A Report on Our PV System After One Full Year of Operation

Its been one year since we put in our PV system, so I thought I would do a little report on how its performed, and what living with the system has been like.

The system is ten 215 watt panels and uses the Enphase  micro-inverters with each panel getting its own grid-tied inverter.

Our ten panel, 2150 watt micro-inverter PV system.

In a nutsehll:

• The system has been trouble free -- no repairs or problems.
• The maintenance has been very minimal -- wash the dust off once in a while, brush off the snow, inspect the system for problems.
• Performance has been about 8% above the PVWatts estimate for the year

The system produced 3320 KWH for the year -- about 8% more than PVWatts going in estimate.

Building the mounts and installing the PV panels.

Its interesting (maybe) to note that when we moved into the house our power consumption was up at around 1000 KWH per month -- near the US average.  We pursed a bunch of conservation and efficiency measures which got our usage down to right around 500 KWH per month.  All these changes are spelled out here in our Half Program.  The cost of all the conservation measures was about $1,200 dollars. 

We then added the PV system, which generates about 275 KWH per month, and takes our net consumption down toward 200 KWH per month.  The PV system cost us about $10,000 ($6,500 after rebates).  So, for us, the conservation measures were about ten times more cost effective in saving electricity than the PV system.
The message is do the conservation stuff first -- after you've gotten your consumption down, then think about a PV system to work on the remaining usage.  This approach will save you a ton of money compared to just installing a PV system that is big enough to meet your current usage.

We are still working on conservation, and I think  we can get down to less than 100 KWH a month -- maybe even down to a net zero for the year.  A 100 KWH per month is a lot of electricity if used carefully -- as any off-grider will tell you.

More details on the first year of use experiences...
(Including how solar thermal DIY systems compare to solar PV DIY systems)

Full "how to" on planning and installing our grid-tie system...

Lots more on building your own PV system...


Gary

Would Wide Solar Collectors Work Better With Horizontal "Risers"?

DIYers will often build collectors that are quite wide (20+ ft) for solar space heating.  The usual approach is to run a manifold along the top and bottom of the collector, and then connect the two manifolds with closely spaced risers that have fins attached to capture the sun's heat  and transfer it into the water flowing through the risers.

It has been suggested by Alan Rushforth that it would save material and might also result in a more uniform water distribution to the risers if they were run horizontally instead of vertically.  You end up with a much smaller number of much longer risers (hisers?).   This reduces manifold material, and reduces the number of manifold to riser joints -- these joints are time consuming and expensive, so reducing the number of them would be a good gain.

In order to push this idea along a little further, I did a test by turning my old prototype copper tube/aluminum fin collector on its side so that the risers run horizontally and the manifolds are vertical. 

In a nutshell, the test appears to show that at least for this small collector, the startup process, flow distribution, and drain back all work without problems -- I think it looks promising. 
What do you think?

All the details on the results here...


This idea has been discussed some in the Yahoo Simply Solar group and the Yahoo Solar Heat if you want to see a bit more on it -- these are both good groups for solar heating questions (and answers :).

Gary

Performance Logging for Neil's UK Solar Water Heating System

Neil has been logging the performance of his very nicely done solar water heating system in the UK.

The collectors for Neil's system

As the plots show, the system performs well.  The plots also give a good view of how the tank thermally stratifies during during the day as the heat exchanger removes heat from the tank.

Performance for 1 day -- see link below for more

For:
- More details on performance of Neil's system...

- Construction details on Neil's system ...

- More examples of $1K style solar water heating systems...

- More on DIY solar water heating...

Gary

Yellow Energy Labels for TVs

Starting in 2011 the FTC will require the yellow Energy Guide labels on new TV sets.
These are the same labels you now find in new dish washers, fridges, ...

The new Energy Guide label for TVs

I think this is a great development and will make it much easier for people who want to buy a low energy use and low carbon emissions TV to do so.

We recently went through the TV buying experience and found it to be very hard to get good data on how much power a given TV uses.  TV power consumption varies over a huge range and its large enough to have a significant effect on household power use.  I found the Energy Star label program for TVs to be very unhelpful -- I'd go so far as to say its misleading.  In contrast to the Energy Star labels, these Energy Guide  yellow labels give actual power consumption and should be very helpful.

If you are looking for a new TV, be sure to take energy use into account -- by looking carefully you can find a TV that performs very well and that uses substantially less power.

I'd like to see these Energy Guide labels on anything that uses more than a trivial amount of electricity -- I think that it would make it much easier for people to take energy use into account when buying.
A good next step would be to put them on those 24/7 power sucking TIVO  type units.

Gary

Large Solar Heating System Made From Surplus Shipping Container

Shawn shows in some detail how he uses a large surplus metal shipping container for general storage space and as a mounting structure for a large solar heating system.

This shows the collector bays mounted to the south side of the container.

Shawn mounted a large 9 bay solar water heating solar collector mounted directly to the south wall of the container.  Water is pumped through the collectors via an insulated buried pipeline that extends from the house to the container.  The heated water will be used for space heating in the house.

The homemade collector absorber plates being installed.

The collectors are homemade.  The collector absorbers use the copper tube and aluminum fin design that is used in our $1K solar system.  This is a closed loop system with antifreeze for freeze protection.

The system is described in some detail over several "Solar Projhects" entries in his blog...
The system is nearly complete -- it will be interesting to see how it performs.

Shawn's blog is the Green Gate Guest House -- this is quite an interesting ongoing story about converting a 1935 barn into a modern and energy efficient home.  Lots of entries on renewable energy projects, rain water harvesting, solar heating, ...

For lots more solar space heating systems...

Gary

Great DIY Websites -- Kris De Voecht's Solar Projects

This is another addition to the series on Great DIY Websites...

Kris's website covers the solar projects that he has tackled with good construction detail.

Kris's DIY collector design.

The projects cover solar space and water heating as well as a solar PV installation.

The thing that really sets Kris's projects apart is the very high level of workmanship that they show.  Everything Kris does is carefully thought out and built with great precision and care.  A good place to get inspiration for taking your workmanship up a notch.

Homemade heat storage tank and heat exchangers.

The website is in Dutch with some pages translated to English -- the Google Translation tool is your friend.

You have to look around a bit to find all the solar projects -- here are a few places to start:

Building solar collectors project - overview...
This page has a list of links to pages that detail the collector and storage construction.  The list is easy to miss -- its right under the "News and blog" entry.

Hot water storage...

The PV project...

Solar home in 1985...


Gary

Great DIY Websites -- John Canivan's JC-Homes Website

This is part of the series on Great DIY Websites...
 
John Canivan JC-SolarHomes website is a good and extensive source of information for people who want to build solar heating projects.

The website has lots of articles that cover: solar collectors, solar heat storage, controls for solar systems, solar home design and lots of other renewable energy topics.  Lots of emphasis on how to build projects.

John and Richard Heiliger are the developers of the MTD (Modified Trickle Down) solar collector.

An MTD collector

John is also the founder of the very good Yahoo Solar Heat discussion group.  A good place to ask questions about (surprise) solar heating.

Gary

Great DIY Solar Web Sites -- Guy Marsden's ART TEC Website

I've started a new little section that provides links to some of my favorite DIY renewable energy websites.  All of these sites are the work of one individual, and they all show many innovative and practical ways to save energy and live a more sustainable life.

The first is Guy Marsden's ART-TEC website.

Guy is a multi-talented engineer and his extensive site covers many of his interests.
He has some very detailed how-to's that cover the design, building, and living with solar energy and energy conservation projects.  The projects include solar space heating, solar water heating, solar electricity, a solar lawn mower conversion, and quite a few conservation projects.  The projects are all carefully designed, and they all provide very detailed descriptions on how to build them.

Collectors for Guy's shop solar space heating system.

Guy and I have the same type of self installed micro-inverter PV systems, and we traded quite a few emails during the design and construction.  Since Guy was several months ahead of me on getting it built, most of the information flow benefited  me a lot more than Guy :)

The micro-inverter PV system being installed.

In addition to the energy related projects, Guy also does some beautiful artwork -- both furniture and some very innovative "paintings" from changing light patterns.

Cairo Sunset

The Home Page for Guy's site...


Gary

Saying Goodbye to the Jelly Bean Car

We bought a Prius back in 2005, and I've been noting the experiences with it over the past few years here...

It picked up the name Jelly Bean car after listening to Click and Clack on Car Talk trying to talk someone into buying a Prius, and him coming back with "but it looks like a jelly bean!".

A couple weeks ago we traded it in on a new Jelly Bean:

Our new 2010 Jelly Bean

The old Prius had 101K miles on it and was still doing fine -- it will very likely go another 100K miles for its new owner.  But, we decided to take advantage of the slump in car sales and get a new one while the prices are down a bit.

The new one (they call it a generation 3), does have some nice refinements -- quieter, a little more roomy, a little more comfortable, better fuel economy, better performance, ...  Nothing dramatic, but small improvements that add up.  Hope this one serves us as well as the old one did.

Some more thoughts here...

Gary

A Low Air Infiltration Pet Door

We had a blower door test recently, and one of the big air infiltration leaks in the house was our pet door.  The pet door leaked so badly that it had to be temporarily sealed off just to finish the blower door test.
This was a bit disappointing as we had paid extra for a double flap model that was supposed to provide good sealing.

While looking around for a good solution, I happened to read a blog on a new home that was being built in which they were enthused about the pet door they had installed.  It was a Freedom Pet Pass pet door, and in looking into it, it did seem like it might help with the air infiltration.

We ordered and installed one, and its been in use for couple months. We are quite happy with it.  It seals very well -- I cannot detect any air leakage even with a smoke pencil.   It also eliminates the problem we used to have with the flaps on the pet door banging noisily when it was windy.

The installation was a bit more involved than the other pet doors I've put in, but not that difficult, and the result is a near air leak free door.

The reason this door works better is the double magnetic seal that it employs.  It basically has one full magnetic seal for the dog going outside to inside direction, and a 2nd full magnetic seal for the dog going inside to outside.  This approach of using separate seals in each direction allows the use of face type magnetic seals with good contact area.

This shows the double magnetic seal arrangement.

View from the inside of the completed pet door.

The door does not include any "tunnel", so be prepared to frame in and trim the little tunnel through the wall.

While estimating energy saving for air infiltration improvements is very difficult, I had a very rough go at it and came up with about $30 per year in propane savings for our case.

Gary