Feasibility and thermodynamic analysis on rural building envelope energy storage-photovoltaic electric heating system on the Qinghai-Tibet Plateau

Abstract

Utilizing the building envelope energy storage-photovoltaic electric heating system to fully realize the rural residential space heating requirements is an effective approach to achieve clean energy utilization on the Qinghai-Tibet Plateau. However, there is currently no research confirming the feasibility of this system throughout the heating season and no performance analysis and optimization research, which leads to a lack of effective system design principles. The task of this paper is to address the above issues. To this end, the feasibility and thermodynamic analysis are completed by numerical simulation methods with a typical rural house on the Qinghai-Tibet Plateau as the object. Firstly, the numerical model of the system is established in the MATLAB software based on the photovoltaic cell engineering model and the finite difference method. Then, the feasibility analysis is carried out based on the two-level feasibility analysis method proposed in this paper, and the effective conclusions of the building insulation renovation ideas, photovoltaic capacity configuration principles, and system operation strategies are summarized. Moreover, the thermodynamic analysis of the system is carried out based on energy and exergy parameters, and the process optimization principle is proposed. The thermal efficiency and exergy efficiency of the system under the typical condition are 85.13% and 14.35% respectively. This paper recommends selecting the inner wall as the thermal storage building envelope and increasing its area as much as possible. Meanwhile, it is recommended to set the electric heating film in the middle of the building envelope. Based on this principle, the process is optimized, and the photovoltaic self-sufficiency ratio for heating of the optimized system improves to 97.69 %. The relevant conclusions provide effective theoretical guidance and process design principles for rural building envelope energy storage-photovoltaic electric heating system on the Qinghai-Tibet Plateau.