Solar Water Heaters Also known as a solar home hot water system, it can be an inexpensive way to produce hot water for your home. They can be used in any climate and the fuel they use – sunlight – is free.
How they work
The solar hot water heating system consists of a storage tank and a solar collector. There are two types of solar water heaters: active with circulation pump and control and passive which don’t.
- The active solar water heater system
- The passive solar water heater system
The active solar water heater system
There are two types of active solar water heater systems.
Direct circulation system
The pump circulates domestic water through the collector to the house. They work well in climates where it rarely freezes.
Indirect circulation system
The pump circulates a non-icing heat transfer fluid through the manifold and the heat exchanger. This heats the water flowing in the house. They are popular in sub-glacial climates.
The passive solar water heater system
Passive solar water heating systems are generally less expensive than active systems but are generally less efficient. However, passive systems are reliable and can last a long time. There are two basic types of passive systems:
- The integrated passive collector storage system
These work best in areas where temperatures rarely drop below freezing. It also works well in homes with plenty of hot water during the day and evening.
- Thermal siphon system
As hot water rises and cold water flows, water flows through the system. The manifold should be installed under the storage tank so that hot water rises into the tank. While these systems are reliable, contractors should pay attention to the roof structure of heavy storage tanks. They are generally more expensive than integrated passive collector storage systems.
Storage tank and solar panel
Most solar water heaters require a well-insulated storage tank. Solar tanks have additional outlets and inlets that are attached or associated with the collector. In a two-tank system, a solar water heater heats the water before it enters a conventional water heater. In a one-tank system, a backup heater is combined with a solar storage tank in tank.
Three types of solar panels are used for residential purposes
A glossy flat plate collector is an insulated, weatherproof box that contains a dark absorbent plate under one or more glass or plastic lids (polymer lids). The unglazed flat plate collector (typically used for heating solar swimming pools) has a dark metal or polymer absorption plate without a cover or housing.
The integrated collector storage system
It is also known as an ICS or batch system and contains one or more tanks or black tubes in an insulated glass box. The cold water first flows through the solar panel, which preheats the water. Water is then a reliable source of hot water that follows traditional alternative water dispensers. These should only be installed in mild, frozen climates, as outdoor pipes can freeze in cold, harsh weather.
Evacuated-tube solar collectors
They have parallel rows of clear glass tubes. Each tube contains an outer glass tube and a metal absorber tube attached to the fins. The lamellar coating absorbs solar energy but reduces radiant heat loss. These collectors are most commonly used in US commercial applications.
Solar water heating systems primarily require a back-up system on cloudy days or periods of increasing demand. Traditional water heaters usually provide backup and may already be part of the solar system. The back-up system is also part of a solar collector, for example, a roof container with a thermal siphon system. In addition to solar heat, the built-in collector storage system also stores hot water, so it can be packed with a water heater without a tank or need.
Choice of Solar Water Heater
Before purchasing and installing a solar water heating system, do the following:
- Estimate the cost and energy efficiency of solar water heating systems.
- Assess the site’s solar resources.
- Determine the correct size of the system.
- Review local codes, rules, and regulations.
Also understand the different components required for a solar water heating system, such as:
- Heat exchanger for solar hot water heating
- Heat transfer fluid for solar hot water heating
System Installation and Maintenance
A good installation of a solar water heater depends on many factors. These factors include solar resources, climate, local building standard requirements, and safety aspects. Therefore, it is best to have the system installed by a qualified solar thermal systems contractor.
Proper maintenance of the system after installation will allow the system to function properly. Passive systems do not require a lot of maintenance. For active systems, discuss maintenance requirements with the system supplier and read the system instruction manual. The piping and other traditional hot water components require the same maintenance as traditional systems. In arid climates where rainwater does not provide a natural flush, the glazing may require cleaning.
Regular maintenance of simple systems can be performed by solar companies, preferably every 3 to 5 years. Systems with electrical components typically require one or two replacement parts after 10 years. Learn more about maintaining and repairing solar water heating systems.
Ask the following questions when looking for potential contractors for installation and/or maintenance.
- Does your company have experience in installing and maintaining solar water heating systems?
- Choose a company that has the experience to install the type of system you need and maintain the application you want.
How many years has your company installed and maintained solar heating?
The more experience you have, the better. Get a list of past customers who can provide a reference.
- Is your company licensed or certified?
Some states require that you have a valid plumber and/or solar contractor license. Contact the city and county for more information. Check your license with the State Contractor License Board. The Licensing Board can also notify you of complaints against contractors licensed by the government.
Improved Energy Efficiency
After you’ve properly installed and maintained the water heater, try a few additional energy-saving strategies that can help you reduce hot water costs, especially if you need a back-up system. Some energy-saving devices and systems are cheaper to install with a water heater.
Other options for water heaters
- Water Heater Sizes
- Selecting a New Water Heater
- Heat pump water heater
- Tankless coil and indirect water heater