With a solar water heating system, you can use the power of the sun to heat water for your household use. This type of system is extremely energy-efficient. There is a great deal of flexibility available in solar water heating methods. There are a number of different types of solar heating units available in the market, so this type of water heating method is available in most climates.
Passive Solar Water Heating
This system uses the power of the sun; you will not need to use electricity from the grid at all. With this type of system, a solar collector will be mounted in a high, sunny location (e.g. a south-facing roof top). This collector will contain a number of pipes at the bottom and the top. The system draws water naturally from a storage tank. Cold liquids will move downward to enter the solar collector. Once they have become warm enough, they will rise to the storage tank. For this type of heating system, grid powered and/or solar pump stations are not necessary. It is only necessary to have the collector in the storage tank placed near each other so that the water can flow from the collector to the storage tank naturally and easily. It doesn’t require much maintenance; however, it’s important to understand that this type of system can freeze in very cold climates.
Solar systems that are termed “active” use power from the sun and power from an alternate source. This type of system usually has a pump, along with the measuring unit for the purpose of moving water into the collector when the temperature differential meets predetermined criteria. Power for this function can come from the grid or solar pump stations. Naturally, when you use the power of the sun for all operations your costs will be lower. This type of system may also include a heating element inside of the storage tank. This can also be powered by the sun, and it works to keep the water at an ambient temperature at all times. This type of system has far less chance of freezing in cold weather than a passive system.
Direct Solar Water Heating System Can Be either Passive or Active
In this system, the water is heated directly by the sun. This type of system may be as simple as a water holding tank painted black and placed on the roof with pipes leading into and connecting with household plumbing. Clearly, this would be the least expensive type of solar system to run.
Indirect Solar Water Heating Systems
In this system, an intermediary liquid is needed to heat the water that is present in the storage tank. This intermediary liquid is termed a heat transfer fluid (a.k.a.-HTF). Water can be used as the HTF, but it’s handy to use antifreeze in cold climates. This helps prevent freezing. The HTF is heated within the collector, and then it is drawn downward into the storage tank. Here, the heat from the HTF transfers through the piping and/or coils of the system. With this type of system, you can expect a more consistent water temperature.