The prefabricated temporary construction project of CCCC Third Highway Engineering Bureau Co., Ltd. (hereinafter referred to as "CCCC Third Highway Engineering Bureau") is located in Mentougou District, Beijing, with a construction area of about 2000 square meters. The system adopts Kcalin modular air conditioning integrated system to provide the working and living needs of the project construction site staff for summer cooling, winter heating and domestic hot water throughout the year. The system selects two Kcalin KLDCS65DW1B2 air source heat pumps, one Kcalin KLDRS20DW1B2 heat pump water heater unit, one Kcalin KLHM80 hydraulic transmission module unit and 49 wall-mounted fan coil units. After the application of the system, the living and office environment of the construction site staff has been greatly improved, beautiful and generous, comfortable and healthy, energy saving and environmental protection, highlighting the overall image and management level of the construction enterprise. The project was completed and officially put into use in October 2019.