The external ventilation conditions have a great influence on the heating performance of the air source heat pump (ASHP) systems. The outdoor units of residential household air source heat pumps are often installed in narrow spaces such as balconies. The ventilation conditions of the outdoor unit will influent the heating performance of the air source heat pump. It is necessary to study the effect of the outdoor unit ventilation conditions on the heating performance of residential household heat pumps. This paper experimentally studied the heating performances of an air source heat pump system with the outdoor unit mounted in a balcony in different external ventilation conditions. The results indicate that the ventilation conditions for the outdoor units have a significant effect on the heating performance of the system. When the inlet of the outdoor unit was close to the sliding door and completely blocked, the ventilation environment was the worst and the coefficient of performance (COP) was the lowest. In addition, the unfavorable ventilation environment could result in a reduction of the COP by 26.2%. When the inlet of the outdoor unit was partially blocked, the heating performance could be improved and the COP was also slightly improved. The great heating performance was obtained under the cross-ventilation condition. This paper can guide the design of the installation position of the household air source heat pump outdoor units in actual engineering.

Western Sichuan region has a variety of traditional heating methods and excellent outdoor air quality, and the difference with the city is clear. The indoor air quality of the western Sichuan region is worth studying. The diffusion law of indoor and outdoor PM2.5 concentration under different heating methods can be explored to provide effective data support for environmental governance. In this context, the indoor air quality under different heating methods in Songpan County was measured with PM2.5 concentration assessment of indoor air quality (IAQ). By analyzing the indoor air quality under different heating modes, the following conclusions can be drawn: the influence degree of indoor activity on indoor particle concentration level depends on the source and characteristics of the house. Air leakage is one of the main reasons for the rise of indoor PM2.5. Heating methods disturb the indoor air, which significantly affects the migration of PM2.5.

It is important to accurately design the installation inclination of solar collector for improving the utilization rate. This paper selected Lhasa area as a typical city which was rich in solar energy, setting a mathematical model for energy collection of vacuum tube collector to dynamically analyse the south towards, 0°∼90° angle of solar radiation on the surface of the collection on 8760 hours. As the results showed: the ability of the vacuum tube collector to collect solar reflection, scattering and direct radiation varied with the installation inclination a lot. When the inclination angle was 90, the maximum annual reflection radiation value was collected by the vacuum tube collector; when the inclination angle was 0, the maximum annual scattering radiation value was collected; when the inclination angle was local latitude, the maximum annual direct radiation value was collected; direct radiation in Lhasa was the main factor, so the maximum installation inclination of solar energy collected during the whole year and heating season was close to the local latitude.