- About SoPro India
- SWHS Basics
- Design & Installation
- Operation & Monitoring
- Case Studies
Solar water heating systems are using sunlight to heat water by converting the solar irradiation directly into heat within a solar collector.
There are two main types of solar collectors on the market:
The solar heat is transported by the heat transfer fluid through insulated pipes either to a storage tank or directly to the point of use. If there is no risk of freezing, usually water is used as heat transfer fluid. To avoid corrosion in the collectors, mostly reverse osmosis water (RO) is used. In regions with cold winters, usually a mixture of glycol and water is used to avoid freezing of the fluid and destroying the collectors. Sometimes air is used as heat transfer fluid too, but then the collectors and the system is designed differently.
A SWHS is called non-pressurized, if no pressure is applied in addition to the static pressure. This means that the system of collectors, pipes and storage tank is open to the ambient atmosphere to compensate the volume expansion of hot water.
A SWHS is called pressurized, if the system is closed to the ambient atmosphere and an additional pressure, e.g. 3 bars is applied to the system. To compensate the variations in the fluid volume caused by temperature changes, an expansion vessel must be installed.
DHW systems heating water in residential homes, hotels, hospitals, etc. for domestic washing and cleaning purposes. Small DHW systems with for example 2 square meter collector area are used to provide hot water for one household. Large DHW systems supply multi family homes, hospitals, hotels and other buildings with hot water demand.
In regions with space heating demand, SWHS can also deliver solar heat for space heating. A bigger number of collectors must be installed to generate sufficient heat in the heating season with usually lower irradiation intensity. However, some regions receive high irradiation also during the heating season, e.g. some mountain areas. In these regions solar space heating support is especially attractive. Beside SWHS, also solar air heating systems are used for space heating purposes.
A significant share of hot water demand in the industry is at low temperatures, e.g. washing processes. To provide hot water up to 60°C and above SWHS are very suitable, especially due to the high solar irradiation in India. SWHS can also be used to preheat water, e.g. for steam generation within a steam boiler. Therefore, the potential of using SWHS to deliver hot water is very high in the industry.