A refrigeration plant (100) for cooling a target fluid to a target temperature between 80 C. and +30 C. by means of ambient air, having a compressor refrigerant system (105) having a compressor (125) and a target heat exchanger (120) for cooling the target fluid; a natural circulation refrigerant system (140) having an ambient air condenser (145) and a control valve (165), and an intermediate heat exchanger (120) which couples the natural circulation refrigerant system (140) to the compressor refrigerant system (105).

A method for controlling a fan (6) of a vapour compression system (1) is disclosed, the fan (6) being arranged to provide a secondary fluid flow across a heat rejecting heat exchanger (3). A temperature difference, T=T.sub.outT.sub.amb, between a temperature, T.sub.out, of refrigerant leaving the heat rejecting heat exchanger (3) and a temperature, T.sub.amb, of ambient air of the heat rejecting heat exchanger (3) is established. A setpoint value, T.sub.setp, for the temperature difference, T, is obtained, the setpoint value, T.sub.setp, being dependent on the fan speed of the fan (6) in such a manner that the setpoint value, T.sub.setp, increases as the fan speed increases. The fan speed of the fan (6) is controlled in order to control the temperature difference, T, in accordance with the obtained setpoint value, T.sub.setp.

An automated refrigerant recharging system determines whether a cooling load parameter of a direct expansion (DX) cooling system that cools information technology (IT) modules of an information handling system (IHS) has reached a defined recharging threshold that results in a response of the pressure value for measurement by the pressure transducer. In response to the cooling load parameter being equal to or greater than the defined recharging threshold, a controller determines whether a pressure value of the refrigerant of the DX cooling system is less than a defined target pressure value corresponding to the defined recharging threshold. In response to determining that the pressure value of the refrigerant of the DX cooling system is less than the defined target pressure value, the controller autonomously opens a control valve to transfer refrigerant to the DX cooling system.

A refrigeration cycle apparatus in which a compressor, a heat-source-side heat exchanger, a decompressor, and a use-side heat exchanger are connected by pipes to allow refrigerant to be circuited as a refrigeration cycle. The refrigeration cycle apparatus includes a controller which controls an operation of each of devices. The controller sets an operation mode to a specific operation mode for determining where abnormality occurs based on states of the compressor, the heat-source-side heat exchanger, the decompressor and the use-side heat exchanger in the case where an operating state of one of a plurality of element devices to be controlled by the controller is changed from a first state to a second state, the element devices being included in the compressor, the heat-source-side heat exchanger, the decompressor and the use-side heat exchanger.

An apparatus includes a first compressor, a first load, a second compressor, a second load, and a heat exchanger. The first compressor compresses a first refrigerant. The first load uses the first refrigerant to remove heat from a space proximate the first load. The first load sends the first refrigerant to the first compressor. The second compressor compresses a second refrigerant. The second load uses the second refrigerant to remove heat from a space proximate the second load. The second load sends the second refrigerant to the second compressor. The heat exchanger receives the first refrigerant from the first compressor and receives the second refrigerant from the second compressor. The heat exchanger transfers heat from the first refrigerant to the second refrigerant. The heat exchanger discharges the first refrigerant to the first load and discharges the second refrigerant to the second compressor.

A method controls the level of liquid within an evaporator of a flooded-type chiller without level sensors. The flooded-type chiller includes at least one compressor, a condenser, an expansion valve and an evaporator. A number of sensors positioned in the system measures a number of first parameter information values. A controller calculates a number of second parameter information values based on the measured first parameter information values and further determines a virtual refrigerant level as a control signal based on the second parameter information values. Based on the determined virtual refrigerant level, the controller opens, closes or holds the expansion valve with respect to a dead zone for maintaining a pre-defined target refrigerant level so as to provide the desired refrigerant level and oil in the evaporator.

A transport refrigeration system includes a compressor, a heat rejection heat exchanger, a flash tank, an expansion device and a heat absorption heat exchanger arranged in a serial refrigerant flow order to circulate a refrigerant; a controller configured to: determine a presence of at least one condition of the transport refrigeration system; and initiate a low refrigerant charge detection process in response to detecting the presence of the at least one condition of the transport refrigeration system.

This air conditioning device for a vehicle has: an indoor condenser; an indoor evaporator; a first expansion valve; a second expansion valve; a refrigerant line; an expansion valve control detector; and a controller. The expansion valve control detector is constituted by: only one temperature sensor that detects the temperature of refrigerant in an inter-expansion valve line of the refrigerant line; and only one pressure sensor that detects the pressure of the refrigerant in the inter-expansion valve line. During a cooling operation, the controller issues, to the first expansion valve, an opening command corresponding to a state quantity of the refrigerant that has been detected by the expansion valve control detector, and during a heating operation, the controller issues, to the second expansion valve, an opening command corresponding to a state quantity of the refrigerant that has been detected by the expansion valve control detector.

Embodiments of the present disclosure are directed to a controller for a heating, ventilation, and/or air conditioning (HVAC) system. The controller is configured to operate in a first defrost mode or a second defrost mode, determine that feedback from a first sensor of the HVAC system is unavailable, receive feedback from a second sensor of the HVAC system, and operate the HVAC system in the second defrost mode instead of the first defrost mode in response to unavailability of the feedback from the first sensor and based on the feedback from the second sensor.

The oil level in a compressor is lowered upon activation of the compressor. A heat pump-type heating device of the present invention includes: a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, a motor-operated valve, and a target-side heat exchanger are provided; and an outdoor fan which is provided for the heat-source-side heat exchanger. The target-side heat exchanger is capable of heating, by a refrigerant, fluid supplied from outside. The rotation number of the outdoor fan upon activation of the compressor when a difference between a temperature of the fluid supplied to the target-side heat exchanger and an outside temperature is equal to or larger than a predetermined temperature difference is smaller than the rotation number when the difference is smaller than the predetermined temperature difference.