Simulation and optimisation study on a solar space heating system in Baotou, China

Dual-water tank energy storage has been adopted in some solar heating systems to mitigate solar energy randomness and instability. Two types of dual-water tank solar heating (DWTSH) system are introduced and analysed in this paper, one is the traditional DWTSH system and the other has a thermal buffer and is named TB-DWTSH. Analysis software called TRNSYS was used for the simulation, the tank water temperatures and solar guarantee of two systems were measured and compared. A new thermal comfort evaluation criterion for the solar heating system is briefly introduced. The TRNSYS model was verified by a pilot project of a traditional DWTSH system. The heating systems were assessed based on the solar guarantee rate of the heating system and the thermal comfort index. The outcome showed that the simulation results are generally consistent with the experimental results. Compared with the traditional DWTSH system, the comfort index could be greatly improved in the TB-DWTSH system between 8 a.m. and 9 a.m. local time. Furthermore, compared with the traditional DWTSH system, the energy consumption of the auxiliary heat source is reduced by 30%. This study provides a good foundation for future research on DWTSH systems.