Abstract: A heat exchange system for recycling waste heat leaving a building stack to supply heat to incoming fresh air or temper stored water of the building water storage system, wherein the building has a source of heat at constant temperature, such as a cooking facility, from which air conveying waste heat is drawn and impelled through a stack in which a closed circuit heat generated refrigerant flow type refrigeration system is established including a heat recovery coil in the stack, heat discharge coils in heat transfer relation to the incoming fresh air and the stored water, liquid refrigerant traps that permit free flow therethrough of the refrigerant adjacent the heat discharge coils adjacent their discharge ends, and thermostatically controlled valves for alternately disconnecting the heat discharge coils from the heat recovery coil in accordance with a predetermined ambient air temperature exteriorally of the building.

Abstract: A heat exchanger coil disposed in a furnace chamber or duct to absorb heat from the furnace to increase the temperature of water passing through said coil from a cold water source to a hot water heater or storage tank is disclosed. An additional feature includes a second heat exchanger coil disposed between the cold water source and the furnace heat exchanger within the confines of a building to absorb heat from the ambient surroundings. An insulated coiled storage unit disposed downstream of the furnace heat exchanger to provide a quantity of additional preheated water to the water heater and a spurge tank overheat and overpressure relief unit for the system is also disclosed.

Abstract: A combinational fireplace arrangement has a plurality of log-shaped members having a hollow center portion with a spiral shaped tube passing serially through each of the logs, which tube conveys a fluid through the log-shaped members. A first fuel burning member, within the log member, heats the fluid passing through the spiral shaped tubing. An arrangement of pipes, encased with heat collectors, placed in the fireplace flue, captures energy escaping from the logs and preheats the fluid. A second fuel burning member, controlled independently from the first, is placed beneath the logs to cause the logs to appear to be burning. A thin gauge twisted pair of copper wire within the spiral shaped tube eliminates the formation of air pockets therein.

Abstract: The invention relates to thermostatic apparatus for controlling the heating fluid supply temperature in a central heating installation having at least two radiators in different rooms. With each room having a thermostat for controlling the radiators therein, the apparatus operates so that the most active thermostat is given priority in controlling the temperature of the heating fluid.

Abstract: A programmable device for controlling the amount of heat supplied to a building by a circulating medium by enabling a circuit to a heater such as an oil or gas burner, or a steam valve to open and close during predetermined times and in response to the temperature of the outside air and the temperature of the medium. The predetermined times can occur during a multi-day cycle such as a week. As the outside air temperature rises and falls, the circuit will be opened or closed depending on whether the device is at a predetermined time and whether that temperature falls above or below a predetermined value and depending on the temperature of the circulating medium. Additionally, the device can be set so that when the outside air temperature falls below a predetermined level the circuit is closed to add heat to the building without regard to where in the program cycle the device is.

Abstract: In a positive or negative heat transfer system with an intermittent source of positive or negative thermal energy, utilization means and a reservoir of heat transfer fluid flowing between the reservoir, the source and the utilization means, the reservoir is divided into two compartments of complimentarily variable volume and excess positive or negative thermal energy not required by the utilization means is used primarily to maintain the enthalpy of the fluid in one of the compartments of the reservoir at a maximum (for positive heat transfer) or mininum (for negative heat transfer) level, the volume of that one compartment being maintained at or reduced to a minimum until the required level of enthalpy is attained.

Abstract: A water heating and forced air heating system that provides potable hot water and that also provides heated air for heating enclosed spaces within buildings, including: a water heater including a water tank filled with water, a burner for heating the water in the tank, and an exhaust flue for removing hot gases generated by the burner; a gas-to-liquid heat exchange unit disposed within the flue; a forced air heater having a casing that defines a chamber, a liquid-to-gas heat exchange unit disposed within the chamber, a gas-to-gas heat exchange unit also disposed within the chamber, and a blower for pulling fresh air into the chamber and blowing it past the heat exchange units to absorb heat; a pump for pumping water through the gas-to-liquid heat exchange unit so that the water becomes heated by the hot gases within the flue; another pump for pumping heated water through the liquid-to-gas heat exchange unit to heat the air flowing within the chamber; and a conduit for connecting the terminal end of the flue t

Abstract: A central heating system comprising a heat exchanger, heat dissipating means, and a connecting piping circuit for liquid flow, has a pump capable of pumping the liquid around the circuit at a lower or a high flow rate, the flow rate of liquid being sensed to control the means which supplies heat to the heat exchanger so that heat is supplied when the pump means is operating at its higher rate and is not supplied when the pump means is operating at its lower rate. The rate of operation of the pump means is determined by means which senses the temperature of the circulating liquid so that the pump means operates at its lower rate when the temperature of the liquid exceeds a selected value and at its higher rate when the liquid temperature is below a selected value.

Abstract: A poultry raising system includes a house having one or more enclosed sections with at least one section provided with a plurality of hovers and all of the sections having peripheral heat assemblies. All hovers and heat assemblies are equipped with sealed heat radiating conduits supplied with a fluid heat transfer medium from a common heating apparatus. A supply and return line serving each section from the heating apparatus includes a thermostatically-controlled valve admitting the heat transfer medium to all of a section's hovers as well as other thermostatically controlled valves regulating the flow of heat transfer medium to each of a section's peripheral heat assemblies. Dampers in roof-top vents are automatically opened and closed in response to signals from a gas sensor in each section to evacuate obnoxious gasses from each section enclosure and the evacuated gas is replaced by fresh outside air admitted through automatic dampers adjacent the house side walls.

Abstract: A compact heating and cooling system in which air ducts are connected to a heat exchanger system through which a coolant fluid from a condensing unit or a heating fluid from a compact water heater is selectively directed by a control circuit so that the system may be mounted outside a building to be heated and/or cooled.

Abstract: A fireplace boiler for heating liquids is disclosed which is adapted to be fitted into a fireplace cavity and combined with a pre-existing domestic heating system. The boiler includes a grate made up of a plurality of heating tubes connected to headers through which a liquid to be heated flows. At one end of the grate is located a vertical sampling tube having an orifice therein through which the liquid flows between the headers. The flow of liquid in the sampling tube is reversible with the direction of flow being dependent upon whether the fluid in the boiler is being circulated through the heating system. The reversible direction of flow enables a temperature sensor located in the sampling tube to accurately sense the temperature of the fluid in the boiler at all times.

Abstract: A heating system utilizing a fuel bearing multi-tube water jacket having a lower header, an upper header vertically spaced from the lower header, a plurality of spaced curvilinear hollow heat exchanging tubes connecting the manifolds, and a hollow plate-like baffle connected between the manifolds. The water jacket may be positioned within a conventional fireplace for supporting burning fuel to heat fluid circulated through the heat exchanging tubes and plate-like baffle for heating areas remote from the fireplace. The water jacket may be utilized in conjunction with a heat exchanger positioned within the warm air duct of a forced air furnace. A pump for circulating fluid through the water jacket and heat exchanger, and a blower associated with the forced air furnace are operated in response to the temperature of the heated fluid.

Abstract: A closed heating system for a building particularly adapted to be installed in a conventional fireplace for supplementing the heat generated by a conventional forced air heating unit. The heating system includes a grate having a log supporting water conduit through which water passes and is heated by the logs supported thereby. The heated water is pumped through suitable valves to a heat exchanger disposed within the air duct of a conventional forced air heating system to heat the air passing therethrough. The heated water may bypass the air duct heat exchanger. The bypassed water is communicated to a coil associated with a tempering tank which is installed in the building cold water supply line that feeds the hot water heater. The hot water preheats the water supply and is then returned to a storage tank for recycling.

Abstract: A remote-controlled forced-circulation central air-conditioning system comprising a central heat-exchanger unit and a plurality of terminal air-conditioning units which are connected to the central heat-exchanger unit through terminal valves, respectively, which are arranged in parallel with one another, wherein a water circulation pump and the central heat-exchanger unit are started and shut off upon detection of variation in the pressure and/or the temperature of the liquid such as hot water in the liquid supply circuit leading to the terminal air-conditioning units when the terminal valve or valves are opened up and thereafter closed. The system may include a terminal heat-exchanger unit such as a bath.

Abstract: A heating system comprises serially connected heating and holding coils connected in a closed heating liquid circulating circuit with a collector coil at the space to be heated. The heating and holding coils are disposed in a compartment wherein both are subject to direct heating by one or more gas burners, and flue gas is drawn through the compartment in heat exchange relation with the holding coil before being exhausted.

Abstract: A system for the efficient control and transfer of energy from a multiplicity of different sources, such as the sun and fossil fuels, using a heat exchanger and various storage units. When solar energy is available, it is transformed and used or stored. When it is insufficient, fossil fuel is used to operate a boiler heat exchanger and meet system requirements.

Abstract: A heating system including a fireplace and a flue for carrying away combustion products, door means being provided to prevent a draft through the space to be heated and to oxygen-starve a fire in the fireplace; and, heat exchanger means is mounted in the flue, the heat exchanger means comprising a plurality of coils for carrying a heat exchange medium, the coils being connected in parallel with one another on manifolds that extend through the coils.

Abstract: A water filled coil in the rear of a fireplace is connected to a hot water storage tank so that heated water in the coil can circulate into the tank. A second hot water storage tank is connected to the first storage tank and an aquastat associated with the first tank controls the flow of water between the two tanks. Heat exchanger coils within the two storage tanks are used to preheat incoming cold water before it is fed to a domestic hot water heater. Another heat exchanger coil within the second storage tank is interconnected with the main baseboard hot water heating system and furnace. Automatic by-pass valves and aquastats are adapted to turn the furnace off and utilize the heat exchanger coil when the fireplace is providing sufficient hot water and are adapted to fire the furnace and bypass the heat exchanger coil when insufficient heat is provided by the fireplace.

Abstract: The invention relates to an apparatus for preventing or limiting water damage caused by leakage from pipes or appliances in which a sensing element in the form of a pair of conductors having current applied thereto is positioned in an area to sense accumulation of water from leakage. The sensing element is connected to a resettable relay to operate the same when current flows between conductors of the sensing element. The relay is bi-stable and resettable and operates to disconnect the sensing element after initial conduction and to further apply heat through the heating element to a thermostatic valve to operate the thermostatic valve in a direction to close off water flow to piping or apparatus in which leakage occurs.

Abstract: A heat transfer system for use in supplementing the operation of the heating/cooling system of a building and its hot water heating system includes a heat exchanger in the flue of the furnace as well as a heat exchanger in the fan chamber. A first liquid circulation loop couples the heat exchangers for transferring heat from the flue exchanger to the air moved through the fan chamber heat exchanger. A second liquid circulation loop includes the flue exchanger and the building hot water heater for supplementing the heating of water therein. In the summer months during the cooling mode of the systems operation, cold water employed, for example, for lawn sprinkling is passed through the fan chamber heat exchanger for cooling and dehumidifying air circulated in the building. A valve control system is employed to automatically control the flow path of fluid in the system as a function of detected temperatures.

Abstract: An on-site system in which means for treating domestic sewage generated within a building located thereon are totally integrated with means for modifing space temperatures and for heating water for sanitary and other purposes therein to form a matrix of interrelated and interdependent functions acting together to deliver only non-polluting products to the environment and to achieve maximal energy conservation.

Abstract: A heating system for heating a confined area with an open-hearth wood-burning fireplace. A fireplace jacket is provided which comprises a multi-chambered double-walled arrangement or a grate member. Log supporting portions of the jacket slant upward slightly in order to prevent a pinging sound by creating convectional force when water is circulating therethrough. The grate member includes first and second headers formed from prisms with triangular bases, and water conducting pipe portions extending on three sides of a fire burning in the open-hearth fireplace. The fireplace jacket is readily utilizable with a conventional forced-air furnace in association with a heat exchanger disposed in the furnace cold air return. Combustion air for the fire is provided from an area external of the confined area to be heated by the heating system.

Abstract: An auxiliary heating device for supplementing the performance of a standard hot water type home heating system with the heat produced by combusting a low cost, readily available fuel is disclosed. The device comprises a cylindrical fire chamber substantially closed at both ends and an elongated annular water chamber closed at both ends surrounding at least a portion of the fire chamber in a noncoaxial relationship thereto. Means are provided for plumbing the water chamber into the main heating system, whereby cool water enters the water chamber and heated water is pumped by the main system's pump to radiators disposed around the home. A combustion air passageway is provided for passing air to the combustion chamber. Means for varying the size of the passageway in response to the temperature of water in the water chamber are also provided so as to control the combustion rate of the fuel. Means for supplying fuel to the combustion chamber are further provided.

Abstract: A compact heating and cooling system in which air ducts are connected to a heat exchanger system through which a coolant fluid from a condensing unit or a heating fluid from a compact water heater is selectively directed by a control circuit so that the system may be mounted outside a building to be heated and/or cooled.

Abstract: A device for controlling the heating of a hot water boiler includes a first temperature sensor sensing the temperature of the boiler liquid and operating means adapted to switch a control switch. It also includes an outside temperature sensor to be arranged elsewhere and comprising a liquid-filled reservoir which communicates via a capillary with a tubular coil spring of the control device, which spring also actuates means which are adapted to switch the first switch. The tubular coil spring is arranged to actuate with an outer winding means adapted to change, through this actuation, the relative position of elements of the control switch and hence the temperature at which the control switch is switched under the control of the first temperature sensor.

Abstract: A system for lowering the temperature of a room where a substantial amount of waste heat is generated, and utilizing the waste heat removed from the room, includes a portion mounted within the room to absorb the heat from the room and a portion external to the room, operable to utilize the heat.The portion mounted in the room includes at least one heat exchanger along with associated means for moving the hot air of the room through the heat exchanger and means for conducting fluid through the heat exchanger and to the external portion of the system.

Abstract: A control device and process for heating an installation, having one zone or a plurality of zones, so that a desired temperature within the installation is attained wherein a comparison is made between the heating medium temperature and the temperature outside the installation and the results of said comparison are used to regulate the temperature of the heating medium to the lowest temperature required to maintain the desired temperature in the installation where said heating medium is constantly circulating through at least one zone of said installation and a temperature sensing means in each of said one zone or plurality of zones is activating the circulators used to circulate the thermal fluid within the installation, provided that at least one circulator will operate as long as the heating medium temperature is higher than a predetermined low temperature set point.

Abstract: A space heating system having a low inertia (low mass and low water content) boiler and a larger heated water storage tank providing a bank of hot water (hereafter called the heat bank) and a "fly-wheel" effect. This provides a thermal bank or load leveler. The temperature of the water in the tank controls "on-off" operation of the furnace of the boiler. The heat sensing means for the heated space controls only the operation of the circulator in the system. A plurality of zones with a common return may be used. The flow rate from the boiler into each of the zones is controlled to be less than the rate of flow from the boiler to the heat bank so that its stored supply of heated water may be quickly established. A domestic water heating coil may be mounted in the heat bank. The connection from the boiler to the heat bank is preferably to the top of the tank which forms the heat bank. The connections to the domestic water heating coil are also preferably at the top of the heat bank.

Abstract: A heat exchanger is provided having coiled tubing and radiating fins about which hot flue gases for the cooking equipment circulate to heat a medium passing therethrough. Temperature control valves are selectively adjustable to pass the heated water along either of two sets of conduits for heating makeup air or heating water for use in the facility, respectively. These temperature control valves are set so that when the ambient room temperature is less than 70.degree. F., the medium heated by the flue gases is passed through a second heat exchanger which intercepts incoming air to warm it before its admission in the building. When the temperature exceeds 70.degree. F., the valves automatically switch to direct the heated medium to a third exchanger for heating tap water. A bypass arrangement recirculates the heat carrying medium through the primary heat exchanger until it achieves a predetermined temperature to prevent condensation.

Abstract: In a circulating water heater, a water heater is located in a flow circuit connected in parallel with a domestic water circuit. A heating circuit is connected in parallel with the domestic water circuit. A change-over valve interconnects the flow circuit containing the water heater with the domestic water circuit and the valve is also connected to the heating circuit. A short-circuit line including a pump interconnects the supply flow line and the return flow line in the flow circuit containing the water heater.

Abstract: A steam-type fireplace heat-extraction apparatus, including an enclosure for utilizing the heat generated in a fireplace, comprising an isobaric or atmospheric, superheated steam system combined with a unique enclosure, said enclosure comprising a fireplace frame having vertical side members and horizontal top and bottom members, with two novel door structures which are hingedly carried by the fireplace frame. Each door structure comprises double panes of tempered glass disposed in spaced, parallel relation, held by a door frame which extends around the peripheral portions of the panes and confines the same. The door frames have special ventilating holes located adjacent the top and bottom members of the fireplace frame, which enable air from the room to be drawn into the space between the panes and then discharged, to not only provide heat to the room but also at the same time hold the temperature of the glass to a lower value.

Abstract: In combination with a heating system comprising a boiler, combustion means for heating water contained in the boiler and a flue for conducting away hot gases resulting from the combustion, the invention comprises a system for recovering heat contained in the flue gas comprising a housing having a flue gas inlet and a flue gas outlet, contained in the housing a coil having a water inlet and a water outlet, director means for directing flue gas into a first path of contact with the coil as the flue gas travels from the flue gas inlet to the flue gas outlet or a second path directly from the flue gas inlet to the flue gas outlet without contacting the coil and means for adjusting the directing means between a first position at which the flue gas is directed into the first path and a second position at which the flue gas is directed into the second path.

Abstract: The water for a central heating system is supplied with thermal energy in a boiler equipped with an oil burner and with a thermostatically controlled mixing valve that mixes the water heated in the boiler with water from a return line by-passing the boiler to maintain a desired temperature in the heating fluid. A secondary heat source (heat pump, wood-burning boiler, solar unit) is connected to the by-pass and automatically actuated when it can effectively relieve the oil burning boiler.

Abstract: Heat storage and/or cold storage are essential in air conditioning systems depending upon weather-sensitive energy sources such as solar heat, including sun and wind. Sufficient supplemental heating sub-systems are also desirable if not essential. Liquid heat storage is the preferred method of storing heat or cold. This invention provides a supplemental heating and dual function heat transfer sub-system for a solar heating system which employs a liquid heat storage medium and a heat storage unit. The sub-system includes a heating unit having a combustion area, a first direct heat transfer means for transferring the heat from the combustion area to the liquid heat storage medium, and a second adjustably regulated direct heat transfer means between the liquid heat storage medium and the living space. If there is combustion in the combustion area, the heat storage medium may be heated or the living space may be heated or both.

Abstract: The invention pertains to an automatic heat storage system comprising two cooperating sources of heat, two heat storage vessels, and a heat emitting system, the heat being transferred by a heating medium common for the entire system. Preferably, one of the sources of heat is a solar energy collector system.

Abstract: A standard hot water heating system is improved by adding a high-low temperature limit controlled auxiliary boiler. The auxiliary boiler is smaller than the main boiler and the burner for the auxiliary boiler is, of course, smaller than the burner for the main boiler and uses less fuel. In a particular embodiment, the auxiliary boiler continuously maintains the temperature in both boilers within the range of about 170.degree.-212.degree. F. As a result of the constantly maintained elevated water temperature in the main boiler, less time is required for the main boiler burner to heat up the system upon the demand of a room thermostat.

Abstract: A method and control arrangement for a heating system including solar heating apparatus and a conventional fuel-fired heating apparatus wherein heat load of the heating system and solar heating source capability are compared, and the heating system is switched to solar heating whenever the heating capability of the solar heating apparatus exceeds the heat load of the system, the heating system being switched to the conventional heating apparatus only when the heat load exceeds the heating capability of the solar heating apparatus.

Abstract: A burner control system for a hot water boiler is responsive to both outlet water temperature and return water temperature to provide a relatively constant outlet water temperature regardless of variations in heat output requirements. A first thermistor responsive to return water temperature is effective to provide on-off control of gas flow to the burner. A second thermistor responsive to outlet water temperature is effective to vary the rate of gas flow to the burner so as to maintain a predetermined outlet water temperature. A timing circuit is effective each time the burner is turned on to delay a high rate of gas flow to the burner.

Abstract: A solar heating system for converting the sun's rays into heat, comprising a level heat absorbtive element whose underside is adapted to absorb solar radiation and to convert it into heat, the absorbtive element being provided with means to conduct the absorbed heat away to be used for heating, reflector means arranged below said heat absorbtive element adjustably positioned to project solar heat rays onto said absorbtive element, the reflector means being movable into an inoperative protected position when not in use, the heat absorbtive element being protected against heavy loss by an insulated housing trapping dead air underneath said heat absorbtive element and being adapted to allow heat radiation to pass from said reflector means to said heat absorbtive element.

Abstract: A heating system for heating a confined area with an open-hearth wood-burning fireplace. A fireplace jacket is provided which comprises a multi-chambered double-walled arrangement or a grate member. Log supporting portions of the jacket slant upward slightly in order to prevent a pinging sound by creating convectional force when water is circulating therethrough. The grate member includes first and second headers formed from prisms with triangular bases, and water conducting pipe portions extending on three sides of a fire burning in the open-hearth fireplace. The fireplace jacket is readily utilizable with a conventional forced-air furnace in association with a heat exchanger disposed in the furnace cold air return. Combustion air for the fire is provided from an area external of the confined area to be heated by the heating system.

Abstract: An improved heating system for a building structure is described. The improved system utilizes heat generated by a fireplace as a supplemental source for a standard furnace heating system. The fireplace heat is used to heat water or another heat exchange medium in a heat exchange coil situated within a fireplace. When the water reaches a predetermined temperature, a first pump is activated and causes the water to be pumped throughout the radiators within the building and subsequently returned to the fireplace. When the temperature of the water falls below a certain level, a thermostatic switch deactivates the pump. When the temperature in the building declines below the thermostat setting for sensing the ambient building temperature, the furnace and a second pump are activated which in turn heat the water and circulate it throughout the structure. A system of one way check valves prevents the water from flowing in the furnace leg when the fireplace leg is operating and vice versa.

Abstract: An expansion tank is connected to a heating system by feed and drain pipes whereby the flow of water into and out of expansion tank is regulated by a valve and a pump. In the expansion tank there is a bellow which is in contact with the outer air.

Abstract: Apparatus and method for providing heat to a hot water storage system in which water from the storage system is circulated through a heat exchanger in the flue of a combustion heat source and circulatory flow is provided by a circulating pump in a secondary circulatory system including a heat exchanger having greater heat transfer capacity than the heat exchanger in the flue so as to dissipate excess heat at a controllable rate.

Abstract: A package heat exchange system having a burner positioned in the central plenum of a first heat exchanger and supplied with a fuel-air mixture through a blower supplied with fuel through a pressure regulator which requires a negative pressure at the blower input to draw gaseous fuel through the pressure regulator. Thermal energy is transferred from the first heat exchanger to a second heat exchanger or from the second heat exchanger to a third heat exchanger by pumped fluids and transferred to or from the second heat exchanger and air blown through the second heat exchanger to heat or cool the air with blowing of the air, operation of the burner and heating of the first heat exchanger when the burner is not operating being used to maintain the temperature of the surface of the first heat exchanger which contacts the products of combustion of the burner above the dew point of the products of combustion.

Abstract: A temperature compensation system using forward biased pn semiconductor junctions as temperature sensing elements to compensate for the rate of heat loss or gain by controlling the temperature of a fluid heat exchange medium. A differential amplifier is driven by changes in the junction voltage drops and controls power to the heating element so as to maintain a controlled relation between the temperature being overcome and the temperature of the heat exchange medium.

Abstract: There is provided a method and apparatus for heating tap water and radiator water by means of a heat pump, and complementarily also by means of a conventional fuel fired furnace. The condensor unit of the heat pump is divided into two heat exchangers. The first heat exchangers takes care of the superheat, and some of the condensation heat of the coolant vapor of the heat pump, and heats the tap water to a temperature which is higher than the condensation temperature. The second heat exchanger condensor heats the radiator water to a temperature corresponding to the condensation temperature of the coolant vapor.

Abstract: System for recovering solar energy, comprising: collector or absorber means for radiant solar energy; a circuit with means for unidirectionally circulating the fluid heated by said collector means, heat exchanger utilization means traversed by said fluid for directly transferring the collected heat to its place of use; and means for preventing circulation when operation of the circulation control means ceases.

Abstract: A motor control apparatus having an electric motor which is driven in one direction by an alternating current power source and in a return direction by a spring return wherein a holding or braking of the motor is accomplished by the application of a source of direct current power to magnetize the motor and hold it in a predetermined intermediate position after the removal of the alternating current power source. The braking or holding action is removed by taking away the direct current power source and momentarily applying an alternating current power source to the motor to de-magnetize or degauss the motor so it is free to return to its initial condition under the power of the spring return.

Abstract: A fireplace jacket assembly and heating system associated therewith. A fireplace jacket assembly including water chambers on five sides of an open wood-burning fireplace having means for providing water communication and circulation therebetween is placed in a conventional heating or hot water system. A pump circulates the water between the component parts of the system including a water storage tank and a radiator, and means are provided responsive to the temperature of water within the storage tank for preventing heating thereof by conventional (i.e., fossil fuel or electricity) means, or by a solar heating system. An opening formed in the bottom of the fireplace jacket provides for greater efficiency.