A system and method of freeze protection for a chiller including a metering device in flow communication with a condenser, a controller in electrical communication with the metering device, wherein the controller is configured to determine whether the difference between the fluid characteristic of the first liquid and the fluid characteristic of the second liquid is greater than a freezing limit, and enter a freeze protection mode if the difference between the fluid characteristic of the first liquid and the fluid characteristic of the second liquid is greater than the freezing limit.

A method of mitigating a freeze event in an HVAC system includes measuring a saturated suction temperature, receiving actual temperature value reflective of the measured saturated suction temperature, determining whether the actual temperature value is less than a first pre-determined minimum threshold temperature value, and responsive to a determination that the actual temperature value is less than the first pre-determined minimum threshold temperature value, initiating a timer to operate for a pre-determined time interval. Determining whether the actual temperature value is less than a second pre-determined minimum threshold temperature value. Responsive to a determination that the actual temperature value is less the second pre-determined minimum threshold temperature value, initiating the timer to operate for a modified time interval, determining whether the timer operating for the modified time interval has expired, and responsive to a determination that the timer has expired, modifying operation of a compressor.

In an embodiment, a method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system is performed by a controller in the HVAC system. The method includes determining a reference saturated suction temperate (SST) via a sensor disposed in relation to an evaporator coil in the HVAC system. The method also includes determining whether the reference SST is below a minimum SST threshold. The method also includes, responsive to a determination that the reference SST is below the minimum SST threshold, increasing a discharge air temperature (DAT) setpoint.

A valve device includes a case having an opened bottom portion and a receiving space formed therein, a base plate covering the open bottom of the case, a flow-in pipe coupled to the base plate to bring in a refrigerant, a boss installed to the base plate and including a plurality of refrigerant flow-in/out holes through which the introduced refrigerant flows in/out, a plurality of flow-in/out pipes coupled to the plurality of refrigerant flow-in/out holes and through which the introduced refrigerant flows in/out, and a pad arranged on the boss and including an open cavity formed therein to selectively opening one of the plurality of refrigerant flow-in/out holes and a connection cavity formed therein to selectively connecting two of the plurality of refrigerant flow-in/out holes.

A data center cooling system has an indoor portion wherein heat is absorbed from components in the data center, and an outdoor heat exchanger portion wherein outside air is used to cool a first heat transfer fluid (e.g., water) present in at least the outdoor heat exchanger portion of the cooling system during a first mode. When an appropriate time has been reached to switch from the first mode to a second mode, the outdoor heat exchanger portion of the data cooling system is switched to a second heat transfer fluid, which is a relatively low performance heat transfer fluid (compared to the first fluid). It has a second heat transfer fluid freezing point, lower than the first heat transfer fluid freezing point, and sufficiently low to operate without freezing when the outdoor air temperature drops below a first predetermined relationship with the first heat transfer fluid freezing point.

A heat pump system and a control method therefor are provided. The heat pump system includes an outdoor heat exchanger and an electromagnetic heating assembly. The electromagnetic heating assembly includes an induction heating sheet, an insulation plate, and an electromagnetic induction wire coil. The induction heating sheet is in contact with the outdoor heat exchanger, the electromagnetic induction wire coil is attached to the insulation plate, the insulation plate is connected to the outdoor heat exchanger or the induction heating sheet, the induction heating sheet is coupled with the electromagnetic induction wire coil by communication.

An outdoor unit for a heat pump includes a refrigerant circuit, the outdoor unit including a compressor, a discharge pipe of the refrigerant circuit connected to a discharge side of the compressor, a bottom plate, the bottom plate having a base and an outer flange protruding upward from an outer edge of the base, a heat source heat exchanger supported on the bottom plate, a liquid refrigerant pipe of the refrigerant circuit connected to the heat source heat exchanger, and a defrosting bypass pipe connected at one end to the discharge pipe and at the opposite end to the liquid refrigerant pipe, the defrosting bypass pipe being arranged between an inner side of the flange and an outer side of the heat source heat exchanger.

An object is to provide a refrigeration cycle apparatus capable of reducing freezing in a lower part of a heat exchanger in which drainage water tends to accumulate and reducing an amount of refrigerant in a refrigerant circuit. The refrigeration cycle apparatus includes the refrigerant circuit 1 connecting, by refrigerant pipes, a compressor, a first expansion device, and a first heat exchanger configured to serve as evaporator during heating operation. The first heat exchanger is provided with a first heat exchange unit and a second heat exchange unit connected to the first heat exchange unit in series in the refrigerant circuit. The first expansion device is connected in parallel with the second heat exchange unit in the refrigerant circuit, and the second heat exchange unit is placed at a position lower than a position of the first heat exchange unit.

Provided is an air conditioning apparatus. The air conditioning apparatus includes a heat exchanger in which the refrigerant and the water are heat-exchanged with each other, a high-pressure guide tube extending from a high-pressure gas tube of an outdoor unit so as to be connected to one side of the heat exchanger, a low-pressure guide tube extending from a low-pressure gas tube of the outdoor unit so as to be combined with the high-pressure guide tube, a liquid guide tube extending from a liquid tube of the outdoor unit so as to be connected to the other side of the heat exchanger, a bypass tube configured to connect a bypass branch point of the high-pressure gas tube to a bypass combination point of the liquid guide tube to bypass a high-pressure refrigerant existing in the high-pressure tube to the liquid guide tube, and a bypass valve installed in the bypass tube.

An inside air-conditioning device includes a refrigerant circuit (50) and a refrigerant that is sealed in the refrigerant circuit (50). The refrigerant circuit (50) includes a compressor (10), a condenser (25), an electronic expansion valve (13), and an evaporator (17). The refrigerant contains at least 1,2-difluoroethylene.