Abstract: A control system controls the temperature of a chemical process vessel by recirculating a heat transfer medium through a jacket surrounding the vessel. In order to control the temperature of the recirculating medium, the control system uses an internal cooling heat exchanger connected in series with an internal heating heat exchanger and can also connect the recirculating loop to a central refrigeration system. Operation of the heat exchangers and connections to the central refrigeration system are automatically controlled by a computer which selects the cooling method in order to minimize energy use while maintaining the selected temperature. The computer also monitors the inlet and internal temperatures of the vessel and the outlet temperature of the cooling heat exchanger to prevent thermal shock damage when the system changes between heating and cooling during operation.

Abstract: A device for changing the temperature in a room includes: a refrigerant circuit including a refrigerant compressor, a condenser and an evaporator for receiving condensed refrigerant from the condenser; a cooling circuit including a cold accumulator for containing a cooling liquid, a heat exchanger for receiving cooling liquid from the cold accumulator and a pump for circulating cooling liquid through the cooling circuit; the evaporator being received in the cold accumulator to generate and accumulate cold in the cooling liquid by absorbing heat from the cooling liquid; a fan arranged to circulate air in the room through the heat exchanger for cooling the air; a control system arranged to start operation of the fan and the cooling circuit in response to a person entering the room and to stop operation of the fan and the cooling circuit in response to a person leaving the room; and a timer arranged to stop operation of the operating refrigerating circuit when a predetermined amount of cold has been generated an

Abstract: A control and method for varying the capacity of a centrifugal chiller system used to cool a liquid to a setpoint temperature. The control permits the user to select the setpoint, the control gain, and two variables that determine a first deadband and a second relatively wider deadband about the setpoint. If the absolute value of the difference (error) between the actual fluid temperature and the septoint is increasing, the control uses the first deadband, and conversely, if the error is decreasing, it uses the second deadband to vary chiller capacity. The control also permits the user to select a limit for various operating parameters associated with protective shutdown of the system to avoid catastrophic failure, and adjusts the chiller capacity according to one of two predefined functions of the deviation of the operating parameter from its limit, dependent on whether that deviation is greater or less than a predefined deadband.

Abstract: The invention relates to a refrigeration unit of the type having a vessel for cooling water and a heat exchanger for the liquid to be cooled mounted in the vessel. Evaporator tubing is mounted on the inner wall of the vessel and a sensor mounted a predetermined distance from the tubing monitors the formation of an ice layer on the tubing. Control regulation which prevents both freezing and undesired heating of the cooling water is based on controlling the compressor providing first and second temperature ranges associated respectively with first and second sequentially generated time periods.

Abstract: The present invention comprises methods and apparatus for controlling the speed of a motor for a piece of ice slab refrigeration equipment, in response to variations in thermal load on the ice slab. The control apparatus comprises thermal load sensing means and motor drive means. The thermal load sensing means detects variations in the thermal load on the ice slab and generates an output signal correlatable with such variations. The motor drive means is operatively coupled to the thermal load sensing means and is connectable to the motor and drives the motor at various speeds correlatable with the variations in ice slab thermal load. The control apparatus of the present invention is particularly adapted to control the speed of an alternating current induction motor of a centrifugal brine pump motor.

Abstract: A control and method for varying the capacity of a centrifugal chiller system used to cool a liquid to a setpoint temperature. The control permits the user to select the setpoint, the control gain, and two variables that determine a first deadband and a second relatively wider deadband about the setpoint. If the absolute value of the difference (error) between the actual fluid temperature and the setpoint is increasing, the control uses the first deadband, and conversely, if the error is decreasing, it uses the second deadband to vary chiller capacity. The control also permits the user to select a limit for various operating parameters associated with protective shutdown of the system to avoid catastrophic failure, and adjusts the chiller capacity according to one of two predefined functions of the deviation of the operating parameter from its limit, dependent on whether that deviation is greater or less than a predefined deadband.

Abstract: When sensors are employed to monitor the evaporator refrigerant pressure and the leaving chilled liquid temperature in an air conditioning system of the type having a liquid chiller, the sensor outputs will normally have a prescribed relationship with respect to each other as long as the sensors are functioning properly and regardless of the operating condition of the air conditioning system. By effectively comparing the output of one sensor relative to that of the other sensor, a faulty condition of either sensor may be detected. This is achieved by calculating the equivalent evaporator temperature, from the evaporator refrigerant pressure, and subtracting the equivalent temperature from the leaving chilled liquid temperature to obtain a difference temperature which is then compared to a predetermined known temperature range representing normal functioning of the two sensors. When one of the sensors is defective the difference temperature will fall outside of the range.

Abstract: A refrigeration apparatus includes a compressor, a condenser and a eutectic plate adapted to be mounted in the refrigerated space in place of, or in heat-conducting relation with, cooling coils. The compressor is of a type operated by a battery which is recharged by a generator. In turn, the generator is powered by any convenient external power source, such as an internal combustion engine. The refrigeration apparatus also includes a control device which senses the voltage at the battery terminals, thereby determining whether or not the engine is running. The control device chooses between two different cooling levels. A low (warmer) cooling level is chosen if the engine is not running. A high (cooler) cooling level is chosen when the motor is running.

Abstract: A circuit for the control of a refrigeration circuit for at least two refrigeration areas such as the carbonated water supply and beverage concentrate chamber of a beverage dispenser. Priority cooling of one area is achieved by use of a combinational logic circuit in conjunction with refrigeration-requirement sensors so that the CO.sub.2 water supply will be cooled first regardless of a requirement for the cooling of the concentrate chamber.

Abstract: A self-optimizing, capacity control system for a refrigeration system including a compressor, a condenser, and an evaporator, all connected in a closed refrigeration circuit is provided. The compressor includes a plurality of adjustable inlet guide vanes, a motor connected to regulate the inlet guide vanes position and an electrical speed motor connected to drive the compressor. The self-optimizing capacity control system includes a microprocessor responsive to continual measurements of a PRV signal, a compressor head signal, a motor current signal and a motor speed signal for determining both the compressor speed and the position of the inlet guide vanes to define a current operating point in an initial surge surface array stored in a random-access memory. The microprocessor will initiate a "learning" mode in which the compressor motor speed will continually be decreased incrementally and the PRV will be moved to a more open position until an operating point is found where the compressor is surging.

Abstract: A refrigeration cycle or heat pump employing an electrochemical compressor. The cycle uses a working fluid at least one component of which is electrochemically active. Another component of the working fluid is condensable. In one embodiment, the electrochemically active component is hydrogen and the condensable component is water. The electrochemical compressor raises the pressure of the working fluid and delivers it to a condenser where the condensable component is precipitated by heat exchange with a sink fluid. The working fluid is then reduced in pressure in a thermal expansion valve. Subsequently, the low pressure working fluid is delivered to an evaporator where the condensed phase of the working fluid is boiled by heat exchange with a source fluid. The evaporator effluent working fluid may be partially in the gas phase and partially in the liquid phase when it is returned from the evaporator to the electrochemical compressor.

Abstract: Control method for a liquid-cooled cable installation with a hollow conductor, through which a coolant flows, as the cable conductor. The hollow space is divided in the longitudinal direction by partitions forming separate canals for the outgoing flow and the return of the coolant and in which canals the coolant is in contact with the conductor at high-voltage potential. Heat exchangers are provided at the start and the end of the cable system or at intermediate stations. The cable flow temperature (.theta..sub.Z *) of the coolant is lowered with increasing load of the cable by influencing the heat exchanger and is conversely raised with falling load in such a manner that the mean value of the coolant (.theta..sub.m) remains constant.

Abstract: A microcomputer system and method for controlling the capacity of a refrigeration system are disclosed. The microcomputer system receives electrical input signals indicative of operator selected settings and refrigeration system operating parameters. The microcomputer system processes these input signals to generate a control signal which is a step function of the temperature difference between a desired set point temperature and the sensed temperature of a heat transfer fluid cooled by operation of the refrigeration system. The width of each step of the step function is directly proportional to a selected capacity control response factor. By selecting different capacity control response factors, capacity control of the refrigeration system is tailored to meet specific job requirements of a particular job application for the refrigeration system.

Abstract: To conserve energy in a large capacity refrigeration or air conditioning system, where liquid (usually water) is chilled by the system's evaporator and is then used to cool a building, the temperature setpoint of the chilled liquid leaving the evaporator may be reset upward from its desired level. Normally, if the temperature of the leaving chilled liquid falls below the setpoint by a fixed differential (such as 4.degree. F.) to a cut-out temperature, the system's compressor is shut down as a safety precaution to prevent freeze-ups. A nuisance compressor shutdown may be avoided when the setpoint is reset to a higher level (since the actual temperature of the leaving chilled liquid at that time may be at or below the desired setpoint and may be more than 4.degree. below the reset setpoint) by lowering the cut-out temperature to a fixed level substantially below the desired setpoint, such as down to 36.degree. F.

Abstract: An integrated control system for both the output and surge protection of a centrifugal compressor in a chilled, water system is provided by biasing the output of a feed forward and cascade centrifugal compressor output control logic module with the output of a coordinating control logic module, which utilized a surge control logic module output to establish the biasing signal.

Abstract: The invention relates to an apparatus for conveying liquids of which the vapor pressure is above atmospheric at ambient temperatures from a storage container to a delivery point, particularly for dispensing refrigerant.

Abstract: A method and control system are disclosed for operating a refrigeration system to protect an evaporator in a refrigeration system against freezeups of a heat transfer fluid cooled in the evaporator by operation of the refrigeration system. A first signal indicative of the temperature of the heat transfer fluid in the evaporator and a second signal indicative of the temperature of the heat transfer fluid leaving the evaporator are provided to a microcomputer system which processes the first and second signals to determine when the temperature of the heat transfer fluid in the evaporator falls below the temperature of the heat transfer fluid leaving the evaporator by a selected amount. The microcomputer system generates an alarm signal to shut down operation of the refrigeration system if the microcomputer system determines that the temperature of the heat transfer fluid in the evaporator is less than the temperature of the heat transfer fluid leaving the evaporator by the selected amount.

Abstract: A capacity control system for a refrigeration system including a compressor, a condensor, and an evaporator, all connected in a closed refrigeration circuit is provided. The compressor includes a plurality of adjustable inlet guide vanes, a motor connected to regulate the inlet guide vanes position, and an electrical speed motor connected to drive the compressor. The capacity control system includes a microprocessor responsive to continual measurements of a PRV signal, a compressor head signal and a suction flow signal for calculating a current operating point. The microprocessor determines whether the operating point is sufficiently away from a surge surface. The microprocessor will cause the operating point to move to a new operating point of a lower compressor speed and a more open PRV position if the operating point is sufficiently away from surge.

Abstract: A refrigerator for a vehicle has a coldness accumulator formed by a container with water therein and an evaporator selectively connectable to a refrigeration cycle of an air conditioner of the vehicle. The coldness accumulator is disposed in a refrigeration space defined in a heat-insulating housing having an openable door mounted thereon. The water is cooled to freezing temperature during vehicle operation to accumulate coldness which is utilized to keep the refrigeration space at a low temperature when the evaporator is disconnected from the refrigeration cycle or when the refrigeration cycle is not operated.

Abstract: A protective capacity control system and method for controlling the capacity of a refrigeration system are disclosed. The protective capacity control system receives electrical input signals indicative of operator selected settings and refrigeration system operating parameters. These input signals are processed to generate a control signal which is a step function, preferably having two steps, of the temperature difference between a desired set point temperature and the sensed temperature of a heat transfer fluid cooled by operation of the refrigeration system. The capacity of the refrigeration system is reduced at a first effective overall rate to provide capacity control which will reduce hunting by the capacity control system when the sensed temperature of the heat transfer fluid cooled by operation of the refrigeration system is less than a lower limit of a selected temperature deadband relative to the desired set point temperature.

Abstract: A refrigerating system comprises screw compressor means which is adapted to control the capacity thereof by means of a slide valve provided in the compressor means and operatively associated with hydraulic actuator means. The hydraulic actuator means has hydraulic fluid supplying means and hydraulic fluid discharging means, both of which are connected thereto and provided with stop valve means, respectively, for controlling the supply and the discharge of a hydraulic fluid to and from the hydraulic actuator means to permit the latter to hydraulically actuate the slide valve. The refrigerating system further comprises means for selectively switching the operation mode of the system, means for detecting the outlet water temperature of an indoor heat exchanger of the system, and temperature control means for setting a water temperature for service.

Abstract: A method and control system are disclosed for minimizing the number of recycle starts of a compressor in a refrigeration system to thereby reduce wear and tear on the mechanical and electrical systems of the refrigeration system thereby prolonging the operating life and improving the reliability of the refrigeration system. The rate at which the refrigeration system compressor's capacity is increased upon the recycle start is greatly reduced compared to a normal, relatively fast rate of increase which is provided when the capacity of the compressor is controlled directly in response to the load placed on the refrigeration system. This prevents the refrigeration system from quickly satisfying a new, increased load placed on the refrigeration system upon a recycle start which will then require a relatively quick shutdown of the refrigeration system compressor due to excess cooling capacity and require a relatively quick subsequent recycle start of the compressor.

Abstract: A method and control system are disclosed for minimizing the number of recycle starts of a compressor in a refrigeration system to thereby reduce wear and tear on the mechanical and electrical systems of the refrigeration system thereby prolonging the operating life and improving the reliability of the refrigeration system. By limiting the load placed on the refrigeration system upon a recycle start the rate at which the refrigeration system satisfies the load is significantly reduced compared to a normal, relatively fast rate of satisfying the actual load which usually occurs when the capacity of the compressor is controlled directly in response to the actual load placed on the refrigeration system.

Abstract: A method and control system are disclosed for checking and verifying sensor operation in a refrigeration system. A microcomputer control system determines whether a signal provided by the sensor is within normal limits prior to startup of the refrigeration system. Also, the microcomputer system verifies an out of bounds sensor signal provided to the microcomputer system from the sensor during operation of the refrigeration system by intermittently monitoring the sensor to determine whether a preselected consecutive number of out of bounds signals are provided to the microcomputer control system from the sensor.

Abstract: A liquid temperature regulator is disclosed which includes a refrigeration cycle comprising a compressor, a condenser and an evaporator, a liquid tank containing a kind of liquid to be temperature-controlled and the evaporator, and inlet and outlet tubes for feeding the liquid into the tank and feeding out the liquid from the tank. The regulator is provided with a by-pass path for the connection of the outlet and inlet ports of the compressor, a valve for opening and closing the valve and a temperature controller for controlling the valve according to the temperature of the liquid. The by-pass path is closed when the liquid temperature is higher than a preset value and it is closed when the liquid temperature is lower than the value.

Abstract: An S.I.R SYSTEM is a self-contained, indirect, refrigeration system which effectively and efficiently removes varying heat loads (i.e. heat of respiration of climacteric fruits) at changeable operating conditions. System design allows for quick and easy installation.

Abstract: A method and control system for protecting an electric motor driven compressor in a refrigeration system are disclosed. The refrigeration system operates to satisfy a load placed on the system and the refrigeration system compressor is turned off when the load is satisfied and the refrigeration system is providing excess capacity. When the compressor is turned off due to excess capacity, current flow to the electric motor driving the compressor is sensed and the refrigeration system is shut down if the sensed current flow is abnormal. In this manner, the compressor and the electric motor driving the compressor are protected against restarting under unfavorable operating conditions which could unduly wear the compressor motor and/or the compressor.

Abstract: A computer cooling system has a mixing valve which supplies coolant to the computer and receives hot return coolant from the computer and also chilled return coolant from a chiller intermediate the computer and the mixing valve. The mixing valve mixes the hot return coolant with the chilled return coolant to adjust the cooling system temperature. Control circuitry senses, or estimates, the dew point temperature of the computer room environment, compares it with the cooling system temperature, and adjusts the mixing valve to maintain the cooling system temperature a few degrees above the dew point temperature. A condensation sensor comprises of a light emitting diode (LED), reflective tape applied about a cooling system supply conduit, and a phototransistor is disclosed. Light from the LED is fully reflected by the reflective tape to the phototransistor in dry conditions, but only partially reflected when condensation forms on the tape.

Abstract: A cold water supply system includes an agitator tank in a cold water supply tank for receiving the cold water from a refrigerating units and a bypass pipe line for directing a calculated amount of return water from the load into the agitator tank. A temperature sensor for sensing the return water temperature is provided and another temperature sensor for sensing the refrigeration unit outlet temperature is provided for controlling regulating means in accordance with the sensed temperatures for automatically regulating the cold water temperature supplied into the agitator tank to a predetermined temperature.

Abstract: A refrigeration system includes a latent heat storage tank having an evaporator coil or tube submerged in water and on which a layer of ice forms in response to circulation therethrough of refrigerant from a motor-driven compressor. Apparatus is provided to measure, indicate and regulate the thickness of the ice layer. The apparatus comprises an ice sensing device which provides an electric signal proportional to ice layer thickness to an electrical control circuit which then operates a meter to indicate thickness and operates a motor controller to stop or start the compressor motor. The ice sensing device comprises a probe which is periodically movable back and forth in a short arc in one cycle to detect ice by a timer-actuated electric motor and a potentiometer which moves in response to probe movement to provide a signal proportional to ice thickness to the above-mentioned electrical control circuit.

Abstract: A dehumidifier for converting warm moist air to dry cool air. The dehumidifier includes a fan for delivering warm moist air to a plenum chamber, a dehumidifier chamber mounted adjacent to and communicating with the plenum chamber and provided with a condensing surface, a device for supplying a refrigerant to the dehumidifier chamber, and a structure for supplying short bursts of heat to the condensing surface. The condensing surface can be tapered or straight lengthwise and can be of any cross-sectional shape. Further, the condensing surface can comprise a plurality of air passages, again tapered or straight and of any cross-sectional shape.

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: A refrigeration system for cooling a beverage as the beverage is drawn from a container filled with water which has an evaporator coil carried adjacent the wall thereof which extends from adjacent the top of the container to the bottom of the container. When a refrigerant is circulated through the evaporator coil, an ice bank is built up on the inner wall of the container. A beverage dispensing coil is centrally located with the container and is connected between a faucet and the container from which the beverage is to be drawn. A helical support coil extends from adjacent the top of the container to the bottom and encircles the beverage dispensing coil. A temperature sensor is threaded inside the helical copper support coil so that any time the ice bank builds up closely adjacent thereto, it will turn off the compressor. A motor driven power paddle is used for circulating the water within the container.

Abstract: An air conditioner includes a plurality of refrigerant compressors, a plurality of ventilating fans and a cooling/warming water pump which is controlled by both a memory and a contact-less control unit in accordance with an outdoor temperature and a refrigerant temperature which are sensed by associated temperature sensors. Alternatively, the control unit may be connected to both protective devices disposed on the fans, the compressors, the pump, etc. and further connected to a digital indicator which indicates the operating status of the air conditioner.

Abstract: An arrangement and method of controlling optimum chilled water temperature supplied to a process by a pump, the water being chilled by coolant in a coolant cycle having a compressor and a load valve, comprises first and second sensors for sensing a supply and a return temperature to and from the process. A value is obtained for the amount of work done by the pump and the compressor with that value as well as the supply and return temperature values being supplied to a supervisory control. The supervisory control operates to generate a reference temperature which is a function of the supply temperature but which is either above or below the supply temperature depending on a ratio between the difference in work and a change in the difference between the supply and return temperatures. When the ratio is about zero this indicates the difference between supply and return temperature is at an optimum and the reference temperature is the same as the supply temperature.

Abstract: A refrigeration system for cooling beverages as they are drawn from a plurality of containers and dispensed through a plurality of faucets. A pair of beverage dispensing coils are centrally carried in a housing which is filled with water. A refrigeration coil encircles the housing causing a build up of ice to take place on the inner wall of the housing. A temperature sensor is carried within a helical coil provided between the beverage dispensing coil and the ice bank for operating a compressor associated with the refrigeration coil. A power-driven paddle is centrally carried within the container for circulating the water therein and a gentle, wiping motion. In order to selectively turn on and off the power paddle, a second temperature sensor is located in a junction provided between the inputs of the beverage dispensing coils.

Abstract: A beverage cooling device which mounts on top of a cabinet so that a warm beverage, such as beer carried in a keg is cooled prior to flowing out of a faucet. The apparatus includes a cylindrical container having an evaporator coil positioned closely adjacent an inner wall and a beverage dispensing coil centrally positioned within the container. A space is provided between the inner wall of the container and the beverage dispensing coil so as to permit ice to build up on the wall of the container. A power-operated propellor is centrally located within the container for circulating water over the layer of ice and around the beverage dispensing coil to enhance the cooling of the beer flowing through the coil. A temperature sensor is carried in the water between the ice layer and the beverage cooling coil for controlling the operation of a compressor for maintaining the proper temperature of water in the container.

Abstract: A method of controlling the operation of a refrigerator of a type having a capacity control mechanism adapted to control the capacity of the refrigerator in such a manner as to make the temperature of the cold water supplied to an air conditioner coincide with a predetermined set temperature of cold water. The apparatus is adapted to vary the set temperature of the cold water in accordance with the level of the load imposed on the air conditioner, and to determine the difference of the new set temperature of the cold water with the actually measured temperature of the cold water. The apparatus effects the control of the capacity control mechanism of the refrigerator such that the above-mentioned difference of the temperature is nullified. In consequence, the efficiency of the refrigerator during partial-load operation is remarkably improved.

Abstract: A method and apparatus for providing a cooling liquid to the heat exchanger in a storage battery mounted on a vehicle for driving the vehicle, wherein the liquid is to be supplied to the battery at an inlet temperature which varies in a time-based relationship. The liquid to be cooled is obtained from the battery itself in a recirculative system located generally outside the vehicle. In accordance with this method and apparatus, the liquid returned from the vehicle mounted storage battery is divided into first and second portions, the first of these portions is cooled at a preselected cooling rate, thereafter, the cooled first portion and the uncooled or bypassed second portion are recombined to provide the liquid supplied to the battery heat exchanger. The ratio of the first and second portions is adjusted in accordance with a time-based relationship wherein the temperature within the battery is intentionally changed during a charging cycle.

Abstract: Liquid is cooled in a batch mode. A batch of liquid is circulated in a cooling loop (12) until it is cooled to a desired temperature at which time it is removed from the cooling loop (12) and a new batch is introduced therein. Preferably, the cooled batch is discharged from the cooling loop by the new batch with as little mixing as practicable. The cooling loop has a desired volume determined by a receiver (36) of suitable capacity. A supply accumulator (14) is used to accumulate liquid to be cooled and from which liquid to be cooled is supplied into the cooling loop. Cooled liquid is discharged from the cooling loop into a product accumulator (16). The liquid may be cooled to a temperature close to its freezing point by freezing a minor portion of the liquid in the cooling loop which is then melted by the liquid of the next batch when it is introduced into the cooling loop. The cooling loop is such as to promote plug flow and to reduce backmixing.

Abstract: A control system for a rotary helical screw compressor of the variable speed type includes a variable speed motor driving the compressor for varying the compressor capacity and a slide valve member which is adjusted optimally for varying the volume of gas trapped in the working chamber prior to discharge as a function of the pressure ratio across the compressor. There is also provided a control system for a rotary helical screw compressor of the fixed speed type which include a first slide valve member for varying the compressor capacity through modulating the volume of gas trapped in the working chamber prior to compression and a second slide valve member for adjusting optimally the volume of gas trapped in the working chamber prior to discharge as a function of the pressure ratio across the compressor.

Abstract: In a refrigerating and air-conditioning system provided with a heat storage tank, variation patterns of load and weather conditions are predicted. On the basis of the predicted values, optimum outputs of a refrigerating machine at individual time points within a predetermined operation period are determined for possible water temperatures of the heat storage tank and stored in a memory. In accordance with the actual water temperature of the heat storage tank, the optimum output of the refrigerating machine is retrieved from the memory and utilized for the operation thereof.

Abstract: An air conditioning system has a freeze tank with a first coolant tank positioned therein with means for freezing a liquid in said freeze tank around said first coolant tank at a predetermined low temperature and cooling a specially prepared coolant as a liquid in the first coolant tank to the same low temperature; a second coolant tank contains a coolant connected to an evaporator coil in a duct means wherein flow from said second coolant tank through said evaporator coil provides for cooling air through said duct means when desired; heat absorber plates being located in said second coolant tank with means connecting said first coolant tank to said heat absorber plates for flowing the specially prepared coolant therethrough when desired.

Abstract: An aircraft cabin is climatized by tapping air from the engine compressors and feeding it into the cabin through a loop which includes a compressor, a cooling turbine driving the compressor, and several cooling stages. A second loop, using preferably helium, includes a second compressor and a second turbine, the second compressor being driven by both turbines, and the cooled helium is in heat exchange with another cooling loop which runs through instrument compartments. Discharged cabin air is used to precool the compressed helium.

Abstract: An evaporator inlet water temperature control system for controlling the inlet water temperature of an evaporator utilized in an inverter driven centrifugal chiller. The system creates the proper chilled water set point at the evaporator outlet needed to maintain the inlet water at its set point for greater efficiency of operation. Control is accomplished by generating an electrical error signal which is a function of an inlet water set point voltage and the actual inlet water temperature. A logic signal is produced as a function of the error signal detected by the circuit and establishes a dead zone band representing a range in which the error signal is acceptable. Output of the control system is passed to the capacity control circuit of an inverter driven centrifugal compressor chiller.

Abstract: A control means is disclosed that is used with a closed refrigeration system having a chiller and a condenser to provide refrigeration to chill the fluid medium and a refrigerant pump for pumping the refrigerant through the system with refrigerant capacity control means determining the capacity of the refrigerant, the control means for the system using signal inputs representative of outside air temperature, return chilled water temperature, supply chilled water temperature, and condenser temperature, in which settable controllers are used to determine the optimum temperature signals for controlling the system at any given time. A timer is also connected to the control mechanism for alternately interrupting an optimum temperature signal to reduce the overall change in the control signal. Additional control may be obtained through the use of signals representative of humidity, strong solution temperature and cooling water output pressure.

Abstract: An economical energy-saving air-conditioning system for cooling air in an enclosure requiring year-around cooling. An outdoor heat exchanger is operative in a recirculating liquid closed-loop cooling system. A temperature controlled actuator provides continuous free cooling when the outside temperature is approximately 35.degree. to 40.degree. F. or less; and provides free pre-cooling of the air when the outside temperature is in the 35.degree. to 65.degree. F. range. The closed-loop comprises conventional components for summer temperature cooling; and, in less-than summer temperatures the present invention utilizes the outside heat exchanger to provide cool heat exchange liquid to a (free) cooling coil positioned to confront the air stream in advance of a refrigerant coil. Reheat for dehumidification is provided in an embodiment wherein thermal energy is taken from the waste heat of the refrigerant system.

Abstract: An automatic chiller control is disclosed for providing a temperature sensitive load limit compressor control on a cooling water system, such as is used in buildings for air conditioning. The controller operates across at least one motor driven compressor and operates to adjust the vane inlet to a typically centrifugal compressor. Control is provided in discrete steps responsive to changes in cooling water temperature as the water typically returns from a building. The control when operated in the automatic position starts the chiller at minimum possible power consumption. Increasing load or unload of the chiller is provided in incremental steps (for example 5% of full load) at preselected time intervals (for example 10 minutes) which are typically adjustable to any other desired time span. The control seeks the required motor power output without waste of power.

Abstract: Modulating system for electrically or pneumatically controlled chillers in which a sensor senses the space condition, in a controlled environment or space. Output signals from an enthalpy sensor or other sensor representing the space condition are fed to chiller modulator electronic controls and thence to the chiller modulator interface controls, be they electric or pneumatic. The sensor monitors the conditions in or returning from the controlled space or environment. By measuring both humidity and temperature, the enthalpy sensor generates an effective temperature or comfort level. The input signal from the sensor is compared to an operator adjustable set-point. If the measured condition is less than the set-point, an error signal is generated which is proportional to the difference multiplied by an operator-set sensitivity control.

Abstract: A control system and a method are disclosed for automatically controlling a hot gas bypass valve as a function for cooling load and head. A valve/controller is provided for controlling the operation of the hot gas bypass valve so as to avoid surging of the compressor in response to temperatures of the chilled liquid entering the evaporator, the chilled liquid leaving the evaporator, and the liquid refrigerant at the outlet of the condenser.