Abstract: A air channeling sub-system may include a mechanical cooling section and a direct evaporative cooling section. The direct evaporative cooling section may be downstream from the mechanical cooling section. Cooling air is channeled through the air channeling sub-system and into the room. If a first set of control conditions is met, the air channeling sub-systems is operated in an adiabatic mode. The adiabatic mode includes channeling cooling air through the direct evaporative cooling section to evaporate water into the cooling air. If a second set of control conditions is met, the air channeling sub-system is operated in a hybrid mode. The hybrid mode includes channeling cooling air through the mechanical cooling section to remove heat from the cooling air and channeling the cooling air through the direct evaporative cooling section to evaporate water into the cooling air.

Abstract: A method for controlling the temperature of a machine part, by the use of a regulating device, is accomplished by determining one respective value of a measured temperature at each of two separate spaced-apart measured points, which two points are located along a control distance. One of these measured values is fed to each of two control circuits of the regulating device which two control circuits are connected to each other in a cascade-type manner.

Abstract: A control method of a multi-air conditioner in which a plurality of indoor units is connected to one outdoor unit and refrigerant flow amount is adjusted by electronic expansion valves comprises a share step in which a plurality of indoor units exchanges their operation information, a comparison and judgment step in which each above indoor unit compares and judges its operation status based on the exchanged operation information, and an adjustment step in which each above indoor unit adjusts refrigerant flow amount supplied to each indoor unit based on the compared and judged operation status.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits. A hot gas re-heat circuit having a hot gas re-heat coil, an evaporator and a compressor, such as the evaporator and compressor utilized in one of the refrigerant circuits, is provided. The hot gas re-heat coil is placed in fluid communication with the output airflow from the evaporator of the re-heat circuit. Humidity control is performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas re-heat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity. During a second stage cooling operation using multiple refrigerant circuits and having a high cooling demand, the request for humidity control is suspended until completion of the second stage cooling demand.

Abstract: A system and method for providing energy assessment and optimization in a data center that includes at least one cooling provider, and at least one cooling consumer, the at least one cooling consumer having cooling requirements. The method according to one aspect includes receiving data regarding cooling availability and power consumption for the at least one cooling consumer, cooling capacity of the at least one cooling provider, and a physical relationship between the at least one cooling consumer and the at least one cooling provider in the data center, storing the received data, determining airflow distribution effectiveness between the at least one cooling consumer and the at least one cooling provider, and displaying at least one value representative of the effectiveness of the distribution of airflow in the data center between the at least one cooling consumer and the at least one cooling provider.

Abstract: Disclosed herein are a multi-air conditioner and a group-unit control method thereof, wherein a plurality of indoor units can be controlled on a group basis. The method comprises the step of grouping the indoor units into a plurality of groups, the step of if an air conditioning operation condition of a specific one of the indoor units is changed, sending, by the specific indoor unit, the changed operation condition to all the other indoor units according to a predefined communication protocol, and the step of by each of the indoor units, receiving an air conditioning operation condition sent from a different one of the indoor units in the same group and performing an air conditioning operation based on the received operation condition. According to the invention, the plurality of indoor units can be more efficiently controlled on a group basis through inter-indoor unit data communication. Further, the group-unit control is not restricted by whether a controller is used or not.

Abstract: Multi-type air conditioner including a plurality of compressors, a plurality of temperature sensors mounted in the plurality of compressors for sensing temperatures in the compressors respectively, and an equalizing pipe in communication with the plurality of compressors, for uniform distribution of oil among the plurality of compressors according to the temperatures sensed at the plurality of temperature sensors respectively, thereby distributing oil among the compressors uniformly at an exact time point at which the oil is distributed among the compressors non-uniformly, not only to permit improvement of the performance of the compressors, but also to permit improvement performance of the air conditioner having the compressors.

Abstract: A compressor controlling apparatus including a bypass unit connected between an outlet and an inlet of the compressor and a control unit. The control unit reduces pressure difference between the outlet and the inlet of the compressor by the bypass unit to start the compressor when the compressor is to be started. The compressor is started while pressure equilibrium is achieved by the bypass unit, thereby preventing poor start-up of the compressor caused due to excessive pressure difference, and thus improving reliability of the compressor.

Abstract: A capacity control algorithm for a multiple compressor liquid chiller system is provided wherein the speed and number of compressors in operation are controlled in order to obtain a leaving liquid temperature setpoint. In response to an increase in the load in the chiller system, the algorithm determines if a compressor should be started and adjusts the operating speed of all operating compressors when an additional compressor is started. In response to a decrease in the load in the chiller system with multiple compressors operating, the algorithm determines if a compressor should be de-energized and adjusts the operating speed of all remaining operating compressors when a compressor is de-energized.

Abstract: A transcritical vapor compression system includes a fluid circuit circulating a refrigerant in a closed loop. The fluid circuit has operably disposed therein, in serial order, a first compressor, an intercooler, a second compressor with a variable capacity, a first heat exchanger, an expansion device and a second heat exchanger. The first compressor compresses the refrigerant from a low pressure to an intermediate pressure. The second compressor compresses the refrigerant from the intermediate pressure to a supercritical pressure. The first heat exchanger is positioned in a high pressure side of the fluid circuit. The second heat exchanger is positioned in a low pressure side of the fluid circuit. The expansion device reduces the pressure of the refrigerant from a supercritical pressure to a relatively lower pressure. Cooling means cools the refrigerant within one of the compressors.

Abstract: Disclosed are an abnormal state detecting apparatus of a multi-type air conditioner and a method thereof. The method comprises: a user's selecting a test operation, and then detecting plural indoor temperatures of indoor zones where a plurality of indoor units are installed and plural outdoor temperatures of outdoor zones where a plurality of outdoor units are installed; selecting a corresponding test operation mode among a plurality of test operation modes preset according to an average indoor temperature of the detected plural indoor temperatures and an average outdoor temperature of the detected plural outdoor temperatures; test-operating the multi-type air conditioner according to the selected test operation mode, and collecting data showing an operation state of the test-operated air conditioner; and comparing the collected data with a preset reference data and judging an abnormal state of the multi-type air conditioner based on the comparison result.

Abstract: A refrigeration system including a refrigeration circuit and a controller. The refrigeration circuit includes a plurality of variable capacity compressors arranged in parallel to compress a refrigerant. A second variable capacity compressor is started after a first variable capacity compressor. An evaporator defines a load while evaporating the refrigerant to refrigerate a space within a predetermined temperature range. The controller is programmed to control the operation of the plurality of variable capacity compressors to match the capacity of the plurality of variable capacity compressors to the load by increasing the capacity of the last compressor in the queue of running compressors when the capacity of the plurality of variable capacity compressors is lower than the load and by decreasing the capacity of the first compressor in the queue when the capacity of the plurality of variable capacity compressors is higher than the load.

Abstract: There is provided a compact centralized management unit of facility equipment, as well as a management system using the centralized management unit, that is capable of accommodating changes in data transmission simply and at low cost. The centralized management unit has an input-side interface connected to the facility equipment, an output-side interface for outputting the management data of the facility equipment, a storage section for storing a control program of the facility equipment, and an arithmetic processing section for controlling the facility equipment in accordance with an instruction of the control program. The storage section stores a first transmission program corresponding to the input-side interface and a second transmission program corresponding to an interface of the connection intermediating device.

Abstract: An air-chiller comprises a primary compressor that circulates a mixture of four refrigerants with different boiling points through a primary condenser and several heat-exchanger coils in series. Each heat exchanger coil includes a large section of tubing in which are disposed four smaller sections of tubing. Two of these smaller sections of tubing carry the air to be chilled. The other two smaller sections of tubing carry high pressure refrigerants from the compressor and condenser. The remaining inside volume of the large section of tubing provides for the suction-return of heat-laden refrigerants. Input air passes through the four heat exchangers in series and comes out the fourth one highly refrigerated. The high-pressure refrigerant coming out of the primary compressor is chilled below ambient temperature by a secondary refrigeration sub-system. Such is circulated, after drying, through an auxiliary condenser for additional refrigeration before going to work in the first heat-exchanger coil.

Abstract: A controller is configured to perform at least one of loading and unloading at least one of a plurality of refrigerant compressors to a refrigeration cooling system based at least upon an enthalpy of circulating refrigerant liquid of the refrigeration cooling system and a rate of change of enthalpy of evaporated refrigerant gas in the refrigeration cooling system.

Abstract: An air conditioner, in which a controller is installed separately from a plurality of indoor units and a plurality of outdoor units so that only the controller is added and conventional outdoor units are used when plural indoor units are required, thereby reducing costs due to the omission of other outdoor units. The controller determines whether or not the outdoor units are respectively operated according to a signal of a temperature sensing unit, and selectively operates the outdoor units according to a required capacity, thereby increasing the operating efficiency of the air conditioner.

Abstract: A controller reduces a rotational speed of a Rankine cycle from a predetermined normal rotational speed during an operation of a compressor in a predetermined state when the controller determines that a predicted refrigerant flow quantity, which is predicted by assuming that the compressor is operated in a sole operation of the Rankine cycle at the predetermined normal rotational speed of the Rankine cycle, exceeds a predetermined flow quantity. The predetermined state is a state that satisfies a predetermined condition, which relates to the sole operation of the Rankine cycle.

Abstract: An HVAC system and method for configuring a controller to control a compressor including a detection system provided to determine a type of compressor. The detection system includes a processor; and a load sensing circuit connected between the processor and a controller. The controller has a plurality of output connections connectable to a compressor. The load sensing circuit senses whether a load is present on each output connection of the plurality of output connections and provides a load signal to the processor indicating whether a load is present on each output connection. The load signals are processed with the processor to determine the type of compressor is present. The controller is configured to control the compressor in response to the determined type of compressor.

Abstract: A method for controlling multiple compressors for use in an airconditioner is disclosed. In the airconditioner having N compressors, the method sequentially and equally operates the N compressors using a two-dimensional matrix which prevents only a specific compressor from among the N compressors from being repeatedly operated, arranges rows and columns of the two-dimensional matrix to allow all compressors to be alternately operated according to the number of operating compressors from among all compressors, and stochastically operates and stops the N compressors using the two-dimensional matrix. As a result, the method controls the N compressors to be equally operated without overlapping operation times of the N compressors, and alleviates fatigue of the compressors, resulting in equally longer lifetimes of the N compressors.

Abstract: A refrigerator has a coolant cooler for cooling a coolant at the entrance of a flow control valve, when the cooling amount in the coolant cooler is deficient as well as excessive. The refrigerator includes a compressor for compressing the coolant, a radiator for radiating heat from the coolant, a coolant cooler for cooling the coolant, a flow control valve for regulating the flow volume of the coolant, an evaporator for evaporating the coolant, and a heat-exchange-amount control for controlling the amount of heat exchanged in the coolant cooler. The coolant is circulated through the compressor, the radiator, the coolant cooler, the flow control valve, and the evaporator, in that sequence.

Abstract: A system and method for providing cool air to a passenger compartment of a hybrid vehicle in an engine off mode is disclosed. This may include operating a HVAC system to provide cold refrigerant flowing through an evaporator while an engine is operating, and forcing air through the evaporator to cool the air. A first portion of the cooled air from the evaporator is directed through a heater core and a second portion around the heater core, and an electric water pump is activated to pump coolant from a thermal storage tank, through the heater core and back to the thermal storage tank to cool the coolant. When the engine operation is ceased, the air flow is directed through the heater core, and the coolant is pumped from the thermal storage tank, through the heater core and back to the thermal storage tank to cool the air.

Abstract: An integrated management system for controlling multi-type air conditioners can effectively enable to perform maintenance, management and after-service to at least one air conditioner systems by adding provision for product information into a communication protocol such that operation information and product information related to multi-type air conditioners from the at least one air conditioner system can be received, stored and used.

Abstract: A refrigerator has a coolant cooler for cooling a coolant at the entrance of a flow control valve when the cooling amount in the coolant cooler is deficient as well as excessive. The refrigerator includes a compressor for compressing the coolant, a radiator for radiating heat from the coolant, a coolant cooler for cooling the coolant, a flow control valve for regulating the flow volume of the coolant, an evaporator for evaporating the coolant, and a heat-exchange-amount control for controlling the amount of heat exchanged in the cooler. The coolant is circulated through the compressor, the radiator, the coolant cooler, the flow control valve, and the evaporator, in that sequence.

Abstract: A conditioned air delivery system is provided for parked aircraft. The system can accommodate elevated thermal loads while maintaining operation, albeit with reduced flow rates or slightly elevated temperatures. When temperature set points are not reached or cannot be maintained, a second compressor of a refrigeration unit is operated in parallel with a first compressor. When refrigerant pressure becomes excessive, a second fan is operated that is associated with a condenser of the system. Still higher pressures, indicative of higher thermal loads, can cause the system to shut down operation of one of the compressors, reducing the overall cooling capacity of the system, while maintaining the supply of refrigerated air to the aircraft. The airflow may be reduced to maintain an air temperature at or near the desired temperature. Coordination of several parallel and redundant refrigeration units may be provided with a single blower and coordinated control.

Abstract: A refrigerant return mechanism (5) is provided for returning liquid refrigerant in a receiver (17) to a circulation path. Whereby, the liquid refrigerant in the receiver (17) is forcedly returned to the circulation path in an operation state where the circulation path is formed in which the refrigerant sent out from compression mechanism (11D, 11E) flows from a second user side unit (20) to first user side units (30, 40) and is then returned to the compression mechanisms (11D, 11E).

Abstract: A multi air conditioner system in one example performs a cooling and heating changeover by selectively granting priority to one or more indoor units, determining whether there is one or more operating indoor units with priorities, and granting a control right for auto changeover to at least one indoor unit with priority.

Abstract: Heating, ventilating and air conditioning (HVAC) equipment units are provided with controllers which may be interconnected to a third or common controller, such as a communicating thermostat, and provide information in a process to determine if two or more of such air conditioning units may be operated as twinned units. Information is transmitted over a data bus between the controllers for the respective air conditioning units and the common controller to determine if the air conditioning units are the same type, of a same family and of essentially the same capacity before permitting twinned operation. If one of the air conditioning units is not twinnable, an alarm signal is generated to prevent operation of the air conditioning units in a multiple-unit configuration.

Abstract: A refrigeration system includes a two-stage linear compressor having a first piston disposed in a first cylinder and a second piston disposed in a second cylinder. The linear compressor is operable in an economizer cycle wherein the first piston operates as a first stage of the economizer cycle and the second piston operates as a second stage of the economizer cycle. A controller is coupled to the linear compressor to control a volume flow ratio of the linear compressor. The controller stores a plurality of coefficients of performance for a range of particular operating conditions of the linear compressor and each coefficient of performance corresponds to a desired volume flow ratio and a desired secondary evaporating temperature.

Abstract: The invention provides a refrigerator having a two-stage compression compressor capable of performing efficient cooling of a both a refrigerator compartment and a freezer compartment. A high-pressure delivery outlet of a two-stage compression compressor 12 is connected to a condenser 14, the condenser 14 is connected to a three-way valve 15, a first outlet of the three-way valve 15 is connected via an R capillary tube 16 and an R evaporator 18 to an intermediate-pressure intake of the two-stage compression compressor 12, is connected and via an F capillary tube 24 to an F evaporator 26, the F evaporator is connected to a low-pressure intake of the two-stage compression compressor 12 via a low-pressure suction pipe 28, the three-way valve 15 can switch between a simultaneous cooling mode and a freezer mode, and when in the simultaneous cooling mode the interior temperature of the refrigerator compartment 2 falls to a predetermined temperature it switches to the freezer mode.

Abstract: A method of determining optimal air conditioner control is provided that includes determining power consumptions of servers and computer room air conditioners, calculating a number of calories processed by each air conditioner and determining a total number of calories processed as a total heat processed load. Moreover, the method includes determining relevant factors between each of the servers and each of the air conditioners, calculating a percentage of the total heat processed load for each air conditioner, adjusting the corresponding percentage of the total heat processed load for each air conditioner using an operating efficiency curve, calculating a respective power to be consumed by each air conditioner, calculating an efficiency value, determining whether the efficiency value is a maximum efficiency value, and setting each air conditioner at the respective power to be consumed when the efficiency value is the maximum efficiency value.

Abstract: A refrigerant circuit (10) of a refrigeration apparatus is filled up with carbon dioxide as a refrigerant. In the refrigerant circuit (10), a first compressor (21) and a second compressor (22) are arranged in parallel. The first compressor (21) is connected to both an expander (23) and a first electric motor (31), and is driven by both of the expander (23) and the first electric motor (31). On the other hand, the second compressor (22) is connected only to a second electric motor (32), and is driven by the second electric motor (32). In addition, the refrigerant circuit (10) is provided with a bypass line (40) which bypasses the expander (23). The bypass line (40) is provided with a bypass valve (41). And, the capacity of the second compressor (22) and the valve opening of the bypass valve (41) are regulated so that the COP of the refrigeration apparatus is improved after enabling the refrigeration apparatus to operate properly in any operation conditions.

Abstract: A subcooling unit (200) includes a refrigerant passage (205) connected to liquid side communication pipes (21, 22) of a refrigerating apparatus (10). When a subcooling compressor (221) is operated, subcooling refrigerant circulates in a subcooling refrigerant circuit (220) to perform a refrigeration cycle, thereby cooling refrigerant of the refrigerating apparatus (10) which flows in the refrigerant passage (205). A controller (240) of the subcooling unit (200) receives the detection value of an outside air temperature sensor (231) or a refrigerant temperature sensor (236). The controller (240) controls the operation of the subcooling compressor (221) with the use of only information obtainable within the subcooling unit (200).

Abstract: An air conditioner includes a fixed displacement-type first compression mechanism and a variable displacement-type second compression mechanism independent from each other in a refrigeration cycle, and further includes second compression mechanism displacement control means, compression mechanism operation switching control means, an evaporator for refrigerant, a condenser, a blower, evaporator temperature detection means, and evaporator target temperature calculation means. When the refrigeration cycle is operated only by the first compression mechanism, referring to a temperature (Teva) detected by the evaporator temperature detection means, a temperature (Toff) calculated by the evaporator target temperature calculation means and a predetermined value A, if a condition of Teva?Toff?A is satisfied, both compression mechanisms are operated simultaneously.

Abstract: A system for controlling an air conditioner includes a plurality of outdoor units each having at least one compressor and an outdoor heat exchanger, an indoor unit connected to the outdoor units by a refrigerant tube, the indoor unit having an indoor heat exchanger, and a pressure regulating tube for equalizing pressure according to an operation mode. The pressure regulating tube is connected between the outdoor units.

Abstract: Methods of configuring a cooling subassembly for an electronics system are provided, that is, for establishing a coolant-carrying tube layout for interconnecting multiple liquid-cooled cold plates in series-fluid communication for cooling multiple heat-generating electronic components of an electronics system. The electronic components are to be plugged in fixed relation into a preconfigured motherboard, and the tube layout includes at least one rigid coolant-carrying tube. Simplified analysis is initially performed to evaluate stress on the rigid tube(s) and determine if loss of actuation load on the electronic components exceeds an acceptable threshold, and if so, at least one tube having high stress is identified and reconfigured. Thereafter, analysis is performed to determine whether, with available actuation load on the cooling subassembly, electrical connection loading between the electronic components and the supporting motherboard is above an acceptable minimum level.

Abstract: A refrigeration appliance system for a residential kitchen having multiple separate refrigerating modules and a single, continuously operating variable capacity central cooling unit with a variable speed compressor for chilling a cooling medium. A cooling medium circuit supplies cooling medium to the plurality of refrigerating modules from the central cooling unit. Flow control devices control flow of cooling medium to the refrigerating modules. A control circuit controls the central cooling unit and the temperature in the refrigerating modules. The refrigerating modules can be refrigerator, freezer or refrigerator freezer modules. The cooling medium can be air, cooling liquid or refrigerant. A below freezing freezer module having an insulated freezer cabinet, a freezer compressor, a freezer condenser and a freezer evaporator can be combined with the refrigeration appliance system for providing 0° F. freezer storage without requiring the central cooling unit to provide 0° F. cooling medium.

Abstract: In a cooling system (10) for cooling heat-generating installations (44, 46, 48) in an aircraft, with a refrigerating installation (12), at least one refrigeration consumer (44, 46, 48) and a refrigeration transport system (14) connecting the refrigerating installation (12) and the refrigeration consumer (44,46, 48), it is provided that the refrigerating installation (12) comprises at least one refrigeration machine (18, 20) which covers the maximum refrigeration requirement of the at least one refrigeration consumer (44, 46, 48) and in that the at least one refrigeration consumer (44, 46, 48) is supplied with cold generated in the refrigerating installation (12) via a refrigerating agent circulating in the refrigeration transport system (14).

Abstract: There is provided a system and method for a modular central plant. In one implementation, the inventive system includes a chiller unit and cooling tower that are designed to be modularly assembled, transported, and interconnected, thereby decreasing system cost and assembly time, increasing system maintainability, and improving scalability for increasing capacity at a future date. The removable wall panels and roof of an embodiment of the present invention aid in maintainability by providing enhanced access to critical system components such as the chiller assembly. The modular architecture of the present invention allows for speedy delivery and installation, and with only external electrical and water connections needed, the system can become rapidly operational.

Abstract: A control is provided for a first HVAC unit that is coupled to a common duct shared with at least one other HVAC unit. The control comprises a twinning connection for communication with at least a second control of another HVAC unit, and a voltage signal applied to the twinning connection. The control further comprises a switching means for switching the voltage signal to ground. A microcomputer for monitoring the twinning connection and for controlling the switching means is configured to actuate the switching means to switch the voltage at the twinning connection to ground for a predetermined time period to communicate a blower speed for the first HVAC unit. The microcomputer monitors the twinning connection to sense the duration that the voltage at the twinning connection is being conducted to ground, and responsively controls the speed of the first HVAC blower according to the prescribed blower speed corresponding to the sensed duration.

Abstract: A water-cooled air conditioning system includes an indoor unit having a first heat exchanger where air and refrigerant are heat-exchanged with each other, an outdoor unit having a second heat exchanger where water and the refrigerant are heat-exchanged with each other, a cooling tower for cooling the water directed to the second heat exchanger, a discharge duct for guiding the air conditioned in the indoor unit to an indoor space for an air conditioning, and an intake duct for guiding the air in the indoor space to the indoor unit. The second heat exchanger is a plate type heat exchanger having a space that is divided into a plurality of sections along which the refrigerant and the cooling water separately flow.

Abstract: An air conditioner is provided. The air conditioner includes two or more heat exchangers, a refrigerant pipe, a compressor, an accumulator, and an overcooler. The heat exchangers perform heat exchanging between air or water and refrigerant. The refrigerant pipe guides refrigerant circulating between the two or more heat exchangers. The compressor compresses refrigerant flowing in the refrigerant pipe to a high temperature and pressure. The accumulator is provided on one side of the compressor, to separate an inflowing refrigerant into a liquid refrigerant and a gaseous refrigerant. The overcooler is provided on one side of the heat exchangers, to further cool refrigerant passing through the heat exchangers.

Abstract: An arrangement for use in a refrigeration system includes a compressor, a condenser, at least one evaporator unit, and at least one expansion valve. The arrangement includes first and second microsystems and first and second controllers. The first microsystem includes a first MEMs sensor configured to measure at least a first operational parameter of a first of the plurality of refrigeration devices. The first controller is operable to generate a first actuator control signal based on a first control signal, and is configured to generate the first control signal based directly or indirectly on the first operational parameter measurement. The second microsystem includes a second MEMs sensor configured to measure at least a second operational parameter of a second of the plurality of refrigeration devices.

Abstract: Disclosed are a central control system for multi-type air conditioners and an operating method thereof. In the central control system, multi-type air conditioners comprise a large number of indoor devices and a small number of outdoor devices, and a central controller is coupled to the multi-type air conditioners over a network. The central controller transmits a control graphic user interface (GUI) program provided therein to the remote control device so that an integrated control operation for respective air conditioners can be carried out. The central controller adjusts a transmission time of the control command signal received from the remote control device and transmits the control command signal to a corresponding air conditioner according to a result of the adjustment so that signal collision can be avoided.

Abstract: An air conditioning system equipped with at least one first air conditioning system in which an outdoor unit is connected to plural indoor units through an inter-unit pipe and the plural indoor units are allowed to execute one of cooling operation and heating operation concurrently, at least one second air conditioning system in which an outdoor unit is connected to plural indoor units through an inter-unit pipe and the plural indoor units are allowed to execute both cooling operation and heating operation in mixture concurrently, and a controller that is connected to the first and second air conditioning systems through a communication line so that communications can be performed between the controller and each of the first and second air conditioning systems, wherein the controller transmits a switching instruction signal for instructing switching of an air conditioning operation to cooling operation or heating operation through the communication line to the first and second air conditioning systems all tog

Abstract: An air conditioner and a power line communication system high in reliability and free of malfunction facilitates the installation work such as the wiring. The air conditioner for conducting communication through a power line includes a bridge unit connected to at least an outdoor unit through a transmission line, and at least an indoor unit connected from the power line through a blocking filter. A side of the bridge unit far from the outdoor unit is connected between the blocking filter and the indoor unit. The bridge unit subjects a signal from the outdoor unit to spread spectrum modulation and transmits it by superposing the resulting signal on the power line. The superposed signal is received and demodulated by the indoor unit.

Abstract: Provided is a geothermal air conditioning system. The system includes a plurality of indoor units, at least one outdoor unit, a ground heat exchanger, and an auxiliary heat source. The plurality of indoor units condition indoor air, the at least one outdoor unit communicates with the indoor units via, a plurality of pipes, and includes an outdoor heat exchanger where heat exchange occurs, and a plurality of compressors for compressing coolant. The ground heat exchanger is connected with the outdoor heat exchanger of the outdoor unit, and laid under the ground to allow heat to be exchanged between ground heat and a circulating medium circulating through the ground heat exchanger. The auxiliary heat source is installed on one side of the outdoor unit to assist heat exchange of the outdoor heat exchanger.

Abstract: A system includes a plurality of distributed refrigeration units respectively coupled to discrete refrigeration circuits. Each refrigeration unit may include a variable compressor, a fixed compressor, a condensing unit, and a controller. The controller compares an operating condition of the refrigeration unit to a refrigeration circuit set point to select a compressor staging capable of achieving the refrigeration circuit set point.

Abstract: A commercial refrigeration system including a compressor, a condenser, a valve, and an evaporator coil, all of which are in fluid communication. The refrigeration system further including a fixture adapted to be cooled by the evaporator coil, a system controller operable to control operation of the refrigeration system, and a subsystem controller in communication with the system controller. The subsystem controller being operable to monitor at least one parameter of a subsystem having at least one of the compressor, condenser, valve, and fixture, and being further operable to execute a command from the system controller to affect the operation of the subsystem.

Abstract: An improved cold climate air-source heat pump comprising at least a primary compressor, a booster compressor, a first heat exchanger associated with an indoor environment and a second heat exchanger associated with an outdoor environment and with one heat exchanger acting as an evaporator and the other heat exchanger acting as a condenser, an expansion device, flow conduit means for circulating a refrigerant fluid in a closed loop, a first sensor means for sensing the temperature of the internal ambient air, a second sensor means for sensing the temperature of the external ambient air, a third sensor means for sensing the temperature of the refrigerant fluid flowing between the booster compressor and the primary compressor, a fourth sensor means for sensing the operative state of the primary compressor, a primary compressor operation control means responsive to inputs from the first sensor means, and a booster compressor operation control means responsive to inputs from the second, third, and fourth sensor me

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 is in parallel one to another with a condenser of the condensing stage and each comprise comprises 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.