Investigation of a solar heating system assisted by coupling with electromagnetic heating unit and phase change energy storage tank: Towards sustainable rural buildings in northern China

• New coupled solar heating system proposed for clean heating of rural buildings. • Hooke–Jeeves algorithm is adopted to optimise four key parameters in a SHS. • LCC reduced by 4.17%–23.62%; CO 2 emission reduced by 13.07–26.73 T. • Based on applicability evaluation, the cost of investment grant is more operative than operating expense grants. Detached buildings in rural areas have considerable potential to promoting the application of solar heating systems (SHSs) from the perspective of low-carbon development. However, SHSs are designed to operate at the maximum building load, leading to energy wastage. To optimally design the key parameters of a SHS assisted by coupling with an electromagnetic heating unit and a phase change energy storage tank (SAEPT), a simulation model was established through the dynamic cosimulation of Designer's Simulation Toolkit and Transient System Simulation Program between the hourly heating supply and the hourly load of the building. The area of solar collectors, collector inclination, tank volume, and electromagnetic energy heating unit power were selected as the optimisation parameters, with life cycle cost (LCC) as the objective function. Generic Optimization Program was used to adopt the Hooke–Jeeves algorithm to iteratively optimise the configuration. Compared with the designed values, LCC was reduced by 4.17%–23.62%, and the CO 2 emission reduction was 13073–39801 kg. To evaluate the applicability of SAEPT in 16 regions, a multiattribute evaluation of energy-economic-environment was conducted based on 11 specific indicators. SAEPT was particularly suitable for regions with abundant solar energy resources and relatively low load of buildings. The payback period was approximately 3.78–7.98 years. The initial investment subsidy by the government can be between 0% and 25%. The findings of this study provide crucial insights for policymakers and SHSs promotion, which can facilitate sustainable low-carbon rural buildings in northern China.