Solar thermal systems are used under tropical climates for years, as it is a reliable and simple way to heat up water for domestic or industrial use.
Unlike solar PV, this technology is used to heat up water, and do not generate power. It exploits different wavelengths of the sunrays, through simple thermal processes (greenhouse effect inside solar collector) and reaches higher efficiency for energy conversion compared to solar PV.
A solar water heating system includes solar collectors and a storage tank. There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don’t.
Two main types of solar collectors are used:
Solar thermal systems are generally speaking a cost-effective way to produce hot water for domestic or industrial application. Payback times of such solar projects in Vietnam have been noticed as being below 5 years, with very competitive cost.
However, quality issues for products in Vietnam has been observed (no national certification of products or company), which can affect negatively the entire image of solar energy.