A recreational vehicle air conditioning system supports multiple recreational vehicle air conditioning units having closed air conditioning circuits and a controller that is electronically coupled to each of the recreational vehicle air conditioning units to control each of the closed air conditioning circuits to regulate an overall power consumption of the multiple recreational vehicle air conditioning units. A recreational vehicle air conditioning system may also support multiple recreational vehicle air conditioning units where a refrigerant line set is coupled between the recreational vehicle air conditioning units such that a compressor in one of the recreational vehicle air conditioning units is capable of supplying refrigerant to the evaporators of the multiple recreational vehicle air conditioning units, and such that valves coupled in series with each of the evaporators may be regulated to control cooling by each recreational vehicle air conditioning unit.

A heat transport system includes: a refrigerant circuit that seals therein a fluid including HFC-32 and/or HFO refrigerant as a refrigerant and that includes a refrigerant booster that boosts the refrigerant, an outdoor air heat exchanger that exchanges heat between the refrigerant and outdoor air, a medium heat exchanger that exchanges heat between the refrigerant and a heat transfer medium, and a refrigerant flow path switch that switches between a refrigerant radiation state and a refrigerant evaporation state; and a medium circuit that seals carbon dioxide therein as the heat transfer medium.

A power converter includes a plurality of inverter modules, each having a plurality of switching elements and each configured to convert a direct current voltage into an alternating current voltage by operations of the switching elements, a plurality of surge absorption circuits provided corresponding to the plurality of inverter modules and configured to absorb a generated surge voltage, and a plurality of current detection devices provided corresponding to the plurality of inverter modules, the current detection devices each having a current detection unit for detecting a current flowing in the corresponding inverter module.

An inverter-converter system includes a DC source, a DC to DC boost converter, a DC link capacitor, an inverter circuit, a variable speed electric machine, and a controller. The DC to DC boost converter receives an input DC voltage from the DC source. The inverter circuit converts the variable boosted voltage to an AC voltage to drive the variable speed electric machine. The controller senses a plurality of parameters from the variable speed electric machine, and controls the DC to DC boost converter to boost up the input DC voltage to a variable output voltage based on the plurality of parameters and/or the voltage (or load) needed by the variable speed electric machine. The design of the inverter-converter system can achieve an electrical efficiency and cost savings for the overall system.

A water distribution apparatus and method including cold and hot water supplies, a fan coil (or chilled beam device), a control valve having cold and hot water inlets and outlets, cold and hot water outputs configured to supply cold and hot water to the fan coil, cold and hot water return inlets configured to receive from the fan coil the water supplied by the cold and/or water outputs and outputting the cold and/or hot water to the cold and hot water supply lines, respectively, via the cold and hot water outlets, respectively. Cold and hot water is supplied from the cold and/or hot water outputs to the fan coil and received into the cold and hot water return inlets, respectively, and the cold and hot water supplied by the cold and hot water outputs to the fan coil is output to the cold and hot water supply lines, respectively.

In order to improve a method for selecting a frequency converter for a refrigerant compressor unit comprising a refrigerant compressor and an electric drive motor in such a way that the frequency converter is optimised for the application in question, it is proposed that a working state suitable for the operation of the refrigerant compressor unit is selected in an application field of an application diagram of the refrigerant compressor, that an operating frequency is selected for this selected working state, and that, on the basis of drive data, a working state operating current value corresponding to the selected working state and the selected operating frequency is ascertained for the operation of the refrigerant compressor unit.

Provided is an air conditioning system capable of detecting in advance a device that consumes more power than the power that can be fed by a power feed unit. An air conditioning system includes a refrigerant cycle, a power feed unit, and a controller. The refrigerant cycle includes an outdoor unit and a plurality of indoor units. In a case where a power source for at least one indoor unit of the plurality of indoor units has been interrupted, the power feed unit feeds power from an auxiliary power source to the indoor unit for which the power source has been interrupted. When a predetermined device has been connected to at least part of the plurality of indoor units and the power feed unit, the controller performs deactivation of at least one of functions of the device.

A heat source unit constitutes a refrigeration apparatus by being connected to a utilization-side unit. The heat source unit includes a low-stage compression element, a high-stage compression element, and a heat exchanger. The low-stage compression element has a discharge pipe provided with a pressure switchgear. The high-stage compression element compresses a refrigerant discharged from the low-stage compression element. When the low-stage compression element is paused in response to activation of the pressure switchgear, the high-stage compression element operates while the low-stage compression element is kept paused.

The purpose of the present invention is to provide an abnormality detection system and refrigerator, an abnormality detection method, and an abnormality detection program which can improve the accuracy of abnormality detection. The abnormality detection system comprises: an acquisition unit which acquires driving data of a refrigerator (11); a creation unit which creates a model capable of estimating a prescribed driving state of the refrigerator (11) on the basis of the driving data, when the driving data is non-trained data; a determination unit which compares an estimation value of the driving state, the estimation value being estimated by the model, with an actual measurement value corresponding to the driving state, and determines whether the driving data is an outlier; and an abnormality detection unit which performs, on the basis of the model, abnormality detection on the refrigerator (11), when the driving data is not determined to be the outlier.

The motor driving apparatus includes a switch that is a mechanical switch for changing coil connection states of a motor; an inverter that generates alternating voltage from direct voltage and outputs the alternating voltage to the motor; and a control device that controls the switch and the inverter. The control device causes the switch to change the coil connection states while the alternating voltage output from the inverter is zero.