EcoSolar Energy Conscious Design Limited
18
Symbols
CIRCULATING
PUMP
TEMPERING VALVE
PRESSURE RELIEF
VALVE TO TUNDISH
STRAINER
ISOLATING
VALVE
NON RETURN
VALVE
TEMPERATURE, PRESSURE,
VACUUM RELIEF VALVE
PRESSURE
REDUCING
VALVE AS REQUIRED
Solar water heating system types and schematics
Direct or open loop systems
Many direct systems are the retrofitting of a solar system on to an existing hot water cylinder as
shown in Figure 8 and 8.
A direct system as highlighted previously is where the water passing through the collectors is drawn
off by the taps.
A direct or open loop system generally has a lower installed cost than other types of system and
generally have a higher maximum efficiency as they have no heat exchanger losses. However, they
are prone to overheating and freezing and so these need to be effectively managed to ensure a cost
effective and resilient system.
