Discussion on heating capacity of indoor air conditioning terminals under variable water temperature conditions

The indoor air conditioning terminal is selected according to the summer cooling load. In winter the heating capacity is often surplus in the area with small indoor heating load. Taking the fan-coil unit as an example, based on the principle of heat transfer, analyses the influencing factors of heat transfer coefficient under the constant flow condition and the variable flow condition. Obtains the maximum indoor heating load that can be matched by different water supply temperatures in winter, providing a theoretical basis for the design of corresponding air conditioning system and the selection of cold and heat sources. When the water supply temperature under constant flow conditions changes from 30 ℃ to 45 ℃, the applicable range of maximum heating-cooling load ratio of the room is 32% to 89%, and the corresponding change interval under variable flow conditions (the temperature difference between supply and return water is 5 ℃) is 15% to 88%.