A heat transfer circuit that includes a compressor with a gas bearing, a condenser, an expander, an evaporator, a lubricant stream, and a heat source. The lubricant stream receives a portion of the working fluid and supplies the portion of the working fluid to the gas bearing of the compressor. A method of supplying lubricant to a gas bearing of a compressor in a heat transfer circuit includes compressing and further heating at least a portion of the working fluid heated in the evaporator, and supplying the compressed and further heated working fluid to the gas bearing of the compressor. A method of the supplying lubricant to a gas bearing of a compressor in a heat circuit includes generating compressed gaseous working fluid within a lubricant stream.

A heat pump includes a refrigerant loop. The refrigerant loop includes a compressor, a first condenser, a vapor generator having a first region and a second region, a first expansion valve, a second expansion valve, and a first evaporator. A branching point is positioned between the first condenser and the vapor generator. The branching point diverts a portion of a first heat exchange fluid circulating through the refrigerant loop to the vapor generator. The first expansion valve is positioned between the branching point and the vapor generator. An outlet of the vapor generator is coupled to a mid-pressure inlet port of the compressor.

A method of operating a refrigeration system. The method includes operating a multi-temperature refrigeration system that has a plurality of heat absorption heat exchangers in a single temperature mode. A number of the plurality of heat absorption heat exchangers are determined that require defrosting a single heat absorption heat exchanger is directed into a different operational state when the number of heat absorption heat exchangers that require defrosting is equal to one. E of the plurality of heat absorption heat exchangers is directed into a defrost mode when the number of heat absorption heat exchangers that requires defrosting is more than one.

A heat pump water heater and systems and methods for its control. The systems are configured to heat water within a water storage tank of a heat pump water heater wherein a controller within the system is operatively connected to a plurality of heat sources including at least one electric heating element and a heat pump and sensors in order to selectively energize one of the plurality of heat sources. The controller is configure to process data representative of the temperature of water within the tank near the top of the water storage tank, and rate of water flowing out of the water storage tank, in order to automatically selectively energize the heat sources. The selection of heat sources by the controller is determined by a mode of operation selected by the user and the data processed by the controller in view of the selected mode of operation.

The invention relates to a method for real-time performance check of transport refrigeration units comprising the steps of: comparing via controller temperature sensors by pairs and determining from these comparisons by pairs if one or more temperature sensors are defective or in some extent deviates from expected temperature readings; at the same time measuring/monitoring the mass flow of cooling agent through a compressor and through an evaporator expansion valve V.sub.exp which the controller by comparison determines if mass flow through the compressor do not deviate more than 25% from the mass flow through that evaporator expansion valve V.sub.exp; if said deviation of mass flow through the compressor is more than 25% different from said mass flow through the expansion device V.sub.exp, an error signal is provided

An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.

Systems and methods for providing hot water to a commercial dishwasher are provided. A first heat exchanger is provided in a first enclosure, and is used to heat water from a cold water source. The heated water is provided to the commercial dishwasher for use. A second heat exchanger is provided in a second enclosure, and is used to collect waste heat from the wastewater of the commercial dishwasher. A refrigerant coil loop passes through the first heat exchanger and the second heat exchanger, and allows for the use of the waste heat. The first heat exchanger is a condenser provided within a condenser chamber, the condenser connected to a compressor. The second heat exchanger is an evaporator within an evaporator chamber, the evaporator connected to an expansion valve.

A method of operating a water heater is disclosed. The method includes obtaining a first input corresponding to ambient temperature and a second input corresponding to evaporator temperature. The method includes determining the ambient temperature from the first input and the evaporator temperature from the second input, followed by determining whether the ambient temperature is less than a first threshold temperature. The method includes determining whether the evaporator temperature is less than a second threshold temperature when the ambient temperature is less than the first threshold temperature, where the second threshold temperature is less than the first threshold temperature. The method also includes actuating a heating element coupled to one or more tubes of the evaporator to heat refrigerant present in the one or more tubes, when the evaporator temperature is less than the second threshold temperature.

A defrosting device includes a heating unit filled with a working fluid and including an active heating part heated to a first temperature that can evaporate the working fluid, and a passive heating part positioned at a rear side of the active heating part and heated to a lower temperature than the first temperature. The defrosting device also includes a heat pipe disposed adjacent to an evaporator to transfer heat to the evaporator while circulating working fluid heated by the active heating part, the heat pipe including an entrance portion configured to receive working fluid evaporated by the active heating part, and a return portion connected adjacent to the passive heating part and configured to receive working fluid that has condensed after circulating through the heat pipe. Condensed working fluid received at the heating unit first passes through the passive heating part before being reheated at the active heating part.

The present invention relates to a method for getting the interior volume of a thermally insulated space (5) up to temperature and maintaining it at temperature using two thermochemical systems (TCU1; TCU2). According to the invention, a suitable device is supplied and steps are taken to ensure that all the fluid of each of said systems (TCU1; TCU2) is contained in the reservoir (1; 2) of each of said systems (TUC1; TCU2); at least one of said systems (TCU; TCU2) is used to bring said space to a setpoint temperature, a) the reactor (15; 25) of one of said systems (TCU1; TCU2) is heated until fully regenerated, while the other system (TCU1; TCU2) keeps the temperature at said setpoint temperature; b) when the reactor (15; 25) is fully regenerated, said system comprising the reactor that has just been regenerated is used to maintain the temperature and the reactor (15; 25) of the other system (TCU1; TCU2) is heated long as said connection means are connected to said external energy.