Category Archives: Solar Energy

Nov 11 1 comments
Electrical, Environment, Solar Energy, yard

Installing our Photovoltaic Solar System, Part I

I have had a pretty good year with the solar business thus far.  Therefore, I decided to roll some of this year’s profits into our own Photovoltaic (PV) system.  This idea has been batted about before, including as a battery back up for the sump pumps, however, a few things have developed since then.

First of all, as technology often does, newer things are available these days that make a solar system in the North East a better proposition.  Secondly, the solar business has done better than I expected.  As a result, I don’t often have much time to work on household projects.  That means that this years “capital improvement” budget has gone unspent for the most part.  Finally, I would like to offset some of the extra income tax from the profits.  What better way than to invest in the technology myself.  The Federal Government offers a 30% income tax incentive and the NY State government offers a 25% tax income incentive up to $5,000.00.  This will cut the overall cost of the installed system by almost 50%.

There are a number of considerations:

  1. How large of a system should be installed.  I decided that I wanted to offset 70-80% of my annual electrical use.  In this climate and environment, that equates to about 4.1 KW DC PV system.  This leaves a little downward room in case I decide to replace the electric stove with a gas unit.
  2. Where can it be installed.  Since the south facing roof has the solar hot water system, the PV system needs to be mounted on a sun shade type structure in the yard.
  3. What type of technology.  I was initially looking at a grid tied with battery back up, however, after I looked into the newest type of inverter, the Enphase microverter, I decided that this was the way to go.  A battery backup can be added at a later date.

The Enphase microverters are really cool.  The way this system works is every solar panel has its own small inverter instead of one large inverter for many panels.   The advantages of this type of system are thus:  In conventional system, shading of one panel can cause the entire solar array to turn off, making it ineffective.  With the microverters, the shaded panel may turn off, but the rest of the unshaded panels still put out full power.  In the Northeast, trees grow everywhere, it is nearly impossible to have a completely shade free site, nor should home owner’s be expected to clear cut their lots to accommodate a PV system.  The Enphase microverters mitigate some of those concerns.

Also, multiple inverters create redundancy.  Any one inverter can fail, leaving the other nineteen still operational.  There is automatic web monitoring for a small annual fee, or the modules can be monitored manually.  I may write a small web based program to monitor and post my energy output here.  The inverters themselves carry a 15 year warranty, whereas most other inverters carry a 5 year warranty.

Finally, there are no DC voltage losses to account for, making the entire system operate much more efficiently.

In anycase, the order has been signed, checks have been written and the excavator has been reserved for this weekend.  The first step is to dig and poor the footings for the sun shade.

More to follow.

Popularity: 1% [?]

Dec 29 0 comments
Alternate Energy, Solar Energy

Happy New Year, enjoy your renewable energy incentives

Let me be the first to proclaim “HAPPY NEW YEAR!”  And good riddance to 2008!

Of course, not all of 2008 was doom and gloom.  One of the bright spots is congress extended (to 2016) and improved the federal tax rebates for renewable energy systems.  As of January 1st, the federal tax rebate is 30% of the installed cost, no cap on photovoltaic and a $2,000.00 cap on thermal (SDHW) systems.  This is on top of any state rebates or incentives available.

Solar panels or house roof (they should all look like that)

Solar panels on house roof (they should all look like that)

The incentives are necessary to make renewable energy, specifically solar, more competitive with traditional energy systems like fossil fuels and nuclear generated electricity.  This is because the companies that supply oil, coal, natural gas and nuclear power get large subsides from the federal government to reduce their costs and keep the energy supply “cheap.”  These subsides are supposed to be used for the discovery and development of new oil and natural gas fields.  They are largely responsible for the Alaskan pipe line and the North Slope/Prudhoe Bay area.  Most geologists agree that the likelihood of finding any more large oil deposits are slim at best.

As we have all found out, oil prices can be quite volatile, I would call last summer’s gas prices anything but cheap.   Last week’s retaining pond accident in Tennessee will not be cheap either.  Nor will the storage of all the spent nuclear power plant fuel in Yucca Mountain be cheap.   One might say that “cheap” is a relative term.

I don’t like incentives or subsides.  I hate living in a controlled environment where I am not sure who is pulling the strings or why.  If it were up to me, we would have no susides or incentives any energy system.  This is the European model and it seems to work well.

Popularity: 4% [?]

Dec 28 4 comments
General, Solar Energy

Our home improvement progress

We have sort of hit a wall this year.  Looking back on it, almost nothing happened that was supposed to.  First off, we sort of ran out of funds and time.  What with the $4.87 per gallon gas this summer, expenses from my children, the ever increasing cost of health care, and all the time I put into starting my solar business, it seemed that the house renovations where put on hold.

My list for 2008 was as follows:

  1. Build a shed in the back yard.  Nope.
  2. Remove the old deck from the front of the house.  1/2 done.
  3. Build a new porch on the front of the house.  Nope.
  4. Expand the garden and install raised beds.  Done.
  5. Install a solar backup power system for critical household loads.  No money
  6. Insulate the basement.  Not yet, might still happen
  7. Build shelves and properly store all the stuff in the basement.  Not yet, might still happen.
  8. Build two solar hot air collectors and attach them to the south wall.  About 3/4 done, ran out of good weather.

I did manage to get one thing done, the garden.  Actually, I am happy with that as we are still eating vegetables that we grew last summer.  As for the rest, oh well, perhaps sometime in the future.  With the involuntary four day without electricity experiment, I would bet #5 becomes a high priority.   I do so love electricity and all of the things that it provides.

The one big thing that was not on the list but got done anyway was the basement water proofing/drainage system.  This was expensive and kind of killed the budget for the rest of the summer.

A little hit at what I am working on now: Solar powered LED grow lights.  Large versions to be used in commercial green houses.

As for next year, I am not making any predictions.

Popularity: 4% [?]

Oct 08 5 comments
Alternate Energy, Environment, Heating, Solar Energy

DIY solar panels, Part II

This is part II of how to make your own solar thermal collector to help offset heating costs this winter.  You will need a good south facing wall to mount this collector on.  In order to be most effective, the wall should be unshaded between 9 am to 3 pm daily.  Some defused sunlight shining through the branches of a deciduous tree is fine.

Preferably this collector will be mounted adjacent to a large reflective surface.  A snow field would be perfect, however, dry sand, concrete and water will also work.  The quality of the reflective surface is called Albedo, which in Latin refers to its “whiteness.”

Here are some albedo figures for some common reflective surfaces:

Material Albedo (percent reflection) Comments
Snow, new 80-90%
Snow, old 65-75% After one week
Sand, dry 35-45%
Sand, wet 25-35%
Ice 30-40%
Concrete (dry) 50%
Water (high angle radiation) 8% Sun angle relative to surface
Water (low angle radiation) 70-100% Sun angle relative to surface

Also, the lower the sun angle, the larger the reflective surface should be.  This is for two reasons; first, the law of reflection states:

  1. The incident ray, the reflected ray and the normal to the reflection surface at the point of the incidence lie in the same plane.
  2. The angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal.

Therefore, the lower the angle of the sun the further away the reflection point will be from the collector.

Secondly, the lower sun angle also means that the energy density of the sun light is much less.  A larger reflective area will aid in gathering more energy.

Solar Collector parts list:

Nomenclature Number Price each Price total
Aluminum cans 560 0 0
Solar Selective coating, Dampney Thurmalox* 2 19.95 39.90
Aluminum angle   1×1x96″  1/8 3 24.72 74.61
Aluminum metal lath 26 x 84″ 2 10.67 21.34
Aluminum angle 1×1x48″m .050 4 4.98 19.92
SunTuff polycarbonate panels 26×96″ 2 19.95 39.90
Polyisocyanurate insulation panel 4×8′x1″ 1 23.50 23.50
24 VDC fan, 224 CFM, Mouser 5912-7114N* 1 90.55 90.55
Draft seal, 4″** 2 5.86 11.72
Diffuser, air 4″** 2 14.95 29.90
Duct connector, 4″** 2 4.20 8.40
Diffuser, air 6″** 1 15.87 15.87
Duct connector, 6″** 1 4.25 4.25
12 watt PV panel, Sunwise SC12-12* 1 143.22 143.22
Snap disk fan control switch, Grainger 4E116* 1 18.66 18.66
1×8x96″ clear pine board 3 9.32 27.96
RTB sealant 1 tube 4.89 4.89
High quality urethane caulk 1 tube 3.34 3.34

*Not required for a passive system
**Quantities doubled for a passive system

Total, active system: $447.16
Total, passive system: $355.74

All parts except snap disk switch, PV panel, and DC fan were priced and purchased at the Home Depot.

Therefore, a passive collector needs to offset $355.74 in the first year’s use, an active collector needs to offset $447.16.  According to NYSERDA, the cost of home heating oil is currently $3.823 a gallon.  I need to save 117 gallons of fuel oil to offset the $447.16 collector cost.  Each gallon of home heating oil has 139,000 BTU. My boiler is 86 percent efficient, therefore, I get 119,540 BTU per gallon.

My solar collector needs to generate 13,986,000 BTU to save 117 gallons.

I expect the active solar collector I build to generate about 45,000 BTU per day.  The heating season lasts from October through April, or 212 days.  I expect 30 percent of those days to be too cloudy to generate significant heat from the collector.  I have 148 days of good solar resource, so 6,660,000 BTU can be expected.  That makes the payback approximately two years vs the one year original design goal.

Solar collector tools:

Ridgid MS1065LZ 10 inch miter saw

Makita 6213D 3/8 inch cordless drill

Ridgid R84001 3/8 inch cordless drill

Bosch 1587A Jig Saw

DeWalt D28110 rotary grinder

Construction details to follow in Part III

Popularity: 9% [?]

Oct 04 8 comments
Alternate Energy, Environment, Heating, Solar Energy

DIY solar panels, Part I

I have been working on this for most of the summer.  The problem with solar energy systems is that they are expensive.  There is no doubt that a photovoltaic (solar electric) panel will save energy and pay for itself in time, however, the initial outlay of money to purchase and install that panel is more than most homeowner’s can afford.  Solar thermal systems are likewise good investments, however, there associated systems are complex and need to be carefully designed and installed so that they function correctly.

What if someone could design a solar collector that can be easily built and installed by the average do it yourselfer.  This is the idea that I had and I think I may have something.

Here are a few design benchmarks:

  1. That solar system would need to be fabricated on site with standard power tools.
  2. It should be constructed of material readily available at most home improvement stores and the like.
  3. The system should be simple and easy to understand and troubleshoot.
  4. It should be simple enough to construct that anyone with basic carpentry and metal working skills can build it and install it.
  5. It should be efficient and relatively inexpensive, paying for itself in one year.

Those are the basic ideas I had and I believe I met most of them with my design.  What I was going for was something that would produce heat during the winter time and be optimized for cold snowy locations.

This solar collector is used to heat air, circulating air over a collector plate and returning it to the conditioned space.  Air heating panels are simpler to construct than water heating panels, their downside is that there is no storage capacity associated with them.  In other words, they work great when the sun is shining, but will not produce any heat at night.  They are suplimental heaters in most cases and cannot replace a central heating system.  That being the case, they can still save a significate amount of energy.

The main collector surface is made from aluminum drink cans.  The cans have the tops cut off and are stacked horizontally like this:

horizontal can solar collector

horizontal can solar collector

This arrangement is more work and requires more materials but it has several advantages over other designs:

  1. Each can becomes a mini solar receiver similar to solar receivers used on large concentrated solar systems.
  2. The array of receivers gathers energy more effectively because there is less reflected energy than an ordinary flat plate collector.  Once the energy strikes the collector surface, it is reflected down into the cans where the convex bottom aids in absorption.
  3. If mounted on a vertical south facing wall in front of a reflective surface such as a snow field or dry sand, the array will gather much more solar energy due to the increased insolation area.
  4. Aluminum is an excellent conductor of heat, thus the heat will move to the back of the collector plate, which will be cooled by forced air.

The main idea here is to make it simple yet effective.  Aside from the collector, a 250-300 CFM DC fan and a PV panel round out the system.  A small “snap disk” thermal fan switch turns the fan on and off depending on the collector temperature.

Part II will discuss tools and materials.  I expect the system to cost about $400-450 to build.  The most expensive item is the PV panel, which can be substituted with an AC wall transformer.

Part III will be a sysnopsis of my own system.

Popularity: 10% [?]