A refrigerating apparatus includes a centrifugal compressor, a capacity control mechanism that controls a capacity of the compressor by changing an opening degree of the capacity control mechanism, an expansion mechanism that reduces a pressure of a refrigerant, and a controller. The controller calculates an opening degree of the expansion mechanism using compressor capacity as one of a plurality of indices of change in load. The compressor capacity is obtained from a current rotation number of the compressor, an opening degree of the capacity control mechanism, and a divergence rate of a current operation head from a surge region.

There is disclosed an air-conditioning device of a so-called heat pump system which acquires comfortable heating in a vehicle interior by preventing or inhibiting frost formation to an outdoor heat exchanger. In a vehicular air-conditioning device 1, a controller calculates a requested refrigerant evaporation temperature in non-frosting TXObaseQtgt which is a refrigerant evaporation temperature of an outdoor heat exchanger 7 when a required heating capability Qtgt as a heating capability required for a radiator 4 is realized in non-frosting of the outdoor heat exchanger 7, and the controller controls heating by the radiator 4 and heating by a heating medium-air heat exchanger 40 of a heating medium circulating circuit 23 on the basis of the requested refrigerant evaporation temperature in non-frosting TXObaseQtgt and a frost point Tfrost to achieve the required heating capability Qtgt without causing frost formation to the outdoor heat exchanger 7.

A control method of a transcritical carbon dioxide composite heat pump system is disclosed, wherein the transcritical carbon dioxide composite heat pump system includes: a CO.sub.2 main circuit compressor, an air-cooling-air-cooling recombiner, a supercooling-evaporation recombiner, an evaporator and a CO.sub.2 auxiliary compressor; wherein the air-cooling-air-cooling recombiner comprises a CO.sub.2 main circuit, a CO.sub.2 auxiliary circuit and a water circuit; the supercooling-evaporation recombiner comprises a CO.sub.2 main circuit supercooling section and a CO.sub.2 auxiliary circuit evaporation section. The present invention includes two working modes according to the return water temperature, so that the unit has a wider application range and meets daily needs. There is only one heat exchanger for refrigerant and water. Compared with the three water and refrigerant heat exchangers in the conventional transcritical CO.sub.2 composite heat pump, the circulating water circuit is a single circuit with one inlet and one outlet.

An air-conditioning apparatus includes a temperature sensor for detecting a temperature of the heat medium sent from each of the intermediate heat exchangers to each of the use-side heat exchangers, and a temperature of the heat medium that has exited each of the use-side heat exchangers, an opening degree controller for regulating a flow rate of the heat medium through each of the heat medium flow control devices, and a computing unit for computing a usage capacity of each of the indoor units from a rotation speed of the pump, an opening degree of each of the heat medium flow control devices, temperatures detected by the temperature sensors, and power consumption of each of the indoor units, and proportionally dividing the power consumption for a common portion among each of the indoor units based on the computed usage capacity and the power consumption of the common portion.

A control device and method for preventing the start and stop of heat source machines from being frequently repeated. The control device determining whether or not basic conditions for decreasing the number of machines are satisfied when the number of currently operating machines is increased by one is determined if a current operational status satisfies basic conditions for increasing the number of machines, and one heat source machine is started if it is determined that the basic conditions for decreasing the number of machines are not satisfied, and determining whether or not the basic conditions for increasing the number of machines are satisfied when the number of currently operating machines is decreased by one are satisfied if a current operational status satisfies the basic conditions for decreasing the number of machines, and one heat source machine is stopped if it is determined that the basic conditions for increasing the number of machines are not satisfied.

Methods and systems for controlling a chiller system to achieve control stability while maintaining optimum efficiency. Particularly, methods and systems for controlling a centrifugal compressor speed and an inlet guide vane position that establishes three distinct regions in the control path: (i) during initial unloading from full load, the inlet guide vane position is kept at a fully open position while the centrifugal compressor speed is changed to achieve the desired cooling capacity; (ii) between an inflection point and a transition point, keeping the centrifugal compressor speed constant while the inlet guide vane position is changed to achieve the desired cooling capacity; and (iii) between the transition point and zero cooling capacity, changing both the inlet guide vane position and the centrifugal compressor speed to achieve the desired cooling capacity.

The present invention is directed to an apparatus for minimizing power consumption in a cooling system. In one embodiment, the apparatus comprises one or more processors, one or more sensors associated with one or more regulated environments and one or more chillers that regulate temperature of the one or more regulated environments and a storage device, coupled to the one or more processors, storing instructions that when executed by the one or more processors performs a method. The method comprises gathering readings from the one or more sensors, determining a cost and power consumption associated with setting values for a plurality of control variables associated with the one or more chiller plants, selecting values for the control variables with a minimum cost as optimized control variable values and applying the optimized control variable values to the plurality of control variables to minimize power consumption of the cooling system.

Embodiments of the present disclosure are directed toward systems and method for cooling a refrigerant flow of a refrigerant circuit with a cool water flow from a cool water storage to generate a warm water flow and to cool the refrigerant flow by a subcooling temperature difference, flowing the warm water flow to the cool water storage, and thermally isolating the warm water flow from the cool water flow in the cool water storage.

Heat pump type heating apparatus capable of performing a continuous dual-stage operation without stopping a high stage side compressor even when a return temperature of a heating medium reaches a prescribed high temperature and, thereby, improving a sense of being insufficiently warmed due to stoppage of the high stage side compressor or a sense of being insufficiently warmed due to execution of frequent defrosting operations. The heat pump type heating apparatus includes an internal heat exchanger (a second internal heat exchanger) that performs heat exchange between a low-temperature refrigerant on a low-pressure side of a low stage side refrigeration circuit and a high-temperature refrigerant on a high-pressure side of a high stage side refrigerant circuit, a bypass pipe bypassing the internal heat exchanger, and flow path control means that controls a refrigerant flow to each of the internal heat exchanger and the bypass pipe.

There is disclosed a vehicle air-conditioning device in which a refrigerant subcool degree in a radiator is appropriately controlled, so that comfortable and efficient vehicle interior air conditioning is achievable. The vehicle air-conditioning device executes a heating mode in which a controller lets a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, decompresses the refrigerant by which heat has been radiated by an outdoor expansion valve 6, and then lets the refrigerant absorb heat in an outdoor heat exchanger 7. In the heating mode, the vehicle air-conditioning device controls a refrigerant subcool degree SC of the radiator 4 by the outdoor expansion valve 6. On a basis of a radiator inlet air temperature THin that is a temperature of the air flowing into the radiator 4, the controller corrects a target subcool degree TGSC that is a target value of the refrigerant subcool degree SC in the radiator 4 in a lowering direction, as the radiator inlet air temperature THin rises.