Abstract: The disclosure relates to a closed refrigeration system wherein refrigerant travelling between heat exchangers in the system is diverted to the evaporator in response to operation of a controller which responds to the temperature at the evaporator. Preferably the diverted refrigerant is the liquid phase thereof, separation of the liquid from the gaseous phase taking place between heat exchangers in a preferred embodiment of the invention. When the temperature at the evaporator is at a predetermined value, the controller can shut off the refrigerant diverting portion of the system to provide standard system operation.

Abstract: An accessory device for conventional refrigeration systems that include an auxiliary compressor of lower capacity piped in parallel with the compressor of the conventional system. The auxiliary compressor cuts in after a certain temperature is reached and automatically the speed of the fan is decreased to compensate for the lower capacity of the system. Time delays are incorporated to each of the compressors to allow the high and low pressure ports to equalize.

Abstract: A unique multi-stage refrigeration system for multiple product-display cases in which each display case has a low-stage booster compressor disposed therein. Each booster compressor compresses refrigerant received from the evaporator in its display case and feeds same to a bank of high-stage compressors disposed in a remotely located equipment room. A mechanical sub-cooler is provided for controlling liquid refrigerant temperature, and an improved lubrication system is provided for balancing the distribution of lubricant throughout the system. Several modifications of the system are also shown.

Abstract: A pressure regulating valve controller for controlling the flow of refrigerant airflow through one of a plurality of air cycle systems is described. The controller includes pressure regulating means (145) for controlling flow in response to changes in ram air temperature as well as pressure regulating means (140 and 315) in response to the number of operating air cycle systems.

Abstract: A method of operating a transport refrigeration system having a six cylinder compressor and a prime mover operable at a selected one of low and high speeds, to control the temperature of a served space by cooling and hot gas heating modes. Below a set point temperature 100, system heating capacity is controlled at the low compressor speed by the step 127 of unloading compressor cylinders and the step 129 of reloading compressor cylinders. A temperature rise of the served space above a set point temperature 106 controls cooling capacity by a combination of alternative steps 135, 137, 139, 141, and 143 which may or may not change the number of loaded compressor cylinders, and may or may not change compressor speed, based upon two predetermined trigger events which relate to what the temperature of the served space does relative to time 136 and 142, a set point temperature 106, and a temperature 108 above set point which is normally associated with a change in compressor speed.

Abstract: A cooling system for maintaining the temperature within electronic equipment has a circulation system for pumping a cooling liquid, such as water, through the electronic equipment where it picks up heat generated by the electronic equipment. The cooling liquid is pumped through a plurality of heat exchangers using a refrigerant which is, in turn, pumped through a compressor-condensor combination, each heat exchanger having approximately the same cooling capacity. A central control selects the number of heat exchangers which are to operate at any given time, on a basis of the differential in the temperature of the water being pumped into and out of the electronic equipment. This maintains a desired and relatively wide range of temperatures. A heating element selectively and controllably heats the cooled water to bring the wide range of temperatures to a selected and fixed temperature.

Abstract: A substantially conventional evaporative cooler assembly is provided incorporating a water sump having an overflow and with which a float valve equipped pressurized supply of cool ground water is operatively associated for admitting water into the sump to an operating level slightly below the overflow level. A pump assembly is provided for pumping water from the sump to an evaporative pad through which air flowing through the cooler passes and a mechanical refrigeration unit including a compressor, evaporator coil and condenser coil is operatively associated with the cooler assembly.

Abstract: Overloading of a plurality of turbine drivers driving compressors in a plurality of compression cycles, such as the compression of refrigerants and the compression of normally gaseous feed in a method for cryogenically cooling such normally gaseous feed, due to changes in compressor limiting operating conditions, is prevented by measuring the suction pressures to the low pressure stages of the compressors, deriving a desired feed flow rate in response to each of such measured suction pressures, selecting the lowest desired feed flow rate (which will be derived in response to the highest measured suction pressure if all set points are equal), and adjusting the feed gas flow rate in response to the lowest flow rate. In a preferred embodiment, a manual set point representing a maximum feed gas flow rate is also applied and the selected feed rate is dictated by the highest suction pressure or the maximum feed rate, whichever is lower, and is utilized to adjust the feed rate.

Abstract: A control system for controlling a closed-loop refrigeration system having multiple parallel commonly piped compressors is disclosed. Various combinations of compressors define the compressor capacity stages of the system. The disclosed control system responds to a system parameter, such as the suction line pressure or the temperature of an area to be cooled by an evaporator of the refrigeration system, to control the selection of the minimum system compressor capacity necessary to maintain the temperature of the area to be cooled to the lowest temperature. Control of the compressor capacity is effected by the sensed system parameter by generating an operating range defined from an upper to a lower operating limit. Operations above or below this range determines whether an increase or decrease, respectively, in compressor capacity needs to be made.

Abstract: An air conditioner includes a first refrigeration cycle with a capacity-variable type compressor, and a second refrigeration cycle with a constant rotation type compressor, both refrigeration cycles having outdoor heat exchangers while utilizing a single common indoor heat exchanger. The first refrigeration cycle has a bypass passage connected, at one end, between the suction side of the compressor and the indoor heat exchanger, and, at the other end, between the indoor heat exchanger and the outdoor heat exchanger. When the second refrigeration cycle is stopped, or the capacity variable compressor operated at a low operation frequency, a part of the coolant which passes through the outdoor heat exchanger in the first refrigeration cycle flows into the suction side of the compressor through the bypass passage.

Abstract: A temperature control system for a building is disclosed utilizing a central demand limit controller. The system includes a number of control modules or thermostats that have both proportional error and integral error functions. The integral error is reset at intervals by an interstage differential to drop single stages of air conditioning. This reduces demand until the maximum allowed demand is met. The integral error function is a timed function and the stages return in a random manner to restore setpoint temperature.

Abstract: A control system for controlling the capacity of a lead compressor of a refrigeration system having a lead and lag compressor when the lag compressor is in surge. A microcomputer system receives electrical input signals indicative of the lead and lag motor currents and closes the inlet guide vanes of the lead compressor when the lag compressor percent motor amps are below the lead compressor motor amps by more than a selected percentage for a specified period of time.

Abstract: An apparatus and method for controlling a multi-compressor refrigeration system. The controller is designed to maintain a target temperature in a specified area. It achieves this goal by selecting compressor configurations which will maintain a target pressure on the common compressor suction line directing refrigerant into the compressors. As part of the process, the controller first establishes a record of the load handling capabilities of all useable configurations of the compressors. Then, periodically, it detects the current temperature and line pressure; selects a preferred configuration of compressors in accordance with a predetermined algorithmic function of the target pressure, the current line pressure, and the record of the load handling capabilities; and activates the preferred configuration if different from the currently active configuration.

Abstract: An outdoor unit of an air conditioner of an engine heat pump type comprises an engine; first and second compressors driven by the engine and having substantially same capacity and heat exchangers for the compressors, said heat exchanger for the first compressor being adapted to utilize an atmosphere as a heat source in a heating operation, said heat exchanger for the second compressor being adapted to utilize a waste heat of the engine as a heat source in the heating operation, a rotation speed of the second compressor being set smaller than that of the first compressor in the heating operation, only the second compressor is adapted to operate in a defrosting operation for the heating operation while utilizing the waste heat of the engine as the heat source, said compressors being adapted to operate in a cooling operation and a rotation speed of the engine and a number of the compressors to be operated being controlled so as to control a cooling capacity in the cooling operation.

Abstract: In one exemplar embodiment, method and apparatus for controlling capcity of a multiple-stage cooling system is disclosed which utilizes means for establishing a single predetermined cooling stage "cut-in" pressure and a single predetermined cooling stage "cut-out" pressure, means for determining that the "cut-in" or "cut-out" pressures have been reached in the system, a delay means for introducing a selected minimum time delay after determining that the refrigerant fluid pressure has either reached the established "cut-in" or "cut-out" pressures, and control means for controlling the turning on or off of the next cooling stage after the time delay has elapsed.

Abstract: A refrigeration system characterized by a first stage booster compressor feeding multiple parallel connected second stage compressors in an otherwise conventional closed loop refrigeration system utilizing an economizer between the condenser and evaporator and returning economizer vapor to the inter-stage pressure point between the first stage and second stage compressors operates in a very flexible and highly efficient manner by driving the booster, first stage compressor at variable speed and the second stage compressor(s) at constant speed, at maximum capacity, with those machines incapable of being unloaded. The control system utilizing a sensor for sensing evaporator pressure, evaporator temperature or suction pressure, varies the speed of the drive motor for the first stage booster compressor to initially slow down the booster and secondly connect or disconnect the second stage compressor from the system. The booster is always operating and the economizer is always active in the system.

Abstract: An air conditioning system which incorporates evaporator coils for extracting heat from air with a liquefiable gas refrigerant, and cooling coils containing a liquid coolant, such as an aqueous ethylene glycol solution, that has been cooled by cold outside air, includes such coils joined in heat transfer relationship to a multiplicity of common heat transfer fins. Due to the improved heat transfer because of a larger fin area transferring heat from either the refrigerant-containing coils or the coolant-containing coils when either refrigerant or coolant is passed through its coils, more coolant coils can be joined to the fins, so that more effective air conditioning is obtainable when the air conditioning system is in the economizing mode (with the compressor being turned off and the cooled liquid coolant being circulated through its cooling coils).

Abstract: An improved oil return system for use with closed circuit mechanical refrigeration systems having multiple compressors. The oil return system is responsive to the flow of refrigeration gas to the individual compressors and enables an optimum flow of crank case oil to each of the multiple compressors. The system is based on the use of oil pick-up means for each of the suction lines connected between the suction manifold and each of the compressors. This pick-up means comprises a venturi tube which provides for the flow of oil through each of the suction lines responsive to the flow of refrigerant gas therethrough. The venturi tube has an outlet end positioned in a downstream orientation with respect to the flow of refrigerant gas through a surrounding suction drop sleeve.

Abstract: A microprocessor based control for tempering supply air in a multi-stage temperature conditioning system. The temperature conditioning stages are normally controlled in response to a comfort temperature sensor to maintain the zone at a setpoint. However, if a sensor in the supply airstream indicates that the temperature of the supply air is less than a predetermined minimum, the primary control algorithm is overridden and the temperature conditioning stages are controlled to increase the supply air temperature. Tempering the supply air prevents personal discomfort due to excessively cold air being supplied to the zone.

Abstract: Apparatus for capacity selecting compressor energization and deenergization in a commonly piped, multiple compressor system comprising largely compressor of unequal capacity wherein the minimum number of such compressors are cycled on/off together and wherein equal capacity compressors in the system are alternately selected to even the wear therebetween.

Abstract: There is disclosed a refrigeration system for a soft drink plant which refrigeration system provides cooling for cooler/carbonators used in the manufacturing of soft drink and which utilizes any access compressor capacity to precool water being used in the manufacture of soft drinks while assuring priority and adequate cooling capacity for the cooler/carbonators.

Abstract: A method and control system for operating a refrigeration unit to permit random loading and unloading sequences of multiple compressors and unloaders. The random loading and unloading sequences of the two circuits of compressors and unloaders is performed by a microprocessor. A random sequence is selected at start-up and the selected sequence loads the compressors to full load, where upon another random sequence is selected to unload the compressors.The compressors are also loaded in response to the water temperature leaving the chiller. The leaving water temperature is compensated for by a return water temperature which determines the temperature drop through the heat exchanger. The temperature drop is divided by the number of active stages to determine the drop/stage, which is an indication of how the leaving water temperature will change when a capacity stage is either added or subtracted.

Abstract: The pumping capacity of an unloadable air conditioning compressor is switched between full and part capacity states. The part capacity state is established during on/off cycling of the compressor, and air conditioning load conditions are sensed during operation of the compressor to control capacity switching in a manner to provide efficient and responsive performance. Refrigerant pressure at the evaporator outlet is used to control on/off cycling as well as capacity cycling, and the rate of decrease of such pressure is used as an indication of the air conditioning load.

Abstract: A control for a multi-stage heating and cooling system used to temperature conditioning a comfort zone. The control includes a microprocessor responsive to a temperature sensor installed in the comfort zone. Heating and cooling setpoints and a lookup table including a plurality of ranges for deviation of the comfort zone from the setpoint temperature and associated limits for the rate of change of the comfort zone temperature used in determining specific staging control actions are stored in solid state memory accessed by the microprocessor.The stages of temperature conditioning are controlled as a function of both the deviation of the zone temperature from the heating or cooling setpoint (depending on the system operating mode), and the rate of change of zone temperature. The mode of operation, i.e., heating or cooling, is determined by the relative values of the zone temperature and the heating and cooling setpoint.

Abstract: A method and apparatus for effecting capacity control of a compressor are described. The electric current to the compressor motor driving a variable step compressor is monitored. The subsequent operating current of the compressor is monitored and compared to the initial reference current value. Upon a predetermined variance between the reference current value and the current operating value being detected the capacity step of the compressor is increased to meet the additional load. Additionally there is provided other means for increasing the capacity step of the compressor including determining that an additional load on the refrigeration circuit has been energized and that the unit has been operating at a particular capacity step for a predetermined delay period. Means are disclosed for altering the capacity step of the compressor in response to any of the above occurrences indicating a need to increase the capacity step of the compressor.

Abstract: A control for a variable capacity reciprocating compressor water chiller system. A microprocessor connected to monitor return and supply fluid temperature sensors in the system is programmed to vary the compressor capacity in response to the deviation of the return and supply chilled water temperatures from desired values. The control determines these desired values as a function of predetermined full load return, supply, and reference temperature setpoints, and as a function of the relative loading of the chiller system. The control also functions to selectively offset the chilled water temperatures in one of three control modes. If zone temperature sensors are connected to the control, the offset is a function of the deviation of the weighted average zone temperature from a setpoint. The second control mode allows offset as a function of the outdoor ambient air temperature, and the third, as a function of a temporary setpoint.

Abstract: A method and apparatus for effecting capacity control of a compressor are described. A compressor having multiple capacity steps is utilized. A control valve being connected to both the compressor discharge pressure and the compressor suction pressure as well as heating and cooling pressure sensors is utilized. The control valve acts to connect appropriate pressure to the pressure sensors such that a variation in pressure level beyond a predetermined range effects a pressure sensor change indicating a need to change the capacity level of the compressor. Upon the capacity level of the compressor being changed the control valve is cycled to apply an opposite pressure level to the pressure sensor to reset the pressure sensor such that the pressure sensor may again detect a change in the pressure level to indicate a further need for a capacity change in the compressor.

Abstract: My invention relates to improvements in cascade cooling apparatus and to a method for maintaining a substantially safe low temperature level within an enclosure. In general, the invention is concerned with an apparatus that is designed for fail safe low temperature cascade cooling operation and specifically with preservation of biological specimen in low temperature storage. The invention incorporates a control system to continuously operate said cascade apparatus despite failure of a component therein, while maintaining a safe level of low temperature within the enclosure whose temperature is produced by said apparatus.

Abstract: A multiple chiller control system includes a temperature controller TC, a data base and optimizer DBO, and a plurality of driven-servo loops DSL1, DSL2, . . . DSLn. The temperature controller and the data base and optimizer monitor various parameters of the chilled water system. At periodic intervals, the system determines and stores the current values of these parameters. From this data, and from data determined from operator-selected signals supplied to the temperature controller, the temperature controller determines if a change in total operating capacity is required. If this determination is affirmative, the temperature contoller supplies a request for a system capacity adjustment to the data base and optimizer, which then proceeds to select the chillers to be operated and to adjust the capacity of the chillers so selected.

Abstract: An air conditioning system comprising an outdoor unit in which a compressor is driven by the power supplied from a variable-frequency power supply and a plurality of indoor units operatively connected to the outdoor unit. Each indoor unit has a circuit for generating a frequency signal to be applied to the variable frequency power supply of the outdoor unit in response to a set room temperature and a temperature detected. In response to the frequency signals transmitted from the indoor units, the control unit of the outdoor unit detects a maximum frequency, a minimum frequency and the number of operating indoor units and determines the operating frequency of the variable frequency power supply in response to the maximum and minimum frequencies and the number of operating indoor units.

Abstract: A cooling system including a compression refrigeration unit and an absorption refrigeration unit, with the compression refrigeration unit including a compressor having a capacity control mechanism; a condenser for cooling and condensing a compressed refrigerant gas through a heat exchange between the refrigerant gas and a cooling medium circulated through the condenser; and an evaporator into which the condensed refrigerant is introduced through an expansion means so as to be evaporated and cool a medium by the latent heat derived from evaporation.

Abstract: The disclosed temperature control system for an air conditioner includes a sensor for sensing an actual air temperature and a comparator for determining the temperature difference between the sensed actual air temperature and a set air temperature after their conversion to digital voltages. The temperature difference is stored in a memory and is also applied to a calculator where a rate of change in temperature per unit time is calculated from the temperature difference thus formed and from that temperature which had occurred just before a predetermined time stored in the memory. A control unit responds to both the temperature difference and the rate of change in temperature per unit time to increase or decrease the number of compressors put into operation with respect to the number of the compressors operated at the just preceeding interval of time.

Abstract: A system for meeting building air conditioning load conditions by optimally selecting a combination of chillers having dissimilar efficiency characteristics, the system having a load sensor for sensing building load a refrigerant head sensor for sensing refrigerant head of the chillers, and a controller connected to the load sensor and to the refrigerant head sensor for sorting the chillers according to their efficiency characteristics data with the chiller having a minimum kw/ton versus capacity point being ranked first and for selecting a combination of the chillers which will require a minimum energy input to meet building load conditions.

Abstract: In an air-conditioning system for a motor vehicle compartment, having first and second air-conditioning units which are arranged to cover mainly first and second zones in the compartment respectively, a seat switch is provided to detect the presence of an occupant in the second zone, and the direction of airflow from the first air-conditioning unit is periodically changed so that the airflow periodically extends to the second zone when the second air-conditioning unit is in off-state in the presence of an occupant in the second zone. The flow rate of the air from the first air-conditioning unit may be increased so that airflow therefrom effectively flows into the second zone. The flow rate of the air from the first and second air-conditioning units may be controlled in accordance with the difference between actual temperature and a setting temperature.

Abstract: A thermal energy compression system wherein the refrigerant in a heat pump or air-conditioner is compressed by thermal energy in the compression system rather than by work in a standard compressor. The compression uses an intermittent compression process with a solid absorbent. The vapor is absorbed by an absorbent at relatively low temperature and ejected as the absorbent temperature is raised and a set of one way valves limits flow to one direction so as to improve heat transfer requirements, to allow for molecular sieve-refrigerant matching, minimizing non-producing mass, solving thermal fatigue and shock problems, and use of the system in parallel with a standard compressor, automobile air-conditioning applications and truck refrigeration applications.

Abstract: A system and method for managing energy in large multistage refrigeration systems and the like having a hot gas defrosting system by continuously monitoring operating parameters and controlling to optimize the refrigeration system compressor pressures and defrosting cycles. A multiplicity of remote sensors is disposed at the appropriate points in the refrigeration system to produce analog electrical signals representative of the evaporator air temperature, evaporator refrigerant temperature, and similar temperatures, and pressures such as the head pressure, booster suction pressure, intermediate suction pressure, and the like. A signal processor is provided to receive signals from the sensors, to condition the analog signals, convert to digital signals and to feed a digital computer which has a memory for storing system design pressure and temperature parameters and refrigerant characteristics.

Abstract: A refrigerating apparatus including a first compressor, a condenser, a first pressure reducer a first evaporator, a second pressure reducer and a second evaporator connected together by lines to form a refrigerating circuit for a refrigerant to flow therethrough, wherein a second compressor is connected at its suction side to the second pressure reducer for receiving gaseous component of refrigerant from the first evaporator and connected at its discharge side to the line between the first compressor and the condenser. An evaporative pressure control valve may be mounted in the line between the first evaporator and the second pressure reducer or the line between the second pressure reducer and the second evaporator. A bypass line mounting an electromagnetic valve may connect the line between the first evaporator and the second pressure reducer to the line between the second pressure reducer and the second evaporator.

Abstract: A control system for heating installations which is responsive to a pre-selected target air temperature and a pre-selected radiant heat output.

Abstract: This invention relates to a refrigeration system having at least two compressors connected in parallel to the refrigeration system suction and discharge lines. Each compressor is adapted to operate singly or in combination in accordance with load requirements. More particularly, this invention relates to a valving arrangement associated with each compressor for preventing refrigerant from condensing in the discharge opening of the idle compressor of such a multiple compressor refrigeration system, and a refrigerant bleed arrangement associated with each compressor which directs refrigerant when present in the discharge of an idled compressor to the system suction line.

Abstract: A multiple-compressor refrigeration system for use in commercial refrigeration applications includes a plurality of compressors of unequal refrigeration capacity connected in a refrigeration circuit that includes a condenser and a plurality of associated evaporators and expansion devices in remotely located refrigerated enclosures. A system controller is connected to a pressure responsive transducer that measures the suction pressure of the system and compares the so-measured suction pressure to a desired suction pressure and selects one of a plurality of 2.sup.n available compressor operating states in accordance with the measured difference. The system advantageously increases overall system efficiency by providing increments or decrements of compressor capacity that are more precisely matched to system load changes as compared to prior multiple-compressor systems.

Abstract: A method of controlling heating and cooling sources utilizes a computer or an electronic thermostat to control a plurality of heating or cooling resources for regulating indoor temperature within a narrow temperature range. The method maintains a temperature within the control range by activating a required number of heating or cooling sources and proportionally controlling one of the sources within the control range. An additional heat source is activated each time the indoor temperature falls below a preset "add heat" temperature, and a heat source is deactivated each time the indoor temperature passes a preset "delete Heat" temperature. Similarly, when the method is operating in the cooling mode, an additional cooling source is activated when the indoor temperature passes an "add cooling" temperature, and an additional cooling source is deactivated each time the indoor temperature passes a "delete cooling" temperature.

Abstract: Fail-safe refrigeration comprised of dual mechanical refrigeration systems and an interdependent control responsive to a failure of a primary system being operated, for automatically placing the other a secondary system into immediate operation, whereby servicing and periodic inspection is conducted with refrigeration continuity, the primary system being manually returned into operation.

Abstract: A lockout control system locks out the lag load upon occurrence of a predetermined condition in a dual load system set up in a lead-lag configuration. The lockout control system utilizes a lead-lag memory circuit for insuring that only the lag load is locked out when the lockout condition exists irrespective of which load is lead and which load is lag.

Abstract: A temperature control system utilizing a plurality of heating or cooling devices to maintain the temperature at a desired level, minimizing rapid multi-stage cycling by using dual deadband zones.

Abstract: Apparatus and method for controlling a temperature conditioning system in which a plurality of stages of temperature conditioning apparatus may be selectively energized to meet a temperature conditioning demand in a comfort zone into which the flow of temperature conditioned air is varied in response to temperature therein. Control means are operative to determine the differential temperature of the return air and the supply air and to energize and de-energize stages of temperature conditioning in response thereto. Means are provided to measure the outdoor ambient temperature, thereby enabling the control means to determine the heating capacity of an ambient air source heat pump relative to the outdoor ambient air temperature, and to energize and de-energize heating stages as appropriate, to meet heating demand.

Abstract: An air conditioning system furnishing temperature conditioned air to a plurality of zones each of which has its own zone damper controlled by its own space thermostat. The system has an air discharge temperature sensor downstream of the temperature conditioning heat exchanger which is connected to a microprocessor controller for controlling a plurality of stages of temperature conditioning apparatus such as heating or cooling apparatus and a damper motor control for controlling the entry of outdoor air into the system.

Abstract: A two-stage refrigeration system including a primary cooling circuit which may be of the mechanical, vapor-compression type and a secondary closed system which is limited to an evaporator, located in the product storage area, a condenser and the necessary interconnecting conduits. The two circuits are operatively linked by a heat exchanger located outside the product storage area. The heat exchanger serves as the evaporator of the primary, caustic refrigerant system, and as the condenser of the secondary, relatively safe, volatile refrigerant system. Means are provided to prevent the refrigerant of the primary circuit from entering the secondary circuit in the event of heat exchange leakage. The heat exchanger design as well as the primary circuit control permits a rapid response to changes in temperature in the product storage area without requirement of controls on the secondary side of the system.

Abstract: A two-stage refrigerator for medicine or similar material storage in the known operation of which the high stage chills the refrigerant of the low stage so that extremely low temperatures can be obtained in the freezer compartment. In a departure from present practice, both stages, not just the low stage, have an on-off operating mode in response to the freezer compartment temperature, with the result that there is a significant reduction in the consumption of electrical power by the unit.

Abstract: A cooling system utilizing cold outdoor air and water for cooling high heat generating equipment such as a computer. The system includes a cold water coil and a cold water switching valve in addition to an ordinary air conditioning apparatus. When the outdoor temperature is sufficiently low, the water is routed through the cold water coil instead of a condensor, and the room air is cooled directly by the cold water.

Abstract: Apparatus for satisfying heating and cooling demands including a cooling circuit having a high pressure side and a low pressure side, and a heating circuit including a booster compressor for drawing and compressing refrigerant from the high pressure side of the cooling circuit. Also disclosed is a sensor for sensing the temperature of vapor discharged from the booster compressor, and a control responsive to the sensor for terminating the heating action of the heating circuit when the temperature of vapor discharged from the booster compressor exceeds a preset value.