To provide a working fluid for heat cycle having a low global warming potential, which can replace R410A, a composition for a heat cycle system comprising it, and a heat cycle system employing the composition.

A working fluid for heat cycle, which comprises trifluoroethylene and 2,3,3,3-tetrafluoropropene, wherein the total proportion of trifluoroethylene and 2,3,3,3-tetrafluoropropene based on the entire amount of the working fluid is from 70 to 100 mass %, and the proportion of trifluoroethylene based on the total amount of trifluoroethylene and 2,3,3,3-tetrafluoropropene is from 35 to 95 mass %, a composition for a heat cycle system comprising the working fluid for heat cycle, and a heat cycle system employing the composition.

In an air-conditioning apparatus, an indoor unit and an outdoor unit are connected to each other by a refrigerant pipe through which refrigerant flows. The air-conditioning apparatus includes: a refrigerant detection unit that detects a leak of the refrigerant in the indoor unit; a notification unit that makes a notification indicating occurrence of the leak of the refrigerant; a controller that controls at least the notification unit; and a remote control unit configured to operate the indoor unit. When the refrigerant detection unit detects the leak of the refrigerant, the controller controls the notification unit to make in a first mode the notification indicating the occurrence of the leak of the refrigerant, and make the notification in a second mode different from the first mode after a predetermined time period elapses from time at which the notification in the first mode is made. Thus, since the notification of the refrigerant leak is made two steps, that is, in the first mode in a first step and in the second mode in a second step, it is possible to cause a user to pay more attention to the notifications, and thus cause the user to easily notice the notification. It is therefore possible to cause the user to sufficiently know the refrigerant leak.

The present invention provides cascade refrigeration systems in which the low stage comprises a refrigerant with a GWP less than 150, and the high stage comprises a refrigerant that is either Class A1 or Class A2L and comprises at least about 75% by weight of HFO-1234ze(E).

To provide a working fluid for heat cycle having a low global warming potential, which can replace R410A, a composition for a heat cycle system comprising it, and a heat cycle system employing the composition. A working fluid for heat cycle, which comprises trifluoroethylene and 2,3,3,3-tetrafluoropropene, wherein the total proportion of trifluoroethylene and 2,3,3,3-tetrafluoropropene based on the entire amount of the working fluid is from 70 to 100 mass %, and the proportion of trifluoroethylene based on the total amount of trifluoroethylene and 2,3,3,3-tetrafluoropropene is from 35 to 95 mass %, a composition for a heat cycle system comprising the working fluid for heat cycle, and a heat cycle system employing the composition.

A heating, ventilating, and air conditioning (HVAC) system includes a refrigerant loop having a compressor, where the compressor is configured to circulate a refrigerant through the refrigerant loop, a first heat exchanger disposed along the refrigerant loop, where the first heat exchanger is configured to place the refrigerant in a first heat exchange relationship with a working fluid, and an air handling unit having a second heat exchanger, where the second heat exchanger is configured to place the working fluid in a second heat exchange relationship with an airflow, and where the air handling unit is isolated from the first heat exchanger to reduce or eliminate mixing of refrigerant with the airflow.

A working fluid for heat cycle, a composition for a heat cycle system containing the working fluid, and a heat cycle system employing the composition are provided. The working fluid has a low global warming potential and can replace R410A. The working fluid contains trifluoroethylene, 2,3,3,3-tetrafluoropropene, and optionally a hydrofluoroolefin other than trifluoroethylene and 2,3,3,3-tetrafluoropropene. The total proportion of trifluoroethylene and 2,3,3,3-tetrafluoropropene based on the entire amount of the working fluid is from 70 to 100 mass %.

A gas heat pump system including an outdoor unit having a compressor, an outdoor heat exchanger, and an expansion device; an indoor unit having an indoor heat exchanger; a refrigerant pipe to connect the outdoor unit and the indoor unit; an engine to combust mixed fuel in which fuel and air are mixed; a coolant tank to store a coolant; a radiator to emit, to an outside, heat which is transferred from the engine to the coolant; and a coolant pipe to connect the coolant tank and the radiator to allow the coolant to circulate therethrough, whereby the gas heat pump system has a cooling capability between 71 kW and 85 kW, the refrigerant is a mixed refrigerant having at least 50% R32, and the refrigerant pipe is a ductile stainless steel pipe having a delta ferrite matrix structure of 1% or less based on grain area.

Disclosed is a gas detector system for a refrigerated interior volume of a transportation refrigeration unit (TRU), the system having: a gas detector that defines an enclosure, the enclosure defines a chamber therein, the cover including a chamber opening, and an infrared (IR) sensor within the chamber; and a heater adjacent to or within the enclosure, the heater configured to reduce moisture within the chamber and/or prevent moisture from accumulating from within the chamber during a refrigeration cycle.

An air-conditioning apparatus includes a refrigerant circuit that is formed of an outdoor unit and an indoor unit connected through indoor/outdoor connection pipes. The outdoor unit includes a compressor, an outdoor heat exchanger, and an expansion valve. The indoor unit includes an indoor heat exchanger. Combustible refrigerant is used as refrigerant flowing through the refrigerant circuit. The outdoor unit includes a refrigerant filling-dedicated connection port to fill the refrigerant and an evacuation-dedicated connection port to evacuate the refrigerant inside the refrigerant circuit. The refrigerant filling-dedicated connection port is provided inside a machine chamber that accommodates the compressor and the expansion valve, and the evacuation-dedicated connection port is provided outside the machine chamber.

A controller of a heating, ventilation, and air conditioning (HVAC) system, the controller comprising instructions that cause the controller to determine an air flowrate of an air blower of the HVAC system and calculate a threshold value based on a minimum required air flowrate. The controller further comprises instructions that cause the controller to send a notification to an operator of the HVAC system indicating that the air flowrate of the air blower is less than the threshold value in response to determining that the air flowrate of the air blower is less than the threshold value and shut down the HVAC system such that the refrigerant is no longer circulated by the componentry of the HVAC system in response to determining that the air flowrate of the air blower is less than the minimum required air flowrate.