-In = 150° C.
accumulator and solar	ERest2 = EWs	TTHDY2-Out = TWs = TSp In = 15 . . . 25° C.
energy		THeiz Ab = TSP Out = TKol Out = 20 . . . 60° C.
FIG. 21		THeiz Rück = THeiz Mit = 100 . . . 140° C.

• • (d) Mode of operation “Filling solar energy reservoir”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
Filling solar	ESP In = ESol	TSP In = TKol Out = 40 . . . 90° C.
energy reservoir		TSp Out = TKol In = 20 . . . 40° C.
FIG. 22

• • (e) Mode of operation “Solar heating and WW”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
Solar heating and WW	ESp OUT = EHW + EWW	THK VL = TSP In = TKol Out = TWW =
by means of heat	ESP In = ESol	45 . . . 90° C.
accumulator		THK RL = TSP Out = TKol In = 20 . . . 50° C.
FIG. 23

In connection with the temperatures indicated above, an ideal situation without losses in the thermal transmission is assumed in which the control unit adjusts the operation at the respectively most favorable temperature spreads.

It is possible, of course, to establish further modes of operation from the above tables by combining several modes of operation or by omitting a generating unit, accumulator or consumer in some modes of operation; these further modes of operation, however, shall not be discussed in further detail here.

How the heating system is operated depends on the current situation. As a rule, the production of heat energy is more efficient than the production of electricity. But when selecting the operating mode, the control unit also takes into account, inter alia, the supply of primary energy, the (predicted) demand for heat energy, the time-dependent degree of utilization of the heat accumulator, and the ratio between the income for electrical power fed and the effective heating costs. The control unit provides for an energy management for a situation-based distribution of energy in consideration of determined and predicted process-influencing parameters.

According to one aspect of the invention, provision is also made for a sequence of different modes of operation which, owing to the resultant high and constant utilization of the heating system accompanied by a simultaneous effective production of electricity, is advantageous whenever the heating and WW energy demand is lower than the maximum heating capacity of the heating system installed. In accordance with such a sequence of modes of operation, alternately the first the mode of operation (a), “Heating, WW and production of electricity”, is active until such time as the heat accumulator is filled sufficiently, and then, after this condition is met, parallelly the modes of operation (b), “Exclusive production of electricity from thermal heat”, and (e), “Solar heating and WW by means of heat accumulator”, until such time as the amount of heat accumulated in the heat accumulator falls below a lower threshold.

To be able to operate the system in all modes of operation, the power throughput P_THDY1(t) and P_THDY2(t) of the conversion systems 116 and 118 must be adjustable for each mode of operation, the following applying to each relevant mode of operation:

• • (a) Mode of operation “Heating, WW and production of electricity” at T_Kond2=T_{Heizk RL}

P_Heiz=P_THDY1

P_THDY2=P_Rück+P_Rest1

• • (b) Mode of operation “Exclusive production of electricity from thermal heat” at T_Kond2=T_Ws

P_Heiz=P_THDY1

P_THDY2=P_Rück+P_Rest1

• • (c) “Exclusive production of electricity from thermal heat and accumulated or direct solar energy”

P_Heiz=P_THDY1

P_THDY2=P_{SP Out}+P_Rück+P_Rest1

Since the condensation temperature of the second stage T_Kond2 is different in the various operating modes, it is advantageous to provide the second stage with a conversion system which has an outlet pressure that can be regulated, such as, for example, the valve-controlled linear generator described above or a DiPietro engine.

Since the condensation temperature of the first stage T_Kond2 is constant in the various operating modes, it is advantageous to provide the first stage with a conversion system without an outlet pressure that can be regulated, such as, for example, a uniflow steam engine or a turbine.

Based on a modified configuration (see FIG. 24), a technical implementation of all modes of operation is possible in which the second stage includes a conversion system without an outlet pressure that can be regulated, such as, for example, a uniflow steam engine or a turbine. This is made possible in that the heating system is realized to have a mode of operation (a) in which only the first stage produces electricity. In the second stage, only thermal heat is produced in this mode of operation in that the thermodynamic low temperature circuit medium does not flow through the conversion system of the second stage in this mode of operation.

The mode of operation (a) modified thereby is characterized by the following features:

• • (a) Mode of operation “Heating, WW and production of electricity”

		Temperature levels and
Function	Energy transmission	preferred temperature ranges
Heating, WW heating,	EHeiz = ETHDY1	TBren = TTHDY1-In = 300° C.
and THDY production of	ETHDY2 =	TTHDY1-Out = TTHDY2-In = TSp In = 150° C.
electricity	ERück + ERest1	THK VL = TWW = TKond = TH In =
FIG. 19	ESp IN = ETHDY2	45 . . . 85° C.
	ESp OUT = EHW + EWW	THK RL = TSP Out = THeiz Ab = TTHDY2-Out =
		20 . . . 60° C.
		THeiz Rück = THeiz Mit = 100 . . . 140° C.

Further general increases in efficiency for all system structures presented are obtained, for one thing, based on the fact that internal heat exchangers (regenerators) are provided for the thermodynamic cycle.

For another thing, it is often difficult in hot summer nights to reach cooling temperatures below the desirable 15° C. One cost-effective solution is constituted here by a sprinkler system which cools down solar collectors additionally, inter alia by the evaporative heat loss produced in the process. This sprinkler system should, of course, be activated by the control unit only when, all in all, cost benefits are expected to result thereby.

It is furthermore conceivable that the conversion system for the high temperature circuit 402 is realized by means of a Stirling engine since Stirling engines are designed for higher temperatures. It would be theoretically possible in this way to produce electrical energy at a high overall efficiency with burner circuit temperatures of >500° C.

Further details of the invention will be apparent from the following description with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic illustration of the thermal interconnections of all components involved and the associated functions of the intelligent energy distribution management of the heating system according to the invention;

FIG. 2 shows a technical realization of the heating system according to the invention;

FIG. 3 shows a schematic illustration of a combined condenser;

FIG. 4 shows a cost-effective realization of the heating system according to the invention;

FIG. 5 shows the mode of operation “Heating, WW and production of Electricity”;

FIG. 6 shows the mode of operation “Exclusive production of electricity from thermal heat”;

FIG. 7 shows a technical realization of the heating system according to the invention using waste gas heat recirculation coupled to the heat accumulator;

FIG. 8 shows a technical realization of the heating system according to the invention using waste gas heat recirculation coupled to the thermodynamic process;

FIG. 9 shows a schematic illustration of a possible linear conversion system for the conversion of thermodynamic into electrical energy;

FIG. 10 shows a schematic illustration of a periodic valve timing;

FIG. 11 shows a schematic illustration of a valve-controlled double-acting pressure cylinder;

FIG. 12 shows a schematic illustration of a power-modulated valve timing;

FIG. 13 shows a schematic illustration of a possible rotational conversion system for the conversion of thermodynamic energy into electrical energy;

FIG. 14 shows a schematic illustration of a double-stage thermodynamic cycle;

FIG. 15 shows a schematic illustration of a mechanical coupling of the conversion systems for converting pressure energy into kinetic energy;

FIG. 16 shows a schematic illustration of an electrical coupling of the generator outputs;

FIG. 17 shows a technical realization of a solar collector circuit;

FIG. 18 shows a technical realization of a double-stage design using solar collectors and waste gas heat recirculation in the THDY circuit;

FIG. 19 shows the mode of operation “Heating, WW and production of electricity”;

FIG. 20 shows the mode of operation “Exclusive production of electricity from thermal heat”;

FIG. 21 shows the mode of operation “Exclusive production of electricity from thermal heat and accumulated or direct solar energy”;

FIG. 22 shows the mode of operation “Filling solar energy reservoir”;

FIG. 23 shows the mode of operation “Solar heating and WW”;

FIG. 24 shows a modified technical realization of a double-stage design using solar collectors and waste gas heat recirculation of a condensation temperature in the THDY circuit;

FIG. 25 shows the modified mode of operation “Exclusive production of electricity from thermal heat”.

FIG. 1 generally indicates the individual components of a heating system according to the invention and their thermal interconnection 5 according to the invention: the heat generators 1, comprising a conventional heating system 2 and optional solar collectors 3, an optional heat accumulator and/or cold reservoir 4, a heat sink 6, heat consumers 7, comprising an apparatus for providing hot water 8, a thermal heat circuit 9 and a thermodynamic cycle 10 which, by means of a conversion system 11, is used for converting thermodynamic energy to electrical energy for the production of electricity. A central control unit 12 controls the operation of this heating system and of its individual components. The control unit incorporates process-influencing control parameters which are continuously detected by suitable sensors 13 and are supplied to the control unit 12. On the basis of the parameters detected and/or specific assumptions, the control unit 12 is also able to estimate or predict (other) parameters which are relevant for the control process of the heating system.

FIG. 2 illustrates the schematic structure of a mini CHP unit according to the invention, having a burner circuit 70 which flows through the heating boiler of a combustion system 71, a thermodynamic circuit 74 that is used for generating electricity, a heating circuit 79 which flows through the radiators 80, and a cooling circuit 77 which transports waste heat to a heat sink, the burner circuit 70 flowing through the vaporizer 73 of the thermodynamic circuit 74 and, depending on the mode of operation, either the heating circuit 79 or the cooling circuit 77 flowing through two separate condensers 75 and 76 on the output side. A heat accumulator 81 is thermally coupled to the heating circuit 79 by means of a heat exchanger.

According to FIG. 3, the separate condensers 210 and 211 are combined in a cost-effective manner in a combined heat exchanger, each having separate inputs and outputs for the thermodynamic circuit 200, the collector circuit 201, and the heating circuit 202.

FIG. 4 illustrates the schematic structure of a further mini CHP unit according to the invention, which is more cost-effective to produce owing to a dual function of some components. For instance, the boiler of the combustion system 331, through which the medium of the thermodynamic cycle 330 flows, is at the same time the vaporizer of the thermodynamic cycle 330. The heat accumulator 332 can be selectively used as a thermal heat sink of the thermodynamic cycle by the condenser 333 being integrated in a cost-effective manner in the heat accumulator 332. In the same way, the heating circuit may be made indirect use of in a cost-effective manner as a thermal heat sink of the thermodynamic cycle in that it receives the required thermal heat by means of a heat exchanger 334 integrated in the heat accumulator 332.

FIG. 5 describes the components and temperature levels included in the overall structure according to FIG. 4, which are required for the mode of operation “Heating, WW and production of electricity”.

FIG. 6 describes the components and temperature levels included in the overall structure according to FIG. 4, which are required for the mode of operation “Exclusive production of electricity from thermal heat”.

FIG. 7 illustrates the schematic structure of a further possible mini CHP unit, including a waste gas heat recirculation 338 which is coupled to a heat accumulator 340 by means of a heat exchanger 339.

FIG. 8 illustrates the schematic structure of a further possible mini CHP unit, including a waste gas heat recirculation 350 which is coupled to the thermodynamic circuit medium 352 by means of a heat exchanger 351.

The system illustrated in FIG. 9 comprises a thermodynamic part 501 having a working medium, one or more pressure cylinders 502, a linear generator 503 including a magnet and a coil, a control unit 506 which acts on both parts and is part of the central control unit 12, a rectifier and filter unit 504 converting the voltage pulses generated by the movement of the magnet to a DC voltage, and an inverter 505 inverting the DC voltage to an AC voltage suitable for feeding into the grid. The condensation heat of the thermodynamic process is supplied to the heat consumers.

FIG. 10 shows a schematic illustration of a periodic valve timing in which each individual inlet valve and outlet valve is opened and closed periodically at the cycle frequency f_Cyc for a time period as defined by the valve timing settings, the cycle duration t_Cyc corresponding to the sum of the duration of one working cycle t_Ausl1 and one contradirectional working cycle t_Ausl2.

FIG. 11 illustrates a valve-controlled pressure cylinder in which the two working cycles are completely independent of each other (in particular in terms of time); this means that no predefined periodic sequence of cycles is provided as is the case in known multiple stroke engines. Rather, an individual working cycle is initiated depending on the situation, i.e. the control unit 609 provides for the performance of a working cycle by opening and, respectively, closing the ports 605, 606, 607, 608 only if specific criteria are fulfilled (in particular a sufficient pressure of the working medium). The four ports 605, 606, 607, 608 coupling the lines 601, 602 to the working chambers 603, 604 can be selectively opened or closed by the control unit 609.

The expanding working medium flows through the first line 601 into the first working chamber 603 of the pressure cylinder 600. To this end, the control unit 609 opens the port 605 and closes the port 606. At the same time, the control unit 609 closes the port 608 of the second line and opens the port 607. This results in a force F_stroke being exerted on the piston 608, causing the piston 608 to move to the right (according to the illustration in the Figure), accompanied by a performance of work. This process, which terminates after one stroke of the piston 608, constitutes a “normal” working cycle of the pressure cylinder.

In the contradirectional working cycle, the control unit 609 closes the open ports 606, 607 and opens the closed ports 605, 608, so that an oppositely directed piston force −F_stroke and a movement of the piston 608 to the left are produced. It depends on the current position of the piston 26 which one of the two working cycles (normal or contradirectional) is carried out.

The volume (inlet volume) flowing into the working chambers 603 and 604, respectively, is controlled by means of the control unit 609. Upon an evaluation of sensor data 610, the start and duration of the inflow process are determined automatically, and the pressure and, hence, the temperature of the medium after the expansion are adjusted thereby such that this temperature corresponds to the maximum required temperature of the heat consumers coupled. That is, the inlet volume is a function of the medium pressure available on the input side and the pressure desired on the output side during condensation, which allows a very efficient energy conversion.

As already mentioned, the control/closed-loop control of the individual circuit processes and of the linear generator is performed taking process-influencing parameters into consideration (thermal energy supply, thermal heating demand, pressure and temperature of the working medium, the heat accumulators, and the surroundings, etc.), which are provided by a large number of suitable sensors 610 (pressure, temperature sensors, etc.)

This principle is, of course, also applicable when using two contradirectional pressure cylinders, as are made use of in conventional free piston systems; in this case, the working chamber 304 remains unutilized and only one pressure cylinder carries out the working cycle at a time alternately while the other one is in the outlet phase.

FIG. 12 illustrates a schematic view of a power-modulated valve timing, in which, after one working cycle is completed, execution of the next working cycle is not started immediately. By means of insertion of a variable dead time t_tot between execution of the working cycles, the repetition frequency and thus the conversion power P_THDY can be controlled. The cycle frequency f_Cyc is dependent on the expansion duration t_Exp and the dead time t_tot: Here, the control unit waits from execution of one working cycle till execution of the contradirectional working cycle until half the period duration T_Cyc has elapsed. Hence, a power modulation on the output voltage generated takes place, the dead times being compensated by the filter and rectifier unit almost without loss. In the process, the outlet valves are alternately opened and closed after half the period duration T_Cyc, that is, synchronously with the cycle frequency f_Cyc.

FIG. 13 illustrates an alternative rotational conversion system which may be employed in place of the linear conversion system described above. The rotational conversion system is coupled to the thermodynamic cycle 701 in which the available thermal energy (heat energy) is first converted into thermodynamic energy (steam pressure). The steam pressure is then converted into rotational energy by means of a valve-controlled expansion engine 702, such as, e.g., a rotary piston engine (in particular a DiPietro engine), the control unit 705 here likewise adjusting the inlet volume of each individual working cycle by means of the inlet and outlet valves such that the pressure and, hence, the temperature of the medium after the expansion corresponds to the maximum required temperature of the heat consumers coupled. The rotational energy is converted into electrical energy by means of the generator 703, the electrical energy being finally converted to AC current by a grid-based frequency converter 704 for feeding into the grid. The control unit 705 incorporates process-influencing control parameters which are continuously detected by suitable sensors 706 and supplied to the control unit 705 (part of the central control unit 12).

FIG. 14 describes a double-stage thermodynamic process which consists of two partial processes 400 and 401 for successive temperature ranges. Each partial process is a separate independent thermodynamic process with a medium suitable for the allocated temperature range. Each partial process includes a separate conversion system for converting pressure to electrical energy 402 and 403. The condensation heat of the partial process for the higher temperature range 400 is used as vaporization heat for the partial process of the lower temperature range 401 by means of an interconnection via a heat exchanger 404.

FIG. 15 describes possible cost-effective solutions—one for a linear system (FIG. 15a) and one for a rotational system (FIG. 15b)—of how to avoid having to provide a double configuration of all individual components of the two conversion systems for the conversion of pressure into electrical energy that are required in double-stage thermodynamic processes. This is implemented by the mechanical couplings as illustrated of the conversion systems for the conversion of pressure energy into kinetic energy 451 and 452, which are realized such that the mechanical forces appearing in the conversion of the pressure energy into kinetic energy add up vectorially by acting into the same direction isochronously as closed-loop controlled by the control unit. As a result, only one generator 453 and one grid-based frequency converter 454 are required, which each transfer the sum of the energies of the partial processes.

FIG. 16 describes a further cost-effective solution how it can be avoided having to provide a double configuration of all individual components of the two conversion systems for the conversion of pressure into electrical energy that are required in a double-stage thermodynamic process. By means of a suitable electrical coupling 462 of the generator outputs 460 and 461, which is realized such that the different voltage potentials generated by the two generators are supplied to the input of the grid-based frequency converter 463 without short circuits occurring between the generators, it is achieved that both voltage potentials serve as an energy reservoir for the grid-based frequency converter 463, for the conversion to a grid-compatible AC voltage. The result of this is that only one grid-based frequency converter 463 is required, which transfers the sum of the energy of the partial processes.

FIG. 17 is a schematic illustration of a multistage solar collector structure which includes a series connection of collectors of lower thermal insulation 50 and higher thermal insulation 51. In addition, each of the types of collectors can also be bypassed, i.e. the solar medium does not flow through it. Based on sensor data, such as, e.g., the ambient or collector temperature, and on the currently intended purpose of use of the collectors as heat generators or as a heat sink, the control unit 12 determines whether the solar medium flows through only one of the collector types or through both in series.

FIG. 18 shows a schematic illustration of a double-stage configuration including solar collectors and a waste gas heat recirculation in the THDY circuit, essentially comprised of a burner circuit 100, a thermodynamic high temperature circuit 101, a thermodynamic low temperature circuit 102, a heating circuit 117, a solar circuit 103, a WW circuit 104, and a cooling circuit 105. The burner circuit 100 flows through the heating boiler of a combustion system 106 and is coupled to a thermodynamic high temperature circuit 101 by means of a heat exchanger 107. The solar energy E_Sol(t) accumulated in the heat accumulator 115 is used for heating the thermodynamic medium up to the temperature level T_{SP Out} by the low temperature circuit 102 being thermally interconnected to the heat accumulator 115 by means of a heat exchanger 112, the heat exchanger 112 having a dual function: in one mode of operation it serves for heating the thermodynamic medium up to the temperature level T_{SP Out}, and in another mode of operation it serves as a condenser for transferring the condensation heat of the low temperature circuit 102 to the accumulator medium. The heat energy E_Rück recovered is used for heating or partial vaporization of the thermodynamic medium from the temperature level T_{SP Out} up to the temperature level T_Rück in that the low temperature circuit is thermally interconnected to the waste gas heat recovery 110 by means of a heat exchanger 111. In one mode of operation, the residual heat of the low temperature circuit E_Rest-Stufe2(t) is transferred to the cooling circuit 105 by means of a condenser 109. The thermal coupling of a solar collector circuit 103 to the heat accumulator 115 is performed by means of a heat exchanger 113. The thermal coupling of a heat accumulator 115 to the WW circuit 104 is performed by means of a heat exchanger 114.

FIG. 19 describes the components and temperature levels involved in the overall structure according to FIG. 18 which are required for the mode of operation “Heating, WW and production of electricity”.

FIG. 20 describes the components and temperature levels involved in the overall structure according to FIG. 18 which are required for the mode of operation “Exclusive production of electricity from thermal heat”.

FIG. 21 describes the components and temperature levels involved in the overall structure according to FIG. 18 which are required for the mode of operation “Exclusive production of electricity from thermal heat and accumulated or direct solar energy”. Rather than the solar collectors, other thermal energy sources may, in principle, also be made use of, e.g., district heating may be utilized. This does not affect the basic functional principle of the heating system according to the invention.

FIG. 22 describes the components and temperature levels involved in the overall structure according to FIG. 18 which are required for the mode of operation “Filling solar energy reservoir”.

FIG. 23 describes the components and temperature levels involved in the overall structure according to FIG. 18 which are required for the mode of operation “Solar heating and WW”.

FIG. 24 is a schematic illustration of a modified realization according to FIG. 18, in which the second stage includes a conversion system without an outlet pressure that can be regulated, such as, for example, a uniflow steam engine or a turbine. This is allowed in that the heating system is implemented to have a mode of operation (a) in which only the first stage produces electricity and the second stage in this mode of operation is only used for producing thermal heat in that the thermodynamic low temperature circuit medium does not flow through the conversion system of the second stage in this mode of operation.

FIG. 25 describes the components and temperature levels involved in the overall structure according to FIG. 24 which are required for the modified mode of operation “Heating, WW and production of electricity”.

The invention has been described with reference to several exemplary embodiments. It is, of course, apparent to a person skilled in the art that modifications may be made without leaving the idea of the invention. In addition, the exemplary embodiments illustrated are of a sketch-like nature. Any missing details are not relevant to the essence of the invention, but may be added by a person skilled in the art.

LIST OF TERMS USED AND THEIR MEANINGS

Conventional   Heating installation on the basis of fuel oil, gas,
heating        coal, electrical energy, wood logs or wooden
system         pellets, wood gasification plant, biomass
               combustion plant, . . .
Heat generator Thermal heat source, e.g. conventional heating
               system, solar thermal process, process waste heat
               (such as the residual heat in biogas production), . . .
Heat consumer  Radiator, WW consumer, and thermodynamic
               process
Heat accumu-   Buffer vessel, latent heat accumulator,
lator or cold  thermochemical accumulator, . . .
reservoir
Heat sink      Deep-water geothermal probe, geothermal
               collector, body of water (pond, pool, rain water or
               domestic service water, river, . . .), air-cooled heat
               exchangers with or without ventilators, air-cooled
               solar collectors, accumulated environmental cold
               energy, heating system return flow installations or
               in-floor heating system return flow installations,
               evaporative heat loss, . . .
Thermodynamic  ORC process with one cooling agent or a mixture
process        of several cooling agents, thermal oils, hydraulic
               oils, gases; Kalina process; water vapor process; . . .
Generator      Asynchronous generator, synchronous generator,
               RMT generator, . . .
Grid-based     Rectifiers or AC converters, frequency changers, . . .
frequency
converters
Sensors        For the purpose of measuring pressure,
               temperature, flow rates, solar radiation, filling level,
               piston position or rotational frequency, . . .
Expansion      Pressure motor, turbine, DiPietro engine, steam-
engine         powered screw-type engine, . . .
Radiator       Radiator for a residential property, in-floor heating
               system, wall heating system, . . .
WW consumer    WW-domestic service water, dishwasher, washing
               machine, . . .
Solar          Flat plate collector, tube collector, parabolic trough
collector      collector, parabolic mirror collector, . . .

LIST OF ABBREVIATIONS

BHKW              Combined heat and power unit (CHP unit)
EHeiz             Thermal energy generated by the conventional heating system
EHW               Energy demand for thermal heat
EKM-Ab            Waste heat arising in a refrigerating machine
EKühl             Energy required for indoor cooling
ERest             Condensation heat energy (process anergy)
ERest1            Condensation heat energy of the first stage of the thermodynamic
                  process
ERest2            Condensation heat energy of the second stage of the
                  thermodynamic process
ERück             Waste gas heat recovered
ESol              Thermal solar energy
ESp IN            Thermal energy to be accumulated
ESp OUT           Thermal energy to be taken from the heat accumulator
ETHDY             Energy of the thermodynamic process for the conversion into
                  electrical energy (process exergy)
ETHDY1            Energy of the first stage (high temperature stage) of the
                  thermodynamic process for the conversion into electrical energy
                  (process exergy)
ETHDY2            Energy of the second stage (high temperature stage) of the
                  thermodynamic process for the conversion into electrical energy
                  (process exergy)
EWq               Thermal energy supply of the heat source
EWW               Energy demand for domestic service water
fcyc              Cycle frequency
FInd              Induction force of the generator
KW                Cold water
PHeiz             Thermal heating power of the conventional heating system (heat
                  flow)
PHeiz- Heiz Solar Thermal heating power of the conventional heating system in the
                  mode of operation (c), “Exclusive production of electricity from
                  thermal heat and accumulated or direct solar energy”
PHeiz- Heizk      Thermal heating power of the conventional heating system in the
                  mode of operation (a), “Heating, WW and production of electricity”
PHeiz- Solar      Thermal heating power of the conventional heating system in the
                  mode of operation (d), “Filling solar energy reservoir”
PHeiz-Stromp      Thermal heating power of the conventional heating system in the
                  mode of operation (b), “Exclusive production of electricity from
                  thermal heat”
PHW               Heat capacity demand for thermal heat (heat flow)
PRest             Condensation waste heat capacity of the thermodynamic process
                  (heat flow)
PRück             Heat capacity of waste gas heat recovered (heat flow)
PSp IN            Heat accumulator input power (heat flow)
PSp OUT           Heat accumulator output power (heat flow)
PTHDY             Power throughput of the conversion system of the thermodynamic
                  process for the conversion into electrical energy
PTHDY1            Power throughput of the conversion system of the first stage (high
                  temperature stage) of the thermodynamic process for the conversion
                  into electrical energy
PTHDY2            Power throughput of the conversion system of the second stage (low
                  temperature stage) of the thermodynamic process for the conversion
                  into electrical energy
PWW               Heat capacity demand for thermal heat for domestic service water
                  (heat flow)
RL                Return flow
SP                Accumulator
t                 Time
tAusl1            Open period of the outlet valve in the working cycle
tAusl2            Open period of the outlet valve in the contradirectional working cycle
tCyc              Cycle duration of an overall cycle
tEinl1            Open period of the inlet valve in the working cycle
tEinl2            Open period of the inlet valve in the contradirectional working cycle
tExp              Expansion duration of a piston stroke
THDY              Thermodynamic cycle
TKond             Condensation temperature of the thermodynamic process
ttot              Standstill period of the piston (dead time)
VEinl             Inlet volume per stroke
VL                Flow line
WT                Heat exchanger
WTHDY             Work performed by a piston stroke WTHDY during the expansion in a
                  working cycle
WW                Warm water

Claims

1. A heating system for a property, comprising a thermal interconnection (5) between a thermal heat generator (1), in particular a conventional heating system (2), and a plurality of heat consumers (7) for simultaneous production of heat and electricity, the thermal interconnection (5) being controlled by a control unit (12), one of the heat consumers (7) including a conversion system (11) based on a thermodynamic cycle (10), in particular a water vapor or an ORC or Kalina process, and provided for conversion of thermodynamic energy into electrical energy, wherein the condensation heat occurring in the thermodynamic cycle (10) is transferred to further heat consumers (7),

characterized in that the heating system is operable in at least one of two modes of operation, wherein in the first mode of operation the heat generated is supplied to the thermodynamic cycle (10) for producing electricity and the residual heat resulting from the thermodynamic cycle (10) is used for heating, and in the second mode of operation electricity is produced independently of the heating demand in that a heat sink (6) absorbs the condensation heat of the thermodynamic cycle (10).

2. The heating system according to claim 1, characterized by a thermal interconnection to a thermal heat sink provided at the property for an increase in efficiency in the electricity production and for realizing a further mode of operation in which electricity is produced exclusively.

3. The heating system according to claim 1 or 2, characterized by a thermal interconnection to thermal solar collectors for generating solar electricity by means of a thermodynamic process in the low temperature range and for realizing a further mode of operation in which electricity is produced with the aid of the thermal solar collectors.

4. The heating system according to any of the preceding claims, characterized by a thermal interconnection to a waste gas heat recovery system which is provided at the property and is exploited by means of a thermodynamic process in the low temperature range for increasing the efficiency in the electricity production.

5. The heating system according to any of the preceding claims, characterized by a technical realization of a combined heat and power generation having a temperature spread of from approx. 20 to 300° C. using a medium which is suitable for the extended temperature range for a single-stage thermodynamic cycle, in particular thermal oils or silicates, having a critical temperature above the exit temperature of approx. 300° C. and which does not create a negative pressure relative to the ambient pressure, in particular also in the low condensation temperature range at the level of the heat sink.

6. The heating system according to any of the preceding claims, characterized by a multistage thermodynamic cycle having a high temperature circuit and a low temperature circuit, electricity being generated from both circuits.

7. The heating system according to any of the preceding claims, characterized by a valve-controlled, possibly double-acting pressure cylinder/linear generator system which is adjustable in respect of both the transfer capacity and the inlet pressure/outlet pressure ratio, in particular by the closed-loop control of the inlet volume per working cycle.

8. The heating system according to any of claims 1 to 6, characterized by a rotational conversion system for converting thermodynamic energy into mechanical rotational energy, in particular using a DiPietro engine, the rotational system including a rotational generator, in particular an RMT generator.

9. The heating system according to any of the preceding claims, characterized in that the control unit controls a capacity (power) adaptation required in the different modes of operation, for example by means of the additional heat generators, and the thermal equilibrium in the different modes of operation is balanced by a power regulation of the heat generator or by power regulation in the conversion system for converting thermodynamic into electrical energy or by means of closed-loop control of an accumulator inflow PSp IN(t) and thus by way of the accumulator filling level of the heat accumulator.

10. The heating system according to any of the preceding claims, characterized in that the heat generator is a high temperature heating system, in particular a high temperature biomass combustion plant having exit temperatures of the medium of greater than 300° C.

11. The heating system according to any of the preceding claims, characterized in that the control unit (12) periodically determines and adjusts an equilibrium between thermal energy generation and thermal energy demand according to the formula where

EHeiz(t)=EWW(t)+EHW(t)+ETHDY(t)+ERest(t)

EHeiz: thermal energy generated by the conventional heating system (2)

EWW: energy demand for domestic service water

EHW: energy demand for thermal heat

ETHDY: energy of the thermodynamic process for the conversion into electrical energy (process exergy)

ERest: condensation heat energy (process anergy).

t: time.

12. The heating system according to any of the preceding claims, characterized by a thermally coupled heat accumulator (4) in which the thermal heat produced by the heating system (12) can be temporarily accumulated and be passed on to at least one heat consumer (7) offset in time, and in that the control unit (12) periodically determines and adjusts an equilibrium between thermal energy generation and thermal energy demand according to the formula where

EHeiz(t)+ESp OUT(t)=EWW(t)+EHW(t)+ETHDY(t)+ESp IN(t)+ERest(t)

EHeiz: thermal energy generated by the conventional heating system (2)

ESp OUT: thermal energy to be accumulated

EWW: energy demand for domestic service water

EHW: energy demand for thermal heat

ETHDY: energy of the thermodynamic process for the conversion into electrical energy (process exergy)

ESp IN: thermal energy to be taken from the heat accumulator

ERest: condensation heat energy (process anergy).

t: time.

13. The heating system according to any of the preceding claims, characterized by sensors (13) for detecting process-influencing parameters, the control unit (12) controlling the operation of the heating system, incorporating the process-influencing parameters, and in that, based on sensor data, the control unit (12) adjusts the heat exchange between individual components of the heating system by a closed-loop control of the heat flows occurring so as to obtain a transfer that is as effective and complete as possible of the thermal energy of the respectively warmer medium to the respectively colder medium.

14. The heating system according to any of the preceding claims, characterized by a coupling of the conversion system (11) to at least one refrigerating machine, the mechanical kinetic energy generated by the conversion system (11) being utilized for cooling indoor air.

15. The heating system according to claim 14, characterized in that the waste heat EKM-Ab arising in the refrigerating machine is utilized on the generator side for electricity production, accumulator filling, or hot water heating, and that the control unit (12) periodically determines and adjusts an equilibrium between thermal energy generation and thermal energy demand according to the formula where

EHeiz(t)+ESp OUT(t)+EKM-Ab(t)=EWW(t)+ETHDY(t)+ESp IN(t)+ERest(t)+EKühl(t)

EHeiz: thermal energy generated by the conventional heating system (2)

ESp OUT: thermal energy to be accumulated

EWW: energy demand for domestic service water

EHW: energy demand for thermal heat

ETHDY: energy of the thermodynamic process for the conversion into electrical energy (process exergy)

ESp IN: thermal energy to be taken from the heat accumulator

ERest: condensation heat energy (process anergy)

EKM-Ab: waste heat arising in the refrigerating machine

EKühl: energy required for indoor cooling

t: time.