There are two types of active solar water heating systems:
- Direct circulation systems. Pumps circulate household water
through the collectors and into the home. ...
- Indirect circulation systems. Pumps circulate a non-freezing,
heat-transfer fluid through the collectors and a heat
exchanger.
Active Solar Water Heating Systems
There are two types of active solar water heating systems:
- Direct circulation systems
Pumps circulate household water through the collectors and into the
home. They work well in climates where it rarely freezes.
- Indirect circulation systems
Pumps circulate a non-freezing, heat-transfer fluid through the
collectors and a heat exchanger. This heats the water that then
flows into the home. They are popular in climates prone to freezing
temperatures.
Passive Solar Water Heating Systems
Passive solar water heating systems are typically less expensive
than active systems, but they're usually not as efficient. However,
passive systems can be more reliable and may last longer. There are
two basic types of passive systems:
- Integral collector-storage passive systems
These work best in areas where temperatures rarely fall below
freezing. They also work well in households with significant
daytime and evening hot-water needs.
- Thermosyphon systems
Water flows through the system when warm water rises as cooler
water sinks. The collector must be installed below the storage tank
so that warm water will rise into the tank. These systems are
reliable, but contractors must pay careful attention to the roof
design because of the heavy storage tank. They are usually more
expensive than integral collector-storage passive systems.