Archive for February, 2008
Solar Hot Water in the Adirondacks (and some windpower for good measure)
On February 24, 2008 in Uncategorized
The girlfriend and I made a trip over to Burlington, VT on Tuesday, and then crossed back over the lake into NY to stay at her sister’s house for the night.
On the drive over to Burlington I got some pictures out the window of the car of some of the huge wind turbines they have been putting up along Rt 11, but only one came out very well. It was a pretty foggy/snowy day. You can see one of the other turbines in the background, though:
After taking these pictures I decided I should take pictures of the smaller turbine that they have setup at the Vermont Welcome Center just across the border from Rouses Point, NY
As you can see, it is actually pretty close to some power lines:
After this the trip was rather uneventful as far as alternative energy stuff goes, so I won’t bother boring you with the details. Let’s just skip ahead to the part where we left my girlfriend’s sister’s house and were heading up through the Adirondacks back home to Potsdam.
We took a route that we never take, because we really didn’t have anything better to do. This turned out to be a good idea. Here is a Google Map of the area. Ordinarily we would have come from Westport on 9N to Elizabethtown, then to Keene, and up to Lake Placid on Rt. 73. This time we decided to go north on 22 by the lake, up through Willsboro, Long Pond, and bunches of other little places we’d never been through.
When we hit Willsboro, we were looking for a gas station as there aren’t many out in the mountains. I happened to see this pharmacy, instead:
The thing that caught my eye was this part:
The girlfriend thought I was crazy when I started screaming about solar hot water on a pharmacy in the Adirondacks and pulled the car over. I do have higher res pics if you want them, but here are the rest:
Unfortunately I didn’t get a chance to stop and talk to anyone there, but hopefully we will be back in the area soon.. If anyone else gets a chance please stop by and have a chat with them, they can’t be all bad if they are heating water with the sun 
Designing a Solar Heated Structure (Part Two)
On February 12, 2008 in Uncategorized
Alright, I know it has been a while, but here is the second installment of the “Designing a Solar Heated Structure” series I promised I’d write.
As I’ve said before, I am a rank amatuer, and am not claiming to be certified, highly experienced, or anything else. I am merely offering my opinions, and carefully organizing my research so that it can be understood by a more broad range of people.
I try to reference my sources as much as possible but if you see something that sounds out of whack and I don’t provide a source, ask me about it. I don’t work on the site while drunk so there shouldn’t be any made-up facts in here unless they are from someone that seemed a credible source at the time.
All ranting aside, let’s get down to designing our solar heated structure.
The first thing you will need to do is talk to a contractor or licensed professional because I am just some guy on the internet and why are you listening to me, anyway? After that is over with you should have an idea of the soil conditions in your building site, and you should already have a basic plan of what you want from Part One of this whole ordeal. Hopefully the contractor helped you form your plan to work well in the area you will be building. You will want to choose the right foundation/building type for your area. Consult with a contractor on this as I only have experience in the deep woods of Northern New York. Different soil types will need different preparation/construction methods.
Places like Florida (an Ode to John, a commenter from the last post, and our friend Matt from diyrobotics.info) have hurricanes and termites and year round humidity and you can see that most buildings are made out of anything but wood (concrete blocks, formed concrete, brick, adobe or whatever). Up here in the north, wood is the primary building material. Apparently Europeans don’t use wood much anymore either, although I can only assume this is due to it being in short supply with the overcrowding and all of that.
All of these are perfectly good reasons for you to not listen to some guy on the internet about what foundation and/or building type to use. Consult with a contractor. Consult the local building codes and Code Enforcement Officer. Observe what others in the area are using, and check prices on the various materials.
Since this is a DIY website, I am kind of targetting this article at people that are going to build themselves a small retreat in the wilderness, not people building a solar heated warehouse or gigantic residential building. With that in mind, I apologize if this article doesn’t fill in all the gaps for anybody trying to figure out how to build a skyscraper by reading something on the internet.
Hopefully once you have taken all of this into account, done your research, ripped out your hair, done more research, sat down at the drawing board, had a few beers, and actually gotten to work, you will end up with something like this (or thereabouts):
Don’t worry about the whole window thing for now, as we haven’t really gotten to that point. Also don’t worry if your plan doesn’t look anything like the one here, this is for a cabin that would be sitting on rock. There was no foundation to be dug. Concrete piers would be poured on the rock and then the beams anchored to the piers.
Hopefully though, you have taken into consideration the “airlock” or “mudroom” I mentioned earlier, and at least have an idea of where your windows will go, if not how big they will be. Also make sure the building is going to be oriented properly with regards to the sun, and that the site you have selected has a good southern exposure that will receive light for as long as physically possible during the day.
I will leave the building materials to you, as that depends on your design. Some will go with shingles for the roof, others will go with corrugated steel or something else. Some will use wood for the walls, others concrete and others straw bales or cordwood. Either way, make sure there are not going to be lots of air leaks and that the structure will be heavily insulated to reduce the chance of losing that precious heat we are trying to gain.
After the site has been selected, the sun’s path verified, the building codes checked, the design of the building roughed out, and the building materials chosen, we need to focus on window and thermal mass sizing/placement.
It is EXTREMELY important to make the windows large enough to gain the amount of heat you want, and equally important to have enough thermal mass to store that heat that came in. You also don’t want to go overboard on either one. As with everything there is a point of diminishing returns.
There is an excellent article at renewableenergyaccess.com called “Balancing Solar Gain and Thermal Storage” that I have linked in the Heating section of the site. The author checked with Ron Judkoff, Director of the Buildings & Thermal Systems Center at the National Renewable Energy Laboratory regarding a question from some readers.
He listed some “Rules of Thumb” for Passive Solar design:
* Place mass inside the insulated envelope of the building.
* Place mass where it will receive as much direct gain radiation as possible and make sure it is at least in the same room/space as where the sun enters.
* Mass for direct gain systems is only effective for the first 2 to 3 inches, so 8″ concrete block is overkill (diminishing returns) unless you are doing a trombe wall system in which case the trombe wall should be 12 to 16″ thick.
* Surface area is much more important than thickness. So the same weight of mass widely distributed in a thin layer is much more effective than a thick layer less widely distributed.
* The mass (except for trombe walls) does not have to be in exterior walls. It can be in interior walls, or floors. In fact a 4″ brick partition wall separating two rooms with each room having South facing windows is a very effective design because you utilize the first two inches of depth from each surface of the mass wall.
* If the floor is used for mass, do not cover in carpet or some other non-conductive material. Use tile or masonry interior floor finishes. Also insulate under the entire floor area (not just perimeter insulation) being used for thermal mass.
* The mass surfaces do not have to be dark in color (except for trombe walls), but it would be bad to have the non-mass surfaces dark and the mass surfaces light. If both the mass and non-mass surfaces are light in color, then there will be enough reflections to get the energy to the mass.
* Be careful with Low E windows. Work with your window dealer to specify high solar transmissivity low e on the south facing windows (not easy to get) (one product is Heat Mirror 88). If you can’t get a high solar transmissivity low-E window then specify triple clear with a krypton fill for the south windows. Windows on all other orientations can be the usual low-E products.
But unfortunately you can’t just go about this all willy-nilly. Different parts of the world receive different amounts of sunlight, and that is where Part Three of the “Designing a Solar Heated Structure” series will come in.
In the meantime, you can check out this Solar Radiation Data page I have linked in the “Charts and References” section of the site. This page has annual BTU’s per square meter for specific latitudes/longitudes. Check out the data for your closest major city and start paying attention to the sun in your area, this knowledge will come in helpful soon.
You might also want to have a look at this Heating Degree Day Map, and the wikipedia article on heating degree days.
Thanks for stopping by, I’ll add some more later.
BBC Article: “The pros and cons of solar power”
On February 08, 2008 in Uncategorized
I just found this BBC Article called “The pros and cons of solar power” and thought I would share.
“Even in grey, overcast Britain, some householders are managing to use solar power to meet their energy needs.
But there are far more ambitious plans for Europe to import solar power from huge installations in North Africa.
Johannes Gleede installed a solar thermal panel in the roof of his semi-detached house in south west London ten years ago and paid around £1,500 for it.
From a flat plate solar collector slotted into his roof, water is conducted into a cylinder where it heats. You don’t need direct sunlight, just light. And when we visited Johannes’ on a December afternoon, the water was certainly hot enough for a shower.
It was an ideal time for Johannes to invest, because he needed to replace the boiler so the total cost was around £5,000 in total.
“I wanted to see if it worked,” says Johannes.”You have to dare to be crazy.” It did work and has cut his electricity bills by 50%.
Most householders should expect to pay upwards of £3,000 for installation depending on the type of house, says David Mathews, Chief Executive of the Solar Trade Association. The cost will also go up if you have to upgrade other parts of your central heating system.
It takes a number of years to get that investment back. But the most recent government figures (2006) state 78,470 UK homes have solar thermal, making domestic water heating by far the biggest area for the use of solar power in Britain.
Expensive option
It is far more expensive to generate electricity from solar power. For a typical British house, this requires a rooftop solar collector in order to provide enough silicon cells to generate sufficient electricity.
The technology is proven, but the costs for a single house are £12,000 to £14,000 according to the British Photovoltaic Association. So far this has been installed in about 1300 homes. But it is also being used in some commercial buildings and public buildings such as schools.
More electricity can be generated in summer and less when we need it most - on dark winter evenings. And at present there is no mechanism for storing electricity generated on long summer days for use in winter.
Dr Thomas Markvart from the University of Southampton says photovoltaics could provide a substantial amount of the electricity Britain needs but fears we risk losing our expertise to countries like Germany and Spain where the industry is booming.
“We need to have the stimulus for manufacturing in this country, and that comes partially from government. Otherwise it will go abroad. Companies like BP are going to Spain where there is government support”
Last year, Spain inaugurated the world’s first commercial solar plant near to Seville. But much of the engineering expertise in solar power has been nurtured in Germany where solar power has really taken off.
Saharan plants
An ambitious plan to build massive plants in the Sahara desert using concentrated solar power (CSP) was unveiled by German engineers last year.
The Desertec organisation supported by Prince Hassan of Jordan wants to use giant parabolic mirrors in the desert to track the Sun and absorb heat in a central receiver which is cooled with water to produce steam. The steam drives a turbine and produces electricity.
Hang on, you’re thinking, there is no water in the Sahara desert. True, but the plants are to be placed near the Mediterranean coast so water can be pumped in and be desalinated in the process.
Franz Trieb of the German Aerospace Center (DLR) who carried out the feasibility studies into the Desertec idea sees it as a win-win scenario creating energy, water and income for the Middle East and North Africa.
“Yes you are creating shade in the desert, but shade in the desert is a good thing. It will create communities. And when I see that there will be 300 million more people in the Middle East-North Africa region in 30 years, we are going to need more water,” he says.
Prince Hassan goes as far as to call it an industrial revolution for the southern Mediterranean that will create further stability in the region.
Trading dependence?
Trieb says a method of storing heat overnight using tanks of molten salt has been developed, and electricity will be exported to mainland Europe via high voltage direct cables under the Mediterranean right up to northern Europe.
Germany and Algeria have already reportedly signed a deal to lay cables stretching as far north as Aachen on the German-Belgian border.
BBC Radio 4’s Costing the Earth visited Egypt where a £30m pilot plant is being built south of Cairo. Rows of parabolic troughs 50-60m wide will cover an area of 130,000 sq m. Initially it will provide electricity for 200,000 Egyptian homes. Further plants are planned or in progress in Libya, Algeria, Israel and Morocco.
In Britain, the idea of importing solar energy has been received with cautious optimism. Energy Minister Malcolm Wicks calls it “an exciting 21st century idea” and says “We have to think in revolutionary terms if we are to move away from a carbon intensive society”.
But he is wary of the costs of establishing a European “supergrid” and concerned about energy security. Could it be that we would simply be trading our dependence on the Middle East for oil for a dependence on sunshine?
However, enthusiasts of the Desertec concept say there is around 8,000 times more energy than we need to be harnessed from the Sun, an unlimited renewable resource. Perhaps the sun over the Sahara could indeed be the future super generator of our electricity.”
