A refrigeration cycle apparatus is a refrigeration cycle apparatus having a refrigerant circuit having a compressor, a condenser, a supercooler, an expansion device, and an evaporator connected by a refrigerant pipe, and configured to circulate refrigerant containing refrigerant having a temperature gradient, wherein the supercooler sets a degree of supercooling of the refrigerant, which is a temperature difference between a temperature from the condenser to a refrigerant flow inlet of the supercooler and a temperature in a refrigerant flow outlet on a downstream side of the supercooler, to be larger than the temperature gradient generated at a time of refrigerant shortage of the refrigerant between the refrigerant flow inlet and the refrigerant flow outlet of the supercooler, the refrigeration cycle apparatus including a refrigerant amount determination unit configured to compare a determination threshold value set to a value larger than the temperature gradient of the refrigerant with the degree of supercooling of the refrigerant, and determine whether or not there is a shortage of a refrigerant amount filled in the refrigerant circuit.

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 heat exchanger includes a pipe made of aluminum, a thermistor, and an attaching portion with which the thermistor is attached to the pipe. The pipe carries a flow of refrigerant. The thermistor detects a temperature of the refrigerant. The pipe includes a sacrificial layer provided on a part of a surface of the pipe. The sacrificial layer is lower in potential than the aluminum of the pipe. The attaching portion is higher in potential than the sacrificial layer. At least one part of the attaching portion is attached to the surface of the pipe where the sacrificial layer is not provided. The attaching portion includes a brazed portion that is higher in potential than the sacrificial layer. The thermistor is attached to the pipe with the brazed portion.

A method of searching for a refrigerant leak location is provided which can easily specify the refrigerant leak location. In the method of searching for the refrigerant leak location in a refrigeration apparatus (100) in which a refrigerant is charged and which includes a refrigeration circuit (10) performing a refrigeration cycle, the refrigeration circuit (10) is prepared in a state that the refrigerant containing an odor component is charged therein, and the refrigerant leak location is specified by letting a dog capable of detecting the odor component to run along the refrigeration circuit (10).

Disclosed is a refrigeration system, comprising refrigeration system components, a connecting pipeline, a switch structure, and discharging channels (123, 124; 623, 624). The refrigeration system components comprise three heat exchangers (101; 102; 112). The refrigeration system components can be connected via the connecting pipeline, and are combined into different working systems via the switch structure. When two heat exchangers are selected by the switch structure to form one working system and the saturation temperature corresponding to the internal pressure of the unselected heat exchanger is higher than the medium or environment temperature of the heat exchanger, a liquid refrigerant accumulates inside the non-working heat exchanger. According to the refrigeration system, the switch structure is arranged at either end of the non-working heat exchanger, so that the non-working heat exchanger is isolated from a working system cycle, and under the condition where the pressure at a low-pressure side (C; Q) of the working system is less than the internal pressure of the non-working heat exchanger, additional discharging channels (123, 124; 623, 624) communicate with the non-working heat exchanger and the low-pressure side (C; Q) of the working system, so that the refrigerant accumulating in the non-working heat exchanger is transferred to the system cycle, avoiding a lack of refrigerant in the system cycle.

A set temperature calculating apparatus, a low temperature treatment system, a set temperature calculating method, and a set temperature calculating program are provided for realizing a low temperature treatment. The set temperature calculating apparatus includes: a first obtaining unit configured to obtain data correlating with a heat load in a container storage; a second obtaining unit configured to obtain a set temperature when performing temperature control in the container storage; and a learning unit configured to learn a cargo core temperature in the container storage according to a data set including a combination of the data correlating with the heat load and the set temperature.

An HVAC system includes a reversing valve configured to receive compressed refrigerant and direct the refrigerant based on an operating mode. One or more suction-side sensors measure suction-side properties associated with refrigerant, including a suction-side temperature and a suction-side pressure. One or more liquid-side sensors measure liquid-side properties associated with the refrigerant. A controller monitors the suction-side pressure and liquid-side pressure and determines a ratio of the liquid-side pressure to the suction-side pressure. The controller further determines whether the suction-side temperature has an increasing trend. If the suction-side temperature has the increasing trend, the reversing valve is determined to be in an equalizing configuration. The equalizing configuration corresponds to a configuration in which the refrigerant provided from the outlet of the compressor is directed to the inlet of the compressor without first being directed to other components of the HVAC system.

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.

The present invention provides a system and method for an improved multistage, cascade refrigeration system using hot gas defrost to rid the evaporator of ice build-up which accumulates over time, while the air in the evaporator enclosure remains below the freezing point of water. The present invention thus provides greater defrost flexibility with increased ease of design and implementation than current refrigeration systems, which allows for more robust hot gas defrost function for multistage refrigeration systems, such that it is unaffected by temperature changes of the condensing fluid (ambient air temperature for air cooled condensers, water temperature for water cooled condensers), and can be readily adapted to any refrigerant suitable for a selected temperature range.

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.