Solar Hot Water Thermal System

The main components added to a conventional heating system when solar thermal energy is used are:

• collector field with collector field piping and support structure
• heat transfer fluid (water or water glycol mixture)
• a storage tank system
• pump for solar loop and other pumps for other loops
• heat exchangers to transfer heat from one loop to another
• expansion and safety devices for each closed loop
• a controller with temperature sensors in collector field and storage tank and that turns the pump on and off.

Since a solar thermal system does not usually act as the main heat source, an auxiliary (back-up) heater is necessary to cover periods of high energy demand or too little solar radiation (usually in winter). Figure 3.1 shows a schematic of a solar domestic hot water system.