A refrigeration machine control device according to an embodiment of the present invention serves to control a turbo refrigeration machine and is equipped with a pressure reduction rate identification unit for identifying a pressure reduction rate at which foaming does not occur in an oil tank, and a pressure adjustment unit for adjusting the pressure of an evaporator on the basis of the identified pressure reduction rate. The pressure reduction rate identification unit is equipped with: a refrigerant precipitation gas volume calculation unit for calculating the volume of refrigerant gas precipitated from lubricating oil when the pressure is reduced at a prescribed pressure reduction rate; and a determination unit for determining whether or not foaming is permissible on the basis of a comparison between the calculated volume and the volume on the surface of the oil in the oil tank.

A management device includes: storage unit which stores a known intake air temperature of a heating element, and a heat transfer characteristic of a cooling device; heat extraction amount calculation unit which calculates a heat extraction amount of the cooling device, by use of the refrigerant information input by the input means, and a cooling capacity of the refrigerant; and air volume calculation unit which calculates an air volume of air supplied to the cooling device, by applying the heat extraction amount to air volume dependence of the heat extraction amount, being derived by use of air volume dependence of a difference temperature between a temperature of the refrigerant and a temperature of exhaust air from the heating element, and the heat transfer characteristic, the air volume dependence of the difference temperature being derived by use of the intake air temperature, the power consumption, and the refrigerant information.

A system utilizing cascading heat pump circuits (HPCs) is employed to efficiently transfer heat from low temperature reservoirs to high temperature reservoirs. The system of cascading (e.g., multistage) HPCs include at least two HPCs that are in thermal communication. The first HPC uses a first refrigerant and is configured to raise a first cold operating temperature to a first hot operating temperature. The second HPC uses a second refrigerant and is configured to raise a second cold operating temperature to a second hot operating temperature. The second HPC is in thermal communication with the first HPC through a thermal exchange block, which allows the transfer of heat between the HPCs and causes the first hot temperature to be equilibrated with the second cold temperature. The cascading HPC system also includes a system controller that is configured to optimize the coefficient of performance (COP) of the cascading HPC system.

A management device includes: storage unit which stores a known intake air temperature of a heating element, and a heat transfer characteristic of a cooling device; heat extraction amount calculation unit which calculates a heat extraction amount of the cooling device, by use of the refrigerant information input by the input means, and a cooling capacity of the refrigerant; and air volume calculation unit which calculates an air volume of air supplied to the cooling device, by applying the heat extraction amount to air volume dependence of the heat extraction amount, being derived by use of air volume dependence of a difference temperature between a temperature of the refrigerant and a temperature of exhaust air from the heating element, and the heat transfer characteristic, the air volume dependence of the difference temperature being derived by use of the intake air temperature, the power consumption, and the refrigerant information.

A refrigeration machine control device according to an embodiment of the present invention serves to control a turbo refrigeration machine and is equipped with a pressure reduction rate identification unit for identifying a pressure reduction rate at which foaming does not occur in an oil tank, and a pressure adjustment unit for adjusting the pressure of an evaporator on the basis of the identified pressure reduction rate. The pressure reduction rate identification unit is equipped with: a refrigerant precipitation gas volume calculation unit for calculating the volume of refrigerant gas precipitated from lubricating oil when the pressure is reduced at a prescribed pressure reduction rate; and a determination unit for determining whether or not foaming is permissible on the basis of a comparison between the calculated volume and the volume on the surface of the oil in the oil tank.

A centrifugal chiller includes a first expansion unit (23) that expands refrigerant that has been compressed and condensed, and an evaporation unit (41) that evaporates the expanded refrigerant and supplies the evaporated refrigerant to a compression unit (15). The first expansion unit (23) has an orifice (20) through which refrigerant condensed by a condensation unit (17) passes, and a flow rate regulation valve (22) that can regulate the amount of refrigerant condensed by the condensation unit (17) flowing through and that is connected in parallel with the orifice (20).

The various implementations described herein include methods, devices, and systems for starting-up a vehicle air-conditioning system. In one aspect, a method is performed at a vehicle air-conditioning system including a blower fan, a condenser fan, and a compressor electrically coupled to a battery system. The method includes: (1) starting the blower fan; (2) after starting the blower fan, measuring a first current drawn from the battery system, the first current indicative of current drawn by the blower fan; (3) in accordance with a determination that the first current meets predefined criteria, starting the condenser fan; (4) after starting the condenser fan, measuring a second current drawn from the battery system, where the difference between the second current and the first current is indicative of current drawn by the condenser fan; and (5) in accordance with a determination that the second current meets predefined second criteria, starting the compressor.

A system for cooling a refrigerant includes (a) an evaporator comprising one or more lengths of tubing each having an upstream first cross-sectional area and a second downstream cross-sectional area, the second cross-sectional area being greater than the first cross-sectional area, the expansion in cross-sectional area between the first circular cross-sectional area and the second circular cross-sectional area being smooth and continuous; and (b) a compressor and a condenser for converting the refrigerant from a gas to a liquid for introduction into the evaporator.

Distributed Climate-Control Systems and Methods with Distributed Protection against Refrigerant Loss: the system includes a central condenser unit in combination with a distributed network of air handling units. Each air handler includes an evaporator, in which condensed refrigerant can undergo a phase change while absorbing heat of vaporization, plus a heat exchanger (e.g. a coil) which permits the heat absorption of the evaporator to be coupled to a forced airflow. Preferably the evaporator includes a metering device to provide variable refrigerant flow, and hence variable rates of heat transfer. The individual evaporators also include a sensor to detect ambient levels of the refrigerant, electrically operable cutoff valves which permit the evaporator to be isolated from both the liquid-phase and the gas-phase refrigerant flows. Local control logic is preferably connected to shut the cutoff valves whenever an ambient refrigerant concentration is found to exceed a tolerable level.

The various implementations described herein include methods, devices, and systems for starting-up a vehicle air-conditioning system. In one aspect, a method is performed at a vehicle air-conditioning system including a blower fan, a condenser fan, and a compressor electrically coupled to a battery system. The method includes: (1) starting the blower fan; (2) after starting the blower fan, measuring a first current drawn from the battery system, the first current indicative of current drawn by the blower fan; (3) in accordance with a determination that the first current meets predefined criteria, starting the condenser fan; (4) after starting the condenser fan, measuring a second current drawn from the battery system, where the difference between the second current and the first current is indicative of current drawn by the condenser fan; and (5) in accordance with a determination that the second current meets predefined second criteria, starting the compressor.