The invention relates to a switch cabinet arrangement with at least one switch cabinet housing and at least one cooling device for cooling air contained in the switch cabinet arrangement, wherein the cooling device has at least one refrigerant circuit including a flammable refrigerant, wherein the switch cabinet arrangement has at least one refrigerant sensor which detects a concentration of the flammable refrigerant in the air and is evaluated by a control unit which is adapted to trigger a safety function for reducing the concentration of the flammable refrigerant in the air below the threshold value if a threshold value of the concentration is exceeded. A corresponding method is also described.

A computing device calculates a quality of a refrigerant flowing out of an expansion device on the basis of an inlet liquid enthalpy calculated on the basis of a temperature of the refrigerant flowing into the expansion device, and a saturated gas enthalpy and a saturated liquid enthalpy calculated on the basis of a temperature or pressure of the refrigerant flowing out of the expansion device; calculates a liquid-phase concentration and a gas-phase concentration of the refrigerant flowing out of the expansion device on the basis of the temperature and pressure of the refrigerant flowing out of the expansion device; and calculates a composition of the refrigerant circulating in a refrigeration cycle on the basis of the calculated quality, liquid-phase concentration, and gas-phase concentration.

Disclosed are methods of recharging an operating system of the type containing a less than full charge of existing working fluid with a recharging fluid that is different than said existing fluid, the method comprising: (a) identifying at least one readily measured physical property of fluids comprising combinations of the existing working fluid and the recharging working fluid wherein said physical property reliably correlates to target component concentrations of the working fluid after recharge; (b) providing a system which contains less than a full charge of the existing working fluid; (c) adding to the existing working fluid a recharging fluid having at least one property superior to that property of the existing working fluid; (d) at least after said adding step (c), measuring said readily measured physical property of the operating fluid in the system; and (e) based on said measuring step, repeating or not said steps (c) and (d) and/or adjusting at least one system operating parameter.

A method of measuring concentrations of gas mixtures is disclosed in which an ionic liquid and/or low vapor-pressure organic solvent is exposed to a gas mixture being tested to form a solution of the gas components in the liquid. The vapor pressure of the solution is then measured at one or more other temperatures and compared to predicted vapor pressures based on known individual vapor pressure profiles of the gas components in the liquid in order to determine the actual proportions of the components in the gas sample.

An air-conditioning apparatus directly detects leakage of a plurality of types of refrigerant by computing refrigerant concentrations, and ensure safety. On the basis of calibration curve information, a computing device computes the concentration of heat source side refrigerant in a heat medium relay unit from detected information received from a concentration detecting device.

An autocascade heat transfer fluid circuit includes an evaporator, a sub-cooler, a heat exchanger, a compressor, a condenser, a working fluid concentration sensor, a pressure sensor, a temperature sensor, and a unit controller. The unit controller converts properties of respective components of a working fluid flowing through the heat transfer fluid circuit; receive a temperature and pressure of the working fluid; convert the received properties, temperature, and pressure of the working fluid into concentration percentages for the respective components of the working fluid; determine a suction super heat of the working fluid based on the concentration percentages for the respective components of the working fluid; and control an expander to regulate a flow of the working fluid into an evaporator based on the determined suction super heat of the working fluid.