Solar Space & Water Heating -- With Folding Collectors

Kenneth has incorporated some very nice and new features in his innovative solar space and water heating system -- including:

• Folding collectors that allow more collector area for winter and less for summer
  
  
• Some unique new tools for collector making, including a homemade "Tee Puller', and new designs for forming and clamping the collector fins to the collector tubes.
  
  
• Use of a surplus stainless steel bulk milk tank for heat storage.

The system is built using the Solar Shed concept, meaning its a separate building that acts as both a storage or garden shed, supports collectors and provides space for the heat storage tank.

A few hightlights below, and 5 pages of construction detail here...

Folding Collectors
The two pictures below show the folding collector feature. 



The top photo shows collectors folded out for winter -- 8 active collectors.
The bottom photo shows collectors folded in for summer -- 4 active collectors (along with Kenneth).

Homemade Tee Puller
Kenneth made a tool for drawing a Tee out of a copper collector manifold part -- this allows the collector risers to be connected to the manifold without using reducing Tee fittings or brazing.

Bulk Milk Tank for Heat Storage
Kenneth used a 750 gallon surplus stainless steel bulk milk tank for heat storage.
The tank is mostly buried (to allow drainback from collectors) and insulated with 4 inches of polyiso insulation.

Gary

3 Ways to Save Energy That are a Bit "Out There"

Here are three areas where significant energy might be saved in a home with fairly simple systems.  One has to do with using some of the heat in the hot air up in your attic, and the other two have to do with recovering some of the heat we waste in showering.

Regular showers are a major waste of energy.  Typically we spend about 3 KWH heating water for a shower, and then send about 85% of that energy right down the drain.  It amounts to about 300 KWH for a family of 4 per month.

Using The Heat In Your Attic
This page looks at some of the ways that all that heat up in the attic might be used productively.  This includes recovering heat for domestic water heating, space heating, pool heating, and cloths dryer air preheat. 
Some of these look fairly practical (to me).

I've been logging the temperatures up in my attic for about 6 months and the plot of these temps is included.  We live in a very cold climate, and it still looks like there is some potential.

Details here...

Recovering Heat From Shower Water Drain Pipes
This page looks at all the energy we send down the drain when taking a shower, and in some of the ways that are currently out there to recover some of that energy. 
It considers one (as far as I know) new method, which is basically to rearrange the drain plumbing to retain the shower water in the homes heated envelope long enough to recover the heat in the water for space heating. 
Some ways of doing this, the resulting energy saving, and a small test to examine the potential of this method are discussed.

It may seem like there is not really much potential here, but for heating climates, the potential energy saving for a family might be of the order of 1200 KWH a year.

Details ...


A Very Energy (and Water) Efficient Shower Design
This is a look at a shower design that was looked at for potential use on very long range commercial jet airplanes.  It is a very efficient design both from a water use and energy point of view.  It may not be for everyone, but have a look.

Details...

So, I'm particularly interested in whether you think any of these ideas have some merit and are worth pursuing (or not). 
Or, maybe you have some of your own "Out There" ideas you would like to share?

UPDATE: Turns out Kenneth has built and uses a recirculating shower... 
Kenneth's interest were more in getting long showers with very high flow (6 shower heads) without breaking the bank on energy use.  Its a nice simple design.

Note that Kenneth has also done a very nice Solar Shed project that does both solar space and water heating -- hope to have the details on this up soon.
Thanks Kenneth!

Gary

New Content on Build-It-Solar

Pop Can Collector From Sweden



A very nicely done aluminum pop/beer can collector.  Lots of attention to detail, and lots of good assembly pictures.  In Swedish, but the pictures plus Google translator make it quite readable.
Pop can solar air heating collectors force room air through connected columns of black painted aluminum soda cans.  The sun heats the pop cans and the heat is transferred to the air.  The even distribution of airflow and large heat transfer area should make them efficient collectors.
Details here...

Update on Chad's Solar Heating System
Chad has made a number of changes to his solar water and space heating system.  He has also logged and measured the performance of the system.

All the details and performance graphs...

Efficient Inflation System for Double Skin Poly Greenhouses
Many
poly skinned greenhouses use two layers of poly with a small blower
inflating the space between the layers.  This gives you cheap double
glazing, and reduces heat loss.
Most of blowers are set up to run 24/7,
but this article shows a way to cut down the run time dramatically using a
small pressure switch and a very simple check valve.  With the check
valve, the blower runs only when enough air leaks out to the point of
needing reinflation.

Details here...



Facebook Page
I've put up a page for Build-It-Solar on Facebook. 
Basically I have no clue how this all works, so if you have any ideas for the Facebook page, please let me know.

We just broke 500 fans today, so have to be doing something right :)

Spring Solar Projects

Solar Hot Water

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Now is a good time to study up on, and start building a solar water heating
system, so you can get it in this summer.
There are several high quality DIY designs that cab be built for inside of $1000. 

 Many solar water heating
downloads
 




Solar Greenhouse or Sunspace

 A place to grow some plants, produce some free heat for the house next winter,
or just a nice place to sit and have a cup of coffee with the newspaper. 

 Many Solar Greenhouses and
SunSpaces  -- ranging from $20 to $200,000.

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Passive and Low Power Cooling

 Here are many ways to keep your house cool, and at the same time save money
and reduce Greenhouse Gas Emissions.  Shading, whole house fans, landscaping, earthtubes, insulation and sealing, reflective and garden roofs, ...
Lots of ideas here.
 Passive (and
efficient active) Cooling






Solar Pool and Hot Tub Heating
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 Solar pool heating is arguably the shortest payback solar technology.  
Take the chill off the pool, and be easy on the planet at the same time. 

 Solar pool heating
information
My favorite quote on solar pool heating from Tom Lane in the Home Power Article Pool Heating Article:
 "Three gallons of oil refined and burned provides 400,000BTU ... Once.
Three gallons of oil, made into a 4 by 12 foot solar collector, can provide
over 10 million BTUs per year ... year after year"


How about a Summer Outdoor Solar Shower?

This is a very simple solar project to get started with.  It can save energy and reuse shower water for plant watering while providing a nice outdoor shower experience!

How to build info for several outdoor solar showers...






Build Your Own Solar Electric System

Solar electric systems have become much easier to self install over the years.  If you are careful about the safety issues, and have done some home wiring, you may want to give this a try.  Plan it this spring, and build it this summer.

Details on my self installed system...

More on DIY PV...



Do a Water Conservation Project

Spring is a great time to get started on an outside water conservation project.
Dozens of projects described in detail here -- rainwater harvesting, greywater reuse,
rain water gardens, ...

All the details on water conservation projects...


Any other ideas --- make a suggestion.

Gary

Collector Absorber Fins from Tom

Tom Sullivan built a couple large water heating solar collectors.  To reduce the work involved in making the heat absorbing fins that go on the collector tubes, Tom built a very nice press to stamp out fins.

Tom has decided to make these fins available as a product from his UP Truck Center business.  He is offering fins to fit 1/2 inch and 5/8 inch tubing in lengths from 24 inches to 34 inches.  He also offers a sort of super fin option that achieves more wrap of the fin around the tube.  The prices are very reasonable, and I think this is a good option for anyone wanting to save some time on building the fins.

Here is the web page describing all the options and some notes on how best to install the fins...

Tom is a long time friend of Build-It-Solar, and has sent in detailed descriptions of some of his very well done solar projects...    Thanks Tom!



Gary

Some New Stuff

This is just a collection of some interesting (at least to me) items added tot he site over the last week or so....

Harvesting Fresh Water From Fog
Areas with regular daily fogs (e.g. some coastal areas) can harvest impressive amounts of fresh water from the fog.  Nets catch the fog and then channel droplets from the fog into a catch basin. 



Details...

Booklet on "Hot Water From Your Woodstove"
This is a good 45 page booklet from Lehman's describing a couple systems for adding a heat exchanger coil to the firebox in your woodstove to heat water.  Good detail on both thermosyphon and pumped systems, and lots of information on troubleshooting and doing the installation safetly.




Details...




Skysails -- Kites for Towing Ships
These are large kites that can be deployed under favorable wind conditions to reduce fuel consumption.  With favorable winds, fuel consumption can be reduced as much as 50%.
Operation of the Skysails is largely automatic.




Details...



Homes From Cylindrical Grain Storage Bins
A collection of links to homes made from cylindrical steel grain bins.  These homes offer a thermally efficient shape, and some options for good insulation thickness -- plus and interesting look.

Details...









Gary

Making, Buying, Designing, Evaluating Fins for Solar Collectors

Many of the homemade
collectors shown on this site use aluminum fins to collect the incoming
solar heat and transfer it to a tube that carries the heat transfer
fluid. 

The fins need to transfer heat efficiently, and need to have a good thermal connection with the tube carrying the heat transfer fluid. 

Copper tube with heat absorbing fin being installed.

This article goes over several fin designs, several ways of making the fins, some of the types of fins you can buy and where to get them. 

The new article also provides calculated fin efficiencies for some of the homemade and commercial designs.  I'm sure you are dying to know Which fins do best?  Does steel work as a fin material?  Are those big, thick, extruded fins worth the extra money? ...

All the details on fin design, fabrication, purchase, and performance here...

Some fin designs that people have sent in...


Kevin's two layer fin


Matt's bicycle powered fin former.


Tom's most impressive fin press

Got any ideas on fin design or fabrication?

Update March 11 -- I've added a couple more entries that have been turned in since this blog entry was written -- all on this page:

All the details on fin design, fabrication, purchase, and performance here...


Gary

Zero Energy Homes for the Rest of Us

While visiting St George Utah recently, we found that we were in
town during the parade of homes, so we looked at a few of them.  One of the
display homes was a very efficient home built by Sun-Savvy Inc.  I was very
impressed by this home and the other homes they offer.

Their design combines a very good and very tight thermal envelope, heat
recovery ventilation, passive solar, solar thermal and PV arrays, and efficient
mini-split heat pumps to make a home that should be able to achieve net zero
energy use in the southern Utah climate.  The display home has a LEED
Platinum rating. 

Even more impressive to me is that these are very nice and very "normal"
looking homes.  These homes appear to be very easy for the homeowner to live with. 
While the energy efficiency does add some cost, the homes appear to be cost
competitive with ordinary construction homes.  In other words, these are
net zero or near net zero energy homes which should have a very wide appeal to
ordinary home buyers -- you don't have to be an eco-freak (like me) to like
these homes. 

We took the full tour, got a lot of pictures -- all the details here...

Much more on solar homes here...

Clerestory windows -- great daylighting.  These open automatically when a set temperature is exceeded.


The energy recovery ventilation unit -- an earthtube is used to precondition the intake air to the ventilator.

It seems like a lot of the "net zero" energy homes you see are a long ways
out of the mainstream -- they tend to be architecturally unique (some would say
strange) and come with an acre of PV panels that would add $100K+ to the cost of
the house were it not for some very very generous (and perhaps questionable)
rebate programs.  I don't see this type of near zero energy home ever
catching on and becoming widespread.  On the other hand, a design like the
Sun-Savvy homes seems like it could have very wide appeal.  I hope it turns into a trend.

Gary

Tom's Larger Solar Heating System

Tom sent in the final update on his new solar space and water heating system.  This update covers the storage tank, controls, heat exchanger and integration with the boiler.

This is a really interesting project.  It includes all of the following:

1. Design and construction of a 336 sqft solar collector -- including some new wrinkles on fin fabrication and installation.
2. Building the 410 gallon heat storage tank that doubles as a workbench.
3. Details on the solar  domestic water heating system that utilizes a heat exchanger made from about 200 ft of 3/4 inch rigid copper pipe. 
   
4. Details on implementing the radiant floor heating system that pumps hot water directly from the storage tank and requires no heat exchanger.
5. Details on adding heat input to the tank from a nearby wood boiler in a very simple way.
6. There is even a way to make use of solar heat on seasonal refills of a hot tub.

Tom's system integrates all of these functions in a simple, straight-forward and cost effective design.


Wood boiler heat source as alternative to solar.

Full details on Tom's space and water heating system...

Many other solar space heating projects...

Tom's other projects on Build-It-Solar....

Thanks again to Tom for taking the time to document this project!

Gary

Storage Tank Kit for DIYers & DIY Solar Kits In General

The Softank is a kit for a 200 gallon water tank for heat storage.  The kit includes the parts that would be somewhat difficult for a DIYer to find or fabricate like the liner and the outer structural support cylinder.  The person building the tank buys the insulation locally, supplies some labor, and saves some money.

Details here...


Note: Heat exchanger not included with tank kit.

I like the Softank kit, but what I like even more is the idea that kits like this could be offered to home owners who want to build solar water or space heating systems.  These kits could bring building such a system to people with modest DIY skills, and also increase the likelihood of a successful build.  

Kits of this kind could include the difficult to obtain and difficult to make parts, while allowing the DIYer to buy readily available parts locally.  This approach avoids shipping large and fragile finished items like collectors, and would save the hassles, expense and CO2 emissions associated with truck shipping finished items.

Well designed kits and good instructions could greatly increase the chances of building a successful system -- even for not so experienced DIYers.

With commercial solar water heating systems selling for north of $8000, there is plenty of room for kit makers to earn a good profit and also save home owners lots of money.  A great opportunity for some new businesses!  How about it entrepreneurs?


Gary

THREE new Owner Built Solar Space Heating Systems

This has been a good week for new solar space heating systems sent in to Build-It-Solar!
Thanks very much to the Eric, Al, and Tom for describing there well designed and built systems. 
These are all large collector systems that can do significant solar heating -- lots to learn from the detailed descriptions of these systems.

The 1st is Eric's space heating and hot tub heating system that uses 300 sqft of water heating solar collectors, and has both a solar and boiler heat source.

The 2nd is Al's space heating collector that is primarily a solar air heating collector, but also has a smaller water heating capability integrated in the same collector.

The 3rd is Tom's new 330 sqft solar space heating system.  This system uses Tom's 3rd generation design for the copper tube, aluminum fin collectors.  This installment covers the design, build and install for the collectors.  The next will cover heat storage, plumbing, and controls.

See below for summaries, and the links for very detailed descriptions.

Al's Hybrid Air and Water Heating Collector
This is a very nicely done collector of about 100 sqft.  It is a space heating collector that primarily heats air that is circulated directly into the house.  But, it also has a smaller water heating capability that is used to store some heat for use during the night.


Its a nice looking collector that is well integrated with the house.

Since the collector area is about 15% of the house floor area, the collector will often generate more heat that can be immediately used on a sunny day, so it makes sense to add the limited water heating capability to store some heat for use later in the evening.

All the design and construction details from Al here...

Eric's Space Heating, Water Heating, Hot Tub Heating Solar System

This is a very nicely designed and built system from Eric -- a fellow Bozeman resident.
The system uses about 320 sqft of commercially made water heating collectors as its main heat source.  The collected solar heat is used for 1) space heating, 2) domestic water heating, and 3) hot tub heating.  The system also integrates a boiler as the secondary heat source.  



This is a pretty complicated system in that it heats floor space, a hot tub, and domestic water, and includes both a solar and boiler heat source into the same system. 
This is a difficult set of things to do, but Eric pulls it off with a pretty simple system.  Maybe the fact that he is in the HVAC business and specializes in solar system helps :)

All the details on Eric's system...

Tom's Large Solar Space Heating System
Tom's new space heating system uses 330 sqft of the aluminum fin/copper tube collector design.  This is about Tom's 3rd generation build of this type of collector, and he has a very refined design.   The collectors are mounted in a good looking common housing, and glazed with twinwall polycarbonate glazing.  Performance should be very good.



All the details on Tom's System...

Much more on Solar Space Heating Systems...

Gary

New Idea for Heating Domestic Water

Energy Alternatives has come up with a new design for heating domestic water.  Their design pipes water/antifreeze through several PEX pipes that are suspended in the attic ridge roof vent. 



The water heated by the PEX tubing is passed through a heat exchanger coil in a domestic water preheat tank.  The domestic water is preheated in this tank before it goes on to the regular water heating tank.

No real data is given on performance, and I suspect that for many climates, this is a three season heater at best, but it does offer an interesting alternative to solar, and it keeps the external look of the roof unchanged.

One article suggests that the cost of a 40 ft section of the PEX ridge vent assembly might be around $300, and that a full kit including the preheat tank with heat exchanger might be about $3100.

Here are some thoughts about DIY implementation of the ridge vent design that could (I think) be done for less than $1000 -- maybe substantially less.

Thanks very much to Chris for finding this and suggesting it!

Gary

First Year Performance for $1K Solar Water Heating System

The first full year of performance for the $1K Solar Water Heating system is in the books.  The graph below shows Solar Fraction by month.

All the details, and detailed plots that show collector, tank top, tank bottom, and ambient temperature are here...



So, this is the end of the promised one year of logging -- I now get my loggers back for other projects!

I've also a added a page that describes how I estimate Solar Fraction,
and considers some sources of error, and describes how my method
differs from the SRCC ratings of solar water heating systems.

Gary

Scott's 24 by 8 foot Space Heating PEX Collector

This is a really interesting solar space heating collector design.  It is built as a single unit that is 24 ft wide by 8 ft high.  Compared to building a bunch of separate collectors, the single unit construction saves some time, effort, and materials, and looks very nice.



The absorber is an extra wide variation on the PEX/aluminum absorber.

For more on the collector, including a link to Scott's site with all the construction details, and a few of my thoughts on the collector...

This is a good example of the kind of freedom to try new things and fit your design to your situation that building your own system gives.

Scott is a founder of the Yahoo SimplySolar group -- a good place to discuss your new solar ideas.

Gary

A well designed compost furnace for space/water heating

Marc has worked out a what appears to be a very nice design for extracting heat from a large compost pile for space heating.



Marc's design includes a blower and air supply manifold system to aerate the pile, a pipe network to add water to the pile as needed, a pipe network to extract heat from the pile, insulation to increase the efficiency of the composting process, and a nice containment and cover system.

Link to Marc's blog entry on heat from compost...

Other heat from compost schemes on Build-It-Solar...

Judging from the emails I get, there is a lot of interest in using compost to generate heat, but there is not a lot of detailed information out there on how to actually build such as system.  I think Marc has taken a good cut at it.  What do you think?

Gary

Energy Fairs

This is the season for a lot of the annual energy fairs, so check around and see if there is a good one to go to in your area.

The fairs are a great way to learn about renewable energy projects, go to workshops, meet some renewable energy people in your area, and find some deals.

I keep a list of all the Energy Fairs I know about here...

If you know of others that are not on the list, please let me know...

Gary

Collector Fins from Tom's Super Press

Sometime back Tom built this super press for making the grooved fins for our homemade solar water heating collectors. Tom has indicated that time and material permitting, he is willing to make plates for others -- details here...

Tom is a long time friend of Build-It-Solar and has contributed plans for several very well done projects.



These appear to me be to be very well formed plates, and very likely will perform better than commercially made heat spreader plates.

If you are wondering what in the world this is all about, see this entry on construction the solar water heating collectors that use these plates...

Gary

Gordon's "$1K" Solar Water Heating -- From New Zealand

Gordon has provided details on how he built his version of the "$1K" Solar Water Heating system.  These systems are high quality, high solar fraction, all climate solar water heating systems that you can build for about $1000 in material costs.

Gordon's system adapts the design to his situation, his changes include:
- A well made, high tilt angle roof mount for the collectors.
- An all copper, single pass heat exchanger that pre-heats water before it gets to his existing hot water heater




Full details and build instructions on Gordon's Solar Water Heating System...

More examples of the "$1K" type solar water here...

Gary

Matt's "$1K" Solar Water Heating System

This is Matt's version of the $1K type solar water
heating system.  Matt tried a few new things that might be just what you
are looking for.  One of Matt's innovations is what might be the worlds
first bicycle powered groove forming machine!

Matt is a very good craftsman, and
provides a wealth of interesting alternative ways of making the components.

 

Some of the unique features of Matt's
system:

- A unique forming machine to
form the groove in the aluminum fins.

- A new method of attaching the fins to the copper tubes.

 

- A copper heat exchanger that
uses 6 parallel coils of 3/8 inch copper pipe.

 

- a galvanized metal collector
frame.

 

- A steel tank instead of the
EPDM lined plywood tank.

- Glass for glazing instead of polycarbonate.

Thanks very much to Matt for taking
the time to document this project!

All the details on Matt's system here...

For those who have not seen it, the $1K Solar Water Heating system aims at providing a quality solar water heating system with a high solar fraction that is simple and easy to build and will work in cold climates.
All the details on the $1K system here...

More examples of $1K systems here...
Gary

Getting the 30% Federal Tax Credit on a DIY Solar Water Heating System

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I've received several emails from people who would like to
build the $1K Solar Water Heating System, but who also don't want to miss the
30% federal tax rebate that is part of the new Energy Bill -- I think you can
do this.

The new federal rebate for solar water heating systems offers a 30% tax credit on the full price of the system.

One of the requirements is that the collectors used in the
system must be certified by the SRCC under their OG-100 program.  Since its only the collectors that must be
certified, you can
build and install your own system and get the tax rebate as long as you use a
commercial collector that is SRCC certified, as most commercial collectors are.

As an example, if you were planning to build
the $1K system with a homemade 40sqft collector, you could substitute (say) a
Heliodyne Gobi 40 sqft collector .  This
will make the entire system qualify for the rebate.  The numbers might work out like this:

The $1K system costs                      $1000
Delete homemade collector         -$200
Add commercial collector            +$1000
--------------------------------------------------
Total cost of system                       $1800

Minus 30% rebate                            $540
----------------------------------------------------
Cost after rebate                              $1260

So, this approach increases the cost of the system a bit, but you get a nice shiny commercial collector, and avoid the work of
making a collector.  You also end up with
a solar water heating system that is about 1/5th the cost of a professionally
installed commercial system, and that will pay back your investment in a fairly
short period.

So, this is a good deal for you, and an even better deal for
the feds in that they are paying a rebate of only $540 instead of a typical rebate
of $2400 on an $8000 system -- as Barack would say, win-win!

Another approach would be to buy off the shelf components
for the full system and install them yourself. 
You save the cost of the installation, and you get the rebate.  Lots of material on how to install a system here...

Most states also have a rebate or tax credit program that might further reduce the cost of the system.  For example, my state (MT) offers a $500 tax credit on solar water heating systems with no stings attached.  Information on state programs here...

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Disclaimer: I'm not a tax expert, so you might want to do
some checking of your own on this.

Gary