Calculation of Heating and Cooling Loads of the Main Unit of Household Central Air Conditioner

The calculation of the heating and cooling load of the household central air-conditioning host needs to pay attention to the following points. First, compared with commercial buildings, residential buildings have less internal heat generation, low personnel density and lighting, and small air exchange. Therefore, internal heating and air exchange load are in the load of the room. The proportion of the medium is low, and the load is greatly affected by the weather conditions and the envelope structure. Shanghai Central Air Conditioning Project

The calculation of the heating and cooling load of the household central air-conditioning host needs to pay attention to the following points. First, compared with commercial buildings, residential buildings have less internal heat generation, low personnel density and lighting, and small air exchange. Therefore, internal heating and air exchange load are in the load of the room. The proportion of the medium is relatively low, and the load is greatly affected by the weather conditions and the envelope structure. Shanghai air conditioning design

Secondly, the residential central air-conditioning load fluctuates greatly. According to the living habits of Chinese residents, residential central air-conditioning generally has several peaks of use, usually 6:00-8:00 in the morning, 11:30-14:30 at noon, 18:00-23:00 in the evening, and 7:00- during holidays. 23:00. Except during a period of heat, people usually turn off or turn off air-conditioning equipment after sleeping at night, and unmanned rooms are also closed from the perspective of energy saving. The fluctuation coefficient of air-conditioning load is significantly higher than that of other air-conditioned buildings. Due to the existence of non-air-conditioned rooms and rooms with no air-conditioning in the residence, the room partition walls have heat transfer, and the heat transfer of the surrounding partition walls should be considered when calculating the air-conditioning load. Air conditioning repair

In addition, the simultaneous use coefficient of the residential central air-conditioning host is relatively low, which can be divided into the following situations:

1. The installed capacity of the room air conditioner should consider the effects of intermittent operation and heat transfer in adjacent rooms.

2. The capacity of the outdoor host of household central air conditioners should consider the simultaneous use coefficient of multiple indoor units. The value is higher for small units, 0.9-1.0 for cooling in summer, 1.0 for heating in winter, and lower for large units. , It can be 0.7-0.8 for cooling in summer and 0.8-0.9 for heating in winter.

3. When a centralized air conditioning system is installed in a single building or several buildings, when calculating the host capacity, both the simultaneous use of indoor rooms and the simultaneous use of rooms should be considered when calculating the host capacity. The summer cooling can be taken as 0.6-0.7 , When heating in winter, it is 0.8-0.9. When the users who set up the air-conditioning system belong to a certain unit and do not adopt heat-based billing, the utilization factor should be considered separately.

4. For the centralized cold and heat source capacity of a large residential community, factors such as the composition of the community, house structure, economic level, and resident rate should be considered comprehensively, and the simultaneous use coefficient should be determined on the basis of full investigation of communities of the same level in the region. The reference value can be 0.4-0.5 for cooling in summer and 0.6-0.8 for heating in winter.

Therefore, considering the demand characteristics of the residential central air-conditioning system, the heating and cooling load of the residential central air-conditioning can be comprehensively considered based on the above situation.