An air conditioning apparatus includes utilization-side units each including a first refrigerant circuit, a heat source-side unit including a second refrigerant circuit, a connection pipe group, and a relay unit. The relay unit is disposed between the first refrigerant circuit and the second refrigerant circuit, and blocks a flammable refrigerant flowing through the connection pipe group. The utilization-side units are disposed in a utilization-side unit group that is a group of two or more utilization-side units. The relay unit blocks a flow of the refrigerant between the first refrigerant circuit and the second refrigerant circuit. The connection pipe group connects the first refrigerant circuit and the refrigerant shut-off unit. The connection pipe group has one or both of a length and an internal volume, which is fixed based on information on capabilities of the two utilization-side units.

A refrigerated display cabinet includes a refrigeration loop including a compressor, a condenser, a throttling element and an evaporator; a main body comprising a storage space, the evaporator is for cooling the storage space and at least one of the compressor, condenser and throttling element are located outside of the storage space; and a fan arrangement located outside of the storage space, configured to direct air to disperse any build-up of gases located in a region surrounding the bottom of the refrigerated display cabinet.

A monitoring and control system/method for use in heating, ventilation, and air conditioning (HVAC) systems is disclosed that incorporates a digital control processor (DCP) controlling and monitoring the operation of a HVAC system incorporating evaporator elements (refrigerant valve (EFV), coil (HEC), fan (HEF), relay (HER)) and condenser elements (refrigerant valve (CRV), coil (HCC), fan (HCF), compressor motor (HCM), relay (HCR)) via a sensor/control bus. The HVAC elements may be monitored by the DCP using sensors measuring ambient refrigerant gas (RGS), refrigerant temperature (RTS), refrigerant pressure (RPS), duct air flow (AFS), ambient temperature/humidity (THS), and operational current/voltage (CVS). The DCP is configured to activate an alarm status indicator (ASI) and HVAC shutdown control (HSC) in the event of a detected HVAC system fault and interact with a wireless user interface (WUI) and mobile user device (MUD) to enable remote monitoring and control of the HVAC system.

A refrigerant cycle apparatus includes a refrigerant circuit that circulates a refrigerant, and a leak sensor that detects a refrigerant leaking from the refrigerant circuit, in which the refrigerant cycle apparatus includes, as an operating mode, a recovery mode for recognizing occurrence of an abnormality in the leak sensor and recovering a refrigerant to a predetermined location in the refrigerant circuit.

A control system for controlling the flow of refrigerant includes: an inlet valve configured to selectively isolate or couple a supply path for supplying refrigerant from a refrigeration system with an inlet of a cooling loop; an outlet valve configured to selectively isolate or couple a return path for returning refrigerant to the refrigeration system with an outlet of the cooling loop; a refrigerant collection valve configured to selectively isolate or couple a refrigerant collection path for collecting refrigerant for the refrigeration system with the cooling loop; a pressure sensor for determining a pressure of refrigerant in the cooling loop; an input for receiving cooling loop disconnect and connect commands; and control circuitry configured to receive signals from the pressure sensor and the commands from the input and to generate control signals for controlling the opening and closing of the inlet, outlet and refrigerant collection valves in response thereto.

A sensor-integrated expansion valve includes: a PT sensor installed in a sensor hole of a valve body to detect pressure and temperature of refrigerant in a refrigerant flow path, the PT sensor including a sensor body assembled to the valve body portion around the sensor hole, a sensing rod inserted from the sensor body into the sensor hole and having an end portion exposed into the refrigerant flow path, and a sensor circuit board configured to process data on the pressure and the temperature of the refrigerant detected by the sensing rod and transmit the data to a main circuit board of the on the valve body; a thread fastening assembly part configured to threadedly fasten and remove the PT sensor to and from the sensor hole of the valve body; and an electrical connection part configured to constantly electrically connect the sensor circuit board to the main circuit board.

A propane gas-utilizing system includes a housing having propane gas and a propane leakage prevention material having a catalyst, scavenger, and/or oxidizer of the propane gas arranged in the housing and including at least one of (a) an oxide material having at least one composition of formula (I): Ru.sub.1-xM.sub.xO.sub.2 (I), where 0<x0.1 and M is Ag, K, Pt, Rh, or Ir, or (b) an oxide material having at least one composition of formula (II): Co.sub.3-xM.sub.xO.sub.4 (II), where 0<x0.3, and M is Pd, Cu, or Sr, or (c) an oxide material having at least one composition of formula (III): MM.sub.xO.sub.y (III), where x is a stoichiometric ratio of M to M, 0x1.5, y is a stoichiometric ratio of O to M, 1y3, M is an alkali metal, and M (if x>0) is Y, Ce, Nb, Ta, La, Nd, Mn, Ag, Au, or Cr.