Abstract: A control box kit for twinning fan coils in a heat pump or AC installation includes electro-mechanical isolation relays and auxiliary limit switches. Existing fan coil transformers are disconnected to avoid component failure due to high voltage wiring variations. A single transformer is connected to operate both systems. Isolation relays for the reversing valves and supplemental electric heaters in a heat pump system allow both heat pumps to have independent defrost cycles. The accessory transformer and isolation relays are packaged and pre-wired in a control box for easy connection in the field.

Abstract: A chiller system includes at least two refrigerant circuits. In a low ambient temperature condition, only one refrigerant circuit is activated, but its condenser fan is de-energized. To provide some airflow across the condenser of the activated circuit, a condenser fan of the inactive circuit is energized. A small air duct allows the condenser fan of the inactive circuit to draw a low volume of air across the condenser of the active circuit.

Abstract: In an ejector used for an ejector cycle system, a nozzle has a first refrigerant passage, a second refrigerant passage, and a third refrigerant passage in this order in a refrigerant flow direction from a refrigerant inlet toward a refrigerant outlet of the nozzle. The first refrigerant passage, the second refrigerant passage and the third refrigerant passage are formed into cylindrical shapes, respectively, each having a constant passage diameter. Further, a pressure increasing portion of the ejector is also formed into a cylindrical shape having a constant passage diameter. Accordingly, the ejector can be readily manufactured in low cost.

Abstract: A two stage reciprocating compressor and associated HVAC systems and methods are disclosed. The reciprocating compressor includes a crankshaft having an eccentric crankpin, a reversible motor for rotating the crankshaft in a forward and a reverse direction, and an eccentric, two position cam rotatably mounted over the crankpin. The crankshaft and cam combine to cause the piston to have a first stroke when the motor operates in the forward direction and a second stroke when the motor operates in the reverse direction. The cam and crankpin also include stabilization means to restrict the relative rotation of the cam about the crankpin. A lubrication system is provided to lubricate the engaging surfaces of the crankshaft and cam and between the cam and the bearing surface of the connecting rod. There is also provided a control for selectively operating the motor either in the forward direction at a first power load or in the reverse direction at a reduced second power load.

Abstract: A refrigerating unit capable of optimum operation with respect to load by finely changing the operating capacity in response to changes in load, and offering energy saving effects. The refrigerating unit has a scroll type inverter-driven compressor and scroll type constant-speed compressors; a pressure sensor installed on the suction side; a circuit for starting the inverter-driven compressor first; and a circuit for deciding the driving frequency of the compressor and the number of constant-speed compressors to operate, based on a suction pressure value detected by the pressure sensor after the compressor was started.

Abstract: A cascade refrigeration system wherein the inlet and outlet pressures and the power consumption of the compressor of the higher temperature refrigeration circuit, and the inlet and outlet pressures and the power consumption of the compressor of the lower temperature refrigeration circuit are ascertained and used to calculate more efficient operating pressures, and the operation of the compressors is adjusted to adjust the pressures of the incoming refrigerants to the cascade heat exchanger toward the more efficient operating pressures.

Abstract: An air conditioning system (multi-air conditioner system) which has a plurality of indoor units installed inside of a predefined space for performing air conditioning and an outdoor unit installed outside of the space for controlling the indoor units, and a method for controlling the same. In an installation process, an installer need not personally set addresses in the indoor units one by one, because the outdoor unit automatically sets the addresses in the indoor units. Therefore, as compared with conventional air conditioning systems, a period of time required for the address setting and an error occurrence probability can be reduced and the convenience to the user can be increased. Furthermore, the address setting can automatically be conducted without additionally using separate hardware modules, thereby reducing parts costs required in manufacturing a multi-air conditioner.

Abstract: An air conditioning system which has a plurality of indoor units installed inside of a predefined space for performing air conditioning and an outdoor unit installed outside of the space for controlling the indoor units, and a method for controlling the same. The indoor units store unique production numbers assigned respectively thereto in manufacturing processes thereof, and the outdoor unit recognizes the production numbers of the indoor units and automatically sets addresses in the indoor units on the basis of the recognized production numbers. Therefore, in an installation process, an installer need not personally set addresses in the indoor units one by one, resulting in greater convenience of installation. Further, as compared with conventional air conditioning systems, a period of time required for the address setting and an error occurrence probability can be reduced.

Abstract: A cooling system for a communication station for cooling a casing of the communication relay station, accommodating communication equipments including heat components, by a boiling-type cooler in a natural circulation refrigerating circuit and an evaporator in a forced circulation refrigerating circuit, activated by a compressor comprising: a common airflow path having a heated air intake port for taking a heated air in the casing; and a common fan for sending an air to the boiling-type cooler and the evaporator, wherein the boiling-type cooler, the evaporator, and the common fan are built in a common airflow path.

Abstract: Disclosed is a method and apparatus for controlling multistage systems where the relative capacities (process gains) of each stage are known. The method uses a split-range control concept in order to control multiple stages with a single feedback controller, such as PID. Stage combinations are generated automatically and sequenced to provide contiguous control and optimum control resolution across the overall range of the multistage system. The control method incorporates hysteretic deadzones to improve robustness around stage transition points. The assumption of a tuned PI feedback controller allows the size of the deadzone to be related to general control performance requirements applicable across classes of similar systems. A simulated HVAC&R system is used to evaluate the method and it is compared an alternative approach.

Abstract: A refrigerating device including a refrigerating cycle including a plurality of compressors driven by motors, the plurality of compressors comprising a variable speed compressor which can be controlled in capacity and a constant speed compressor which is driven by a motor of which rotor core comprising a cage type conductor and permanent magnets.

Abstract: A method for refrigeration system control according to the invention includes identifying a lead circuit having a lowest temperature set point from a plurality of circuits, wherein each circuit includes at least one refrigeration case. The suction pressure set point for a compressor rack is initialized based upon the identified lead circuit, and a change in suction pressure set point is determined based on measured parameters from the lead circuit. The suction pressure set point is updated based upon the change in suction pressure set point. A first valve position for a first electronic evaporator pressure regulator associated with a first refrigeration circuit is determined based on the determined change in suction pressure set point, which is based upon the measured parameters from the lead circuit. A second valve position for a second electronic evaporation pressure regulator associated with a second refrigeration circuit is based upon a second measured parameter.

Abstract: A control box kit for twinning fan coils in a heat pump or AC installation includes electro-mechanical isolation relays and auxiliary limit switches. Existing fan coil transformers are disconnected to avoid component failure due to high voltage wiring variations. A single transformer is connected to operate both systems. Isolation relays for the reversing valves and supplemental electric heaters in a heat pump system allow both heat pumps to have independent defrost cycles. The accessory transformer and isolation relays are packaged and pre-wired in a control box for easy connection in the field.

Abstract: A repository including: an input unit (3) for setting the temperature of the interior (2) of a repository (1); a measuring unit (5,6) for measuring the temperature of the interior of the repository (1); a controller (4) for holding ID data to specify the repository itself and communicatively outputting the measurement data to the external; and an auxiliary power source (13) for communicating the measurement data to the external even during interruption of power supply. A central controller 11 for collecting the measured data from each repository and judging whether abnormality occurs or not is connected to plural repositories to fabricate a monitoring system. When abnormality is detected, the measured data as well as ID data and time data are transmitted to a user through the Internet.

Abstract: A commercial refrigeration system has a control system (70) which distributes intelligence to increase granularity of the control and simplify wiring, assembly and installation. Compressors (14A-C) of the refrigeration system each have a bus compatible compressor safety and control module (48) including a processor and sensors. All control and safety modules (48) communicate over a single power and communications line (80) with the controller (70), providing digital transmissions to the controller of measurements taken by the sensors. The control and safety modules (48) are capable of executing commands from the controller (70) to cycle the compressors (14A-C). The control and safety modules (48) preferably contain sufficient intellignece to continue system operation upon failure of the controller (70). A compressor (14) is also disclosed which has an intelligent control and safety module.

Abstract: Disclosed is a method for controlling an air conditioner having a multi-compressor. The method comprises the steps of: first determining, in order to accomplish a set temperature after a user starts the air conditioner, a cooling load of a room by measuring an on-time for which at least two compressors are run, in a manner such that the more the one-time of the compressors is long, the more the cooling load of the room is judged to be large; and operating the air conditioner by changing a compressing capacity of the compressors in response to a first determined cooing load, in a manner such that, when the cooling load is large, the air conditioner is operated by a first combination of compressors, having a large compressing capacity, and, when the cooling load is small, the air conditioner is operated by a second combination of compressors, having a small compressing capacity.

Abstract: The invention relates to a cascade refrigeration system with screw compressors (3) connected with each other thermally via a heat exchanger (20) wherein the refrigerant of the low-temperature circuit is condensed in said heat exchanger (20), and the refrigerant of the high-temperature circuit is expanded in said heat exchanger (20), and in addition to said heat exchanger (20) a desuperheater (8) is arranged in flow direction ahead of said heat exchanger (20) in which the working medium of the low-temperature side is cooled down, while the working medium of the high temperature circuit is expanded.

Abstract: In order to magnify capacity control of a refrigeration cycle for an increased efficiency and achievement of compactness, the refrigeration cycle includes a compressor, a four-way valve, a heat exchanger on a side of a heat source, a liquid receiver, a heat exchanger on a side of use, and an electronic expansion valve, all of which are connected other by pipes, and comprises a refrigerant circulating in the refrigeration cycle and being a non-azeotropic refrigerant, a second liquid receiver for taking out a refrigerant vapor from an upper portion of the liquid receiver to condense and store the refrigerant, and a pipe connecting the second liquid receiver to the liquid receiver via a shut-off valve.

Abstract: A method for controlling corresponding energy supply of a heat source unit of a refrigeration air conditioning system based on required energy value calculated from output power value mainly includes a controller coupled with a heat exchanger unit at the refrigeration air conditioning loading side that matches a heat source unit of a refrigeration air conditioning system. The controller includes a power value detection unit to detect the delivered loading power value, and through a center micro processing unit to process air conditioning required energy value which is transferred to a refrigeration air conditioning required energy value calculation unit to accumulate total required energy value. The total required energy value is dynamically fed to a heat source controller to control optimal heat source supply of the heat source unit such that the system is maintained the optimum operation condition to effectively save energy and achieve higher operation efficiency.

Abstract: A refrigeration system having a main refrigeration circuit having a condensing stage, wherein a first refrigerant in a high pressure gas state is condensed at least partially to a liquid state. The condensing stage has a pair of stand-alone condensing stage closed loops in heat exchange relation with the main refrigeration circuit. The stand-alone condensing stage closed loops are parallel one to another and each comprise a second refrigerant circulating between at least a heat absorption stage, wherein the second refrigerant absorbs heat from the first refrigerant in the main refrigeration circuit so as to condense the first refrigerant to the liquid state, and a heat release stage, wherein the second refrigerant releases the absorbed heat. The condensing stage has modulating valves for selectively and quantitatively modulating the temperature of said first refrigerant and compressor head pressure.

Abstract: An air conditioning system includes an engine driven compressor, and an independent electric motor driven compressor in a common housing. A controller adjusts the independent operation of the engine driven compressor and electric motor driven compressor in response to cooling demand input, and operational parameters of the engine and the battery, as well as optionally the electric motor driven compressor output and engine driven compressor output. A method of independently operating an engine driven compressor and electric motor driven compressor is also provided. The air-conditioning system, controller, and method are particularly useful in hybrid vehicles that use smaller displacement internal combustion engines and electric motor drive means.

Abstract: An electronic control for an air conditioning system is provided. The system includes first and second air conditioning packs located in the air craft remote from one another. Each pack includes a pack controller in the same location as the pack. The pack controllers produce operating instruction signals to the packs for instructing the packs to produce conditioned air in response to a reference signal. A supervisory controller is centrally located in aircraft, preferably in the electronics equipment bay, and is connected to each of the pack controllers. The supervisory controller produces the reference signal to the pack controllers. In addition to controlling the operation of the packs, the pack controllers preferably include prognostics for monitoring the packs and diagnosing problems. The distributed electronic controllers of the present invention utilized for the packs may similarly be applied to the zone trim system and the engine air bleed valves.

Abstract: In an ejector cycle system using carbon dioxide as refrigerant, an ejector decompresses and expands refrigerant from a radiator to suck gas refrigerant evaporated in an evaporator, and converts an expansion energy to a pressure energy to increase a refrigerant pressure to be sucked into a compressor. Because refrigerant is decompressed and expanded in a super-critical area, a pressure difference during the decompression operation becomes larger, and a specific enthalpy difference becomes larger. Accordingly, energy converting efficiency in the ejector becomes higher, and efficiency of the ejector cycle system is improved.

Abstract: A two stage reciprocating compressor and associated HVAC systems and methods are disclosed. The reciprocating compressor includes a crankshaft having an eccentric crankpin, a reversible motor for rotating the crankshaft in a forward and a reverse direction, and an eccentric, two position cam rotatably mounted over the crankpin. The crankshaft and cam combine to cause the piston to have a first stroke when the motor operates in the forward direction and a second stroke when the motor operates in the reverse direction. The cam and crankpin also include stabilization means to restrict the relative rotation of the cam about the crankpin. A lubrication system is provided to lubricate the engaging surfaces of the crankshaft and cam and between the cam and the bearing surface of the connecting rod. There is also provided a control for selectively operating the motor either in the forward direction at a first power load or in the reverse direction at a reduced second power load.

Abstract: A refrigerating apparatus comprising a refrigerating cycle having compressors, a condenser, a liquid receiver, expansion valves and evaporators; and a suction pressure sensor for detecting a pressure on suction sides of the compressors; wherein when the suction pressure has at least a capacity-up pressure value, it causes an increase in the number of compressors being operated or the operating frequency; and wherein when a time period, in which the suction pressure remains in at least the capacity-up pressure value, and a time period, in which the suction pressure remains in at most the capacity-down pressure value, are compared with each other and calculated, and the latter time period is longer than the former time period, at least one of the capacity-up pressure value and the capacity-down pressure value is made larger than said each pressure value.

Abstract: In order to magnify capacity control of a refrigeration cycle for an increased efficiency and achievement of compactness, the refrigeration cycle includes a compressor, a four-way valve, a heat exchanger on a side of a heat source, a liquid receiver, a heat exchanger on a side of use, and an electronic expansion valve, all of which are connected other by pipes, and comprises a refrigerant circulating in the refrigeration cycle and being a non-azeotropic refrigerant, a second liquid receiver for taking out a refrigerant vapor from an upper portion of the liquid receiver to condense and store the refrigerant, and a pipe connecting the second liquid receiver to the liquid receiver via a shut-off valve.

Abstract: An HVAC control system for a vehicle with multiple environmental zones includes a datalink between the control elements of the HVAC systems that regulate the climate in the multiple environmental zones. Control elements for the HVAC systems include an electronic control unit and a control head. A user of the HVAC control system may assign master status to the control head of the zone in which the user is located, and from that control head, control the environmental settings for HVAC systems servicing other zones in the vehicle. A data communication bus implemented in the vehicle may be used as the datalink.

Abstract: An environmental test chamber provides a fast cool down to a temperature of about −125° F. and a fast heat up of an element under test.

Abstract: Disclosed is a method for controlling an air conditioner having a multi-compressor. The method comprises the steps of: first determining, in order to accomplish a set temperature after a user starts the air conditioner, a cooling load of a room by measuring an on-time for which at least two compressors are run, in a manner such that the more the on-time of the compressors is long, the more the cooling load of the room is judged to be large; and operating the air conditioner by changing a compressing capacity of the compressors in response to a first determined cooing load, in a manner such that, when the cooling load is large, the air conditioner is operated by a first combination of compressors, having a large compressing capacity, and, when the cooling load is small, the air conditioner is operated by a second combination of compressors, having a small compressing capacity.

Abstract: Method for controlling a linear expansion valve in an air conditioner with two compressors, which can prevent breakage of the compressor, and starting failure caused by liquidus refrigerant introduced into the compressor at an initial starting, and preventing drop of cooling performance caused by reduced refrigerant flow coming from a low suction pressure of the compressor at an initial unsteady state.

Abstract: In a refrigerating/air-conditioning apparatus including operating/controlling units such as outdoor units, indoor units and control devices for individually or collectively controlling the driving of the outdoor units and the indoor units, each operating/controlling unit being equipped with a controller for controlling the driving of the operating/controlling unit, the controller having a rewritable memory for storing a control program, control parameter data, control data, etc.

Abstract: A method and apparatus for refrigeration system control is provided. The refrigeration system includes a plurality of circuits with each circuit having at least one refrigeration case. An electronic evaporator pressure regulator is in communication with each circuit and is operable to control the temperature of the corresponding circuit. A plurality of compressors are also provided with each compressor forming a part of a compressor rack. A pressure sensor is used for measuring the suction pressure of the compressor rack. A sensor is in communication with each circuit and is operable to measure a parameter from each circuit. A controller controls each electronic evaporator pressure regulator and the suction pressure based upon the measured parameters from each circuit.

Abstract: A control used in a two stage HVAC system has a power supply from a 24 VAC transformer which is full wave rectified (D1, D2, D3, D4) to create DC voltages for a microcontroller (U1) and relays (K1-K3). All of the control information needed for the two stage control system is sent to the control from a room thermostat (12) having first and second stage cooling signal terminals (Y1, Y2) over a single line by connecting a diode between the Y1, Y2 terminals creating separate microprocessor recognizable signals.

Abstract: A refrigerating apparatus comprising a refrigerating cycle having compressors, a condenser, a liquid receiver, expansion valves and evaporators; and a suction pressure sensor for detecting a pressure on suction sides of the compressors; wherein when the suction pressure has at least a capacity-up pressure value, it causes an increase in the number of compressors being operated or the operating frequency; and wherein when a time period, in which the suction pressure remains in at least the capacity-up pressure value, and a time period, in which the suction pressure remains in at most the capacity-down pressure value, are compared with each other and calculated, and the latter time period is longer than the former time period, at least one of the capacity-up pressure value and the capacity-down pressure value is made larger than said each pressure value.

Abstract: It is an object of the present invention to provide an operation control method of an air-conditioning apparatus and an air-conditioning apparatus that prevent a plurality of air-conditioning apparatuses from simultaneously restarting upon their automatic recovery after a recovery of power and from stopping again due to a voltage drop. The air-conditioning apparatus of the present invention is provided with an automatic recovery control circuit (21) for deciding a delay time until a restart based on set data for deciding operation works of the air-conditioning apparatus or randomly, thereby to restart the air-conditioning apparatus with the decided delay time.

Abstract: Air conditioner for multiple rooms of a building having a network provided thereto including an outdoor unit, an outdoor unit controller for controlling operation of the outdoor unit, more than one indoor units, an indoor unit controller for controlling operation of the indoor units, and a main controller connected to the outdoor controller and the indoor controller through the network for receiving information on operation states and operation conditions of the outdoor unit and the indoor units, and controlling the outdoor unit controller and the indoor unit controller according to the information and a preset system algorithm, thereby permitting an easy installation of the air conditioner, and to save an installation cost, and an efficient and optimal air conditioning operation.

Abstract: A refrigeration system having a refrigeration cycle which provides optimized consumption, comprising a main section, which is constituted by at least one main compressor, a main condenser, which is connected between the compressor and at least one expansion valve, and at least one evaporator, which is connected to the expansion valve, which comprises an auxiliary section comprising at least one auxiliary compressor which is connected to a low-pressure intake line of the main compressor, at least one auxiliary condenser which is connected to the auxiliary compressor, and a first auxiliary reservoir and a second auxiliary reservoir which are respectively connected to the output of the auxiliary condenser and to the output of the main condenser, for connection to the at least one expansion valve.

Abstract: The refrigerating system includes a low stage side refrigerant circuit (2) formed by connecting a low stage side compressor (4), a cascade condenser (5), a low stage side receiver (6), a low stage side expansion valve (7) formed of a temperature-sensitive expansion valve and an evaporator (8) in this order. The system also includes a high stage side refrigerant circuit (3) formed by connecting a high stage side compressor (9), a condenser (10), a high stage side receiver (11), a high stage side expansion valve (12) formed of a motor-operated expansion valve and the cascade condenser (5) in this order. The opening of the high stage side expansion valve (12) is adjusted so that the pressure sensed by a high-pressure sensor (SPH2) for sensing the high pressure in the low stage side refrigerant circuit (2) reaches a predetermined target high pressure.

Abstract: A two stage compressor which provides a high capacity stage and a low capacity stage is used with multiple evaporator condensing units. A control system for controlling the compressor receives inputs from two indoor locations via thermostats. The compressor runs in the low capacity stage when cooling is called for from only one of the thermostats, but runs in the high capacity stage when cooling is called for from both of the thermostats. The control system controls the transition of the compressor from the low capacity stage to the high capacity stage, and from the high capacity stage to the low capacity stage.

Abstract: A heat exchange assemblage is adapted for use with other such heat exchange assemblages for cooling or heating a controlled environment, or controlling the humidity thereof. Each heat exchange assemblage is intended for use in conjunction with a communication network linking all such heat exchange assemblages, but each can operate autonomously if the network fails. Each heat exchange assemblage includes a heat pump and a controller. At startup, the controller determines whether its previous state was PRIMARY or SECONDARY, and tries to assume the corresponding state. If no one assemblage assumes PRIMARY status, a random scheme in conjunction with communications aids in establishing one of the assemblages as PRIMARY, while others remain SECONDARY. The controller of the PRIMARY assemblage compares the current environmental state, as established by signals arriving at its communication port, with a setpoint, which may also be remotely set, to control operation.

Abstract: Method for controlling a linear expansion valve in an air conditioner with two compressors, which can prevent breakage of the compressor, and starting failure caused by liquidus refrigerant introduced into the compressor at an initial starting, and preventing drop of cooling performance caused by reduced refrigerant flow coming from a low suction pressure of the compressor at an initial unsteady state.

Abstract: A system and method for controlling refrigeration including a temperature sensor operable to measure a temperature from a refrigeration case and a transceiver in communication with the temperature sensor and operable to wirelessly transmit data. A repeater receives the wirelessly transmitted data and further wirelessly transmits the data to a receiver. A controller in communication with the receiver controls the refrigeration system based upon the wirelessly transmitted data from the refrigeration case. The refrigeration case also includes a mode switch for suspending temperature reading and control for a period of time. For example, the mode switch can be used by an operator during cleaning or maintenance of the refrigerator case. Temperature control algorithms are used by the controller, and include: dead-band range (DB), proportional/integral (PI), proportional/integral/differentiation (PID) and fuzzy-logic (FL).

Abstract: A multiplex system is disclosed for maintaining the temperature of a product during a warehouse and distribution process employing a vehicle. The multiplex system may include a plurality of temperature control zones at which it is desired to maintain the temperature of the product. A cargo temperature control zone includes a parking area for a number of delivery vehicles having cargo containers. A primary refrigeration system is utilized to refrigerate a secondary fluid which is a non-compressible fluid that may be pumped over long distances to the cargo temperature control zone, as well as other temperature control zones. The secondary refrigerated fluid is pumped to air handling units which are advantageously disposed is heat exchange relationships to create and deliver refrigerated air into the cargo container of one or more parked delivery vehicles.

Abstract: A refrigerating unit capable of optimum operation with respect to load by finely changing the operating capacity in response to changes in load, and offering energy saving effects. The refrigerating unit has a scroll type inverter-driven compressor and scroll type constant-speed compressors; a pressure sensor installed on the suction side; a circuit for starting the inverter-driven compressor first; and a circuit for deciding the driving frequency of the compressor and the number of constant-speed compressors to operate, based on a suction pressure value detected by the pressure sensor after the compressor was started.

Abstract: A refrigeration system having a flow control mechanism to selectively increase or decrease refrigerant flow in response to system temperature. In the preferred embodiment, a cascade refrigeration system having a high temperature first stage with a compressor, condenser, flow control device and heat exchanger. The low temperature second stage has a compressor, flow control device, evaporator and heat exchanger. The first stage is in a heat exchange relationship with the second stage through the common heat exchanger, which functions as condenser in the second stage. A controller responsive to temperature sensed at the second stage evaporator outlet operates a valve to increase or decrease refrigerant flow in the first stage. Increased refrigerant flow improves refrigeration system response to large heat loads, while maintaining efficient operation under normal conditions.

Abstract: A controller monitors the saturated suction temperature and the saturated discharge temperature of a system that includes a compressor operating as part of a chiller and/or heat pump. When the compressor operates outside its compressor map, the controller takes action to ensure the compressor operates only within its compressor map. Such actions include defrosting the compressor coil if the system is in heating mode or unloading the unit.

Abstract: An electronic digital thermostat adapted for installation in locations with or without an external power supply preferably includes a compartment for receiving a replaceable internal power supply, such as a batteries, for powering the thermostat if an external power supply is not available, and a connector for connecting the thermostat to an external power supply for powering the thermostat when the external power supply is available. The thermostat is configured to preferentially draw power from an external power supply connected to the thermostat, if power from an external power supply is available, and draw power from an internal power supply connected to the thermostat, if power from an external power supply is not available. An additional power backup, such as a capacitor, may be provided to maintain power to the thermostat for short durations when power is unavailable from both the internal power supply and the external power supply.

Abstract: An automotive dual air-conditioning system having No. 1 air conditioner and No. 2 air conditioner arranged separately in an automobile, for controlling air-conditioning operation, and a bus line connected between No. 1 air conditioner and No. 2 air conditioner. No. 1 air conditioner transfers air-conditioner control information to No. 2 air conditioner through the bus line during operation of No. 1 air conditioner and No. 2 air conditioner, to thereby control the operating condition of No. 2 air conditioner in accordance with the information thus supplied. Furthermore, No. 2 air conditioner changes the control of its operating condition to manual control in case a communication error of air-conditioner control information to be transferred through the bus line continues over a specific period of time.

Abstract: In an ejector cycle system using carbon dioxide as refrigerant, an ejector decompresses and expands refrigerant from a radiator to suck gas refrigerant evaporated in an evaporator, and converts an expansion energy to a pressure energy to increase a refrigerant pressure to be sucked into a compressor. Because refrigerant is decompressed and expanded in a super-critical area, a pressure difference during the decompression operation becomes larger, and a specific enthalpy difference becomes larger. Accordingly, energy converting efficiency in the ejector becomes higher, and efficiency of the ejector cycle system is improved.

Abstract: The invention relates to a refrigeration system that includes a first and a second refrigeration circuit wherein the first refrigeration circuit uses CO2 as the refrigerant, the second refrigeration circuit uses a second refrigerant, and the second refrigeration circuit is arranged to refrigerate the first refrigeration circuit by means of a cascade heat exchange connection. The first refrigerant is at a pressure above about 120 psig. The refrigeration system is energy efficient and is particularly useful in the food industry. The invention further relates to a method of refrigeration using the refrigerator system.