METHOD AND APPARATUS FOR UTILIZATION OF HOT WATER PLANT WASTE HEAT RECOVERY BY INCORPORATED HIGH TEMPERATURE WATER SOURCE HEAT PUMP

- UNIVERSITY OF MARIBOR

The invention relates to a method and apparatus for low temperature waste heat utilization. In the scope of the hot water plant (HWP) there are few low temperature sources, which cannot be used by heat consumer (HC) directly. The method and apparatus for hot water power plant (HWP) waste heat recovery comprises at least one, preferably condensing type heat exchanger (HE), which collects the waste heat for water source high temperature heat pump (HP) employment, wherein a low temperature heat is upgraded to a high temperature heat, hence heat pump (HP) hot water outlet is fed to the boiler in a return line or in a supply line of hot water plant (HWP), wherein the thermal energy balance adjustment of generated heat is executed by adapting the power of said heat pump (HP) and/or by adapting the power of said furnace and/or by adapting the mass flow of the primary heat transfer medium in at least one open loop heating network and/or in at least one closed loop heating circuit in the scope of heat distribution network.

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Description
FIELD OF INVENTION

The object of this patent application relates to the methods and apparatus for gas fired hot water plant waste heat recovery with incorporated high temperature water source heat pump for waste heat source utilization.

BACKGROUND OF THE INVENTION

Heat pumps that have been used in prior art to enhance the heating power of hot water and power plants for the supply of industrial and district heating networks by utilizing the waste heat recovery have been deployed in a various designs. According to CN101900318A the waste heat of flue gas is used by incorporated air to air type heat pump to improve the heating performance of gas fired power plant, wherein the heat generated by integrated heat pump is fed to the air to water type heat exchanger being connected with supply pipeline of heat distribution circuit. In accordance the main disadvantage of represented approach is relatively low thermal performance compared to the proposed solution with water source type heat pump as explained hereinafter.

SUMMARY OF THE INVENTION

This invention relates to the hot water plants for the supply of industrial and district heating networks, wherein at least one incorporated water source high temperature heat pump is used to upgrade a low temperature heat from at least one waste heat source to the higher temperature heat output, which can be afterwards used directly or indirectly by at least one heat consumer for space or process heating, preferably in the scope of district heating. It is important to notice, that the heat pump according to the invention is used to heat up and rise the temperature of a primary heat transfer medium in a supply line of an open loop heating network, and/or in a return line of a closed loop heating circuit, wherein a design (i.e. operational) temperature of the primary heat transfer medium in a forward line of the heat distribution network is substantially higher than 45° C., at least when operating at normal operating conditions. It can be understood, that operating conditions of the heat distribution network are provided after commissioning and warm-up process where at least basic design temperature of the heat distribution network is successfully achieved and maintained (i.e. established) over at least a short period of time, hence at least one first heat releasing unit is turned on and operating by firing the fuel in the fuel burning (i.e. combustion) process in the scope of substantially a continuous operation, and at least one second heat releasing unit (i.e. heat pump) is turned on and operating for liquid-vapor phase change thermodynamic cycle process and waste heat source utilization. In accordance, at least one furnace with at least one incorporated boiler in the scope of said hot water plant and at least one water source high temperature heat pump are used to provide a first and a second heat source respectively in the scope of the heat distribution network, where individual unit shall substantially operate in the range between its minimum and maximum rated (i.e. full load) operating power, preferably at normal rated power for highest power efficiency developed in continuous operation.

Exemplary embodiment of the present invention will now be described with reference to the accompanying drawing, i.e. schematics of a hot water plant with incorporated water source high temperature heat pump in the scope of a heat distribution network, here shown as a simple single closed loop heating circuit.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a schematic representation of a hot water plant preferential embodiment with incorporated water source high temperature heat pump (HP) having a condenser unit, an evaporator unit, and a compressor with adopted lubrication oil cooling system (CS) for heat pump principle utilization, where following items are further shown and marked: first heat releasing unit of depicted hot water plant (HWP), heat distribution circuit and exhaust system comprising a network of pipes (PI-P13), valves (VI-V2) and pumps (PU1-PU4) which interconnects the heat consumer (HC) with stated heat sources, heat exchanger (HE), hatch (HI), fan (FI), ambient (O) and control temperature sensors (TI-T12).

Referring to the preferential embodiment of the power plant with incorporated water source high temperature heat pump (HP), the system comprises a furnace with incorporated boiler in the scope of first heat releasing unit of hot water plant (HWP), which preferably runs on a gas fuel, such as natural gas, liquefied petroleum gas, landfill gas, wood gas, biogas or coal for example. While hot water plant (HWP) first heat releasing unit is used for heat generation when powered, a significant amount of heat is released by the flue gas, wherein the heat is either used by heat consumer (HC) rather than discharged and dissipated to the ambient (O) through the exhaust pipe (P12) (i.e. chimney). It is important to notice, that the first heat source for heat consumer (HC) is preferably represented by boiler in the scope of the hot water plant (HWP), having an inlet and outlet aperture, whereby plurality of waste heat sources arise in the scope of the hot water plant (HWP) and incorporated heat pump (HP), at least when the hot water plant (HWP) and heat pump (HP) are turned on and powered, preferably at optimum efficiency or full load regime.

Effective recovery of waste heat is critical to provide a good total utilization of fuel energy, thus, first and most important waste heat source is represented by the stream of high temperature flue gas in exhaust system, which is a product of the combustion process within the hot water plant (HWP). Secondly, there is at least one additional waste heat source represented by heat pump (HP) compressors lubrication oil cooling systems (CS), which is under certain circumstances still important for good total waste heat source utilization.

According to the depicted preferential embodiment as represented on FIG. 1, the hot water plant (HWP) boilers inflow (i.e. inlet port) and outflow (i.e. outlet port) apertures are operably coupled to the closed loop heating circuit comprising a network of pipes (PI-PII) that operably interconnects the heat consumer (HC) and heat sources in the scope of hot water plant (HWP) with incorporated water source high temperature heat pump (HP). The heat distribution network further comprises a primary heat transfer medium and automated regulation means comprising a control unit (i.e. control electronics), valves (VI-V2) and pumps (PU1-PU4) for primary heat transfer medium stream flow regulation, wherein the heat of heat sources is preferably transferred to the heat consumer (HC) by principle of primary heat transfer medium circulation in the closed loop heating circuit.

As partially known from prior art, the waste heat of flue gas is eventually utilized by incorporated heat exchanger (HE) which collects the high temperature waste heat of flue gas in exhaust system, wherein the exhaust heat exchanger (HE) is capable to collect and transfer the heat of said waste heat source due to the significant temperature difference between the temperature of flue gas in exhaust system and the temperature of primary heat transfer medium in incorporated heat exchanger (HE). In addition, as explained in CN101900318A, the heat of the flue gas is not only collected, but also upgraded by incorporated air source heat pump, wherein it is essential to notice, that according to stated solution from prior art, the waste heat collected by heat pipe is used to upgrade the heat of flue gas by air to air heat pump principle utilization, hence the heat of high temperature flue gas is transferred to the primary heat transfer medium in a chamber of incorporated air to water type heat exchanger.

According to the invention, the exhaust system preferably comprises at least one condensing type heat exchanger (HE) to collect the heat of flue gas, wherein collected heat is transferred to the evaporator unit of water source high temperature heat pump (HP) by circulation of secondary heat transfer medium with aim to upgrade and enhance the heating power of the hot water plant (HWP). While the temperature of flue gas in exhaust system is rapidly reduced (preferably below 45° C.), the exhaust system may further comprise a suction fan (FI) for removal of flue gas from exhaust system. Furthermore, depicted embodiment comprises the lubrication oil cooling system (CS) in form of a heat exchanger, operably coupled to the evaporator unit with aim to collect the waste heat of heat pump (HP) compressors lubrication oil, which is afterwards upgraded by a liquid-vapor phase change thermodynamic cycle utilization process and transferred to the heat distribution network by incorporated water source high temperature heat pump (HP).

Since the apparatus according to preferential embodiment comprises at least one motorized valve, preferably hatch (HI) for flue gas stream manipulation (i.e. regulation), regulated by main control unit, the utilization of flue gas waste heat source is maximized by high temperature heat pump (HP), when the flue gas stream is fully enforced through the condensing heat exchanger (HE), hence it collects the waste heat required for heat pump (HP) principle utilization. If appropriate, the heat exchanger (HE) and heat pump (HP) shall be implemented in a multistage or cascade principle approach comprising a plurality of heat pumps (HP) and/or heat exchangers (HE) in parallel and/or serial connection to reach the optimized total waste heat source utilization.

While there are several options for waste heat source utilization it is essential to notice, that preferential embodiment of water source high temperature heat pump (HP) utilization uses at least one low temperature waste heat source for vaporization of working medium of incorporated heat pump (HP), wherein the condenser unit outlet is preferably fed (i.e. operably coupled) to the heat distribution circuit return line, more precisely to the inflow of the boiler in the scope of closed loop heat distribution system. It can be understood, that proposed concept is suitable for open loop heat distribution system as well, where it is essential to notice, that in such an embodiment the condenser unit outlet of said high temperature heat pump (HP) is fed to the inlet of the boiler in hot water plant (HWP) with aim to preheat the primary medium of said open loop heat distribution circuit, hence the temperature difference between involved heat transfer medium in the supply line and working medium in condenser unit is the highest. It can be understood, that suggested approach is essential for total waste heat source utilization, since the coefficient of performance is depended on temperature difference of involved heat transfer medium in the heat pump (HP) condenser and evaporator unit.

Furthermore, the invention relates to a method of the heat pump (HP) integration process and to a method of hot water plant (HWP) waste heat source utilization.

The following steps represent the key features of a heat pump (HP) integration and novel method for hot water plant (HWP) waste heat source utilization:

1. Integration of the water source high temperature heat pump (HP) having a condenser and evaporator unit with working medium for liquid-vapor phase change thermodynamic cycle utilization and at least one heat exchanger (HE), wherein:
A) the high temperature heat pump (HP) condenser unit is operably coupled to the heat distribution return line in a closed loop heat distribution system or to the supply line in an open loop heat distribution system;
B) the high temperature heat pump (HP) evaporator unit is operably coupled with at least one heat exchanger (HE) in a closed loop piping system with secondary heat transfer medium involved.
2. Collecting the heat by incorporated heat exchanger (HE) from at least one waste heat source, wherein the heat source is:
A) The stream of a flue gas in exhaust system; and/or
B) The lubrication oil in heat pump (HP) compressors lubrication oil cooling system.
3. Transfer of the heat from at least one heat exchanger (HE) to the high temperature heat pump (HP) evaporator unit, preferably by circulation of secondary heat transfer medium in the closed loop piping system.
4. Transfer of the heat from secondary heat transfer medium to the working medium in evaporator unit of the high temperature heat pump (HP), wherein at least low temperature heat from at least one waste heat source is upgraded by working medium liquid-vapor phase change thermodynamic cycle, hence the temperature of the working medium in condenser unit is substantially higher than the temperature of the working medium in evaporator unit.
5. Transfer of the heat from working medium in the high temperature heat pump (HP) to the primary heat transfer medium in the heat distribution network, wherein the
temperature of the primary heat transfer medium at condenser unit outlet is substantially higher than temperature of the primary heat transfer medium at condenser unit inlet, hence the high temperature output of condenser unit is fed to at least one boiler inlet in the scope of hot water plant (HWP), where the primary heat transfer medium is reheated by firing the fuel in the boiler.
6. Transfer of the heat from at least one boiler in the scope of hot water plant (HWP) to at least one heat consumer (HC) in open or closed loop heat distribution network.
7. Usage of high temperature primary heat transfer medium by at least one heat consumer (HC) in the scope of the district heating, industrial or technological process.

Furthermore, the following steps represent the key features of a method of using an apparatus according to the invention:

1. A fuel combustion process, where preferably at least one furnace is used for burning the fuel in the scope of the hot water plant (HWP) with aim to provide a first heat releasing unit for heating at least one heat transfer medium in the boiler, wherein at least one waste heat source arise when said first heat releasing unit is turned on and operating by firing the fuel in the combustion process. Accordingly, plurality of boilers and/or furnaces in parallel or serial connection shall be used to provide an advanced embodiment of the first heat releasing unit.
2. A waste heat recovery process which comprises a process of collecting the waste heat, wherein at least one waste heat recovery unit (i.e. heat exchanger (HE)) is used to collect at least a portion of the heat of at least one waste heat source from group of waste heat sources comprising a flue gas in exhaust system and lubrication oil in lubrication oil cooling system in the scope of the integrated heat pump (HP). Accordingly, plurality of waste heat recovery units in parallel or serial connection shall be used to provide an advanced embodiment of apparatus for waste heat recovery process utilization.

A liquid-vapor phase change thermodynamic cycle utilization process, wherein at least one water source high temperature heat pump (HP) shall be used to provide a second heat releasing unit for heating at least one heat transfer medium in said heat distribution network, at least when said heat pump (HP) is turned on and operating. Accordingly, plurality of heat pumps (HP) units in parallel or serial connection is used to provide an advanced edition of the second heat releasing unit.

Usage of collected heat for liquid-vapor phase change utilization, wherein at least a portion of collected heat is used for the liquid-vapor phase change cycle utilization and wherein at least a portion of the heat generated by at least one heat pump (HP) in the scope of the second heat releasing unit is used for heating the primary heat transfer medium in heat pump (HP) condenser unit.

Distribution of the heat in at least one closed loop circuit of said heat distribution network by circulation of at least one heat transfer medium, wherein the lowest temperature of the heat distribution medium in at least one boiler inlet in the scope of the first heat releasing unit is substantially higher than the lowest temperature of the heat distribution medium in at least one heat consumer (HC). Hence, at least one heat transfer medium in at least one return line of said closed loop heat distribution network is reheated by the heat pump (HP) principle utilization, at least when a design temperature of the heat distribution network is reached and said hot water plant (HWP) and heat pump (HP) are operating at full load; and/or

Distribution of the heat in at least one open loop heat distribution network by at least one heat transfer medium, wherein the inlet temperature of the primary heat distribution medium in at least one boiler inlet in the scope of the first heat releasing unit is substantially higher than temperature of the primary heat distribution medium in at least one heat pump (HP) condenser unit inlet, wherein said condenser unit inlet is operably connected to supply line of heat transfer medium source in open loop connection. Hence, at least one line of primary heat transfer medium in at least one supply line of said open loop heat distribution network is preheated by the heat pump (HP) principle utilization, at least when a design temperature of the heat distribution network is reached and said hot water plant (HWP) and heat pump (HP) are operating at full load.

In addition to represented method of using the apparatus according to the invention, few explanations and definitions are required, wherein combustion process is substantially a continuous process, while at least one furnace with incorporated boiler in the scope of hot water plant (HWP) normally operates in the range between its minimum and maximum rated operating power, preferably at normal rated power in continuous operation. Similarly the liquid-vapor phase change thermodynamic cycle utilization process is substantially a continuous process, wherein said heat pump (HP) operates in the range between its minimum and maximum rated operating power, preferably at normal rated power in continuous operation. If appropriate, the fuel combustion process in an advanced hot water plant (HWP) embodiment shall be provided by plurality of boilers and/or furnace units in the scope of the first heat releasing unit, wherein the heat in the scope of the first heat releasing unit is transferred in serial and/or in parallel connection and similarly, the liquid-vapor phase change thermodynamic cycle utilization process shall be utilized by plurality of heat pump (HP) units to provide a second heat releasing unit of the advanced hot power plant (HWP).

While one of the key features of a method and apparatus according to the invention is establishment of predetermined set point value of primary heat transfer medium temperature in heat distribution system, the thermal energy balance adjustment is executed by adapting the power of said heat pump (HP) and/or by adapting the power of said furnace in the scope of first heat releasing unit and/or by adapting the mass flow of the primary heat transfer medium through the heat distribution system. Accordingly the mass flow of the primary heat transfer medium in said closed loop heat distribution circuit is adapted by changing the flow velocity in said heat distribution circuit and/or the mass flow of the secondary heat transfer medium in said closed loop circuit is adapted by changing the flow velocity in said closed loop circuit, wherein the velocity of heat transfer medium in heat distribution network is adapted by switching (i.e. on/off regulation) and/or by adjusting the power of at least one circulation pump for mass flow adjustment. In addition, the mass flow of the primary heat transfer medium in depicted heat distribution circuit is alternatively adapted by stream flow regulation, wherein at least a portion of the primary heat transfer medium stream in the return line of said heat distribution circuit is redirected to the return line of said heat distribution circuit to provide a heat pump (HP) bypass connection, and/or wherein at least a portion of the primary heat transfer medium stream from said heat pump (HP) is redirected to a forward line of the heat distribution circuit to provide a hot water plant (HWP) bypass connection with aim to balance the power generated by first and second heat releasing units. Similarly the mass flow of the secondary heat transfer medium in said closed loop circuit for waste heat source utilization is adapted by stream flow regulation, wherein at least a portion of the secondary heat transfer medium stream is redirected in said closed loop circuit to provide a bypass connection for at least one waste heat recovery unit. Accordingly, the mass flow regulation of the primary heat transfer medium and/or the mass flow regulation of the secondary heat transfer medium for thermal energy balance adjustment is determined, controlled and executed by at least one control unit (i.e. electronic controller), wherein the position and/or the state (i.e. open/closed or on/off regulation) of the automated regulation means is adjusted in respect to the heat demand in said heat distribution network.

Apparatus according to the invention further comprises at least one control unit, wherein such a controller shall be an autonomous device for thermal management regulation or alternatively, at least basic functions of the thermal management controller for determination process, comparison process and execution process could be incorporated and implemented to the hot water plant (HWP) controller or in to the heat pump (HP) controller as well. In the determination process the environment and thermal conditions of heat distribution network is determined by the group of thermal, pressure or other sensors, wherein at least one input from at least one sensor of heat distribution network or hot water plant (HWP) is used for comparison process, where at least one value of at least one input parameter (i.e. preferably the value of an inlet temperature of the primary heat transfer medium hot water plant (HWP) is analyzed and compared to the nominal values, preferably being pre-defined and stored in the control unit. Accordingly the execution process comprises a process of executing instructions stored in control unit to generate appropriate output signal, where at least one parameter for thermal energy balance adjustment is generated, executed and performed by control electronics in cooperation with automated regulation means in order to reach and maintain the threshold set-point value, wherein said threshold value is defined between the maximum value and the minimum value for set point equal value with aim to provide a hysteresis for thermal energy balance adjustment.

It can be understood that control unit (i.e. electronic module) may communicate with various output devices where the temperature of the heat transfer medium in the heat transfer network is determined, controlled and regulated by a group of automated regulation means comprising motorized valves, pumps and sensors, wherein regulation means are preferably adapted to be manipulated by at least one control unit. And furthermore, the heat distribution process in heat distribution network is provided by at least one heat transfer medium, preferably by plurality of heat distribution mediums. Accordingly the heat in said heat transfer network is transferred from first heat releasing unit to the heat consumer (HC) by circulation of the primary heat transfer medium in at least one closed loop circuit, and similarly the heat from waste heat recovery unit is transferred to the heat pump (HP) by circulation of the secondary heat transfer medium in at least one closed loop circuit, wherein the heat upgraded by at least one heat pump (HP) is furthermore transferred from heat pump (HP) condenser unit to at least one boiler inlet in the scope of said hot water plant (HWP) by said primary heat transfer medium.

Summarizing, the heat of flue gases in the scope of the hot water plant (HWP) is used for utilization of water source high temperature heat pump (HP), wherein upgraded heat is preferably used for reheating or preheating of primary heat transfer medium in at least one heat distribution network. It can be understood, that all vital components of heat distribution circuit are preferably operably coupled for heat transfer medium circulation, wherein the compressor of the incorporated heat pump (HP) shall be driven by electric machine, powered by electricity from grid or generator, or alternatively if appropriate, a high temperature heat pumps (HP) compressor shall be mechanically coupled to and driven by additional internal combustion engine as well. Furthermore, as can be dearly read out from previous description, the primary heat transfer medium in preferential embodiment is water and similarly, the secondary heat transfer medium in preferential embodiment is mix of water and glycol.

In the foregoing description those skilled in the art will readily appreciate that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims expressly state otherwise.

Claims

1. A method of using a heat generation apparatus for heating at least one heat consumer (HC) in a heat distribution network by adopting the principle of a water source high temperature heat pump (HP) for waste heat source utilization, wherein said heat distribution network comprises at least one open loop heating network and/or at least one closed loop heating circuit, the method comprising:

a fuel combustion process, wherein at least one furnace with incorporated boiler is used to provide a first heat releasing unit for heating at least one heat transfer medium in said heat distribution network, and wherein at least one waste heat source arise when said first heat releasing unit is turned on and operating by firing the fuel in the fuel combustion process;
a waste heat recovery process, wherein at least one waste heat recovery unit is used to collect at least a portion of the waste heat produced by said first heat releasing unit;
a liquid-vapor phase change thermodynamic cycle utilization process, wherein at least one water source high temperature heat pump (HP) is used to provide a second heat releasing unit for heating at least one heat transfer medium in said heat distribution network when said heat pump (HP) is turned on and operating, wherein the heat required for the liquid-vapor phase change cycle utilization is gained fully or in part by said waste heat recovery process, and wherein at least a portion of the heat collected in the waste heat recovery process is used for liquid-vapor phase change thermodynamic cycle process utilization; and
a heat distribution process, wherein the heat in said heat distribution network is preferably distributed by the stream of at least one heat transfer medium, characterized in that
at least a portion of the heat generated by said liquid-vapor phase change thermodynamic cycle utilization process is transferred to the heat transfer medium in said heat distribution network, wherein at least a portion of the heat generated by said heat pump (HP) is transferred to the boiler by stream of the heat transfer medium in said heat distribution network, hence at least a portion of the heat transfer medium in said heat distribution network is reheated in a return line of the closed loop heating circuit or at least a portion of said heat transfer medium is preheated in a supply line of the open loop heating network by water source high temperature heat pump (HP) principle utilization, at least when a design temperature of the heat distribution network is reached and said hot water plant (HWP) and heat pump (HP) are operating at full load.

2. A method as in claim 1 characterized in that

the fuel combustion process is substantially a continuous process, wherein said furnace of hot water plant (HWP) operates in the range between its minimum and maximum rated operating power, preferably at normal rated power in continuous operation;
the liquid-vapor phase change thermodynamic cycle utilization process is substantially a continuous process, wherein said heat pump (HP) operates in the range between its minimum and maximum rated operating power, preferably at normal rated power in continuous operation;
the waste heat recovery process comprises a process of flue gas condensation, wherein the collected heat is used for heat pump (HP) principle utilization and wherein the temperature of the flue gas is reduced below 45° C., hence the flue gas in exhaust system is removed by ventilating the exhaust system by incorporated fan (FI);
the waste heat recovery process is used for cooling principle utilization, wherein the waste heat recovery process is used for cooling the lubrication oil of heat pump (HP) compressor unit;
the temperature of the heat transfer medium in the heat transfer network is determined, controlled and regulated by a group of automated regulation means comprising valves, pumps and sensors, wherein said regulation means are preferably adapted to be manipulated by at least one control unit.

3. A method as in claim 2 characterized in that

the fuel combustion process is provided by plurality of furnaces with incorporated boiler units, wherein the heat generated by individual boiler unit is transferred to the heat distribution network in serial and/or in parallel connection in order to provide a first heat releasing unit;
the liquid-vapor phase change thermodynamic cycle utilization process is provided by plurality of heat pump (HP) units, wherein the heat generated by the individual unit is transferred to the heat distribution network in serial and/or parallel connection in order to provide the second heat releasing unit;
the heat distribution process in said heat distribution network is provided by plurality of heat distribution mediums, wherein the heat from waste heat recovery unit is transferred to the heat pump (HP) by circulation of the secondary heat transfer medium in at least one closed loop circuit.

4. A method as in claim 3 characterized in that

the temperature of the primary heat transfer medium in the heat distribution network is maintained at predetermined set point value, wherein thermal energy balance adjustment is executed by adapting the power of said heat pump (HP) and/or by adapting the power of said hot water plant (HWP) and/or by adapting the mass flow of the primary heat transfer medium through the individual boiler unit and/or by adapting the mass flow of the primary heat transfer medium through the heat pump (HP) and/or by adapting the mass flow of the secondary heat transfer medium in said closed loop circuit for waste heat source utilization.

5. A method as in claim 4 characterized in that

the mass flow of the primary heat transfer medium in said heat distribution network is adapted by changing the flow velocity in said heat distribution network and/or the mass flow of the secondary heat transfer medium in said closed loop circuit is adapted by changing the flow velocity in said closed loop circuit, wherein the velocity of heat transfer medium in heat distribution network is adapted by switching and/or by adjusting the power of at least one circulation pump.

6. A method as in claim 4 characterized in that

the heat generated by the first heat releasing unit and second heat releasing unit is transferred to the heat consumer (HC) by stream of heat transfer medium in said heat distribution network, wherein said heat distribution network comprises at least one open loop heating network and/or at least one closed loop heating circuit.

7. A method as in claim 5 characterized in that

the mass flow of the primary heat transfer medium in said heat distribution network is adapted by stream flow regulation, wherein at least a portion of the primary heat transfer medium stream in the return line of said closed loop heat distribution circuit is redirected to the return line of said heat distribution circuit to provide a heat pump (HP) bypass connection, and/or wherein at least a portion of the primary heat transfer medium stream from said heat pump (HP) is redirected to a forward line of the heat distribution network to provide a first heat releasing unit bypass connection;
the mass flow of the secondary heat transfer medium in said closed loop circuit for waste heat source utilization is adapted by stream flow regulation, wherein at least a portion of the secondary heat transfer medium stream is redirected in said closed loop circuit to provide a bypass connection for at least one waste heat recovery unit.

8. A method as in claim 2 characterized in that

the mass flow regulation of the primary heat transfer medium and/or the mass flow regulation of the secondary heat transfer medium for thermal energy balance adjustment is determined, controlled and executed by said control unit, wherein the position and/or the state of the
automated regulation means is adjusted in respect to the heat demand in said heat distribution network.

9. A method for controlling a hot water plant (HWP) and at least one adopted water source high temperature heat pump (HP) to enhance the heating power of the furnace with incorporated boiler by collecting the waste heat of at least one waste heat source and liquid-vapor phase change thermodynamic cycle utilization, the method comprising:

a determination process, wherein at least one input from hot water plant (HWP) sensors and/or heat distribution network sensors is determined by at least one control unit for comparison process;
a comparison process, wherein at least one of the inputs from determination process is checked and processed, wherein the value of at least one input parameter is analyzed and compared to the limiting values, preferably defined in said control unit;
an execution process, wherein instructions, preferably stored in at least one control unit, generate appropriate output signal for control of hot water plant (HWP) and/or heat pump (HP) and/or heat distribution network automated regulation means adjustment, characterized in that,
at least one parameter to control the power of the hot water plant (HWP) and/or the power of the heat pump (HP) and/or the state and/or the position of automated regulation means in heat distribution network is determined for waste heat source utilization and thermal energy balance adjustment execution, wherein at least a portion of the heat required for heat pump (HP) principle utilization is gained fully or in part by waste heat recovery process, and wherein at least a portion of the heat generated by the heat pump (HP) is used for preheating the heat transfer medium in a supply line of an open loop heating network and/or at least a portion of the heat generated by the heat pump (HP) is used for reheating the heat transfer medium in at least one return line of a closed loop heating circuit to establish the set-point value of heat transfer medium temperature.

10. A method as in claim 9, characterized in that

the heat is distributed in the heat distribution network by stream of a heat transfer medium, wherein at least a portion of the heat generated by hot water plant (HWP) is transferred to at least one heat consumer (HC) through the heat distribution network, wherein the heat transfer medium in at least one supply line and/or in at least one return line of said heat distribution network is preheated and/or reheated by said heat pump (HP) with aim to reach and maintain the threshold value, wherein said threshold value is defined between the maximum value and the minimum value for set point equal value in order to provide a hysteresis for thermal energy balance adjustment;
the heat required for heat pump (HP) principle utilization is gained fully or in part by utilization of at least one from group of waste heat sources comprising a flue gas in exhaust system, and a lubrication oil in lubrication oil cooling system, wherein utilization of waste heat sources comprises at least two waste heat recovery units, wherein the collected heat is transferred to the heat pump (HP) by circulation of a secondary heat transfer medium in plurality of closed loop circuits in parallel and/or serial connection, wherein received heat is furthermore upgraded by the heat pump (HP) principle utilization and furthermore transferred to the primary heat transfer medium for preheating and/or reheating at least one heat distribution medium in said heat distribution network;
the mass flow of the primary heat transfer medium and/or the mass flow of the secondary heat transfer medium and/or the temperature of at least one heat transfer medium in said heat distribution network is determined and regulated by at least one control unit in cooperation with automated regulation means, preferably by motorized valves and pumps, wherein the heat generated by first heat releasing unit and the heat generated by second heat releasing unit and the state and/or the position of the automated regulation means is adjusted by said control unit in respect to the heat demand in said heat distribution network.

11. An apparatus assembly for hot water plant (HWP) waste heat source utilization comprising:

a first heat releasing unit comprising at least one furnace and boiler for heating at least one heat transfer medium in a heat distribution network, wherein said furnace further comprises an exhaust system, and wherein said boiler further comprises at least one inflow aperture and at least one outflow aperture;
a second heat releasing unit comprising at least one water source high temperature heat pump (HP), wherein said heat pump (HP) further comprises a lubrication oil cooling system (CS), an evaporator unit and a condenser unit, and wherein said evaporator unit and said condenser unit further comprises an inlet aperture and an outlet aperture;
and at least one waste heat recovery unit, preferably a heat exchanger (HE) adapted to be associated with said evaporator unit in a closed loop circuit characterized in that
said waste heat recovery unit is adapted to be associated with at least one from group of waste heat sources comprising an exhaust system and a lubrication oil cooling system (CS) for collecting the heat of said waste heat source;
said evaporator unit is adapted to be associated with said waste heat recovery unit in a closed loop circuit for transferring the collected heat from said waste heat recovery unit to said evaporator unit by a secondary heat transfer medium in said closed loop circuit;
said outlet of the condenser unit is adapted to be associated with said boiler inflow aperture for transferring the heat of condenser unit to the boiler by a primary heat transfer medium in said heat distribution network;
said inlet of the condenser unit and said outflow of the boiler are adapted to be associated with said heat distribution network, wherein said heat distribution network further comprises at least one thermal energy receiving unit, preferably a heat consumer (HC).

12. The apparatus assembly for hot water plant (HWP) waste heat source utilization as in claim 11 characterized in that

said heat distribution network comprises at least one forward line to transfer the heat generated by said first heat releasing to said heat consumer (HC), and furthermore, said heat distribution network further comprises at least one supply line of an open loop heating network and/or at least one return line of a closed loop heating network, wherein said primary heat transfer medium circulate in said heat distribution network to transfer the heat of heat source to the heat consumer (HC);
said outflow of the boiler is operably coupled to the forward line of said heat distribution network;
said inlet of the condenser unit is operably coupled to at least one supply line and/or at least one return line of said heat distribution network;
said outlet of the condenser unit is operably coupled to the inflow of said boiler wherein said heat distribution network comprises a primary heat transfer medium; and
said heat exchanger (HE) is incorporated to said exhaust system to receive at least a portion of the heat of flue gas, wherein said heat exchanger (HE) is operably coupled to said evaporator unit in the closed loop circuit comprising a secondary heat transfer medium, wherein the heat collected in heat exchanger (HE) is transferred to the evaporator unit by secondary heat transfer medium circulation in said closed loop circuit, and furthermore, the heat of said condenser unit is transferred to the boiler by primary heat transfer medium circulation in said head distribution network at least when the first heat releasing unit and second heat releasing unit are turned on and powered at operating conditions;
said closed loop further comprises a heat exchanger in form of a lubrication oil cooling system (CS) for collecting the heat of said waste heat source, wherein said lubrication oil cooling system (CS) is adapted to be associated with a compressor of said heat pump (HP).

13. The apparatus assembly for hot water plant (HWP) waste heat source utilization as in claim 12 characterized in that

said heat distribution circuit comprises a plurality of the heat consumers (HC) in parallel connection and/or in serial connection;
said heat distribution circuit comprises a plurality of the heat pumps (HP) in parallel connection and/or in serial connection, wherein closed loop circuit of said evaporator unit comprises a plurality of heat exchangers (HE) in parallel connection and/or in serial connection, and wherein at least one of the condenser unit outlet aperture is operably coupled to the inflow of said boiler.

14. The apparatus assembly for hot water plant (HWP) waste heat source utilization as in claim 13 characterized in that

said hot water plant is designed as a furnace which runs on a gas fuel selected from group comprising a natural gas, liquefied petroleum gas, landfill gas, wood gas or biogas;
the primary heat transfer medium in preferential embodiment is water;
the secondary heat transfer medium in preferential embodiment is mix of water and glycol;
said waste heat recovery unit is designed as a condensing heat exchanger (HE), wherein the temperature of flue gas is reduced under 45° C., hence the exhaust system further comprises at least one fan (FI) for flue gas extraction.

15. The apparatus assembly for hot water plant (HWP) waste heat source utilization as in claim 12 characterized in that

said compressor of the heat pump (HP) is adopted to be driven by electric machine, powered by electricity from grid or generator and/or said compressor adopted to be coupled with and driven by additional internal combustion engine.
Patent History
Publication number: 20180245800
Type: Application
Filed: Mar 24, 2016
Publication Date: Aug 30, 2018
Applicant: UNIVERSITY OF MARIBOR (Maribor)
Inventors: Goricanec DARKO (Maribor), Jurij KROPE (Orehova vas), Stane BOZICNIK (Maribor)
Application Number: 15/757,462
Classifications
International Classification: F24D 15/04 (20060101); F22B 1/16 (20060101); F22B 5/00 (20060101); F24H 8/00 (20060101); F24D 7/00 (20060101); F24D 17/00 (20060101);