Saturday, March 31, 2012

Doug's Solar Projects

For those of you who don't know about Doug Kalmer, he is a renewable energy expert who lives in Tennessee, and who really walks the talk on the renewable energy and sustainable living fronts.
His projects use simple, elegant, well thought out designs that are durable and cost effective.  Most of the projects can be built by any reasonably skilled DIYer.

The projects cover an amazing range of renewable energy and sustainable living areas.

Note that Doug's house is going to be on the solar tour this year, so if you live in the area, go have a look.

Here is a list of Doug's projects on Build-It-Solar -- follow the links for full details:

Doug's 1985 solar passive home in Tennessee has been largely heating itself through several decades.
It uses a combination of passive solar gain for heat and earth berming to reduce heat loss.
Backup heat is provided by the masonry heater described below.

This is Doug's latest project.  It is a 4.6 KW grid-tied PV system that uses Enphase micro inverters on each PV module to make utility compatible solar electricity.  The mount system is all Doug designed and built and is simple, strong, durable and very cost effective.

Doug designed and built this efficient and very beautiful masonry stove to provide backup space heating for the passive solar home.

The masonry stove is designed to burn hot, fast, and clean while capturing the heat in the stone and radiating heat for hours after the fire goes out.

The attached solar greenhouse was built for and amazing $300 using sliding glass door panels.

The solar greenhouse allows plants to be started in January and February and then moved out.  The greenhouse also provides some heat to the house.

These thermal shades provide R values equivalent to the best of the commercial thermal shades and also look very nice -- all for about $15 a shade!

They use the Reflectix as the insulating material.

In my climate, this thermal shade can pay for itself in a single season over a double glazed window.

Doug has two solar water heating systems.  
Both are simple and cost effective designs that work well.

The closed loop system heats water for his house.
The thermosyphon system heats water for the shop/studio.

Doug used slipform walls for his home, and this project explains how to build slipform walls.

This is a technique that owner builders can use to provide a wall that is very durable, cost effective to build, and looks beautiful.

This is an interesting project that uses a salvaged AC unit and "Corny Kegs" to make an efficient heat pump for cooling the beer keg.

The heat pump takes heat from the beer and uses it to heat domestic water.

I want to thank Doug again for doing these projects and for taking the time to document them and make them available  -- Thanks!


Wednesday, March 14, 2012

Simple Solar Bird Bath Heater

This is Jim's nice simple solar bird bath heater that keeps the  bird bath water unfrozen during the daytime in cold PA winters.

The finished birdbath with collector panel facing right.

This shows the internal construction -- its a passive thermosyphon solar collector that circulates the solar heated air across the bottom of the metal bird bath container.

All the details on Jim's solar birdbath...

More on solar heating water for animals of all sizes...


Monday, March 12, 2012

An Exceptional Video on Climate Change

Even though Climate Change is one of the main reasons for starting Build-It-Solar, I don't say much about it because talking about it seems to turn a lot of people off, and it seems more effective just to provide a lot of projects that both help on the Climate Change front and save money.

But, I thought that this video by Jim Hansen was exceptional in that it gives a simple and sensible statement of the Climate Change problem, AND it proposes a solution that might be acceptable to a much wider audience.

Have a look -- its only 17 minutes:

If you want to leave a comment on the video, that's great, but comments that are not constructive and thoughtful will be removed.


Friday, March 9, 2012

Time In a Can -- Pinhole Solargraphy

Kevin has sent in the details for a really interesting project that combines pinhole photography and seasonal solar paths through the sky.  This would make a really nice school project for learning about both pinhole photography and understanding the path of the sun across the sky through the seasons.

A couple month Solargraphy "photo"
The project uses a pinhole camera made from an aluminium can to capture images of the suns path through the sky for an extended period.  The picture just above shows an example for 54 days.

Pinhole camera operation

The pinhole camera captures an image on photographic paper.  Kevin gives all the details on how to get the pinhole size right and how to set up the photographic paper in the can.

Putting the pinhole in the aluminum can.
Once the camera is done, you mount it outdoors with a view of the southern sky and wait.

A Solargraphy camera setup outside.
All the details on how-to on Solargraphy...

Gary March 8, 2012

Wednesday, March 7, 2012

An Under the Radar Plug and Play Grid-Tie PV System

Ken has done a very interesting grid-tie PV system.   Its a system that just about anyone can do for a few hundred dollars.  Basically, using Ken's scheme, its possible to do a grid-tie system at less than $2 per peak watt.

Two things make the the low cost possible:

- The use of a low cost China import grid-tie inverter.

- The glut of low low cost PV modules on the market right now.

The inverter comes in at about $0.35 a peak watt, and PV modules can can had in the $1 per peak watt area (plus some expensive shipping).   With some homemade mounts and a few odds and ends it will probably all come in under $2 per watt.  The recent US average for commercially installed grid-tie systems in the US is $6.80 per watt (from Solar Today) -- so, this is a substantial saving.

Ken's 500 watt PV system

The only real fly in the ointment is that the inverter is not UL approved for grid-tied operation.  But, it does have the anti-island feature, so it shuts down automatically if the utility grid goes down.  This is basically a bootleg system.

Even though the system is simple, there is some know-how involved in putting it together correctly, but Ken's blog entry goes through all this.

The Ningbo Sun 600G -- other sizes available.

Of course, you won't get net-metering with this system, so if the system is producing more power than your house is using at a given time, you won't get credit for the power that goes out to the grid.  But, with a small system like this, that won't happen very often.

So, if you want to save a few bucks on your electric bill and a half a ton of CO2 emissions, this offers a way to do it.  

All the details on Ken's system on his blog...

Ken is, of course, aware of the bootleg nature of this system, and is interested in hearing what people think of the whole idea -- pro and con.  Probably best to leave comments on Ken's blog to keep everything in one place.

There are some commercial systems in the works that may offer a way to buy these kind of plug and play systems down at the local Home Depot with all the approvals  -- some listed here...

If the low budget and significant saving are appealing, but you are hesitant about the whole bootleg thing, bear in mind that there are a lot of small solar heating projects that come in well under $0.10 per peak watt :)


Sunday, March 4, 2012

Doug's New 4.6 KW Grid-Tie PV Array

Doug Kalmer who has contributed a number of projects to Build-It-Solar has completed his new 4600 watt PV system and documented all the deign and construction detail.

Doug and friend in front of the new PV array
The PV array is grid-tied and uses the Enphase micro-inverters with one micro-inverter per PV module.   Each micro-inverter runs its PV module at its maximum power point, and converts the DC from the PV module into grid compatible 240 VAC.  These  micro-inverter systems are well suited to DIY installations, and are also easy to expand over time.

The homemade mount system that Doug used is very simple, very durable, and saves a lot of money over commercial mounts -- well worth looking at if you have a welder.

The mount system uses welded 1.5 inch galvanized pipe --
simple, strong and durable.
The cost of the system worked out to about $2.50 a peak watt before rebates and incentives -- this is well under half the $6.80 US average that Solar Today reported a couple of months ago for commercially installed grid-tie PV systems over the US.  So, there is a very significant saving here for doing the work yourself.

This shows the old meter on right, the new meter that tracks the PV
production, and the PV array AC disconnect in the middle.

Doug's power is provided by the TVA, and they have a nice program that pays a $1000 incentive when the system is first installed, and also pay $0.12 per KWH over the base rate for 10 years.  Pretty nice.

All the details on Doug's new grid-tied PV system...

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

Thanks very much to Doug for sending in all the details!

Gary March 4, 2012

Saturday, March 3, 2012

Heating Greenhouse Soil With Solar Air Heaters -- And Other Applications?

I ran across a paper from the University of Minnesota Extension that describes a simple way to heat the soil in a greenhouse through the winter using very simple solar air heating collectors.   In a nutshell, the air heated by the solar air heating collectors is blown through corrugated plastic pipe that is buried in the soil under the greenhouse.  A layer of insulation around the soil prevents the heat from being lost downward and outward.

The results in terms of keeping the greenhouse soil and air warmer well into the winter were impressive.

Burying the solar heated pipe in the greenhouse soil

The nice thing about this scheme is that efficient solar air heating collectors can be built for about $4 per sqft and they are very fast and easy to build.  The only other components to the system are a blower and a $10 thermal snap switch to turn the blower on when the collector is warm.  Really simple.

This all got me to wondering if this might not also be a good method to use with homes that use sand-bed heat stores for space heating.   Currently, these designs use more expensive and more complex solar water heating collectors to store heat in the sand-bed.   It seems like using simple, site built, solar air heating collectors would make the simple sand-bed solar heat storage system even simpler and more cost effective?

All the details on the solar ground heating scheme here...


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