NOVELTY - The heat exchanging system (1) includes a compressor (12), first heat exchanger (14), first decompressor (16), second heat exchanger (18), heat exchanging portion, bypass passage, second decompressor, and selector valve (52). The heat exchanging portion is connected in parallel with the second heat exchanger for exchanging heat between the refrigerant and temperature regulated portion. The second decompressor is provided in the bypass passage to decompress the refrigerant flowing through the bypass passage. The selector valve allows or interrupts the flow of refrigerant via the bypass passage.    USE - Heat exchanging system used in exchanging heat between refrigerant and temperature regulated portion. Can be used in e.g. hybrid vehicles, fuel cell vehicles, electric vehicles.    ADVANTAGE - Provides a heat exchanging system capable of appropriately regulating a temperature regulated portion by adjusting heating or cooling the temperature regulated portion with a further simple configuration. Ensures reduced components required to cool the hybrid vehicle (HV) device and simplified system configuration, thus ensuring reduced manufacturing cost of the heat exchanging system. Ensures reduced power consumption for cooling the HV device since it is not necessary to operate a power source, such as a pump and a cooling fan, in order to cool the HV device and power consumption for operating the power source is not required. Ensures reduced size of the heat exchanging system and easy installation of the heat exchanging system on a vehicle while ensuring cooling performance for cooling the vehicle cabin due to reduced size of the heat exchangers used in the heat exchanging system. Prevents excessive cooling of the HV device since the amount of refrigerant required to cool the HV device is caused to flow to the cooling portion for appropriately cooling the HV device. Ensures reduced pressure loss associated with the flow of refrigerant via the cooling portion, thus reducing power consumption required to operate the compressor for circulating refrigerant. Ensures appropriate cooling performance for cooling the cabin and the HV device. Cools the vehicle battery efficiency by supplying the heat exchanging portion with refrigerant adjusted into a low-temperature low-pressure state by the expansion valve. Improves the fuel economy of the vehicle by reducing the power consumption of the compressor. Extends the life of the compressor, thus improving the reliability of the compressor. Ensures the cooling performance of the HV device, thus preventing overheating of the HV device. Ensures improved merchantability of vehicle that includes the heat exchanging system since the vehicle cabin can be pre-heated during charging of the battery using the heat exchanging system.    DETAILED DESCRIPTION - The compressor circulates the refrigerant. The first heat exchanger is provided to exchange heat between the refrigerant and outside air. The first decompressor is configured to decompress the refrigerant. The second heat exchanger is provided to exchange heat between the refrigerant and air-conditioning air. The bypass passage provides fluid communication between a path of the refrigerant between the compressor and first heat exchanger, and a path of the refrigerant between the first decompressor and second heat exchanger. The temperature regulated portion is provided in the form of a battery.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view that shows the configuration of the heat exchanging system.    Heat exchanging system (1)    Compressor (12)    First heat exchanger (14)    First decompressor (16)    Second heat exchanger (18)    Selector valve (52)