Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: In an automotive automatic air conditioning system having at least a variable displacement compressor, a condenser, an expansion valve, and an evaporator; an improvement comprising a refrigerant temperature sensor disposed between the outlet of the expansion valve and the inlet of the evaporator for detecting a refrigerant temperature, and a controller for setting a target refrigerant temperature are disclosed. The controller controls the discharge of refrigerant from the compressor such that the refrigerant temperature reaches the target refrigerant temperature. Thus, the system provides optimum dehumidification under conditions of high humidity and relatively low ambient temperature, such as a rainy spell in autumn.

Abstract: This invention provides a refrigeration system which includes in a closed loop connection a compressor for compressing a refrigerant into a condenser for condensing the compressed refrigerant into a liquid refrigerant, a control valve for controlling the discharge of the liquid refrigerant from the condenser into a reservoir, a sensor for measuring the temperature of the liquid refrigerant near the control valve, a fan for circulating air through the condenser, a sensor for measuring the ambient temperature of the airflow through the condenser and an electronic control system to control various functions of the refrigeration system, including the flow of the liquid refrigerant through the condenser as function of the temperature difference between the ambient temperature and the temperature of the liquid refrigerant. During operation, a minimal flooding of the condenser is always maintained, i.e.

Abstract: A condensing unit has a housing with a pair of compartments separated by a common wall. Within each compartment is a coil, a fan for passing air over said coil and a compressor operatively interconnected with the coil. There is an opening in the common wall that is opened and closed by a damper. The damper is rotatably or pivotally secured to the common wall to open and close the opening therein. A damper motor is provided for actuating the damper is response to attainment of a predetermined refrigerant pressure in the refrigeration system in the first compartment. Opening of the damper allows air to be drawn from the inoperative second compartment through the first compartment, resulting in a reduced pressure differential across the coil in the first compartment and a reduction in the air flow across the coil in the first compartment. With the reduced air flow, the pressure in the refrigeration system in the first compartment will rise to a predetermined level and the damper motor will be deenergized.

Abstract: A vapor cycle cooling system (10) in accordance with the invention includes a compressor (12) for compressing refrigerant vapor; a condenser (14) receiving compressed refrigerant vapor from the compressor; a fan (18) having at least two controllable speeds for blowing a fluid (16) in contact with the condenser to remove heat from the compressed refrigerant at the condenser to cause the refrigerant to liquify, the speeds of the fan being controllable by a control signal; an expansion valve (22) receiving liquid refrigerant from the condenser which expands the liquid refrigerant; an evaporator (24) receiving the expanded refrigerant which exchanges heat with a fluid stream (26) coupled to a heat load (28); and a controller (20) for generating the control signal, responsive to a sensed evaporator temperature, a sensed ambient temperature and a sensed altitude which controls two speeds of the fan as a function of the sensed temperatures and altitude by generating the control signal.

Abstract: A total cooling capability requested from one or a plurality of indoor units is compared with a total heating capability requested from one or the plurality of indoor units to set a cooling or heating operation mode.

Abstract: An air conditioner comprising a heat-pump refrigeration circuit including a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger, connected in this order, a refrigerant heater arranged in the refrigeration circuit, the heating capacity thereof being variable, release control for reducing the heating capacity of the refrigerant heater when a detected temperature Tc exceeds a first set temperature Tsl, mode switch for setting the air conditioner in a hot air blow-off mode in which the indoor fan rotates at a low rate during a heating operation. When the mode switch sets the hot air blow-off mode, the rotation rate of the indoor fan is controlled so that the detected temperature Tc is kept lower than the first set temperature Tsl, thereby preventing release control in the hot air blow-off mode.

Abstract: A total cooling capability requested from one or a plurality of indoor units is compared with a total heating capability requested from one or the plurality of indoor units to set a cooling or heating operation mode.

Abstract: A refrigeration system employing a mechanical thermal expansion valve with a self-heated thermistor sensing saturation temperature at the high pressure inlet. A microprocessor based controller compares the sensed temperature with stored limits and provides output signals to a relay for cycling the condenser fan responsive to high side pressure means are provided for varying the current through the thermistor for operating same in the non-self heated mode to sense actual refrigeration temperature for generating a control signal to disable the compressor clutch when refrigerant temperature exceeds desired low limits.

Abstract: An air conditioning system with a variable sensible heat ratio. The system includes a servomechanism that monitors the sensible and latent heat in the air being conditioned and adjusts the operation of the system accordingly. A microprocessor calculates the respective rates of change in sensible and latent heat and adjusts the operation of the system so that the desired amount of sensible and latent heat is removed at the same time, thereby conserving energy. The system includes a variable speed supply air fan and a plurality of subcooling coils. Under a first set of conditions, the fan is slowed down and the subcooling of the refrigerant fluid is increased. Under a second set of conditions, the fan is sped up and the subcooling is decreased.

Abstract: In a refrigeration system including a compressor, a condenser exposed to a cooling medium for causing condensation of the refrigerant within the refrigeration system and an apparatus for controlling the flow of the cooling medium, a control method and apparatus for operating the flow control apparatus in response to suction pressure or suction temperature as sensed at the compressor. In an exemplary system utilizing air as the cooling medium and a fan for causing airflow, the fan is started after compressor start-up when sensed suction pressure rises above a predetermined amount. An additional feature includes an adaptive time limited compressor cut-out protection for low ambient temperature operation.

Abstract: An improved method and apparatus or control system for electronically sequencing the main components in central air-conditioning and heat pump systems normally comprising an outside fan motor, a compressor motor, and an inside blower motor, is disclosed. When comfort production or conditioned air is needed, the outside fan motor is initially turned on. After a predetermined programmable period of time, the compressor is turned on, and then, after another predetermined programmable period of time, the inside blower is turned on to deliver production air to the space or area being serviced. At the end of the comfort cycle, the outside and compressor motors are turned off while the inside blower motor continues to run for a third predetermined programmable period of time.

Abstract: A cooling-fan controlling apparatus for an air conditioner system including a variable volume compressor, including a work-performed detecting device for detecting the work performed by the variable volume compressor, a discharge-pressure detecting device for detecting the pressure discharged from said compressor, and a controller for controlling the drive speed of a cooling fan on the basis of both the values detected in said work-performed detecting device and said discharge pressure detecting device.

Abstract: A geothermal heating and air conditioning system having heat exchange coils located vertically in the ground is provided with a condenser receiver and a metering system which allows a relatively large amount of refrigerant to be used within the system for maximum efficiency without the problems of liquid refrigerant buildup which have been previously associated with geothermal systems using vertical coils.

Abstract: A system for controlling refrigerant flow in an air conditioning system employing an electrically operated valve for controlling flow of refrigerant from the condenser to the evaporator. Separate thermistors sense the temperature of the refrigerant entering and discharging from the evaporator. A comparison of the sensed temperatures is used to modify the control signal to the valve for maintaining proper refrigerant flow to the evaporator.

Abstract: A refrigerant control system employing a "self-heated" thermistor disposed in the high pressure refrigerant line to sense refrigerant temperature from the condenser as it enters the expansion valve or capillary. The voltage drop is detected across a resistor in series with the thermistor and converted to saturation pressure from known refrigerant properties. A microprocessor de-energizes the compressor and turns on the condenser fan when excessive saturation pressure is detected. An optional second thermistor senses actual refrigerant temperature for comparison with the saturation temperature to determine sub-cooling and the microprocessor disables the compressor in the event of excessive or insufficient sub-cooling.

Abstract: The dry cleaning machine according to the invention comprises: a rotating drum (1) disposed in an enclosed chamber (2); an air flow duct (3) in the form of a closed loop in association with the chamber (2); and a cooling circuit having a condenser (6) disposed in the air flow duct (3) downstream of an evaporator (10) and is characterized by a control circuit (11) comprising: an internal heat exchanger (12) interlaced at least to some extent with the condenser (6); and means (13) for controlling the flow of a fluid in the control circuit (11).

Abstract: There is disclosed by the present invention a device for increasing the efficiency of the condenser unit of an air conditioner which consists of a predetermined length of copper tubing having perforations punched into it at regular intervals of approximately two inches, and which is covered by a sleeve made up of a woven textile material which is of the length equal to that length of tubing having perforations punched into it. The perforated length of tubing, ensheathed in the sleeve of woven textile material is laid atop the fins, of a condenser unit, which have been bent to accommodate this portion of the device resting on top of the condenser unit. When ambient atmospheric temperature rises above a certain temperature a thermostat causes a valve to allow water to flow into the device, when it flows out of the perforations in the copper tubing and is diffused by the wicking material along the length of the device until the wicking material is saturated.

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

Abstract: An energy transfer apparatus transfers energy from and to a source liquid, such as well water. The apparatus includes a refrigeration system having an evaporator, a compressor, a thermal expansion valve, a main condenser and a superheated condenser. The well water is provided through conduit into heat exchange relationship with the evaporator and then transported into a first set of cooling coils for cooling air. First and second storage tanks have a heat-absorbable fluid. Suitable conduit is used to transport the heat absorbable fluid into heat transfer relationship with the superheated condenser and the main condenser, respectively. The heated absorbable fluid is stored in the first and second storage tanks for use as an energy source. The heat-absorbable fluid is then transferred through conduit to a heating unit which transfers heat to air conveyed over the heat exchanger.

Abstract: A combination refrigeration circuit and hot water preheater is disclosed. Specific temperature sensing arrangements in combination with a bypass circuit and a continually operating pump are disclosed to obtain effective control of the hot water preheating system in combination with a refrigeration circuit. Additionally disclosed is an air conditioning system having a combination desuperheater hot water preheater built into a compressor section thereof to eliminate field connections to a hot water preheater.

Abstract: A water heating system comprising an outdoor heat exchanger including a heat collection chamber, solar collector panels, collector fins, an evaporator for passing refrigerant therethrough to perform the heat exchange between the refrigerant and the heat transferred from the panels and fins to evaporate the refrigerant. The panels, fins and evaporator are incorporated integrally in the heat collection chamber. A variable rotational speed compressor is connected to the outdoor heat exchanger for compressing the vaporized refrigerant from the evaporator. A heat exchanger disposed on the bottom side in the water storage tank passes the refrigerant vapor from the compressor to perform the heat exchange between the water in the tank and the refrigerant vapor to condense the refrigerant vapor.

Abstract: An ambient air assisted cooling system comprising: vapor-compression refrigeration means; air-cooled heat exchanger means; and means responsive to the temperature of the ambient air for advancing the matter to be cooled through said refrigeration means and/or said heat exchanger means. Said means for advancing said matter preferably comprises microprocessor means.

Abstract: A heat pump type airconditioner wherein a heat exchanger serving as a vaporizer during a warming operation mode is heated by a heating means such as combustion gas from a burner, so as to heat the refrigerant before flowing through the heat exchanger before it is compressed, in which a bypass bypasses part of the refrigerant delivered from the compressor back to the suction side of the compressor during the refrigerant heating operation, and a temperature sensor is disposed in the refrigerant outlet pipe line from the heat exchanger serving as the vaporizer in the refrigerant heating operation and controlling the turning "on" and "off" of the combustion in order to keep the degree of superheat of the refrigerant lower than the deterioration temperature of the refrigerant as well as the refrigerating machine oil and a temperature controller adjacent the indoor heat exchanger and which controls the air flow rate over the indoor heat exchanger in dependence on the temperature of the air stream.

Abstract: A forced air heating and cooling system employs a water source heat pump as the primary heating source and as a back-up or supplementary source of cooling. Supplementary heating is supplied by an electrical heater such as resistance heater, while primary cooling is provided by a water coil heat exchanger. Separate thermostats control the heat pump on the one hand, and the resistance heater and water coil heat exchanger on the other hand; the two thermostats can be combined in a simple unit. The thermostats automatically control two valves which control system water flow. For cooling, a first valve opens to permit water flow in series through first the water coil and then the heat pump. For heating, only the second valve is opened to bypass the water coil and deliver water directly to the heat pump. The water is ground water derived from a well, spring or lake. The thermostats automatically switch on the heat pump, heater and/or heat exchanger to effect the necessary heating or cooling.

Abstract: A heat pump system in which the compressor speed is varied in response to load conditions by a programmed control system and the indoor coil fan speed, during heating operations, is proportioned to compressor speed as further modified by the outdoor air temperature.

Abstract: A water heater construction and the method of operation thereof including a water tank containing water to be heated; a heat pump having condenser heat exchanger externally of the water tank; circulation means for circulating water from the lower end of the water tank through the condenser heat exchanger to heat the water and then back into the upper end of the water tank; and control means for controlling the circulation of the water by the circulation means so that the water returning to the water tank from the condenser heat exchanger has been heated to at least a predetermined return water temperature by the condenser heat exchanger sufficient for immediate use.

Abstract: A refrigerant condensing system for heating water includes a thermostatically-operated valve for delivering 140.degree. F. water from a condenser to the top of a water storage tank and a by-pass valve for allowing the heated water from the condenser, which is then heated to a lower temperature, to flow directly to the bottom of the storage tank after the upper third of the tank has been filled with 140.degree. F. water, thereby increasing the efficiency and heating capacity of the refrigeration system.

Abstract: A desuperheater control system for use in a refrigeration apparatus includes a thermostatic expansion valve which responds to the temperature and pressure at the outlet of a desuperheater for bypassing refrigerant flow from the condenser back to the suction side of the compressor. A pressure chamber is connected to the outlet of the expansion valve to sense the pressure therein. A water regulating valve is responsive to the pressure in the pressure chamber for regulating the water flow through the desuperheater so that the superheated refrigerant gas from the compressor is cooled to a pre-selected temperature having a minimum superheat.

Abstract: An air conditioning control system is disclosed for controlling a refrigeration unit located in a building which has both interior zones and exterior zones, the refrigeration unit being capable of supplying both chilled water for cooling and hot water for heating. The hot water temperature is controlled by first controlling the amount of heat rejected by a cooling tower, then by controlling the position of an outdoor air damper as a source of free cooling, then by overriding both the chilled water and hot water temperature controllers and finally by controlling the amount of fuel heat supplied to the hot water. The chilled water temperature controller is overridden to lower the chilled water temperature thus increasing the rejected heat from the refrigeration unit. The hot water temperature controller is overridden to increase the rejected heat supplied by the refrigeration unit.

Abstract: Condensing head pressure in a refrigeration system having its condenser exposed to low outside ambient temperatures is controlled to provide the minimum head pressure required for a given mode of operation. A hierarchy of operating modes, each with its associated pressure is established, including normal refrigeration, evaporator defrost and heat reclaim. The control system prevents system head pressure from going below the minimum required for the operating mode in effect at a given time, with modes requiring higher pressure overriding lower pressure modes when required. In heat reclaim operation, high pressure gas from the compressor is diverted through a heat reclaim coil, and a subcooling sensor or other sensing means controls system head pressure to the minimum pressure that will maintain full condensing in the heat reclaim coil, which is the most economical mode of operation.

Abstract: Apparatus responsive to leaks occurring in a heat exchanger between a first tubular passageway which transports a heat transfer fluid at a relatively low pressure and a surrounding concentrically second tubular passageway which transports a refrigerant at a relatively higher pressure and including a sensor positioned to respond to the occurrence of a leak permitting the refrigerant to pass into the first passageway, a relay which is actuated by the sensor upon detection of a leak, and a plurality of valves which may be selectively actuated to interrupt the flow of either or both fluids through the heat exchanger.

Abstract: Constant condenser pressure is maintained in an air-cooled condenser of a refrigeration system which operates at either full capacity or reduced capacity depending on the heat load requirements. When operating at full capacity, the condenser head pressure will be held generally constant at a relatively high control point even in the presence of wide variations in condenser cooling air temperature. On the other hand, when the heat load requirements decrease and the refrigeration system switches to its reduced capacity operating mode, the control point automatically drops to a substantially lower level, whereupon the condenser pressure is maintained relatively fixed at that lower control point despite major changes in the condenser cooling air temperature. By automatically lowering the control point at reduced system capacity, maximum efficiency and economical operation are obtained.

Abstract: An air conditioner suitable for use in a hazardous environment. The air conditioner, which may be of the conventional window type, is modified in such a manner that sparks are either eliminated, suppressed or contained to the extent that there is no danger of igniting an atmosphere that may contain an excess of dangerous particles. Any switching required in the electrical circuit is done by solid state devices, or with open contacts that carry such low power that sparking cannot occur, with the main load of the air conditioner being carried by the solid state device. The air conditioner is designed to withstand hostile elements such as salt spray from the ocean without excessive corrosion. A bypass valve is included to prevent frost collection on the evaporator coils if the air conditioner is unattended for long periods of time.