Features of Solar Water Tanks

The most common application of solar heating is in domestic hot water supply systems. An internal component of such systems is the solar water tank, which stores solar thermal energy. A heat exchanger transfers heat generated by the collectors to drinking water in a well-insulated tank, where hot water is stored for hours or even days until use, such as for bathing or showering. Typical features of solar water tanks compared to traditional boilers or hot water tanks are as follows:

1. The volume (and water storage capacity) of the solar water tank is usually designed according to the specific house type, and therefore quite large.

2. The structure of the solar water tank must be tall and slender to achieve thermal stratification within the tank: the solar heat exchanger at the bottom of the tank operates with cold water; heated water rises into the tank. Therefore, the hottest water is used first; pipes run from the top of the tank to the heater.

3. Insulation prevents heat loss, thus helping to store heat for days, not just hours.

4. A heat exchanger at the bottom of the tank transfers solar heat to the water. There's an additional heat exchanger on top of the tank; if the water temperature at the top of the tank is lower than the set temperature, it can draw heat from other heat sources. This means there's always hot water available. Typically, a solar water heater's capacity is twice the daily water usage. For example, a family of four, with a standard daily hot water usage of 40 liters per person, would need a tank capacity of around 300 to 320 liters. Since larger families require more hot water for hygiene and their water needs vary, solar water heating systems are a better choice. Category: Wikipedia

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