Long-term performance of a solar water heating system with a novel variable-volume tank

A novel variable-volume tank is lately designed to cater for the varying needs of tank volume. Based on the validated models of collector and the novel tank, a mathematical model for the solar heating system with the novel tank is proposed in this paper. The system is designed for space heating and consists of solar collector, variable-volume water tank and auxiliary heat source. A case of office building using the solar heating system for space heating is studied. The thermal behaviour of the system during a 4-month heating season is simulated and investigated. The studied case shows that the novel tank system has clear advantage in providing 11.6% more useful heat and reducing 19% system heat loss compared to a conventional system. A parametric study is also conducted to analyse the impacts of tank insulation, tank volume and collector size on the long-term system performance. The results show that the long-term performance of the novel tank system is more resilient to a degraded tank insulation or an oversized tank volume, which contributes to a robust heating system to cope with extreme operating conditions. (c) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study introduces a novel variable-volume tank design for solar heating systems, which provides more useful heat and reduces system heat loss compared to conventional systems. Parametric analysis shows that the novel tank system is more resilient to degraded insulation or oversized volume, contributing to a robust heating system.