Research Article

Some Aspects of Photovoltaic/Thermal Systems Operation in Central European Climate

Institute of Heat Engineering, Warsaw University of Technology, Warszawa, Poland

^* e-mail: dchwied@itc.pw.edu.pl

Received: 7 July 2021
Received in final form: 20 September 2021
Accepted: 20 September 2021

Abstract

The paper analyses the operation of a photovoltaic/thermal system in a single family house in a central European climate through simulation studies. The PV/T system is used for DHW heating and electricity generation. Glazed and unglazed modules are considered. Effective utilization of solar energy for heating purposes requires the use of heat storage, which is particularly visible not only in cold, but also in moderates climates. Consequently, the operation of solar systems is more complex, different modes of operation are possible to provide heat or electricity, or both. Possible modes of operation were appropriately modeled and the obtained energy gains were analyzed. When modeling the heat storage process, the heat stratification effect in the storage tank was taken into account. Monthly shares of solar energy in providing DHW heating energy and electricity for all months of the year are presented. The glazed modules can fully cover the DHW demand during 5 warm months, but they cannot cover the electricity demand. The share of electricity provided by PV can vary from 67% to 93%. On the contrary, in the case of unglazed PV/T modules during these 5 months the share of thermal demand can be covered only from 62% to 90%, but the electricity demand can by covered fully. In winter there is no significant solar thermal energy gained in both cases. Unglazed PV/T modules should be used in central European climate, if electricity generation is a priority. If DHW heating is equally important, then their operation should be coupled with glazed thermal collectors.