Tuesday, December 20, 2011

Restoring an Elec-Trak Tractor and Integrating it With Our PV System

Last summer, we bought a used Elec-Trak tractor -- I suppose "used" is a bit redundant since the last Elec-Trak left the factory in the 80's.

Our "new" Elec-Trak after some TLC.

The Elec-Traks are all electric tractors powered by a set of on-board lead acid (golf cart) batteries.  They were made by GE for several years during the 70's, and were popular with more than 30,000 made.  They are very durable and functional machines with a wide range of all electric accessories.  The Elec-Traks have a strong following with an online owner forum and good parts support.   Many of these tractors have been rebuilt and are serving people well.  Being electric, these machines are cleaner, cheaper to run, and low maintenance than equivalent gasoline models.

The Elec-Trac with new charger/inverter supplying 120 VAC power out in the field.

In addition to the usual mowing and snow blowing tasks, we wanted to be able to use the Elec-Trak to power our home during power outages -- it has a large enough battery pack to power a few critical loads like the fridge and furnace for something in excess of a day.   This proved to be a relatively easy thing to do using a commercial charger/inverter from Tripplite.

In addition,  we wanted to work out a way to use our grid-tied PV array to charge the Elec-Trak battery pack during power outages.  This proved to be more of a challenge in that grid-tied PV arrays are designed to stop operating as soon as a power outage is detected, and to stay offline until the grid comes back.  After a bit of head scratching, we did work out a way that is fairly easy and effective if not terribly elegant.  The nice thing about our arrangement is that we get most of the benefits of a grid-tied with battery backup PV system, but without the considerable initial expense of these systems and without the need to maintain and replace a set of batteries that is almost never used.  See the link below for details.

Charging the Elec-Trak batteries during a simulated power outage using our PV array.

All the detail on our Elec-Trak project -- from scraping and painting to integrating it with our grid-tie PV system -- about 20 pages in all...

More Elec-Trak stuff:
For a rundown on the history of the Elec-Trak and a description of the various models, see Mark's article...

The Build-It-Solar section on Elec-Traks and similar electric machines...

One of my favorite Elec-Trac sites is George's My Elec-Traks site...  He has restored just about every model and also has lots of the Elec-Trak manuals and brochures.

The online Elec-Trak owners forum...

Just a bit of rust to clean up.

The new charger/inverter rides with the Elec-Trak when power is needed for 120VAC loads, or can stay back in the barn for charging.

The new charge controller that allows the grid-tie PV
array to temporarily be used as an off-grid PV array to charge
the Elec-Trak during power outages.

December 21, 2011

Friday, December 16, 2011

Solar Site Survey Based Aerial Photos

Bright Harvest offers a somewhat unique solar site survey.  They use aerial photos of your house to build a digital model, and then show you alternative arrangements of collectors.  They also model any shading objects near your home, and show the monthly and yearly effect of this shading on the output of the array.  Estimates for yearly output are also shown.

Overview of the model and panel layout with shading.
They offered to do a survey of my house, and I took them up on this and the link at the bottom of this post is to a page with the details on the survey and some thoughts on it.

In a nutshell, I was favorably impressed by the survey.  They did a good job of identifying potential PV array placements and a good job of finding shading sources.  Even though I've done a couple "manual" solar site surveys on my home myself, they found some things that I had missed or not thought about.  

The cost of the survey is not trivial at $150, but it may well be worth it to get a good handle on shading -- especially for complex situations.

I would always recommend doing the "manual" solar site survey yourself, as it will make you aware of how the sun interacts with the house and shading objects over the course of the year -- its just something everyone should do before tackling any solar project.  But, if you are uncertain about the shading situation or array mounting possibilities after the manual survey, the Bright Harvest survey or a SketchUp model would be a very good follow up.  I get a lot of emails from people who put their collectors up, and then come to find that the shading situation is worse than they thought -- it is just very important to have a good handle on shading before starting.

December 16, 2011

Monday, December 12, 2011

DIY Solar Garden Helper Machine

This is Randy's pretty amazing solar powered garden helper machine.

Randy made the machine to make it easier to do the planting, weeding and picking chores in the garden.  The seats on each side are adjustable side to side to accommodate wide or narrow rows of plants.  The speed control is a joystick that can be mounted left, right or center.

The frame is made from 1 inch welded steel tubing.  It is solar powered using 4 golf cart batteries and two on board 80 watt PV panels that also provide shade for the driver.

The drive train is from an electric wheelchair, but is geared down for more torque.  Maximum speed is about walking speed.

Thanks very much to Randy for making this available!

All the details on Randy's solar garden helper machine...

More solar powered garden tractors and lawn mowers...

Note the batteries over the rear wheels for more traction and
less weight on front wheels for easier steering.


Friday, December 2, 2011

Greenstar Blox -- A New Energy Efficient Wall Block

Greenstar Blox are a new wall building product that has been under development for several years.  The Greenstar Blox offer the promise of high strength, durability, high R values, reasonable cost, and a relatively straight forward build process.  It looks to me like they might make a good material for owner built homes.

A Greenstar Blox project
The standard Greenstar Block is 10 by 14 by 4 inches and is made from roughly 65% selected recycled paper, 25% Portland cement, and various additives.  This is similar to papercrete, but the difference is that Greenstar Blox are commercially made to a standardized recipe  using  a standardized process to produce a consistently high quality block.  The Greenstar Bloxs are currently going through an extensive testing program at Texas Tech University.  The results of the testing program are being used to seek building code approval, which is anticipated in early 2012.

The blocks are laid in courses as usual (kind of like Legos).  The mortar is made from the same
material that the blocks are made from.

The blocks appear to be relatively straight forward to build with.  They are much lighter and easier to handle than concrete blocks.  They offer the big advantage of a high R value right in the block without the need for additional layers of insulating material.   Greenstar says that walls made with their blocks will be about R25.  

An important item for anyone thinking about building with these blocks is that building code approval is in the works -- this will make it much easier for people wanting to build to get building permits.

I'd love to hear from anyone using the Greenstar Blox.

Notes from a consversation with Greenstar Blox...

The Greenstar Blox website...


Thursday, November 24, 2011

Boat in a Hole -- George's Unique Rootcellar

Could not help passing this on.
This is George's solution for a cost effective, relatively easy to build, and very functional root cellar.

After thinking about a number of ways to build a root cellar for their new place, they tumbled to the idea of using a fiberglass boat hull.  It turns out these are available for reasonable prices.   They provide a good, waterproof and strong root cellar.

Buried for root cellar use.
They use it for both a root cellar and also as a bunkhouse.
The entry.
While I suppose this might seem a bit sad to some boat owners, George points out that there are a number of derelict boats around that will never see use again, and this is a 2nd life that I'm sure any boat would like a lot better than just rotting away unused.

George's full description of the boat for root cellar...

More on various root cellar designs...


Sunday, November 20, 2011

Flow of River Hydro -- Using Only Stream Velocity to Drive a Turbine

I get email questions from people who live on a stream and would like to use the stream to make electricity.
If the stream has some elevation drop over the property and the flow is decent most of the year, then the answer is that if you can meet the legal requirements, its possible to make electricity, and that it can be quite cost effective.

Quite a nice underflow water wheel.

But, if the stream has no elevation drop, and you just want to make use of the velocity of the stream water to make electricity, then its more challenging.  I've added a new section that goes into what's involved in generating electricity only from the water velocity.  It covers how to estimate the amount of power your stream might generate, provides a bit of design information, and it lists all of the home scale example projects I could find that seemed like they might actually work.  Its a place to get started on your quest for free no pollution energy from your stream.

One of the reasons getting power from your stream is difficult is that while its clear that there is energy in that flowing water, it not nearly as dense as the energy you can extract from water dropping through an elevation difference.  This plot shows you roughly how much power you can get from 1 sqft of flow area at various stream velocities.

Just a glance will tell you that if you have a 2 mph 6 inch deep stream, your power generation possibilities are pretty limited.  But, if you have a deep 5 mph stream, there is some worthwhile power there.

I found a few commercial and few homemade examples of flow of river turbines and water wheels -- the link below provides pointers to all the ones I could find.  If you know of others please let me know.

The new section on Flow-Of-River hydro installtions...

The micro-hyro page for info on more conventional hydro...


Tuesday, November 15, 2011

Bottom-Up Insulating Shades for Light and Insulation -- Our R8.3 Window

On some of our windows that we have no need to look out of, but still want some light, we use a 3/4 insulating shutter on the bottom of the window.   I like the 3/4 shutter idea because it does a very good job of insulating most of the window, while still letting a lot of light into the room.

The 3/4 shutter got us to wondering if a top-down/bottom-up insulating shade could be used in the same way -- we decided to try this on one of our windows.

Our first try at an insulating top-down/bottom-up shade.
This window is a bit odd with the triangular top, and I had to add a support board to hold the top bar of the shade in place.

This arrangement allows us to have the shade fully up at night for privacy and maximum insulation, or during the day to have the shade part way up to allow more light and views with some insulation.  Normally we would have it up more than the picture shows during the day to get somewhat more insulated area.

The new shade is from Symphony Shades and in addition to being a good double cellular insulating shade, it has side tracks that reduce air flow around the sides of the shade.

The side tracks prevent airflow around the edges of the shade.

Closeup of track showing notch in shade that track engages.
It turns out that this window already has a double Mylar inside storm window on it (bet you could not even see it :), so the total insulating value is:  low-e window (R3) + double Mylar storm (R2) + insulating shade with side tracks (R3.3) is a sort of amazing R8.3!


Friday, November 11, 2011

Large 1986 Solar Space Heating System Marches On

In 1986 Mike Smith built his own home.  The home included very high insulation levels and a large (360 sqft) solar air heating collector.  

Mike's home with the large solar air heating collector.
After 25 years of service, the collector is still going strong.  Amazingly, in 25 years the system has required zero maintenance.

The hot air from the collector is ducted down to a rock bin in the basement to store heat.  When the house needs heat, hot air from the rock bin is ducted to the house.  A regular furnace provides backup.

The very good insulation levels (especially for 1986) allows the solar heating system to provide a large fraction of the home heating.

More examples from people who built great solar homes...


Tuesday, November 8, 2011

How Much Money Do You Save Installing Your Own PV System?

When we did our PV system two years ago, I did not really have a good way to evaluate how much money I saved by doing the install myself, let alone how this might vary over the country.  I knew how much it cost me, but, I did not really have a good number on how much an equivalent professionally installed system would cost.

Our 2.1 KW micro-inverter DIY PV array.
The Nov/Dec issue of Solar Today answered that question by providing a state by state installed cost per watt survey.  The current US wide average turns out to be $6.80 per peak watt.  

So, armed with this new data on what professional installs typically cost, I decided to update what our PV array would cost at today's prices and compare that to the $6.80 average professional install.  The results surprised me a bit.

Using the latest prices, a setup similar to what we put in two years ago would be about $3.30 per watt.  So, the savings for for DIY install is a bit over 50%.  For the 2300 watt system I looked at, this is a bit over $8000.  Not exactly chicken feed.

Being a fan of solar thermal I'll just mention that that the cost per peak watt for our $1K Solar Water Heating system is less than 50 cents a peak watt  -- Holy Cow! :)


Thursday, November 3, 2011

Solar Water and Space Heating Project With Unique Collector Design

Rob's new solar heating system provides both solar space and water heating.  The system is based on the $1K drain back design, but incorporates a number of very interesting design variations that may be helpful if you are doing a system.

Rob's finished system with the two hizer design collectors.
Side view of the collectors.
One unique feature of Rob's system is that the collector uses the new hizer design.  In most collectors the finned tubes that absorb solar radiation and transfer it to water flowing through the tubes run vertically with manifolds along the top and the bottom to supply water to the riser tubes at the bottom and collect heated water from the riser tubes along the top.  The hizer design was invented by Alan Rushforth to provide a more efficient design for wide collectors.  In the hizer design, the "riser" tubes run horizontally and the supply and return manifolds run vertically along the left and right sides.  The resulting horizontal risers have been dubbed hizers.  The hizer design results in shorter manifolds, and fewer riser to manifold connections -- a saving in both material and labor costs.   I

Rob's collectors are the first ones I know of to use the hizer design in a drain back system.  In order to insure that the collector water drains back to the storage tank (for freeze protection), all of the hizer runs are sloped slightly downward toward the supply manifold.
One of the collectors showing the hizer arrangement.
While Rob used two 10 ft wide hizer collectors, it would also be feasible to build a single 20 ft wide hizer collector.  For large solar space heating applications that might now use 5 or 6 or more side by side 4 ft wide by 8 or 10 ft wide collectors that must all be installed separately and plumbed together, the hizer design offers the possibility to build one large collector in place with with 25 or more ft long horizontal hizers instead of many many vertical risers.  It could be a real plus for wide, large site built collectors.  In addition to the saving in time and material, it is believed that the hizer design will be easier to get even collector filling and flow.

This shows the vertical manifolds being laid out.
Rob did a very careful job of working out the structural and plumbing details for the system, and much can be learned by just going through the detailed construction pictures and seeing how Rob handled the various construction details.

For space heating distribution to the house, Rob will be using a water to air heat ex changer mounted in the furnace ducting.  He plans to make some use of this same heat exchanger for summer cooling using well water.

Full details on designing and building the system...  (including a 42 page pdf)

Many other solar water heating systems...
Many other solar space heating systems...

An example of closed loop hizer design from Bob...

Thanks very much to Rob for taking the time to carefully document the system!


Tuesday, November 1, 2011

A Small, Portable PV System for Camping, Emergencies, ...

This is a nice, small, inexpensive, easy to build, very portable PV system from Kevin.  He uses it primarely for camping -- lights, radio, charging cell phone...   But, it also would make a good power source to have around in emergencies, and a good project to learn something about solar electricity.

Single box contains the charge controller, battery and other circuitry.

The system is all contained within the single box shown above except for the 50 watt PV panel.

The charge controller, meters, fuses and outlets are mounted in the box cover.

The battery (a deep cycle RV battery) is housed in the main part of the box.

An inverter on the back of the box provides 120VAC.

All the details on how to build Kevin's portable PV system here...

Many more PV projects of all sorts...


Monday, October 31, 2011

A $1K Solar Water Heating System AND Open Source Differential Controller

Nathan did a really nice job of building and documenting his solar water heating system.  

The system is an offshoot of the $1K solar water heating systems with some useful new design features.
The twinwall glazing is a very nice look.
The system uses the usual 300 ft coil of PEX pipe as the heat exchanger, but Nathan recoiled the PEX for better heat transfer performance:
The 300 ft of PEX is recoiled into a two layer coil for
more water exposure to each coil.
Be aware that this recoiling can be a challenge -- think about about your method if you don't want to end up imprisoned in a coil of angry PEX.

Nathan also offers details and source code for making an open source Arduino based differential controller.
Arduino based differential controller.
Nathan has the Arduino based controller equipped with an Ethernet shield.  This allows the Ardduino to log data directly through his router to an free online logging service called pachube.com -- there is no need to have a PC running 24/7 for this kind of logging, and it gives you access to the data from anywhere -- very nice!

All the details on Nathan's website....

For more on the $1K solar water heater and dozens of other DIY solar water heaters...


Thursday, October 20, 2011

Recycled Bulk Milk Tanks for Solar Heat Storage

Tom uses recycled bulk milk tanks from dairy farms for solar heat storage in some of his solar installations.
Bulk milk tank reborn as solar heat storage tank.
These tanks are made from stainless steel, and will provide a very long life.  The tanks already include some insulation of some of the surfaces.  The tanks are typically in the 300 to 500 gallon range, and the price of the used tanks is about $1 per gallon.

Heat Exchangers mounted in bulk tank.

Tom has provided some details on using these tanks...

Tom's very interesting renewable energy website...


Saturday, October 15, 2011

A Very Nice Small Solar Greenhouse on a Budget

Andrew designed and built this small solar greenhouse using mostly materials from the local Habitat Restore.

Solar greenhouses use a variety of features such as double glazing, insulation for non-glazed exterior surfaces, added thermal mass, and passive ventilation systems to reduce or eliminate the need for backup heating and for powered ventilation.

Andrew's design incorporates all of these, and he provides some summer and fall temperature and humidity logs to show how the greenhouse is doing.

Inside view showing water barrel thermal mass.

Performance plot for the greenhouse.

In addition to performing well, Andrew's greenhouse looks great!

All the details on Andrew's solar greenhouse...

Lots more on solar greenhouses and sunspaces here...


Tuesday, October 11, 2011

Bill's Large, Closed Loop $1K Style Solar Water Heating System

This is a very interesting $1K style system from Bill with quite a few interesting design variations.  Among the unique features:
  • Closed loop rather than drain back for freeze protection
  • Glazed with dual wall polycarbonate glazing.
  • A unique collector frame that uses EPDM rubber roofing for weather protection.
  • Using a custom made PVC tank liner instead of the usual folded EPDM liner.
  • Lots of detail on roof mounting the collector, including the site made collector hoist shown just below.
  • A unique design approach to handing differential expansion issues in the absorber design.

Bill's system with the first collector in place

Bill used a closed loop system because he was not able to maintain a good slope on the plumbing to and from the the collector.  This requires adding a 2nd heat exchanger to the tank that transfers heat from the collector circuit (which has antifreeze) to the storage tank which is plain water -- this is Bill's heat exchanger arrangement:

The collector loop and domestic hot water heat exchangers in the storage tank.
Another unique feature of the system is the that Bill used a custom made PVC liner instead of the folded EPDM liner.  This is a picture of the liner:

Custom PVC tank liner
This seems like a good way to go if you can get a competitive price on the liner.

I also like the special hoist that Bill made to get the collector up on the roof:
Custom made hoist to lift collector to roof.
These collectors are heavy, and Bill has several of them to get up on the roof -- the hoist will save a lot of work and be safer.

Go here for all the details on Bill's system....

Go here for the details on a hundred or so other solar water heating systems...


Tuesday, September 27, 2011

PV Systems for Homeowner Installation

I added a new section on the PV systems that are just beginning  to come out that are aimed specifically at being installed by the homeowner.  They are small grid tied systems that use microinverters to simplify the systems and to allow one to start with a small system and then easily expand it over time.

The recent news in this area is the announcement from Westinghouse on their new set of systems for homeowners:

Westinghouse announced the release of solar PV kits for DIY installation.  The kit includes the PV modules, microinverters, parts for roof mounting, and the other bits needed to complete the system.  

It appears that each PV module mounts to the roof independently, and that the mounting hardware is included.  It appears that the microinverters are integrated with the PV panel.  The kits will be offered in 3 sizes: 1 panel, 4 panels, and 20 panels, where each panel is 235 watts.  As with all microinverter based systems, it is easy to expand the sytem.

The Westinghouse Solar website provides more information on the system.  There are some resources for DIYers, and what looks to be a detailed and well written installation guide.   Westinghouse appears to be pretty serious about this effort.

The Westinghouse sales person told me that the systems can be ordered via Lowes Hardware, and the the cost for a 4 panel (940 watt) system is about $2600.  This does not include the Enphase EMU monitoring unit, which many people will want to monitor the system.
The system is based on the Enphase microinverter -- you can get a detailed understanding of how this system works and goes together by reading the first two entries in the Grid Tied PV section ...

I would love to hear from anyone who gives this system a try.

Some additional systems and approaches are listed in the new section...


Saturday, September 24, 2011

The Sungrabber Unglazed Solar Water Heating System

The Sungrabber is an interesting newish commercial solar water heating system that makes use of unglazed plastic collectors (pool heating style collectors) rather than the traditional glazed flat plate collectors -- this allows a substantial reduction in the system price.  
Just to give an idea of the potential, unglazed plastic collectors sell for about $5 per sqft while traditional glazed flat plate collectors are about $30 a sqft.

Their website is: http://www.sungrabber.net

This diagram from their website shows how the system works:

The collectors are unglazed plastic pool heating style collectors.   The system is a drain back system, meaning that when the sun goes off the collector, and the pump turns off, all of the fluid in the collector drains back to the drain back tank -- this is a well established method of providing freeze protection and works well even in the coldest climates.  It also means that plain water can be circulated through the collectors, and the hassles of dealing with antifreeze are avoided.

To transfer the collected heat from the collector loop to the hot water tank, the collector heated water and the water tank water are circulated through a heat exchanger in the the "Circulation Module".

Of course, with unglazed collectors, performance will suffer dramatically in colder climates -- the link below gives a rough estimate on how much. 

But, the system price is much lower, and in spite of the hit in cold weather performance, in many climates the payback period will be substantially less than for a conventional $8000 commercially installed solar water heating system.  

It seems to me that the solar water heating industry has been in a bit of a rut (an expensive rut) for some time, and this kind of system shows some good innovation -- it would be nice to see more of this.

This would make an ideal DIY solar water heating system, as it looks to be relatively straight forward to install.  I don't know if Sungrabber offers it this way or not.

There are some other interesting DIY versions of the system.  For example, the regular $1K DIY drain back system could be set up with the same kind of unglazed plastic mat collectors.  This would significantly reduce the work involved, and it would result in a system that was somewhat more efficient than the regular Sungrabber system as the storage and collector area could both be pushed up some with very little cost increase.   
In an interesting twist, I believe that if one used an SRCC OG100 certified unglazed collector (of which there are many), the full cost of the $1K system would qualify for the 30% federal rebate!   This would get the payback down to less than 2 years for many people.   State rebates might further decrease the cost getting it down near the zero area in some places.


Friday, September 23, 2011

The Solar Decathlon is Starting

The Solar Decathlon is starting tomorrow, September 23, 2011.

There will be teams from 20 universities around the US and the world with full sized demonstration homes that aimed at winning the decathlon competition that emphasizes energy efficiency and sustainability.

This from the Solar Decathlon website explains the decathlon:

The U.S. Department of Energy Solar Decathlon is an award-winning program that challenges collegiate teams to design, build, and operate solar-powered houses that are cost-effective, energy-efficient, and attractive. The winner of the competition is the team that best blends affordability, consumer appeal, and design excellence with optimal energy production and maximum efficiency.
The first Solar Decathlon was held in 2002; the competition has since occurred biennially in 2005, 2007, and 2009. The next event will take place at the National Mall’s West Potomac Park in Washington, D.C., Sept. 23–Oct. 2, 2011. Open to the public free of charge, visitors can tour the houses, gather ideas to use in their own homes, and learn how energy-saving features can help them save money today.


The Solar Decathlon:
  • Educates student participants and the public about the many cost-saving opportunities presented by clean-energy products
  • Demonstrates to the public the opportunities presented by cost-effective houses that combine energy-efficient construction and appliances with renewable energy systems that are available today
  • Provides participating students with unique training that prepares them to enter our nation's clean-energy workforce.

There are some interesting looking projects this year, and it appears that this year there is quite a bit more detail on the features used in each project -- this is a very welcome improvement.
Have a look on the Teams link for each team for the Construction Documents.

The decathlon is at the National Mall's West Potomac Park in Washington, D.C., Sept. 23–Oct. 2, 2011.

University of Calgary entry
I'm going to try to take some time to go through each entry and pick out the features and projects that might of of particular interest to the Build-It-Solar folks.


Saturday, September 17, 2011

The Black Side Pool Heater

This is a really simple idea for heating an above ground swimming pool from Deane:

From Deane:
I had been heating my above ground 24 foot x 4 foot swimming pool in NH  with some eight 4x10 roof mounted pool collectors.   The roof faced west and had a 20 degree slope.   Needless to say early mornings and spring output weren't great.

One day I decided to paint the vertical south exterior  wall of the pool black.   Boy did that help.   First the wall was exposed to the April sun much more directly and throughout the day.  Second the heat transfer to the pool was great because the sun struck the  black metal pool wall directly and the only thing between the heated wall and the water was the very thin 20 mill pool liner.    In spring the object is to get the water up from freezing so the pool wall barely runs above ambient air during the day resulting in near zero loss back to the air. 

In my case I doubt the addition of a glazing would help much although it might be worth it as the pool temp rises to swimming level.

Of courses the pool heat losses were the same.  

In summary the cheap black paint extended the season 3 weeks on either end. 

Imagine the effect if all above ground pools came with black exterior walls.   Even better if they were selective.

Further in summer the south wall of the pool got less sunlight so didn't overheat. 

September 12, 2011

I really like this -- its about as efficient a pool heater as you could devise, costs almost nothing, does not take up any space, and an HOA could not possibly object to it!

More details, thoughts, and heat saving estimate on this idea...

More solar pool heating projects...


Wednesday, September 14, 2011

Soda Pop Bottle Solar Light

This is a really simple and cheap idea to bring solar light into a dark room.

A regular 2 litter polycarbonate soda pop bottle is fitted into a sealed hole in the roof.  The bottle is filled with water and a bit of bleach.  The sun shines in the top of the bottle, through the roof opening, and then the bottom of the bottle spreads the light around the room.  It is said to work much better than simple window in the roof.



Saturday, August 27, 2011

An Interesting Roof Integrated Solar Water Heating Collector for Picky HOAs

Just ran across this interesting collector design from Velux -- the people who do the very popular skylights.

The collector sits flat to the roof and looks exactly like a regular Velux skylight.  There are no visible plumbing connections.  They use the same flashing system on the collectors as they do on their skylights.

It seems like this look might be a lot more acceptable to a picky HOA?

The SRCC performance ratings are comparable to other good flat plate collectors.

Mixed skylights and solar collectors.
Seems like a good idea, and I don't see any reason there could not be a DIY one.

More details on the Velux site...


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