Solar water heaters as a pre-heating system for industrial processes

Although solar heating for hot-water production is a mature technology, the general public’s knowledge is mostly confined to domestic uses such as cleaning and washing. In the industrial sector, there is a demand for thermal energy of lower than 250 °C, but to develop applications for industrial heat processes, real energy savings are one of the key issues determining customers’ choice of energy. However, the solar gain from solar water heaters based on the lab tests may be misleading, so field measurements are important to evaluate a system’s financial viability. This study presents 1 year of field measurements for solar water heaters installed as the pre-heating system in a poultry slaughterhouse. The system efficiency is compared with that installed in a dormitory, where the hot-water consumption pattern is similar to that in the domestic sector. These results demonstrate that the amount of global solar radiation and hot-water consumption patterns have a significant effect on the system’s efficiency. A simple cost-to-benefit analysis is also presented based on this real application for solar water heaters.