Building a Solar Heated Well House

This is a very nice and well documented project on the Alt. Build Blog that covers building a freeze resistant well house.  The idea is to keep the well plumbing and tanks above freezing with a passive solar heating system.

The well house and Trombe wall solar heater.

The well house is built from dry stack concrete blocks that are insulated with rigid foam insulation on the outside and then stucco for the outer weather surface.

A Trombe wall solar collector covers most of the south face of the structure -- the south wall concrete blocks are used for the mass of the Trombe wall, and twinwall polycarbonate is used for the Trombe wall glazing.

The advantage of using a Trombe wall for this situation is that the wall absorbs heat when the sun is on it, and this stored heat is released over the night time period to keep the structure above freezing for the full day.  The mass of the other wall concrete block walls should also help in maintaining a more even temperature -- putting the insulation on the outside of the block allows the wall mass to be effective in regulating the temperature of the space.  The mass of the water in the tanks should also help to even out temperature variations.

Trombe wall opening surrounded by stucco walls.

The entire project is described in 9 blog entries covering the whole build in a great deal of detail.  To my eye, the overall design and details are well thought out and executed -- a really nice job.

For colder climates, some changes that might be considered -- 1) use thicker insulation to reduce the heat loss out the roof and walls (possibly polyiso), 2) add insulation under the floor to reduce heat loss to the ground.  For really challenging climates, you  could consider going to a drain back solar collector on the outside that heats water in a relatively large unvented water tank on the inside that stores heat.  The heat loss from the heat storage tank would then heat the well house so that it stays above freezing.  The tank insulation could be set at a level such that the tank loses heat at a rate that keeps the inside of the structure above freezing all day -- even with some cloudy days.   The drain back circulation pump could be something like a PV powered TopsFlo pump, so that no separate differential controller would be needed.  While the drain back solution is more complicated and more expensive than the Trombe wall, the advantage is that its about twice as efficient as the Trombe wall collector -- so, it may payoff for cold climates.

All the details on the solar heated well house here...

Lots of interesting article on the  Alt. Build Blog -- have a look.

For hundreds more solar space and water heating ideas and projects...

Inside the well house.

Gary

A Simple and Inexpensive High Lift Solar Pumping Setup

Stan was faced with a difficult garden watering problem in which he had to get water from a spring to a greenhouse that was located several hundred feet away and 50 ft uphill from the spring. The flow requirement was relatively small at about 3 gpm for for an hour and half a day about 3 times a week.

Using a conventional AC powered pump would have meant running a lot of wire, and the 800ft distance would have meant a larger than normal wire gage to keep the voltage drop from being excessive.

Using one of the submersible well pumps that are made to run directly from solar PV panels is a nice solution, but the pumps are expensive and they require quite a bit of PV panel area to drive. So, this would have been an expensive solution for the relatively low flow required.

PV panel at spring -- green bucket covers pump and battery.

Stan's solution was to use a relatively inexpensive 12 VDC Shurflo pump that is intended for spraying and RV applications. The pump draws about 8 amps, so, to drive it directly with PV panels would have required at least 100 watts of PV array, and perhaps a linear current booster for startup. Instead of direct PV drive, Stan incorporates a deep cycle 12 volt battery to drive the pump, and then uses a small (30 watt) PV panel to charge the battery over the course of the day. This works well because the run time for the pump is not very long and can be handled by the battery, and the PV panel has all day to recharge the battery.

Pump, battery and charge controller under PV panel.

All the details on building and sizing this system...

More on solar water pumping...

Gary

Waterbag Solar Water Heating Collector Using Inflatable Film Cover and Soap Bubble Insulation

This is an innovative new wrinkle on the Integral Collector Storage (ICS) design from Nick Pine.

With ICS solar water heaters, the collector and the storage are combined into a single unit. Basically they consist of a water container that typically sits inside of of a glazed enclosure. Solar radiation heats the water container during the day. This is an example of a commercial ICS design.

One of the downsides of the nice simple ICS design is that it tends to lose quite a bit of heat at night through the glazing. Nick has addressed this problem by filling the area between the water container and the glazing with soap bubbles at night. The soap bubbles are good insulators and greatly reduce the night heat loss.

The design has several other innovations:

• A film bag is used to hold the water, which reduces the cost of the water container.
• A greenhouse polyethylene film cylinder is used for the glazing and is inflated to hold its shape -- a significant cost saving over conventional glazing. Similar to a hoop style greenhouse.
• The north half of the glazing cylinder is reflectorized to reflect more solar onto the water bag.

One upshot of the inexpensive materials used in Nick's design is that it is not expensive to build a solar water heater with a large collection area and a large storage capacity -- this increases the solar fraction.

Thanks to Jay Burch for this diagram.

To transfer the heat stored in the bag to the domestic water, a large coil of PEX pipe is immersed in the bag, and the cold water from the house takes ones pass through this large coil of PEX and is heated by the water in the bag. This heat exchanger scheme has been used quite successfully on the $1K solar water heater.

Be the first on your block to build one!

All the details here....

If you have any thoughts or ideas on this design, please leave them at the link above.

Gary

Dave's £900 Homemade Solar Water Heating System

David lives at 52 degree North latitude in the UK -- a pretty tough location for solar water heating, but his homemade system works quite well.

This is a really nice build with lots of good ideas and details to learn from.

The system is loosely modeled after our $1K system, but has a number of noteworthy features:

• Very nice workmanship and details.
  
• Solar heat is stored in the existing house thermal storage tank (which is used for both space and domestic water heating).
  
• An aesthetically pleasing collector and mounting arrangement.
  
• A pumping station that is mounted in a weather protected box on the back of the collector.
  
• A freeze protection system that takes into account his unique circumstances.

Dave is a professional plumber who now teaches plumbing, and this shows in the attention to detail in the design and the careful workmanship.

Thanks very much to David for sending this in!

All the details in a 25 page pdf...

The copper riser, aluminum fin collector under construction.

The pump was located at the collector in the box as there was no
space near the tank.

This is the existing thermal storage tank for the house that
is used for space and water heating and now stores solar heat as well.

Gary April 26, 2013

Elektra One Solar Airplane

Being an old airplane guy, I though this development in solar airplanes was really interesting.

The Elektra One Solar from PC-Aero is a single place, electric airplane with a maximum range of 1000 km.  While flying, it is about half powered by solar cells mounted on the wings and tail.

The empty weight is only 100 kg -- it is constructed mostly from carbon fiber.

There is also a 2 place version.

Seems like solar powered airplanes may be coming out of the extreme experimenter class into something more interesting to regular small airplane users?

Makes you wonder what an electric, aerodynamic, 100 kg car with solar cells could do?

All the details...

Gary

A 2 Year Update on Gordon's Unique Khanh Solar Water Heating Collector

A couple of years ago Gordon did a solar water heating collector for his home that uses the Khanh design.

This design improves the performance of conventional water heating collector by extending the area of the collector to include an air heating collector that warms the area around the water heating collector to reduce heat losses from the water heating collector.

The design is explained in detail in Shurcliff's book: New Inventions in Low-Cost Solar Heating

Gordon's original article on his implementation of the design along with construction details is here..

Its been two years and Gordon has a good report on the things that worked and the things that did not work so well and had to be fixed or improved.

The report covers: performance, a new differential controller, pumps, backup water heaters, and some plumbing issues.... 

All good stuff to know if you plan to use this design.

Gary
March 31, 2013

Rain Water Collection -- Year Two Update -- Freeze Problem

Our 2200 gallon rain water collection system has been working well, but we did have a freeze damage problem this winter.

The full rain water system is described here...

This winter the first flow diverter reservoir managed to fill up with water and freeze over the winter.  The expanding ice did an impressive job of breaking the large PVC pipe that serves as the reservoir.  The valve at the bottom of the reservoir was open for the winter, but must have plugged up and allowed water to accumulate.

Freezing water breaks the pipe that serves as first flow diverter.

For now, I've just removed the first flow reservoir where it threads into the collection plumbing and put a threaded PVC plug in to make the system functional, but with no first flow diverter.  Will need to work out a better system that is less subject to freeze damage.

A PVC threaded plug replaces first flow reservoir for now.

More details on the 2nd year of operation here...

Gary

Renewable Energy Magazine Article on DIY Renewable Energy

Richard Crume's latest blog for Renewable Energy Magazine is about the DIY area of renewable energy.  I'm happy to say the article features Build-It-Solar.

Richard describes some of the rewards of doing DIY renewable energy projects, and some of the achievements of the the DIY crowd.

One of the Richard's projects that is featured on our Solar Homes section is this article describing the this very energy efficient and very nice to live in house they built.

Gary

Adding Glazing to the Off The Shelf Solar Water Heating System Collector

This is an update on the project to develop a simple, efficient, low cost and reliable DIY solar water heating system that is easy to install because it uses all off the shelf parts.

The system uses an unglazed pool heating collector because it is inexpensive, easy to install, and allows the system to qualify for the federal tax rebate.  The performance of this collector is good for warm and moderate climates, but falls down during the winter in cold climates.

This update covers adding glazing to the pool heating collector to improve its performance when when its cold and for part sun conditions.

The pool heating collector with glazing.

The glazing used is SunTuf corrugated polycarbonate, which was chosen because it is tough, long lived, readily available (eg Home Depot), and has a high service temperature.  The glazing is supported by a simple frame that just plunks down over the collector -- the weight of the glazing assembly is supported by the collector manifold, and the glazing assembly is held down by a couple of straps in the same way the the collector itself is held down.  The whole glazing assembly for the 4 by 10 ft collector is light weight and can be handled by one person.

The glazing includes some openings at the bottom and at the top that allow a controlled amount of air to circulate between the glazing and the absorber.  This is to mellow out the temperature that the collector gets to if the collector is stagnated (no water flow).   The idea is to keep this air flow small enough to not significantly effect collector performance, while at the same time keeping stagnation temperatures within bounds.

The link below gives all the details on the construction.

The performance of the system is definitely improved with the glazing in place.  For some conditions that are typical of moderate to cold climates, the improvement is of the order of 50% in heat output.
The link below gives complete performance details, and compares the performance of the glazed and unglazed pool heating collector to commercial flat plate and evac tube collectors on both heat output and heat output per dollar of collector cost.

Comparing efficiency of several collectors to our collector.

All the details on the updated collector with glazing...

The main page for the Off The Shelf DIY Solar Water Heating System....

Comments, suggestions, questions are most welcome.

Gary
March 17,2013

ASES Solar Citizen Program

ASES (American Solar Energy Society) has been been working for more than 50 years to bring about a transition to solar and renewable energy in the US.

ASES has started a new program called the Solar Citizen that is aimed at providing families with the information and tools needed to get their own solar energy projects going.

"We know that most Americans would produce their own clean local energy if it were easy and affordable. We don’t tell you why you should want it. We tell you ­how to get it. We show you who figured it out, and how they did it. We connect you to news and tools to help make it happen on your home, in your town, on your farm, on your church, or on your school."

The latest addition of the Solar Citizen Newsletter "Do-It-Yourself Solar", provides some good information and links for DIY projects and information.

I think its great to see ASES concentrating on helping families get the practical information and tools they need to get solar projects done, and in particular the interest in DIY projects.  Please let them know you think this is a good direction.

Sign up for the Citizen Solar Newsletter....

Also, have a look at these ASES offerings:

• Solar Today magazine -- very good magazine on solar and renewable energy
• The annual ASES conference -- papers and workshops on the latest in solar -- this year in Baltimore
• The National  Tour -- a fall tour of solar homes  in your area

ASES would love to have you post your solar or renewable energy projects on their Facebook Page...

Gary