Abstract: In a refrigerating system comprising a reciprocating compressor (1), a condensor (2), an expansion means (3), an evaporator (5), a temperature-sensitive control element (6) for on/off control of the compressor, a refrigerant-pressure-dependent valve (4) is used for shutting off the flow of refrigerant between the condensor and the evaporator when the compressor is off and for allowing the flow of refrigerant between the condensor and the evaporator when the compressor is on. The valve (4) comprises a pressure-sensitive means (9) which is movable under the influence of the condensor outlet pressure which prevails at one side of the pressure-sensitive means, while the pressure at the other side of the pressure-sensitive means depends on the saturation pressure of a liquid in a circuit which includes a bulb (15) arranged at a location where it is exposed to the influence of ambient temperature.

Abstract: A cooling unit for an automotive air-conditioning system, comprising an evaporator, a compressor, an expansion valve connected to the inlet port of the evaporator, an accumulator connected to the outlet port of the evaporator, a temperature sensor for detecting the temperature of the refrigerant at the outlet port or within the evaporator, and temperature control means which controls the degree of opening of the expansion valve so that the temperature of the refrigerant at the outlet port or within the evaporator is maintained above a predetermined temperature which is slightly higher than a temperature at which the evaporator becomes frosted. The degree of opening of the expansion valve is increased to raise the vapor pressure of the refrigerant in the evaporator, instead of stopping the compressor, when the temperature of the refrigerant at the outlet port or within the evaporator drops to the predetermined temperature, so that the frequency of starting and stopping the compressor is reduced.

Abstract: A system for controlling the flow rate of a refrigerant for refrigeration cycles which comprises an electronic expansion valve disposed at the inlet of an evaporator and a controller for controlling the opening-closing movement of the valve. The controller comprises a calculating unit for comparing the degree of superheat of the refrigerant measured at the evaporator with a preset degree of superheat and feeding a valve opening adjusting signal to the valve according to the value obtained by the comparison, and a valve full-closing signal generator for comparing the measured temperature of the space to be cooled with a preset temperature and feeding a valve full-closing signal to the valve based on the value obtained from the comparison of temperatures, in preference to the opening adjusting signal.

Abstract: A refrigeration system including a solenoid actuated on-off modulated expansion valve and a controller for controlling the expansion valve is disclosed. The controller includes a low ambient start-up means responsive to the presence of liquid refrigerant at the inlet end of the expansion valve for overriding normal operations of the valve and maintaining the expansion valve open for refrigerant flow therethrough when liquid refrigerant is not present at the expansion valve. The low ambient start-up means includes temperature sensors upstream and downstream from the expansion valve to detect the temperature differential across the expansion valve. The temperature differential is compared to a threshold value and depending upon the comparison, either overrides the expansion valve to permit full flow therethrough or to allow the expansion valve to operate in response to the controller.

Abstract: A pulsed controlled solenoid flow control valve suitable for use in a closed vapor cycle air conditioning system is disclosed. A pulsewidth modulated control signal is generated for cyclically opening and closing the flow through the expansion valve. The duty cycle of the pulsed control signal determines the average flow rate through the valve. An exponential response control curve is used in conjunction with an integrator offset to obtain a single set point control operating point for all flow rates through the valve, where a given change in the second superheat of the evaporator produces the same percentage change in flow rate regardless of the flow rate.

Abstract: A refrigerating apparatus adapted for storage of cold storage goods as well as frozen goods and having both a heater and a cooler is controlled by an improved temperature control device, which includes a detector for detecting a temperature of return air from the interior of a storage area of the refrigerating apparatus and a detector for detecting a temperature of an air output which is blown into the interior of the storage area, and which controls either the higher one of the two detected temperatures or the lower one of the two detected temperatures depending upon a set temperature. In the case of storing cold storage goods, the lower one of the two detected temperatures is controlled so as to be maintained at the set temperature, whereas in the case of storing frozen goods, the higher one of the two detected temperatures is controlled so as to be maintained at the set temperature.

Abstract: A heat pump system in which the amount of opening of an expansion valve is set to an optimum value in dependence upon the inlet temperature of water undergoing heat exchange at a utilization side heat exchanger and an inlet temperature of air undergoing heat exchange at a non-utilization side heat exchanger. In response to the sensed temperature values, a controller determines the optimum amount of valve opening so as to provide a maximum system capacity and efficiency. The controller may be implemented with a microprocessor and a read-only memory. In the read-only memory are stored data values representing optimum opening settings of the expansion valve corresponding to various values of the sensed inlet temperature of water at the utilization side heat exchanger and the inlet temperature of the air at the non-utilization side heat exchanger.

Abstract: An air conditioner has a refrigeration cycle and a regulating circuit. The refrigeration cycle includes a compressor of variable exhaust amount type, a 4-way valve connected to the discharge side and suction side of the compressor, indoor-side and outdoor-side heat exchanges connected to the valve, and an expansion valve of a motor-driven tape. The regulating circuit regulates the flow rate of refrigerant into the indoor or outdoor side heat exchanger by adjusting the opening degree of the expansion valve in response to the amount of the refrigerant exhausted from the compressor, thereby setting the temperature of the refrigerant to be discharged from the compressor to a predetermined temperature responsive to the exhaust amount of the compressor.

Abstract: A refrigeration system including a refrigeration control system for controlling the operation of the refrigeration system so as to insure that the temperature of the refrigerant discharged from the evaporator coil is above the saturation temperature. The refrigeration system includes at least one refrigerated display case having an evaporator within the primary air conduit and an expansion valve coupled to the inlet end of the evaporator coil. The control system includes: a pressure sensor arranged within the refrigerant discharge line, i.e. suction line to compressor, from the evaporator coil; a first temperature sensor arranged at the air discharge side of the evaporator coil for sensing the temperature (T.sub.1) of the air that has passed over the evaporator coil, a second temperature sensor arranged adjacent to the refrigerant discharge end of the evaporator coil for measuring the temperature (T.sub.

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 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: A method and apparatus for controlling the operation of a refrigeration system, for example, is provided which includes a first sensor for monitoring the sump temperature of a compressor used in conjunction with the refrigeration system, and a second sensor which monitors compressor ambient air temperature. The refrigeration system includes an electrically operable expansion valve and the sensors are employed in a control device operatively connected to the electrically controlled expansion valve to control the operating position of that valve. Refrigeration system operation can be controlled precisely, thereby maximizing the efficiency of the system, by monitoring the sump temperature and ambient temperature of the compressor.

Abstract: A controlled space is maintained at a desired set point temperature by adjusting the refrigerant temperature at the evaporator outlet in a refrigeration system, thereby controlling the evaporator effectiveness or capacity which is inversely proportional to the outlet temperature. When the space temperature tends to vary from the desired set point due to a changing heat load, the control system automatically changes the refrigerant flow through the evaporator to establish the evaporator outlet temperature at the control point required to maintain the controlled space at the desired temperature. More specifically, in response to a space temperature increase, the flow rate of the refrigerant increases; and in response to a drop below the set point, the refrigerant flow decreases.

Abstract: A solid state starter for a chiller compressor motor mounts directly on the compressor motor and comprises a bank of SCR's which are controllably switched to conduct current to the motor for starting and running. Electronic control modules are provided including a trigger module for triggering the SCR's, a current module (including current overload protection) for controlling the trigger module so that motor current is controllably delivered to the motor, and a voltage safety module for protecting against electrical faults. The SCR's are cooled by liquid refrigerant.

Abstract: A control system for air conditioning apparatus particularly of the type utilizing a variable displacement compressor, the capacity of which is modulated in response to a cooling demand control signal. More specifically, the capacity of the compressor is controlled in response to a first signal developed in response to the temperature of air within the space to be controlled and a second signal which is indicative of potential freezing of the evaporator coil. Both of these signals are applied to a control valve actuator which directly varies the capacity of the compressor in a modulated fashion above a predetermined combination of coil and air temperatures and reduces the capacity to zero when below said predetermined combination.

Abstract: A method and apparatus for transporting perishable commodities provides recirculation of moisture saturated air at a predetermined optimum storage temperature through the cargo from bottom to top of individual van containers. Temperature sensors are provided in each container and, if possible inside the commodity itself to enable monitoring of the conditions of storage by remote recorders. A central station powers the containers and maintains records for all containers of selected storage parameters such as temperature and humidity.

Abstract: A control valve for controlling refrigerant circulation in a vehicle air conditioning system has an inlet port and an outlet port for connection to the evaporator and the compressor inlet respectively of the system, and a valve controlling communication between these two ports. First control means in the valve body control the valve in dependence upon one or more external controls including manual controls and second control means control the operation of the valve in dependence upon the thermodynamic conditions, such as the temperature, of the refrigerant fluid.