Monday, June 18, 2012

A New DIY Solar Water Heater That Goes Together Like LEGO's

I'm taking a cut at a new solar water heating system that is an easier and quicker DIY project than our current $1K system.

While our current $1K solar water heating system has been popular and lots of people have built it with good success, it does require the building both the collectors and the solar storage tank yourself, and that takes a bit of time.

The aim of the new system is to make the job of doing your own solar water heating system quicker and easier by using all off the shelf components that just need to be mounted and hooked up together.

A prototype system is in the works using these components:
  • Collectors are 80 sq ft of plastic matt style pool heating collectors 
  • The tank is the 175 gallon Softank 
  • The controller is a standard differential controller from sun-pump
  • The pump is a Grundfos HVAC circulation pump
The prototype is very much a work in progress, and I'm looking for ideas and comments.  Please look over the design and build, and if you have any thoughts on the system please leave comments on that page.

The system design is very much like the existing $1K system in that it is a drain back system that uses a large, non-pressurized tank for both the drain back tank and for heat storage.  It also uses the one pass large coil of pipe heat exchanger to preheat cold water before it gets to your hot water heater.

Overview of the Components

The 80 sf of pool heating collector in place.
The collectors are lightweight and easy to handle and install.  You can put 40 sf of collector under one arm and easily climb a ladder.  The three season performance of these collectors is good in a solar water heating application, and there are some ideas on how to improve the not so good winter performance -- maybe you have more ideas?

A nice side benefit of using these collectors is that they are SRCC OG100 certified, and therefore the whole system qualifies for the federal tax credit, and maybe state rebates depending on where you live.

The prototype collectors are Fafco SunGrabbers bought on ebay.

Solar Storage Tank:
The tank is the Softank kit offered by American Solartechnics.  The kit goes together easily and the tank holds about 180 gallons of solar heated water.  
The Softank with 175 gallons of water.
The top of the tank looks like a mess because I've not finished the lid
and not trimmed things back and tucked things in.
The controller and pump are visible at the left.
The insulation bulges on the pipes are covering temperature logging sensors.
The controller is an off the shelf differential controller from sun-pump that has all the advanced features at a not so advanced price.
The controller -- the wiring showing here is
most of the wiring for the whole system.
The pump is a Grundfos 15-58 three speed HVAC circulation pump.  These pumps are relatively efficient and very rugged with a reasonable price.  
The Grundfos pump -- this is the rest of the wiring.

Heat Exchanger:
The heat exchanger is a large coil of PEX pipe that is immersed in the tank.  Cold water from the street takes one pass through this coil to be preheated on its way to your hot water tank.  It is the same one that is used in the $1K system and is explained in detail there.

Plumbing and Electrical:
The system is plumbed together with easy to use CPVC pipe.  This is the easiest system for people new to plumbing.  You cut it with a scissors like device and the joints are just glued together.  Goofs are easy to fix.  There is a  little bit of electrical wiring is that is easy and safe to do.

The target cost for the system is around $1300 before rebates.  Depending on your rebate situation, payback may inside one year.

All the details on the Off-The-Shelf DIY Solar Water Heating System...

The "going together like LEGO's" title is no doubt an exaggeration, but the system is designed from the bottom up to be easy to put together.

Let me know what you think.


Thursday, June 14, 2012

Solar Hot Water and Space Heating System With Integrated Boiler

This is Norm's very nicely done solar space and water heating system.

The system uses a large, unpressurized tank that serves as both the solar heat storage tank and the drain back tank for the collectors.  The solar heat is used both to preheat domestic water and also for space heating, which is integrated with a propane fired boiler.

The solar storage tank with the copper coil heat exchangers.

Heat is extracted from the tank using one heat exchanger for space heating and a 2nd for domestic water heating.  Both heat exchangers are made from two coils of copper pipe with parallel flow and are very nicely done.  Norm provides good detail on making these heat exchangers.

The system uses four Sun Earth flat plate collectors.
The four 4 by 10 ft Sun Earth Collectors.
In Norm's system the boiler is integrated with the solar system such that the boiler only provides heat when the solar collectors cannot.
Boiler is at upper left -- solar components are mounted on the tank wall.

Heat distribution is to PEX runs in concrete and to the radiant floor done with Warm Board shown just below.
Warm Board hydronic radiant flooring distributes solar heat.

All the details on Norm's olar Hot Water and Space Heating System With Integrated Boiler...


Saturday, June 9, 2012

Energy Fair Season!

Its the Energy Fair season!

Energy Fairs provide a great way to learn about renewable energy and sustainable practices.  They typically include workshops, seminars, demonstrations and exhibitors -- everything you need to get started on that next project.

From the point of view of Do-It-Yourselfers, the MREA Energy Fair in Wisconsin is probably the best of the best.  June 15-17, Custer, WI.


MREA Workshops
The MREA workshops alone are amazing in their scope and the level of expertise of the workshop hosts...
More than 200 workshops...

Or, find an Energy Fair near you.

A list of the Energy Fairs I know about in the US is here:...
Its hard to keep this list up to date and websites, dates, ... change each year -- so, if you find an Energy Fair on the list, but the link is broken, just Google for it.
There are also MANY fairs that are not on the list, so check around and see what you can find in your area.

If you are putting on an Energy Fair, let me know the date and place and I'll add it to the list -- contact Gary...


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