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

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

Our New Grid-Tied PV System -- First Sun

The new PV system we have been working on putting in is up and running.  There are many pages of detail and a hundred or so pictures that go through the whole planning, design and installation process in mind numbing detail here...
Sections on performance and economics of the system are also included.




The system is a 2150 watt grid-tied system.  It uses the new micro-inverter approach from Enpahse -- so, each PV panel gets its own small grid-tie inverter.

The panels are ground mounted with our own mounting racks. 

We did the whole installation ourselves, and I've tried to include enough detail to be helpful to anyone who wants to install a PV system of their own.  I've tried to cover not only the details of the component installs and wiring, but also the stuff like deciding on what kind of system, locating the panels, doing a solar site survey, and going through the permiting and net metering process.  It should be enough reading to put you to sleep for a week of nights.



It was a technically interesting and fun project -- not having any previous experience with solar electric stuff, I learned a lot. 
But, the economics are also interesting.  Basically, the system cost was right near $10K or $4.65 a watt -- after rebates this gets down to $6.5K and $3 per watt.  Better than what I was expecting.  The $ saving per year if you pay 10cents a KWH would be $300, or about a 5% return on the $6,500 -- tax free and energy price inflation protected.
Not so bad, but when you compare our PV to well thought out conservation/efficiency projects, or to DIY solar heating projects its comes out a very very distant 2nd -- some examples in the Economics section.

I've fallen behind in getting other projects that people have sent in up, but now that the PV is done, I plan to catch up right after Thanksgiving -- so, keep the projects coming in!

Gary

Our New PV System

I've been trying to get the new PV system in the last week or so, and as a result I'm falling behind on getting new entries up on the website.  Thought I would just give a short progress report on the PV system. 

I do plan to do a new section with a lot of detail on the whole PV system process with lots of detail on design, site survey, mount construction, wiring, installation, ...   probably a lot detail more than you ever wanted to see :)

After much looking at a lot of options, I chose the type of system that uses one Enphase micro inverter for each PV panel.   In this kind of system, each PV panel gets its own grid-tie inverter, which is mounted right at the PV panel.  Each inverter takes one PV panel's DC output and converts it to 240 VAC that is grid compatible.  Each inverter plugs into the next inverter in the array, and you end up with all the power from up to 15 PV panels being available as 240VAC at the last panel/inverter in the string of panels.  My system has 10 PV panels at 215 watts each for a nominal total of 2150 watts. 

I bought the system as a "kit" from Wholesale Solar -- this one...

The more common approach on grid-tie systems is to wire several PV panels in series so that the they produce a high DC voltage.  This string of PV panels are then wired to an single inverter which takes the several hundred volts from the string of PV panels and converts to grid compatible 240 VAC. 

There are pros and cons to each approach, but (I think) both are pretty simple systems that can be DIY projects as long as you are VERY careful to mind the safety precautions. 

In my system, the PV panels are mounted on the ground and are located about 100 ft from the house out in the weeds.  The wires are run underground from the PV panels to the area where power comes into the house, and the grid-tie is made there.


I rented a power trencher to dig the trench for the wires.  In our hard soil, this saved a lot of time and effort.

After some debate with myself, I settled on a rather robust mounting system made from 4X4 treated lumber.  I wanted something that would withstand the high winds we get occasionally, and that would last 30 years.  Treated lumber may not be the best choice for long life in some areas, but around here, if properly installed it lasts a very long time.


This shows the framework that the PV panels will be mounted on. 
Anchored in about in 3200 lbs of concrete!



Running the wire (in conduit) from the house to PV array.


I clamped the PV support rails and a PV panel in place just to get the spacings
right and to plan where the inverters would go (they mount to the same rails as the PV panels)

This is where I am -- just waiting for a day or two of descent weather to finish it up.

Gary

Some New Content Items for Build-It-Solar

Three New Content Items

1. Lee's Solar Mower
Some time back, Lee sent in the details for his solar lawn mower.  The article basically tells you how to convert a gasoline powered mower to a battery powered electric mower with solar charging.
One issue with doing this is finding a good electric motor.  The one that Lee originally used is no longer available.  So, Lee has found a new source of motors that should work well and are cheap and easy to find....



2. Performance Update for Marc's  Compost Furnace

Last week, Marc provided a description of his system to provide space heating via heat extracted from a compost pile.
Marc has provided some performance data and other observations based on the first full season of operation...


3. A Home Built Grid-Tied PV System with Battery Backup
A
detailed account of the design and installation of a grid-tied PV system
with battery backup.

A home built ground mount system from treated lumber
is also described.

Installing Your Own Grid-Tie PV System

Guy Marsden goes through the whole process of designing, building, and installing a grid-tie PV system for his home. 


Guy and friends finishing the install.

The system uses the new Enphase micro inverters.  In this scheme, each PV panel gets its own inverter, which is installed on the back of the PV panel.  The output from the inverter is 230VAC.  The 230 VAC outputs from the inverters are tied together and hooked to your circuit breaker box via a regular circuit breaker.  Each inverter is UL certified for a grid-tie connection, so this is basically the all there is to it.  Power generated is monitored and reported by the Enphase Envoy unit.  The Envoy monitors and reports on each microinverter, and provides troubleshooting and power output reporting on the Enphase website.

Details on Guy's PV system...

Much more information on doing your own PV system...

While this system does simplify the installation, it is still a big job, and there are serious safety issues to be understood and deal with -- so, if you plan to do your own installation -- do your homework first!

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

Another very detailed "How-To" on Building PV Panels from Cells

On his website, Hange provides a very detailed set of instructions and pictures on how to build PV panels from individual PV cells...   The site covers finding cells, laying cells out to make a panel, soldering instructions, and glazing instructions...  



Several other articles on building your own panels...


Gary

Home Build PV Panels and System

In this new article, Hans describes in detail the solar electric (PV) system he built from the solar cells up.  The system includes 3 homemade PV panels, as well as the balance of system components to make a full functioning solar electric system. 

Full description of the PV system ...


Hans maintains a web site that provides more information on the project as well as other renewable energy projects.

Gary

EcoRider -- Converting a riding gas mower to electric

This is an interesting ongoing set of entries on the Eco-Renovator site about converting a riding gas mower into an electric operation running on lead acid batteries.

This could become a solar charged mower with the addition of PV panels and a charge controller.

Details on the EcoRenovator conversion here...

More on converting mowers and tractors to solar electric operation...

 

The EcoRenovator site has a number of interesting articles.

Gary