A refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port.

A method of heating a component within a heating, ventilation and air conditioning (HVAC) system is provided. The method includes maintaining a non-heating condition of the HVAC system component when the HVAC system component is in a non-operational state. The method also includes determining when the HVAC system component will switch from the non-operational state to an operational state, the determination based on a threshold parameter being met. The method further includes operating a heating device from the non-heating condition to a heating condition to heat the HVAC system component from a temperature to a target temperature suitable for the operational state of the HVAC system component.

A refrigeration system having a refrigerant circuit including a condenser, a flow control device, an evaporator, and a compressor connected in series. The compressor is configured to circulate a cooling fluid through the refrigerant circuit. The refrigerant circuit has an inlet line fluidly connecting the condenser to the evaporator and a suction line fluidly connecting the evaporator to the compressor. A heater is positioned to heat the cooling fluid during a defrost mode, and a pressure control is coupled to the refrigerant circuit downstream of the evaporator. In the defrost mode, the pressure control apparatus is configured to increase system pressure during the defrost mode to maintain flow of refrigerant into the evaporator and to control flow of cooling fluid to the compressor.

A refrigeration system includes a compressor connected to a first heat exchanger and a second heat exchanger. An expansion device is connected between the first heat exchanger and the second heat exchanger. A ratio of a volume of the first heat exchanger to a volume of the second heat exchanger is between 0.6 and 1.8.

In one aspect, a refrigeration system is provided. The refrigeration system includes a compressor coupled to a variable frequency drive (VFD), a condenser, an evaporator, an oil separator, and an oil conditioning circuit. The oil conditioning circuit is thermally coupled to the VFD and configured to heat oil from the oil separator with heat produced by the VFD.

A vaporizer has: an inlet (72); an oil outlet (90; 94); a vent (120); a hot gas inlet (132); and a cooled gas outlet (134). A gas flowpath (130) extends from the hot gas inlet to the cooled gas outlet. A vaporizer chamber (192) is downstream of the inlet along a primary flowpath. A gas conduit (220) is along the gas flowpath in heat exchange relation with the primary flowpath. A sump (194) is below the vaporizer chamber. A housing (180) encloses the sump and the vaporizer chamber. A passageway extends from the vaporizer chamber to the sump.

A heat pump device includes: a compressor that compresses a refrigerant; a motor that drives the compressor; a wiring switching unit that switches a wiring structure of the motor; an inverter that applies a desired voltage to the motor; and an inverter control unit that generates a PWM signal for driving the inverter, that includes, as an operation mode, a heating operation mode in which a heating operation is performed on the compressor and a normal operation mode in which a refrigerant is compressed by performing a normal operation on the compressor, and that controls a switching operation of the wiring switching unit in accordance with an operation mode.

The disclosure presents a heat exchanger assembly for a heat pump system, having a heated condensate drainage system. The heat exchanger assembly includes a manifold with a plurality of pins extending substantially in the direction of gravity. A condensate drainage tray is positioned beneath the manifold. The drainage tray includes a plurality of drainage holes corresponding with the number and position of the pins. The pins extend from the manifold and through the corresponding the drainage holes of the drainage tray. Each of the plurality of pins includes a diameter smaller than the diameter of the drainage hole to allow for condensate to drain through the drainage hole. At least one of the pins includes a distal end and is tapered toward the distal end. The drainage tray may be tilted with respect to the manifold.

A refrigeration system includes a compressor having a first stage and a second stage; a heat rejecting heat exchanger including an inter-cooler and a gas cooler, the intercooler coupled to an outlet of the first stage and the gas cooler coupled to an outlet of the second stage; an unload valve coupled to an outlet of the intercooler and a suction port of the first stage; a flash tank coupled to an outlet of the gas cooler; a primary expansion device coupled to an outlet of the flash tank; a heat absorbing heat exchanger coupled to an outlet of the primary expansion device, an outlet of the heat absorbing heat exchanger coupled to the suction port of the first stage; and a controller for executing a startup process including controlling the unload valve to direct refrigerant from the intercooler to the suction port of the first stage.

A temperature control system according to one embodiment includes: a refrigeration apparatus in which a compressor, a condenser, an expansion valve and an evaporator are connected in this order for circulating a refrigerant; a fluid circulation apparatus that causes a fluid to be heat-exchanged in the evaporator, then sends the fluid to a temperature control object, and again causes the fluid having passed through the temperature control object to be heat-exchanged in the evaporator, the fluid circulation apparatus having a heater at a position downstream of the temperature control object and upstream of the evaporator; and a control apparatus. The control apparatus activates the heater to heat the fluid by the heater, when the fluid circulation apparatus has become in a no-load operation state or a no-load-operation transition operation state, wherein the no-load operation state is a state in which the fluid and the temperature control object do not heat-exchange, the no-load-operation transition operation state is a state that is in transition to the no-load operation state.