A Solar Water Heater System Overview
Like Solar Panels These Green Building Systems Lower Utility Bills
Nov 2, 2008
As mentioned above, solar water heater systems come in two flavors: active systems which utilize controls and circulating pumps, and passive, which do not.
A good time to consider installing this hot water alternative is during a bathroom remodel project or a kitchen makeover.
How do These Green Technology Systems Operate?
Why are these systems part of green building technology? Like the residential solar panels, they use the sun's energy which is free and renewable!
The basic system is made up of one or two insulated storage tanks and a solar collector. As the name implies, the collector is the component that gathers the radiant energy.
Types of Solar Collectors
- Evacuated-Tube Solar Collectors – This type utilizes parallel rows of transparent glass tubes. These are more commonly found in commercial systems although they are found in homes as well. Inside each glass tube is a metal absorber tube with a fin.
- Flat-Plate Collectors – In this case, a dark colored absorber plate (either glazed or un-glazed) under a polymer or glass cover is used.
- Integral Collector-Storage – These are made up of either black tubes or tanks encased in a glazed, insulated box. They are also called batch or ICS systems. The purpose of this type of collector is to preheat cold water which is then passed on to a conventional tank heater or to a more efficient tankless water heater.
Passive Solar Water Heating Systems
Compared to active systems, there are trade offs here. Being simpler, passive systems are more reliable and last longer. On the other hand, they are not as efficient. There are two types available.
- Thermosyphon models – These are composed of a storage tank with the collector installed at the bottom. This heats the water at the bottom of the tank which rises as the cooler water sinks.
- Integral Collector-Storage Passive models – This is the type most often found in conjunction with a tankless or instantaneous water heater.
Active Solar Water Heating Systems
These are more complex and expensive. Again, there are two basic types.
- Indirect Circulation Systems – These are used in climates that experience a hard freeze. They utilize a heat-transfer fluid similar to automotive antifreeze. Pumps are used to circulate the fluid through the collector and a heat exchanger. From there, the heated fluid moves through coils in the storage tank to heat the water.
- Direct Circulation Systems – These are a bit simpler in that no heat-transfer fluid is used. The water itself circulates through the collector and heat exchanger.
What Happens on Shady Days?
Solar systems are rarely a one hundred percent solution for hot water. Rather, they are part of the equation. A backup system such as a tankless water heater is ideal for picking up the slack and ensuring the simple pleasure of a hot shower or tub soaking.
 |
 |
