Methods and systems for detecting and correcting improper operation of a compressor in a refrigeration system and/or an HVAC system include a component level detection and prevention and a system level detection and prevention. The system level detection and prevention can be a backup or a confirmation of the component level detection and prevention. The component level detection and prevention can detect and prevent improper compressor operation within a predetermined time so that the compressor's operation period in an improper direction can be minimized, thereby minimizing wear and damage to the compressor.

A heat pump system includes a compression device 12, a heat rejecting heat exchanger 14, an expansion device 18 and a heat absorbing heat exchanger 16; wherein the expansion device 18 provides a controllable degree of expansion. The heat pump system is operated in accordance with a method including determining a temperature indicative of frosting conditions on an exterior surface of the heat absorbing heat exchanger 16; operating the heat pump system in a first mode if the temperature indicative of frosting conditions is above a threshold value, and operating the heat pump system in a second mode if the temperature indicative of frosting conditions is within a range of temperatures that is below the threshold value.

A method for operating an air-conditioning system of a motor vehicle, wherein the air-conditioning system comprises a refrigerant circulation and a water circulation which are thermally coupled with one another across a condenser/gas cooler. Water circulation flows through the condenser/gas cooler at a low volumetric rate of flow and a high temperature difference so the water circulation transfers heat in the heating heat exchanger to the air in a similar temperature range. Refrigerant circulation cools from 65° C. to 70° C. to −10° C. to +30° C. and water circulation raises to a temperature of 55° C. to 65° C. and that an adaptation of the temperature profile of the water circulation to the temperature profile of the refrigerant circulation takes place in the condenser/gas cooler utilizing a temperature glide of the refrigerant. The refrigerant is significantly cooled.

A refrigerant control system for controlling a first refrigerant flowing through a first circulation passage connected to a compression unit, including a storing unit which stores a first refrigerant, a first sub-pipe which is connected to an outlet side pipe, a second sub-pipe which is connected to an inlet side pipe, a first opening/closing valve which is provided in the first sub-pipe and is capable of switching whether to flow the first refrigerant in the outlet side pipe to the storing unit, a second opening/closing valve which is provided in the second sub-pipe and is capable of switching whether to flow the first refrigerant in the storing unit to the inlet side pipe, and an opening/closing control unit which controls an opening/closing state of the first opening/closing valve and the second opening/closing valve on the basis of a setting temperature of a second refrigerant set according to a predetermined method.

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 temperature (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.

The present disclosures discloses a precooler-based transcritical CO.sub.2 heat pump system and a control method of a waterway two-way valve thereof, in which a transcritical CO.sub.2 heat pump system is assisted by a precooler system. A circulating waterway is divided into two parts in the system through a three-way diversion valve and a three-way confluence valve and is connected to a waterway bypass valve through a waterway two-way regulating valve. An ambient temperature sensor, an evaporation fin temperature sensor and an evaporation pressure sensor are provided, and a programmable logic controller is used as a core for acquisition, operation and control.

An actively cooled waste receptacle comprises an insulated container including (i) an inner wall defining a chamber having an opening for receiving the waste, and (ii) an outer wall surrounding the inner wall and joined to the inner wall at the opening. The receptacle also includes a cover configured to prevent access to the chamber via the opening in a closed position, and to allow access to the chamber via the opening in an open position; and a heat pump including an interior heat exchanger exposed to the chamber, the heat pump configured to cool the chamber by absorbing heat from air within the chamber via the interior heat exchanger, and transferring the heat outside the insulated container.

An HVAC system includes a compressor, condenser, and evaporator. A sensor measures a value associated with the refrigerant in the condenser or the evaporator, and a controller is communicatively coupled to the compressor and the sensor. The controller determines, based on an operational history the compressor, that pre-requisite criteria are satisfied for entering a sensor validation mode. After determining the pre-requisite criteria are satisfied, an initial sensor measurement value is determined. Following determining the initial sensor measurement value, the compressor is operated according to a sensor-validation mode. Following operating the compressor according to the sensor-validation mode for at least a minimum time, a current sensor measurement value is determined. The controller determines whether validation criteria are satisfied for the current sensor value. In response to determining that the validation criteria are satisfied, the controller determines that the sensor is validated.

A solar distillation system for producing a distillate and providing cooling for a structure or appliance, and a method of using the system to produce a distillate and cool a structure or appliance. The system includes a distillate cooling coil, a secondary cooling coil, an expansion valve which is capable of controlling an amount of a coolant that flows through each of the coils. The system also includes a compressor, a plurality of sensors including a temperature sensor and a distillate flow sensor, and a controller which receives input from the sensors and controls the activity of the compressor and expansion valve. The system is capable of producing distillate at night in the absence of solar radiation.

Provided are a multi-split air conditioning system and a method and device for controlling oil return of the multi-split air conditioning system. The method includes: acquiring a minimum refrigerant flux required for carrying a lubricating oil in the system back to an outdoor unit and a current refrigerant flux of the system every a first preset time during operation of the system; detecting and determining that the current refrigerant flux is less than or equal to the minimum refrigerant flux; acquiring a total oil discharge amount of a compressor since last time oil return; detecting and determining that the total oil discharge amount is greater than a maximum safe oil discharge amount; and controlling the system to return oil.