Abstract: A cleaning system includes a liquid heating system utilizing heat from the cooling air and the exhaust gases of an internal combustion engine. A heat pump driven by the engine is utilized to extract heat from the cooling air and impart that heat to a first heat exchanger. A second heat exchanger is associated with the exhaust gases for extracting heat therefrom. Liquid to be heated is conveyed through said first and second heat exchangers.

Abstract: The invention relates to a method for recovering latent heat from a heat transfer medium comprising a mixture of water and alcohol, which is circulated through a heat collector and a heat exchanger for heat exchange with the evaporator in a refrigerating circuit. The heat transfer medium is sucked from the heat exchanger to provide an underpressure for atomization of the heat transfer medium with following generation of bubbles in the heat transfer medium, ice crystals then being precipitated and the ratio of water and alcohol thus being changed, the heat transfer medium with ice crystals entrained therein then being supplied to the heat collector under overpressure.

Abstract: This invention relates to a method of supplying desired quantities of heat, generated from selected inexpensive fuel burns in the firebox of a boiler, to an electric heat pump's refrigerant, while operating in its heating cycle. This supply of heat can be of sufficient quantities to satisfy the total ouput of the heat pump, minimizing its use of electricity, thereby creating a substantial savings, as the cost of the heat generated by the inexpensive fuel used by the boiler is much less than the cost of electricity.

Abstract: An apparatus for heat recovery by using a heat-pump system comprising an evaporator (14) configured as an air, water and/or earth collector and an internal combustion engine (2) as drive means, the exhaust gases from the internal combustion engine (2) being subjected to post-combustion in a separate post-combustion unit (3). The waste heat from the internal combustion engine (2) and the heat liberated upon post-combustion of the exhaust gases therefrom is supplied to a heat energy carrying medium, especially water of a heating system or the like, which has already been preheaed by the heat-pump system (5, 6). To this end the internal combustion engine (2) and the post-combustion unit (3) have heat exchangers (4, 15) cooperating therewith, respectively. Furthermore, measures are provided (exhaust gas coolers 7, 8, 9) for cooling the exhaust gases escaping to the atmosphere.

Abstract: High-efficiency heating unit for producing hot water, which includes in combination a heat pump which exploits the thermal energy of the sun and/or that of the environmental air for heating water or for producing sanitary water, namely warm water, and an electric burner or boiler for possible supplementary heating of the heated water or water preheated by the heat pump and designed either to be supplied to a heating system or for sanitary use.

Abstract: A heat pump installation for substantial heat extraction from an internal combustion engine has a heat pump for extracting waste heat such as from air drawn over the engine and a generator enclosed in a common housing and also extracts heat from the engine exhaust gases either by direct heat exchange in a tank or by means of a specially adapted evaporator coil exposed to the exhaust gas stream. The heat pump installation includes a compressor and condenser which are positioned in a liquid bath.

Abstract: The delivery side of a refrigerant compressor is connected through an inside heat exchanger to a refrigerant heater, the outlet side of the refrigerant heater being connected with the suction side of the compressor. First and second temperature sensors are provided at inlet and outlet sides of the refrigerant heater, respectively for sensing inlet and outlet refrigerant temperatures. A fuel gas supply unit for the refrigerant heater is fitted with a fuel gas control value which is controlled by the temperature differences existing between sensed temperatures by the first and second sensors.

Abstract: A solar heat collector system including a heat collector circuit containing a compressor that compresses and outputs thermal media and is capable of varying its own capacity by conversion of operative frequencies; a condensor being part of the heat collector circuit, which is connected to the output of the compressor; a plurality of heat collectors integrally built with housing materials, one end of which being connected to the condensor via a squeezer and the other end of the heat collector system being connected to the compressor, where each unit heat collector contains a plurality of thermal media tubes allowing thermal media to pass through the inside thereof and heat collect fins connected to the thermal media tubes for transferring heat; a hot-water pool storing hot water for use inside the house; and a fluid heating circuit inclusive of a fluid heater held in heat-exchange relationship with the condensor outside of the hot-water pool.

Abstract: A heating method and device for vehicles with limited power requirement, more particularly for light vehicles such as helicopters and light aircraft. For limiting the weight of the auxiliary airborne equipment, the invention provides at least partially heating of the cabin by reversal of the cooling cycle. For that a valve diverts coolant fluid to the evaporator for reheating the recirculation air of the cabin.

Abstract: A heat accumulator (18) arranged in heat exchange relation with a heating system. The accumulator comprises a body of a material having a high heat capacitivity and a high melting point, for instance cast iron, ceramics material. The accumulator is arranged for being heated by electric energy (19) to a temperature considerably higher than the maximum temperature of the heating system. A conduit (22) containing heat transporting fluid in a liquid phase is arranged for communication with the water system for settling the heat accumulator in heat exchange relation with the water system of the heating system. In a preferred embodiment the conduit (22) is an open conduit in direct communication with the water system.

Abstract: A thermochemical heat pump for the transfer of calories between two calorie sources (1, 4) and (2, 5). The heat pump embodies a monovariant system for which the relationship between the logarithm of the pressure and 1/T is singular and quasi-linear. Application to heating.

Abstract: A control for the indoor air circulating fan of a heat pump when the heat pump is operating in the heating mode. After the compressor starts, the control delays the operation of the indoor fan if the temperature is below a predetermined reference temperature. The delay time increases as the outdoor temperature decreases.

Abstract: A heat pump installation for generating, for example, either hot water or cool air utilizing a low grade heat source. The installation comprises an oil filled inner tank having mounted and immersed therein an electric motor-compressor unit and an external tank for heating and circulating such water having mounted therein the inner tank in such a manner as to avoid contamination of the oil by the water. Mounted near the bottom of the outer tank in the immediate proximity of the cold water intake is an internal sub-cooling coil which helps to increase the efficiency of the installation. Also, to further increase the efficiency of the installation, preferably there is included an external sub-cooling coil mounted externally from the external tank. Such external sub-cooling coil comprises a primary coil through which the major portion of the refrigerant flows and a secondary coil which serves to withdraw heat from the primary coil.

Abstract: A temperature setting unit is operated to set a desired temperature. An indoor temperature detector detects an indoor temperature. A timer is operated to set an operation start time. An indoor unit includes at least an indoor heat exchanger, an air duct associated with the indoor heat exchanger, a heat radiation member located in the air duct, a heat accumulator thermally coupled to the heat radiation member, and an electric heater for selectively supplying heat to the heat accumulator. An outdoor unit includes at least a compressor for cooperating with the indoor heat exchanger to constitute a heat pump refrigeration cycle for heating operation, and an outdoor exchanger. A controller outputs a first control signal for preheating the electric heater a predetermined period of time before operation start time by counting preset data of the operation start time from the timer, and a second control signal for setting the heat pump refrigeration cycle in a drive state at the operation start time.

Abstract: An outdoor unit for a heat pump is usable under very cold weather conditions since the outdoor unit includes an auxiliary heating system which heats a heat exchanger in order to prevent the heat exchanger from forming frost and which also compensates for the decline in heating capacity. Further, the outdoor unit has an air flow preventing arrangement which prevents the flow of air through the heat exchanger when the absorption of the heat from the atmosphere is not efficient. The outdoor unit drives compressors by an internal combustion engine in order to reduce the consumption of electric power and the coolant for the engine is also utilized to provide auxiliary heat to the heat exchanger. The outdoor unit also includes a boiler to compensate for the lack of heating capacity in the engine waste heat. The boiler is operated when the atmospheric temperature is less than the predetermined value.

Abstract: Periodic absorption apparatus with the substance pair zeolite/water being used as electro-head storage devices. Due to the heat pumping effect there can be a 30% savings of power.

Abstract: A heating apparatus includes a refrigeration cycle having a compressor, an indoor heat exchanger, and a refrigerant-heating unit. The unit includes a heat exchanger section through which a refrigerant flows, a burner, and a guide duct for guiding a combustion gas produced by the combustion of the burner so as to heat the refrigerant flowing through the heat exchanger section. A combustion rate of the burner is controlled in accordance with the difference between a room temperature and a preset temperature. When the combustion rate is within a specified range, it is shifted, in accordance with the temperature of the refrigerant flowing into the heat exchanger section, so as to prevent the condensation of water vapor in the combustion gas flowing through the guide duct.

Abstract: A solar collector-heat pump heating system which comprises metallic plates which are directly exposed to the ambient atmosphere and which are in direct heat exchange relation with tubes. A compressor receives a heated low-boiling working fluid, e.g., R-22, from the tubes as a vapor, compresses it and delivers it to a condenser. The fluid then passes through a throttling valve where it partially vaporizes, then to the tubes, where vaporization continues, utilizing heat absorbed by the plates from solar radiation, the ambient air, rain, and long-wave infrared radiation. Heat is extracted from the condenser and used for space heating. Preferably, heat storage means, e.g., a tank of water or a body of low-melting salt, are provided. Preferably, the heat-absorbing plates are long and narrow. In one embodiment they are spaced from a diffuse reflective backing and are laterally spaced from each other. In another embodiment they form a siding for a building.

Abstract: A method and apparatus for utilizing heated water from an air conditioning condenser to heat water used to control temperatures in a large building including a heat exchanger connected to an air conditioner condenser for receiving water heated by the air conditioner condenser and transmitting said water from said heat exchanger to a cooling tower, the heat exchanger also having connected thereto a liquid circuit means for circulating hot water to heating coils located in the building, the heat exchanger effecting a heat exchanger between the hot water received from the condenser and the water to be utilized for heating the building.

Abstract: The invention relates to a space heating system comprising an air cooled solar collector, a heat store, air ducting, a forced draught mechanism valves, auxiliary heating means and a control system. According to the invention the auxiliary heating means includes a heat pump. The heat pump and heat store are located in a thermally insulated air-tight housing divided into different regions for the evaporator, condenser and heat store. The heating system is operable in a mode in which it circulates air from the heat store to the heat pump evaporator and back in a closed air-tight circuit while simultaneously circulating air from the heat pump condenser to the space to be heated and back. The arrangement minimizes heat loss and defrosting of the heat pump evaporator. The invention also provides air ducting made from seamless lengths of foamed plastics material and provided with a vapor-proof lining.

Abstract: This invention relates to an integrated heat pump construction including a housing having mounted thereon a first air-to-refrigerant heat exchanger coil assembly, a blower assembly, a compressor, a second refrigerant-to-liquid heat exchange coil assembly and, a third refrigerant-to-potable liquid heat exchange coil assembly, wherein said compressor and said first, second and third heat exchange coil assemblies are connected together to form a heat pump circuit with potable liquid heating capacity.

Abstract: A prime-motor-driven room-warming/cooling and hot water supplying has a heat exchanger which includes each part of a cooling water circulating circuit, a supplied water circuit, a refrigerant heating circuit and a supplied water heating circuit so as to perform mutual heat exchanging of cooling water for the prime motor in the water heating circuit, the refrigerant in the supplied water heating circuit and the refrigerant in the refrigerant heating circuit.

Abstract: A control arrangement for a heat recovery system which can be retrofitted onto existing equipment in order to utilize otherwise wasted heat. A heat source such as a conventional refrigeration system used as a source of superheated condensible heat exchange medium for supply to a heat recovery system. A liquid medium system, such as a water system is connected to the heat recovery system for receipt of heat transferred. The heat recovery system includes a plurality of heat exchangers connected in series. A control arrangement responsive to the operating conditions and safety of the heat recovery system and to the systems with which it interfaces with respect to its effect on said interfaced systems.

Abstract: A refrigeration system control method for minimizing off cycle losses in a heating mode of operation includes the steps of closing a valve in a refrigerant line between an indoor coil and an outdoor coil for a first predetermined period of time starting with a deenergization of a compressor and ending before a reenergization of the compressor to retain the refrigerant in the indoor coil and maintaining an energization of an indoor coil fan for a second predetermined time period after the deenergization of the compressor which second time ends before the first time period.

Abstract: The invention relates to an energy saving system for heating and/or cooling of plants, particularly of animal raising plants, having areas suited for the containment of a plurality of living bodies, which system is suited for reducing the spread of infection between the various areas, characterized in that(a) there is provided an air treating unit (2) connected to a heat pump (3) for condensing the water vapors (steam) generated in the areas (1) and for recovery of the so obtained amount of heat with the aid of a vapor condenser;(b) there is provided a dust filter (18) for eliminating the mechanical contaminations in the air of the areas (1);(c) there is provided a chemical filter (7) for reducing, or respectively eliminating the gases that are contained in the air of the areas (1); and finally(d) there is provided a biological filter (16) for the biological filtration of the air exiting from the areas (1).

Abstract: An energy-saving system for an air conditioning system includes: a silencer box encasing an air compressor of an air conditioning system and an engine directly coupled with the air compressor, an air heat exchanger adapted for absorbing the heat as laden by an air stream passing the air compressor and the engine, a refrigerant heat exchanger recovering the condensation heat of the air conditioning system, a water heat exchanger recovering the heat as absorbed from the water jacket in an engine body, and a flue gas heat exchanger recovering the waste heat laden in the exhaust gas from the engine, so that all the heat recovered may serve to drive a turbo-generator for power generation, or to warm an utility water or to preheat a boiler feed water.

Abstract: A closed, high-efficiency, ambient-energy-assisted heating and cooling system incorporating a unidirectional flow of refrigerant to achieve simultaneously the functions of space and water heating and/or cooling is described, along with an improved ambient-energy collector panel to be used in conjunction therewith.

Abstract: Disclosed is a method of and apparatus for heating and cooling. The method and apparatus employ a thermodynamic moat across which heat energy conductance can be entirely prohibited. The moat comprises a heat source for a heat pump. The heat pump can be contained within the thermal protection of the moat. Thus its energy of operation may be added to, rather than lost from, the system. Structures for absorbing solar irradiation are disclosed, as are means to contain these structures within the protection of the moat, thereby to overcome grave deficiencies of solar collectors used in cold climates. A method of and apparatus for utilizing the solar absorber structures for summer cooling are also disclosed.

Abstract: A heating system employing a heat pump utilizes heat from the cows in a dairy barn as a low grade source of heat to heat a residence. A closed loop circulation system between a heat exchanger in a house and the heat exchanger in the barn employs a water-based heat transfer fluid. This eliminates the need for long refrigerant lines running between the house and the barn. The heat exchangers in the residence convert the barn heat to Freon and transfer heat from the Freon to the residence. The house heat exchangers are divided into two sections connected in parallel to improve heat transfer and overall efficiency and reduce pressure losses.

Abstract: An air-conditioning and hot-water supplying system has a dual function water-heating heat exchanger; a heat pump circuit circulates a heat-transmitting medium for air conditioning the interior of a housing. The heat pump circuit includes a compressor driven by a prime mover. The system also includes a hot-water circulation circuit having a tank for storing hot water and a pump for circulating water to be stored therein. The water-heating heat exchanger comprises three concentric, different length pipes including an outer pipe, a first heat transfer pipe disposed in the outer pipe, and a second heat transfer pipe disposed in the first heat transfer pipe. Hot water from the hot water circulation circuit flows between the outer and the first heat transfer pipes. Cooling water from a prime mover cooling circuit flows between the intermediate first heat transfer pipe and the innermost second heat transfer pipe. The heat-transmitting medium flows through the second heat transfer pipe.

Abstract: The present invention relates to transforming a pre-existing heating installation comprising a main heat generator such as a boiler which is associated with a modulating mixer valve controlled by a P or PD type regulator which is responsive to outside temperature and to the departure temperature of the heating water.

Abstract: Method and equipment for the utilization of the freezing heat contained in water as a source of heat of a heat pump. The water flow to be utilized as the source of heat is evaporated in one or several stages (4) at such a low pressure that, when the vapor that is formed binds its evaporation heat out of the water, part of the water freezes. The vapor formed is condensed in one or several heat exchangers functioning as the evaporator of the heat pump, whereat the vapor, on being condensed, delivers its heat to the heat transfer medium used in the heat pump.

Abstract: A heating system having buried, outwardly directed loops through which freon is routed for partaking of ground heat. The buried loops are inclined downwardly from an expansion valve and distributor with the loops each discharging into a central collector from where the freon vapor is directed to a liquid trap and thence a compressor. A medium-to-air heat exchanger is located in a cold air duct. A receiver tank stores liquid freon and supplies in a constant manner to the expansion valve.

Abstract: Method and device for operation of a heating plant comprised in a heating system which works with circulation of air. A partial flow (16) of the consumed air in the heating system is supplied to a heat exchanger (4) for heat exchange with intake air (12) coming from outside and with a return flow (14) of circulation air from the heating system. After passage through the heat exchanger (4) the mixture of intake air and return air is fed as heat delivering medium to the evaporator in a circulation heat pump (5). The quantity of air circulating through the heat pump is kept greater than the partial air flow which is exhausted from the heating system via the heat exchanger. With increasing demand for energy the partial flow is exhausted by means of a suction fan (7) and can, in addition, be mixed with the flue gases from a preferable water-carried heating boiler (2).

Abstract: A thermochemical heat pump for the transfer of calories between two calorie sources (1, 4) and (2, 5). The heat pump embodies a monovariant system for which the relationship between the logarithm of the pressure and 1/T is singular and quasi-linear. Application to heating.

Abstract: A method of purifying flue gases from refuse incineration by cooling and of recovering heat energy as well as an arrangement for performing the method. According to the method the flue gases are cooled in three stages, with the most beneficial structural material with regard to the temperature range, process conditions, and economy being selected in each cooling stage among the materials glass, plastic or alloyed steel. The sizes of the various cooling surfaces are determined such, that the temperatures of the flue gases immediately before the last cooling stage lie closely above the water dew point. The arrangement disclosed by the invention comprises a first cooling member, a second cooling member connected thereto, and a third cooling member connected to the latter and having its outlet connected to a droplet separator which is followed by a flue gas fan which in turn is connected to a chimney.

Abstract: A flue gas heat pump is provided for extracting heat from the discharged hot flue gas of a furnace. The heat pump includes a condenser at the inlet of the furnace cabinet in heat transfer relation with the flow of air to be conditioned, and an evaporator disposed at the outlet of the furnace heat exchanger for extracting heat therefrom. A compressor is provided for compressing a refrigerant and delivering it to the heat exchangers. The compressor is located in the flow path of the air to be conditioned so that the heat generated by the compressor is transferred thereto.

Abstract: Improvements in the system for heating and cooling liquids as disclosed in prior U.S. Pat. No. 3,513,663. This prior system utilizes components of refrigeration such as a compressor, a condenser coil, an evaporator coil, a refrigerant, and expansion valve, in their well-known interrelationship and includes a first and second liquid source, which are pumped in heat-exchange fashion through segregated condenser and evaporator coils simultaneously with, and in the opposite direction to, that of the refrigerant. One broad improvement embodies the elimination of the second liquid source, typically a ground water well, and to alter normal liquid flow to achieve either heating or cooling. Another broad aspect of this invention is to optionally alter the path of both first and second liquid source flows in segregated heat-exchange fashion through the condenser and evaporator coils, whereby heating or cooling of either liquid source may be easily selected and controlled. Refrigerant flow may also be altered.

Abstract: A self contained heating system comprises a closed circuit containing a refrigerant. The closed circuit includes a heat exchange portion, a condensing portion, an evaporator portion and a compressing portion. Superheated, evaporated gas is introduced into the compressing zone to raise the temperature of the evaporated gas discharged therefrom and introduced back into the heat exchange portion. The amount of heat energy contained by the refrigerant is increased while it is in a heat transfer zone. The additional heat energy is released from the refrigerant in a condensing zone. A smaller volume of evaporated gas is exposed to the higher heat being transferred from the condensing zone and is saturated with the heat energy within the evaporator zone before being directed to the inlet side of the compressor. The heat generating system does not require drawing any heat from any other source outside the heat generating system of this invention.

Abstract: An absorption cooling and heating apparatus and method, in which generator means evaporates a refrigerant from a solution therewithin to form refrigerant vapor, and condenser means then condenses the refrigerant vapor so produced within the generator means. Evaporator means receives the condensed refrigerant from the condenser means, and evaporates the same to form vapor therewithin, with absorber means being provided to absorb the refrigerant vapor that was formed in the evaporator means. The absorber means also receives a concentrated solution conveyed from the generator means, and delivers a dilute solution to the generator means. Heat exchanger means is provided for effecting heat exchange between the concentrated solution being passed to the absorber means, and the dilute solution being returned back to the generator means. Also, switch means for alternately changing to a cooling or to a heating cycle is provided.

Abstract: The invention relates to a heating installation of the type having a heat pump, radiators having valves, and a control device having a desired value generator for controlling the upstream temperature that delivers as an effective desired value, a guided desired value guided by guide parameters such as the external temperature and/or a reference room temperature. The invention involves providing a heating installation of the aforementioned kind in which the efficiency and life of the heat pump are improved. Pursuant to this objective the control device has a comparator which compares the guided desired value with a variable limiting value higher then the downstream temperature by a predetermined temperature difference and the desired value generator reduces the effective desired value at least down to the variable limiting value when the latter is exceeded by the guided desired value.

Abstract: A heat pump system for a building provides space heating or cooling, together with a supply of hot water available in both the heating and cooling seasons or when the building space is neither heated nor cooled. The system is also versatile in that it can be readily accommodated to new construction (forced air systems) or to the retrofitting of existing buildings, the majority of which are fitted with convection type hot water radiators. These results are achieved by a refrigerant circuit that includes three heat exchangers (12, 15, 16), one (12) linked to a heat source (10), one (15) to a forced air system including a blower (17) and the third (16) to a hot water circuit (40-49) that supplies heat to the radiators (47) and to a hot water tank (41). A reversing valve (13) in the refrigerant circuit and a two way valve (42) in the hot water circuit enable selection of one of several operating modes, i.e.

Abstract: The energy requirements of a sock finishing factory consisting at least of a dye house, boarding room and a warehouse are greatly reduced and the working conditions of employees are improved by utilizing waste heat from the boarding room to provide heat for the dye house water requirements and seasonal heat for the warehouse and by supply some of the heat for the dye house water from the air conditioning condenser system.

Abstract: An air conditioner comprises an air-to-air heat exchanger; a fresh air supply duct, a fresh air by-pass duct, a used air exhaust duct, and a used air by-pass duct, the fresh air supply duct and the used air exhaust duct being respectively connected to the air-to-air heat exchanger, the fresh air supply duct having a part in common with the used air by-pass duct, and the used air exhaust duct having a part in common with the fresh air by-pass duct. Included are a condenser provided in the common part of the fresh air supply duct, and an evaporator provided in the common part of the used air exhaust duct, the condenser and the evaporator being parts of a heat pump. A blower is provided in the common part of the fresh air supply duct and is connected to the used air by-pass duct, and a separate blower is provided in the common part of the used air exhaust duct and is connected to the fresh air by-pass duct.

Abstract: An air conditioning system and method wherein a central pumping system circulates a heat-exchange liquid, through heating and cooling paths of a refrigeration system to and from air-treating units, and to and from a fluid cooler which acts as a heat sink and also as a heat source. The air-treating units have fans or blowers positioned upstream of the air cooling coils so that the fan heat is discharged through the fluid cooler system during cooling load operation, and that heat is available in the air-treating units during heating-load operation. One embodiment includes a separate line for supplying neutral water to each air-treating unit. The neutral water is mixed with either the hot water or the cold water supplied to each treating unit for temperature control. Another embodiment has only hot and cold water with separate supply and return lines.

Abstract: Provided is a water heating device of heat pump type which comprises a compressor, an evaporator, a duplex-pipe condenser and a blower means, characterized in that the blower means and the compressor are laid horizontally and, at the back of this arrangement, the evaporator is disposed, and the duplex-pipe condenser wound in a slender elliptic form is disposed on tops of the evaporator and blower means.

Abstract: A non-reversible multiple-refrigeration-cycle solar apparatus, including a variable directing valve mechanism for conditioning a medium, defrosting the apparatus, and absorbing, storing and using solar energy.

Abstract: A reversible mode heating and cooling system comprises a reversible heat pump unit having a compressor, a reversible valve, an indoor heat exchanger in heat exchange relationship with indoor ambient air a water cooled concentrator, refrigerant expansion means, an outdoor heat exchanger in heat exchange relationship with outdoor ambient air and an auxiliary heat exchanger in heat exchange relationship with a water source for enhancing the capacity and efficiency of the system to transfer heat to the refrigerant during the heating mode at low outdoor ambient temperatures. The concentrator is disposed downstream of the outdoor heat exchanger (condenser) in the cooling mode of operation to cool the refrigerant exiting the heat exchanger for enhancing its ability to absorb heat in the indoor heat exchanger (evaporator).

Abstract: The invention relates to a method and a plant for the central heating of a building provided with at least one thermodynamic machine such as a heat pump or a refrigerating machine. The method is characterized in that, without affecting the normal operation of the thermodynamic machine, during the heating period:when the temperature of the heat transfer fluid in the exchanger-accumulator tank reaches a certain threshold, the conduits via which the auxiliary boiler is connected to the circuit supplying the exchanger network are isolated and the return of this circuit to the tank is released while, on the other hand, when the temperature of the heat transfer fluid in the exchanger-accumulator tank drops below a certain threshold, the return to the exchanger-accumulator tank of the circuit supplying the exchangers is cut off and the auxiliary boiler whose discharge and return conduits are connected to the circuit is actuated.

Abstract: A control system for an electric domestic water heater operatively associated with an external heat source, such as a heat pump, and including a water storage tank having an internal electric heater unit controlled by a tank thermostat responsive to the water temperature in the tank. The control system maintains the tank heater unit effectively turned off and turns the external heat source on in response to an indication from the tank thermostat that there is a demand for hot water. The control system turns the external heat source off in response to an indication from the tank thermostat that the demand for hot water has been satisfied. The control system may include devices, such as an evaporator thermostat, high pressure cut-out switch, etc., indicative of the condition of the external heat source for turning the external heat source off, turning the tank heater unit on and maintaining the tank heater unit on until the demand for hot water has been satisfied.