When completely developed, the schematic becomes a piping and instrumentation diagram and is the overall guide for the detail solar energy system design efforts. Overall solar energy system configuration and interfaces with the loads and auxiliary energy sources 2. Relative location of required sensors and instrumentation. I is a solar heating system with an un-pressurized storage tank. System II is the system with pressurized storage tank.
Heat is transferred to the potable water by way of a heat exchange coil within the storage tank.
The advantages of the system are that the entire system is at low pressure so only potable water flows through the heat exchange coil. As the stored potable water is at any time at a minimum, this means isolated pockets of water cannot stagnate and become Legionella breeding ground. Initial cost of antifreeze fluid can be higher. Potable water in the tank is heated by the coil. During the heating process pressure in the storage tank will gradually be built up.