Solar hot water heater
A complete overview of solar powered water heaters
A solar hot water heater is undoubtedly the most energy saving water heating option available. The biggest advantage to a solar powered system is the renewable source of energy that's used. Currently, and in the foreseeable future, the sun's radiant heat is both cost free and free of carbon emissions.
Using the sun to heat indoor domestic water is far from new. Solar water heating systems have a long history throughout the United States, and throughout much of the world. Over a hundred years ago solar powered water heaters were commonly used.
But by the mid 1900's, inexpensive fossil fuels become more readily available throughout much of the United States. With the introduction of cheap fuels, solar hot water heaters all but disappeared, and so did much of the industry and many of the professionals that once supplied and serviced the systems.
Most experts agree that the days of inexpensive and plentiful fossil fuels are long gone. This in large part is due to the increased demand for energy caused by the simultaneous industrial development of various countries throughout the world.
With the steady increase in fuel costs, the residential and commercial demand for renewable energy sources has sizably increased. Most renewable industry experts agree that solar, and specifically solar water heating systems, are more cost effective than any other renewable energy application currently available.
Today's American solar industry is aggressively supported by both federal and local subsides, and would be consumers are further enticed by several additional financial incentives. With that said, there's never been a better time to consider installing a solar hot water heater.
How solar hot water heaters work
In most instances, solar hot water heaters are designed to accommodate an existing system. In effect the solar powered system is retro fitted to a secondary fuel powered water heating unit that serves as a back up. Since the sun's natural radiation isn't always accessible, a sufficient back up source is required.
The sun's thermal radiation pre heats domestic water during peak daytime hours. The pre heated fluid is then circulated throughout the system's loop, or circulation pipes, and is eventually distributed to the back up unit.
If the overall system is sized correctly, the back up heating source should only be needed sparingly. The back up source simply boost the pre heated water to a desired temperature setting on either very overcast days, or during nights or at times when hot water demand is unusually high.
In most instances, the back up water heating source is either a conventional storage tank or a tankless hot water heater. Solar powered water heaters and tankless units together are the most energy efficient combination.
A single tank solar water heater is ideal for newly constructed buildings that don't have an existing system. This design comes equipped with an integrated back up heating source, effectively combining the solar powered source and the secondary source into one water heating system.
Solar resource is the amount of direct sunlight a building, or site, receives. A site's solar resource is determined by several factors; geographic location and the particular climate season being some of the more important factors. A site's solar resource is the first major consideration to make before installing a solar hot water heater.
Maximizing solar resource during installation is important because seasonally shifting the system's major components won't be very cost effective, in fact it would be down right impractical, and in most cases impossible.
Throughout the entire northern hemisphere a building's south and southwest position receives the most direct solar radiation on an annual basis, with the exception of those sites that have significant landscape or structural obstructions.
Determining a site's solar resource is also required for proper system sizing. A local solar installer can both determine if your site is suitable for installation and accurately determine your site's solar resource.
Solar water heating is underutilized
One of the biggest misconceptions about solar hot water heaters is that only those homes or businesses in the Sunbelt or southern regions are suitable for installation, this perception is entirely false. Even residents in the Northeast region of the United States stand to benefit.
The average annual solar resources throughout the Northern regions of the U.S are more than adequate. Solar powered water heating systems are under used in large part because many confuse solar radiation with regional climate. Even in the coldest climate regions, a site can have an ample amount of solar radiation.
Type of systems and designs
There are several solar powered water heater designs, and which system is suitable for your home or business will largely depend on your regional climate.
Some systems and designs provide little freeze protection, while others are designed to efficiently operate in even the coldest climates. All solar hot water heaters are divided into two categories;
Major system components
System designs can be very simple or very detailed. Since the designs vary, the components within the design vary as well. All passive as well as active solar powered water heaters contain hot water panels (also called solar collectors) and solar storage tanks.
Understanding how these two essential system components function is strongly recommended.
- Solar hot water panels; are the engine or the heart of the system. These panels, or collectors, both absorb and distribute the sun's radiant heat.
- Solar hot water tanks; along with the back up source, solar tanks allow the system to provide hot water rain or shine and day or night.
Again it's important to note that since there are several solar designs, the parts required for a particular system will vary. With that being said, there are other additional components required for some designs.
Solar Hot Water Pump; is used to distribute and circulate fluid throughout the system. Solar water pumps are required in active solar hot water heaters.
Solar Heat Exchanger; is used to transfer heat from one fluid to another fluid. This system component provides a substantial amount of freeze protection and is required in some active designs.
Durability is one of the most important aspects to consider with any long term investment, and water heating systems are no different. Without a doubt, a solar hot water heater can pay for itself several times over, but only if the system's components are efficiently functioning properly.
The manufacturing and plumbing knowledge that goes into both the design and the installation will prove vital to the system's overall durability. Proper maintenance will also increase the energy efficiency and the life expectancy of the solar hot water heater. A properly sized, installed and maintained solar water heater can last well over 30 years.
The U.S government, as well as some U.S states, are offering significant tax incentives to homeowners and businesses who install a solar hot water heater. These incentives, if applicable, can significantly reduce the out of pocket expense of purchasing and installing solar powered water heating systems.
With the federal solar tax credit, and several other solar incentives, home and business owners can reduce the cost of going solar by thousands of dollars.
Consider improving efficiency first
Whether your considering installing a solar water heater in an existing home or a new construction, making some small upfront investments in energy efficiency can reduce the size and cost of the system.
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