Generating Hot Water from sunlight is still the most cost
effective method of transforming the sun's energy into heat. Since the
Solar Domestic Hot Water (SDHW) system does not have grid connection
problems many homeowners are now building and installing their own solar
collectors for a fraction of the cost of a commercial system. A typical
commercially installed SDHW system has an initial cost in excess of
$6,000 and a payback period of 10 years. If your handy with tools you
could build and install a homemade SDHW system for less than $1000 that
could pay for itself in 2 years.
Solar Applications can be cost effective if we're willing to roll up our sleeves and do a little work so let's take a look at some of the materials used to build a homemade collector and homemade heat storage tank.
Commercial Flat Plate Collectors are framed in aluminum with 3/8" copper flow tubes soldered to 1" header pipes. A copper absorber plate is then soldered to the flow tubes and coated with a selective coating such as Cr02 that traps about 97% of the sunlight that strikes it. Unfortunately the materials and labor involved in building a homemade collector like this are not cost effective.
Homemade Flat Plate Collectors can be practical.. They can be made by a variety of methods that use inexpensive aluminum flashing to make absorber plates and they are almost as good as copper plates soldered to copper flow tubes. Aluminum is less expensive than copper.and individual 4" wide aluminum plates may be pressure bonded to copper, flow tubes or they may be siliconed onto a serpentine PEX tube.
A Serpentine Copper Flow Tubes may also be bonded to an aluminum absorber plate rather than a PEX tube. Copper as you know conducts heat better than plastic, but the main reason I use a copper tube instead of PEX is that copper remains hard when it gets hot. Side and central supports are used to hold copper against aluminum but this support method is not practical when using PEX. Multiple screws through the aluminum absorber plate are needed to hold the PEX serpentine tube it in place. Another thing that's nice about a copper flow tube has to do with the method of installing two 20"x 95" aluminum absorber plates first rather than sixteen 4"x40" absorber plates last. The entire 60' long serpentine flow tube is pre-bent inside on an easy to build bending jig. This facilitates a one step installation of the copper into the aluminum.
A Continuous Aluminum Absorber Plate may be fabricated with a pounding jig made with 2"x6" boards and some 3/8" steel rods. The two 20"x95" absorber plates made from a roll of aluminum flashing takes less than 10 minutes to hammer out. Just think of all the collectors you could make with one jig like this.
The Absorber Plate Coating is made with a mixture of tar and lamp black and mineral spirits. The tar seeps between the copper and the grooves to bind the flow tube to the absorber plate. The absorbance of the tar/carbon black mix is only slightly less than expensive selective coatings. Sunlight is used to dry out the tar before the glazing is installed.
A Pair of 4'x8' Serpentine Collectors work in harmony when they are connected in parallel. The 3/8" flow tube used in the collector is inexpensive and easy to bend, but if two collectors were connected in series the flow restriction would be excessive. To remedy this problem and also facilitate the plumbing connections the serpentine collectors are connected in parallel.
A Home Made Heat Storage Tank can be made from a used hot water tank and a copper heat exchange tube. Instead of installing the heat exchange tube inside the storage tank it may be wrapped around the exterior of an old tank and bonded with wire and aluminum foil and insulation. An alternative to exchanging heat with copper would involve the use of PEX, but you'll need more PEX than copper to get the same heat exchange rate and the PEX may be harder to work with.
Solar Applications can be cost effective if we're willing to roll up our sleeves and do a little work so let's take a look at some of the materials used to build a homemade collector and homemade heat storage tank.
Commercial Flat Plate Collectors are framed in aluminum with 3/8" copper flow tubes soldered to 1" header pipes. A copper absorber plate is then soldered to the flow tubes and coated with a selective coating such as Cr02 that traps about 97% of the sunlight that strikes it. Unfortunately the materials and labor involved in building a homemade collector like this are not cost effective.
Homemade Flat Plate Collectors can be practical.. They can be made by a variety of methods that use inexpensive aluminum flashing to make absorber plates and they are almost as good as copper plates soldered to copper flow tubes. Aluminum is less expensive than copper.and individual 4" wide aluminum plates may be pressure bonded to copper, flow tubes or they may be siliconed onto a serpentine PEX tube.
A Serpentine Copper Flow Tubes may also be bonded to an aluminum absorber plate rather than a PEX tube. Copper as you know conducts heat better than plastic, but the main reason I use a copper tube instead of PEX is that copper remains hard when it gets hot. Side and central supports are used to hold copper against aluminum but this support method is not practical when using PEX. Multiple screws through the aluminum absorber plate are needed to hold the PEX serpentine tube it in place. Another thing that's nice about a copper flow tube has to do with the method of installing two 20"x 95" aluminum absorber plates first rather than sixteen 4"x40" absorber plates last. The entire 60' long serpentine flow tube is pre-bent inside on an easy to build bending jig. This facilitates a one step installation of the copper into the aluminum.
A Continuous Aluminum Absorber Plate may be fabricated with a pounding jig made with 2"x6" boards and some 3/8" steel rods. The two 20"x95" absorber plates made from a roll of aluminum flashing takes less than 10 minutes to hammer out. Just think of all the collectors you could make with one jig like this.
The Absorber Plate Coating is made with a mixture of tar and lamp black and mineral spirits. The tar seeps between the copper and the grooves to bind the flow tube to the absorber plate. The absorbance of the tar/carbon black mix is only slightly less than expensive selective coatings. Sunlight is used to dry out the tar before the glazing is installed.
A Pair of 4'x8' Serpentine Collectors work in harmony when they are connected in parallel. The 3/8" flow tube used in the collector is inexpensive and easy to bend, but if two collectors were connected in series the flow restriction would be excessive. To remedy this problem and also facilitate the plumbing connections the serpentine collectors are connected in parallel.
A Home Made Heat Storage Tank can be made from a used hot water tank and a copper heat exchange tube. Instead of installing the heat exchange tube inside the storage tank it may be wrapped around the exterior of an old tank and bonded with wire and aluminum foil and insulation. An alternative to exchanging heat with copper would involve the use of PEX, but you'll need more PEX than copper to get the same heat exchange rate and the PEX may be harder to work with.
There are many alternative DIY heat storage tanks. Here are a few: http://jc-solarhomes.com/diy_solar_heat_storage.htm
Do-it-yourself, home made solar hot water systems are practical and cost effective. The average American household consumes between 1000 and 2000 gallons of fuel oil per year. Efficient use of the sun's energy could easily cut this consumption in half or eliminate it entirely. If you have carpentry skills you'll have no trouble assembling a serpentine collector. The one long continuous serpentine tube is bent on a homemade jig so there are very few solder connections. Union Ts are used to join collectors so that soldering on top of a roof is also unnecessary.
For more information about how to build a solar hot water system go to: http://www.jc-solarhomes.com/how_to.htm
Article Source:
http://EzineArticles.com/?expert=John_Canivan
Do-it-yourself, home made solar hot water systems are practical and cost effective. The average American household consumes between 1000 and 2000 gallons of fuel oil per year. Efficient use of the sun's energy could easily cut this consumption in half or eliminate it entirely. If you have carpentry skills you'll have no trouble assembling a serpentine collector. The one long continuous serpentine tube is bent on a homemade jig so there are very few solder connections. Union Ts are used to join collectors so that soldering on top of a roof is also unnecessary.
For more information about how to build a solar hot water system go to: http://www.jc-solarhomes.com/how_to.htm
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