Apparatus to control device temperature wherein a thermal fluid path transfers a thermal transfer fluid to heat or cool the device; wherein a first path in thermal contact with a heating assembly is fluidly connected at a first end to the thermal fluid path, a second path in thermal contact with a cooling assembly is fluidly connected at a first end to the thermal fluid path, a third path is fluidly connected at a first end to the thermal fluid path, and a valve assembly regulates flow of thermal transfer fluid flow through the first, the second, and the third paths.

Described is, among other things, a method and an apparatus for control of a cooling device. The cooling device comprise a circuit in which a refrigerant fluid is circulated in a fluid path where the circuit comprises a compressor and a condenser provided down streams the compressor. A fluid expansion device is provided down streams the condenser and an evaporator is provided between the fluid expansion device and the compressor. The circuit further comprises a valve provided in the fluid path between the condenser and the fluid expansion device. The method comprises to during an on-cycle of the compressor controlling the valve opening to provide a variable fluid mass flow of the refrigerant fluid circulated in the circuit where the valve opening is controlled to decrease during the on-cycle of the compressor.

A pulse width modulation control is provided for a suction valve located on a suction line. When the flow rate through a refrigerant system needs to be reduced, the suction valve is rapidly cycled from an open position to a closed position. A bypass line connecting compressor discharge to compressor suction with a bypass valve and a discharge valve positioned on the discharge side of the compressor are also provided. When the control closes the suction valve, it also closes the discharge valve to prevent the refrigerant to backflow into the bypass line, and, at the same time, the control opens the bypass valve. Opening of the bypass valve reduces discharge pressure, leading to reduction in compressor power consumption and subsequent operating efficiency gain.

A system includes a flash tank, a load, a first compressor, a second compressor, and a liquid injection line. The flash tank stores a refrigerant. The load uses the refrigerant from the flash tank to remove heat from a space proximate the load. The first compressor compresses the refrigerant from the load. The second compressor compresses the refrigerant from the first compressor. The liquid injection line is coupled to the flash tank and to the second compressor and sends a liquid refrigerant from the flash tank to mix with the refrigerant from the first compressor before the refrigerant from the first compressor is received by the second compressor.

A refrigeration system including a condenser; a (single) linear compressor that is activated and deactivated by a pulse width modulation switching device; a pulse width modulation refrigerant flow switch; at least two evaporators operably connected in parallel with one another with at least one evaporator associated with the refrigerator compartment that operates at a first refrigerant fluid pressure and with at least one other evaporator associated with the freezer compartment that operates at a second refrigerant fluid pressure; and a plurality of refrigerant fluid conduits operably connecting the condenser, the linear compressor and the evaporators into a refrigerant fluid flow circuit and such that the evaporators are capable of running simultaneously at different pressure levels and refrigerant flows from the evaporators, to the pulse width modulation refrigerant flow switch and through the pulse width modulation refrigerant flow switch.

A system includes a temperature sensor, a pressure sensor, and a controller. The temperature sensor measures a temperature of a refrigerant at a compressor. The compressor receives the refrigerant from a second compressor. The pressure sensor measures a pressure of the refrigerant at the compressor. The controller receives one or more of the measured temperature and the measured pressure and determines that one or more of the measured temperature and the measured pressure exceed a threshold. In response to that determination, the controller actuates a pulse valve coupled to a liquid injection line. The pulse valve controls the flow of a liquid refrigerant from a flash tank through the liquid injection line to mix with the refrigerant at the compressor.

A method for distributing a refrigerant charge level in a refrigerant vapor compression system includes restarting a stopped refrigerant compression device in a first mode; operating a primary expansion device independent of refrigerant heat absorption heat exchanger superheat; comparing a condition at a refrigerant reservoir to a prescribed condition; wherein when the condition is below the prescribed condition for a prescribed interval, operating the primary expansion device to control the refrigerant heat absorption heat exchanger superheat; and transitioning the refrigerant vapor compression system to a second mode.

A refrigeration system including a condenser; a (single) linear compressor that is activated and deactivated by a pulse width modulation switching device; a pulse width modulation refrigerant flow switch; at least two evaporators operably connected in parallel with one another with at least one evaporator associated with the refrigerator compartment that operates at a first refrigerant fluid pressure and with at least one other evaporator associated with the freezer compartment that operates at a second refrigerant fluid pressure; and a plurality of refrigerant fluid conduits operably connecting the condenser, the linear compressor and the evaporators into a refrigerant fluid flow circuit and such that the evaporators are capable of running simultaneously at different pressure levels and refrigerant flows from the evaporators, to the pulse width modulation refrigerant flow switch and through the pulse width modulation refrigerant flow switch.

A refrigeration system including a condenser; a (single) linear compressor that is activated and deactivated by a pulse width modulation switching device; a pulse width modulation refrigerant flow switch; at least two evaporators operably connected in parallel with one another with at least one evaporator associated with the refrigerator compartment that operates at a first refrigerant fluid pressure and with at least one other evaporator associated with the freezer compartment that operates at a second refrigerant fluid pressure; and a plurality of refrigerant fluid conduits operably connecting the condenser, the linear compressor and the evaporators into a refrigerant fluid flow circuit and such that the evaporators are capable of running simultaneously at different pressure levels and refrigerant flows from the evaporators, to the pulse width modulation refrigerant flow switch and through the pulse width modulation refrigerant flow switch.

A system includes a temperature sensor, a pressure sensor, and a controller. The temperature sensor measures a temperature of a refrigerant at a compressor. The compressor receives the refrigerant from a second compressor. The pressure sensor measures a pressure of the refrigerant at the compressor. The controller receives one or more of the measured temperature and the measured pressure and determines that one or more of the measured temperature and the measured pressure exceed a threshold. In response to that determination, the controller actuates a pulse valve coupled to a liquid injection line. The pulse valve controls the flow of a liquid refrigerant from a flash tank through the liquid injection line to mix with the refrigerant at the compressor.