Experience with Unglazed Solar Collectors in District Heating Systems

Abstract

Over the past decade, the solar industry in Russia has been rapidly developing, and its technical means have become cheaper. The effort of general engineering has been focused on the technology of photovoltaic converters; its commercial indicators and implementation level now prevail over that of liquid solar collectors. In some cases, however, solar collectors can still be cost-effective, e.g., if the consumer does not have alternative low-cost energy sources, such as natural gas or low-cost electricity from a centralized supply system. Nevertheless, some applications can be identified where they will be proved competitive and economically viable even within centralized energy supply systems. This paper discusses an example of efficient implementation of unglazed solar collectors mounted on the roof of central heat supply gas stations for pre-heating cold water in the city of Gelendzhik, Krasnodar krai. The low cost of generated heat, 0.005 USD (kWh)–1 with the cost of solar collectors being 107 USD m–2, is ensured by the simplicity of the chosen system design. The payback period was less than 3 years. The experience of using unglazed solar collectors in a district heating system of Gelendzhik has proved to be successful and can be recommended for distribution under similar climate conditions.