Design optimization of the solar heating system for office buildings based on life cycle cost in Qinghai-Tibet plateau of China

The Qinghai-Tibet Plateau is rich in solar energy resources (SER), and the operation conditions of office buildings are consistent with the daily fluctuations in solar radiation. Solar heating for office buildings on the plateau has great potential. To obtain the optimal capacity ratio of solar heating system (SHS) for office buildings in plateau area, an optimization model of SHS capacity matching was established. The minimum life cycle cost (LCC) was taken as the objective function, and collector area, tank volume and auxiliary heat source (AHS) power as the decision variables in the model. The Qinghai-Tibet plateau was divided into five typical regions, and optimization was carried out for each region. The results show that the system LCC optimized by the intermittent heating load is 12% lower than that calculated by the average intermittent heating load and 44% lower than that calculated by the average parameter method for Lhasa. From an economic perspective, the AHS is suitable for electric boilers or gas boilers in regions with rich or general SER and cold regions with abundant SER. The AHS is suitable for electric boilers, air source heat pumps, or gas boilers in severely cold regions with abundant SER.