Friday, July 29, 2011

Large Horizontally Oriented Water Heating Collector with a Unique Heat Storage System

This is a very nice solar water heating system done by Bob and Dave.  
The 24 ft wide collector fits nicely under the deck.
Aside from being very well built and aesthetically pleasing, it has some unique design features:

  • Instead of running the collector manifolds horizontally along the top and bottom and connecting the manifolds with many vertical risers with fins, this collector runs the manifolds vertically on the left and right ends.  The vertical manifolds are then connected a small number of 24 ft wide "hizers".  This saves a lot of fittings, a lot of soldering, and a lot of labor.  This is one of the nice things about building a system yourself -- you can adapt the design to your specific situation.
  • The heat storage for the system takes the form of a an insulated vault containing several plastic barrels that store the heated water.  Since the barrels were free, this makes for pretty inexpensive storage.  The heat exchangers are pipe coils that are wound inside of smaller drums that fit inside the larger barrels.   

Picture shows the 24 ft "hizers" being laid out.
The heat storage vault with the 4 barrels that store heated water.
The heat exchanger pipe coils wound inside of smaller drums.
So far, the system is being used primarily for domestic water heating, but the collector design and heat storage scheme certainly make it a good candidate for solar space heating as well.

Several pages of design, construction, and cost details on the system here...

More solar water heating systems...
More solar space heating systems...

Thanks very much to Bob and Dave for taking the time to document the system!


Wednesday, July 20, 2011

Converting a Clothes Dryer to Use Solar Heated Attic Air

Randy has done a really interesting new project that reduces the energy used to dry clothes at his house by a factor of five!

His scheme converts a regular dryer to use hot air supplied by his unique attic solar heating collector instead of heating the air within the dryer.  A duct from his attic collector supplies air to the revamped intake of the converted dryer.  The dryer exhaust air is vented out through the wall in the normal way.

The converted dryer on the left and the new intake ducting on the right.
The upper duct connects to the attic solar collector.
Dryers are major users of energy in homes. A Canada study shows that dryers typically use 930 KWH a year to do 416 dryer loads (2.23 KWH per load). Nearly all of this heat energy is simply expelled outdoors (wasted). In addition, as the dryer vents air outside, it pulls fresh air into the house which has to be heated or cooled (depending on season) to room temperature -- this can easily add another 300 KWH plus per year.    Since refrigerators have become much more efficient over the years, dryers now stand out as the applicance using the most energy in many homes.  It is amazing to me that Energy Star has taken no action in this area -- but, I guess that's another story.

For all the details on Randy's dryer project...

I've also added a new section that gathers together several ideas and projects that save energy on clothes drying ...

Some highlights on Randy's dryer conversion:

The silver duct on the right is the dryer air inlet.
It takes air from the dryer cabinet on the lower right, and supplies it to the drum.  The idea is to change this so that
the air source is the attic solar collector.
Randy pluged the normal air inlet (lower right), and
added the 4 inch connection for the new attic air source.

The upper duct is the new air inlet ready to be hooked up to the attic air source.
Lower duct is the normal dryer exhaust vent that goes to the wall.

The duct that brings the hot air from the attic collector
down to the dryer inlet.

The temperature on the right is the attic collector temperature.
Temperature on the left is the dryer inlet temperature.

Drying a full load of mixed clothes takes 90 minutes, and uses only 0.6 KWH.

Gary July 20, 2011

Tuesday, July 19, 2011

A DIY Solar Water and Space Heating Project

Eric describes his new solar water heating system that will be used for both domestic water heating and radiant floor heating.

The first collector for Eric's system.

The design is based on the $1K Solar Water Heater, with some refinements and improvements for Eric's situation.  The system is extended to do both domestic water heating and some space heating.

All the details are posted on Eric's blog --

Here are a couple highlights:

Very nice job on the absorber plate.

The base for the tank on conrete pavers.

The pump that cirulates tank water to the collector.

Thanks very much to Eric for sharing the details.

For more examples of $1K systems and other solar space and water heating systems...


Thursday, July 7, 2011

Our New 2500 Gallon Rain Water Collection System

We just finished up a rain water collection system a couple weeks ago and now have the full construction details up on the site.
The system uses the roof of my shop and carport (925 sf total) to collect rainwater into a 2500 gallon polyethylene container.  We then use  a small pump to pull water out of the container for watering the garden and trees.
The new water collection system.

Building the system included adding gutters to the roof, running 3 inch PVC collection plumbing from the gutters to the tank, doing a first flow diverter, adding an overflow pipe, and working out a simple pump arrangment to get the water over to the garden.

Getting the tank off the truck

The writeup goes through the details on how we picked the tank size using the very handy CLIM20 weather summary  (free from the gov).  And then goes on to show all the details on placing the tank and putting in all the plumbing.  All in all a pretty easy job.

Gutter to tank plumbing.

All the details on the rain collection system here...

More on rain water harvesting, grey water, toilets, ...

It looks like the system will provide about 7000 gallons a year depending on how our actual usage pattern works out.  We are planning to use the water only for garden and tree watering.  Of curse, it also provides some water for emergencies.  We may do a larger system using the house roof later depending on how this works out.

So, this system coupled with the switch over to all dual flush toilets is saving a lot of water use at our place.   This is gettting to be more and more important in our valley.  The one troubling aspect of all this is that we still use a lot of water to water the lawn through the summer.  I don't even want to do the estimate on how much because I'm sure I won't like the number.  I guess that the answer to this is to go to a more native plant, low water landscaping scheme -- anyone know any good resources for planning this kind of landscaping in the Rockies?

By the way, I've added a new comment system for articles on Build It Solar, so it will be possible to easily comment on, ask questions, and discuss each article -- I encourage everyone to use this.
The first article with the new comment system is Randy's attic, and the writeup on the new rain water harvest system is the 2nd.


Monday, July 4, 2011

Randy's Invisible Solar Attic Space Heating Collector

Here is another simple scheme for using solar heat from the attic to provide free space heating.
The lower plenum and collector channels formed by
the roof trusses.
Randy sheeted across the back of some of his attic roof truss bays to from the channels for a collector.  He then added an intake plenum at the bottom and a exhaust plenum at the top.  So, air flows from his living room via a 12 inch duct to the intake plenum, then up through the truss bays picking up heat from the under surface of the roof, and then into the exhaust plenum, and finally back to the living room via another 12 inch duct.  The flow is powered by an attic vent fan that includes a 93F thermometer to turn the system on when the attic air gets up to a useful temperature.

While the system is currently prototyped in cardboard to see how well it worked, Randy plans to replace the cardboard with rigid polyiso foam board.

One remaining challange is a good backdraft damper to prevent cold air from thermosyhphoning into the living room at night -- any ideas?

All the details on Randy's solar attic heat project...

Randy is planning to try picking up attic air to run the clothes dryer with.

The collector is invisible from the outside.

For more information on using solar attic heat ...

Note that I'm trying a new comment system that you will see when you go to Randy's project page -- I'd appreciate hearing any feedback on the system or problems using the system.

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