Category Archives: Renewable Energy

Solar Metal Roofing – How to Make your Metal Roof work for you!

In this solar roofing guide you will learn about the pros and cons of metal roofing with laminated thin-film PV panels such as the ones manufactured by Uni-Solar Ovonics, or simply UniSolar, which is an Energy Conversion Devices company/brand.

UniSolar thin-film solar panels have been specifically designed to be installed with a standing seam metal roof and have a nominal width of 15.5 inches, which fits perfectly onto a 16″ standing seam panel. With a special butyl adhesive backing, the installation of thin-film solar panels is very simple and fast.

Watch how the the solar metal roof is installed and how free electricity is produced right away:

Benefits of Solar Metal Roofing and Roof-Integrated Solar Systems

Installing a solar metal roof is the most cost effective way to get a lifetime roof together with a solar PV system. The savings come from the fact that the installation of a solar power system is greatly simplified, because there is no need to install the racking system, which is needed to hold your conventional solar panels. This saves you about $1 (one dollar) per watt DC of solar system, and eliminates an additional $0.50 per watt for the installation of the racking system and solar panels. With thin-film solar PV laminates, the installation is reduced to cleaning the inside of the metal roof panels, applying and rolling in the PV laminate and installing the metal roofing panels.


Later, when all the standing seam metal roofing panels have been installed, the solar integrator connects the mom and pop contacts on each solar panel to form one, two or more strings of solar panels, and runs the wiring down to the inverter, which then converts the DC power from solar panels into AC power at 240 volts and feeds the electricity into your home’s power network. All excess electricity is sent into the grid (for grid-tied solar systems), or to your storage batteries (for off-grid systems).

Installation of Solar Metal Roofing

Why use a Roof-Integrated Solar System vs. Conventional Solar Panels?

The main problem associated with general solar PV systems that you can now see on many homes around the country, is the fact that an asphalt shingles roof will fail much sooner than the PV solar panels. When that happens, those homeowners will be faced not only with the re-roofing expense, but also with complete removal re-installation of the solar array. This MUST be performed by both the roofer and the solar integrator, as the roofer alone will 99% of the time screw things up. And bear in mind that a roofing warranty will usually not cover damages to the solar equipment, let alone all the possible short-circuit type situations.

Solar Metal Roof Installation Video:

The additional cost associated with these procedures should be at-least the same as the cost of the new roof itself. Think about it: Electricians unlike roofers have to be licensed. An apprentice electrician needs at-least 4 years of schooling/work experience. This is like an undergraduate degree. A master electrician needs another 4 years. Therefore, electricians usually charge $75-100 per man-hour. You’ll need at least two electricians for this job, which will take a whole day to remove the panels and another day to put them back, if not more.

The math is simple: 2 guys * $75/h * 8 hrs. * 2 days = $2400 plus any possible parts and supplies that may be required. So let’s say it costs you $2500 extra. In some parts of the country that is how much an average 1200 sq. ft. cape house roof will cost to install (materials included).

Thin Film Solar Panel Installation Video:

Metal Roofs vs. Asphalt Shingles

Unlike the very “popular” asphalt shingles, metal roofs are pretty much permanent. They are for the most part manufactured from recycled metals, and when installed by a trained professional, they will not leak for decades. More Info: http://www.newenglandmetalroof.com

Metal roofs combined with Renewable Energy technologies can create an ideal, long lasting and affordable solution for residential Solar Electric and Solar Hot Water needs.

Solar electric, hot water and heating

There are other numerous benefits to having a metal roof combined with Solar PV and other renewable energy technologies. When looking at a metal roof vs. asphalt shingles, also consider that a metal roof will save our landfills from getting more shingles dumped there in 10 years or so. With metal, you get a beautiful, permanent roofing solution that you can combined with a solar system, and if you choose to add a Geothermal system, you can design a 100% energy-free home!

Solar Thermal Mass Windows – Free Passive Solar Heat



Although winter is finally over, it is still somewhat cold outside and we have to turn on the heat. Recently, I have found a very interesting product which can be used by anyone to heat their home or apartment for free. Even if you rent, you can do it without getting the land lord involved. The only things you’ll need are south-facing windows and a thermal mass solar window.

Solar mass thermal windows

As you can see from the image above these windows measure 72 degrees F, while outside temperature that day was 22 degrees, with a 27 F high. (Historic weather data).

The 50 degree difference in temperature is the free heat that enters your home and stays. Here is how the Solar Thermal Mass windows work in a nut shell: it as a 2 inches thick air and water-tight container filled with special liquid that collects and stores solar thermal energy. Special chemicals added to the liquid prevent stain deposits on the inner walls if the unit. In the picture above, these units are used as building blocks, and cover almost half of the south-facing wall.

In the winter, when the sun is low, these windows collect solar heat since the sun hits them directly. In the summer, the sun is much higher and with appropriate shading, these thermal mass windows keep the home well insulated without collecting any heat. Additionally, a special low emittance and high solar gain argon filled window unit is installed just outside the thermal windows, so they are not directly exposed to the outside temperature.



How to heat your existing house for free

The picture above was taken in a new construction house, but for most people the interesting question is how to use these thermal mass windows in an existing home or apartment?

My plan was simple: I have 6 large windows that face south and an unheated balcony, which cannot be used in the winter because it is too cold there. In the heated living space, we have new double pane Low-E windows installed, which are much more efficient than the original single-pane wood windows from the 50’s. I am going to build an enclosure in which I can stack 4-6 thermal mass solar window units, and have them up in the window during the winter months, and take them out in the summer.

This will not be as efficient as the one in the new construction home above, but it will certainly help reduce my heating bill and carbon footprint.

As for the balcony, I first need to replace all the single-pane glazing and then I can stack the thermal mass windows all along the bottom of the windows. I’ll build special shelves to make the process of putting them up for the winter, and removing them in the summer, easier.

Traditional Sash Windows – Thermal Performance Solution

Here is how to make your traditional sash windows more energy efficient…

Sash Windows Traditional vertical sliding sash windows, are based on a simple design of two of sliding glass panels (top and bottom sashes) and have been part of the UK’s architectural heritage for over three hundred years. The sash window originates from 17th century England, where the first prototype, the single hung sash window, was created by Robert Hooke, an inventor who specialized in mechanics and architecture. The first type was more basic than those created nowadays and can still be seen in some historic buildings, predominantly of aristocratic ownership.

Solutions

Instead of replacing traditional sash windows, there are multiple reasons why owners should opt for restoring them to their initial appearance and at the same time optimize their thermal performance.

Sash Window Repair

It is best for the restoration process to be carried out by specialized companies and it should always be adapted to the specific type of sash windows and its particular deficiencies. Common sash window repair works (http://www.sashwindows.co.uk/services/sash-window-repairs.html) include: replacing sections of the box frame (normally the lower section of pulley stiles), lower sections of outer linings, bottom rails and window sills and replacing missing puttying and repainting. Using traditional carpentry and joinery methods with advanced modern epoxy resins ensures a permanent repair. This process does not alter their original appearance but instead, mends the alterations brought to it by time and natural phenomena.



Sash Window Draught Proofing

This is also a very effective process, and if done correctly, it maximizes heat retention in the home and minimizes heat and energy loss. Sash window draught proofing is less known perhaps, yet once a sash window has been overhauled and draught correctly, even old sash windows can equal or surpass modern ones in terms of energy efficiency.

In this process, the staff beads and parting beads are replaced with new beadings with a draught proofing material permanently machined into the beads, top and bottom sash re-fitted and also fitted with a draught proofing material (usually a brush pile).

Sash Window Draught proofing

Sash Window Draught proofing

weight to the correct counter balance ensuring the sash close with a minimum gap.

Resources:

Find more green Home Improvement Ideas at http://greenhomeideas.blogspot.com – Green Home Ideas blog.

Solar Decathlon 2009

It was a great Columbus Day weekend in Washington DC, and Solar Decathlon was making waves on the news… Well, actually it did not. Not even bigger green sites and blogs covered this truly green event. Probably there were much more important things happening in our capital – like Obama’s newly “adopted” dogs :).

So I’ll let the big guys do their things, while I tell you about the event, which so many people waited 2+ years for, and worked so hard to make it happen – ladies and gentlemen – Solar Decathlon 2009!

Solar Decathlon 2009 at the Mall in Washington, DC



This was our first Solar Decathlon, but certainly not the last. Since we were sponsors of Team Boston Solar Home, most of my coverage will be focused on it. However, there were many great solar homes this year: Team California and Team Germany were battling for first place (you can see Team Germany solar home in the picture above – a black house, second from the right).

As I wandered through the Mall, looking at these homes and being hesitant to stand in line to see very similar interior set-ups, my main focus was on the outside. Solar technologies, energy efficiency and exterior design were my main concern, as these factors make a true solar home, while the inside can always be remodeled.

Team Boston Solar Home:



As a future architecture student, and a “construction worker” now, I look at these houses with a slightly different perspective than most people. For me, the ease of construction, highest energy efficiency and reasonable cost are the most important things, followed by a nice design. Unfortunately, many of the innovative approaches used for this competition are not accessible to the masses, and remain to be a privilege for the most extravagant home buyers with deep pockets. While I have no problem with it in general, in my opinion, the purpose of a Solar Decathlon is to move innovative green building technologies into the mass housing market, so that such technologies would actually make a major difference in improving the environment and reducing CO2 emissions.

Team Boston solar home at the Solar Village in Washington DC



It is expected of all these homes to be super insulated and have solar PV panels on their roofs. I was interested in innovative new approaches at achieving maximum effect (energy efficiency or energy generation) using the least expensive methods. In this regard, the Boston Solar home has (had) great potential, if not for the massive glass array on the northern side of the house. All these windows and doors will let all the heat escape in the winter, which makes it that much less efficient. This is a fixable situation however – just remove most windows and put a wall there :)

Despite potential heat loss, the liquid-filled glass units on the southern side of the house will collect tremendous amounts of solar heat and store it, making it much easier to heat this house. Find out more about these liquid-filled solar thermal windows and wall panels.

In addition to solar thermal wall panels, Boston solar home has about 6.4 KW solar pv system on the roof and a solar thermal hot water heater, for heating and domestic use. There are many other new and innovative design features used by BAC (Boston Architectural College) and Tufts University students in the construction of this home – too many to list here. You may check out the project’s website – www.livecurio.us.

Team Spain solar home:

Another solar home that attracted my attention was the one build by Team Spain (which for some reason was doing VERY poorly in this competition).

Team Spain solar home: Rotating solar panels array and solar PV cells built into walls.

Apparently, these bi-pv cells are very good at capturing indirect sunlight and help the house generate the most electricity it possibly can.

Team Spain used a very interesting (in my opinion) approach at capturing ALL available solar energy with their powerful solar PV array. This roof mounted array can rotate at the center, following the sun going across the sky, thus always keeping the most efficient angle of the PV panel to the sun. It is basically a gigantic solar tracking system, which is however complicated and expensive to implement, making this house not as competitive in terms of costs and ease of building.

Additionally, the glass walls of this home have integrated solar PV cells, which capture even more solar energy. It is a good idea, but an overkill in my opinion, as the roof mounted solar system should be more than sufficient and, unless they used “dummy” cells on east, west and north sides of the house, it is a waste of solar capacity, as the sun will barely or never hit those solar cells.

Building-integrated solar panels mounted on glass walls.

Cornell University Solar Home:

Another interesting design, which for some reason reminded me of the Water World movie was a solar home built by Cornell University students. It featured three round “rooms” connected to each other, and a large solar PV system, which for some reason was mounted flat to the ground.

Cornell University solar home - round steel frame with flat, roof mounted solar panels.

It may not be the best designed house (in terms of competition rankings), and round rooms make it ever more difficult to build, but the steel frame and a VERY cool vintage design made it very attractive. As I was writing this, Cornell’s solar home was in 6th overall place, with a few more contests to go. You can view current team rankings here: http://www.solardecathlon.org/scoring/

As a side note, as of Oct. 13th, Team Boston solar home is in 12th position and Team Spain is in 18th place, while 1st place belongs to Team California.

Let the best solar house win!

The Solar Decathlon will continue for another week or so, and there are a lot of contests left in which either team can pull forward dramatically. Therefore, I will not even try to predict the winner. All houses presented in the Solar Village this year were very well designed and built, and the green building technologies used in them will in the (hopefully) near future migrate into traditional construction markets and help home and building owners reduce the overall energy use and make our environment better. This competition is also an inspiration for the new wave of architects who will be literally building our future homes and infrastructure, and as you can see, they all have great ideas. I will continue to cover the Solar Decathlon 2009 in future posts, and soon you will be able to review the IB flat roof installation which we did on the Curio Home – look forward to seeing it soon on our cool roofing blog.

Solar PV and cool roofing

Reducing Energy consumption to Maximize Solar PV system efficiency

Part II of solar PV design Guide:

As a rule  of thumb, an average house in the US will need about 5 kW solar system to become self-sufficient and  independent of grid electricity. As another rule of thumb, an average Solar PV system installed in the US is about 2.5 – 3 kW, and you still have to buy about half of your electricity from a local utility company.

Before you start shopping for a Solar PV system, you will need to do some homework, and it is also in your best interest to do the preparations, which will reduce your energy use. As a result, you will need a smaller Photovoltaic System.

On average, every dollar you spend on reducing resources consumption will provide 2 dollars in savings. Things you can and should do to reduce your energy consumption (even if you do not plan to have a solar system installed):



  1. Get small florescent light bulbs – you should have done it a long time ago, as these have been available for years. Benefits include reduction in electricity use by 3 times. Service life of SFB is… well, I have a bunch of them that are 3 years old, and I have not had to replace a single one of them yet. I bought mine for $0.50 each, 4 years ago, from Ann & Hope in Cumberland, RI, and some from Building #19. You should have some similar discount retailers near you.
  2. Replace your inefficient appliances with new Energy Star certified ones. Do your research on energy savings. I calculated that if I replace my old fridge with a $200 new Energy Star fridge, I will recoup its cost in 1 year, as it contributes probably half of my $40 monthly electric bill. You can go to a Sears Appliances Outlet and buy brand new stuff for almost 50%  off in store prices.
  3. Insulate your home! Over 80 percent of homes built before 1960’s do not have any insulation. If you increase your insulation from a 3-r for a standard stick-construction walls with no insulation, to lets say 13-r by having a blown-in insulation installed, you will reduce your heating and cooling bill by 25 to 30 percent. Do the same to your windows. If you still have old, drafty single-pane windows, replace them with at least an Energy Star certified double-pane with Low-E film. the best option is to have a Triple Glazed, 2x Low-E, 2x Argon or Krypton gas premium window, that can go to almost 10-r value. Insulate your doors with weather-stripping. A lot of cold air enters the house through the doors, especially, if there is no second door. If you make your home super-insulated, your heating/cooling bill can be reduced to almost 10% of its original amount. That is a 10 times reduction, for which you pay only once, and it will save you money for years to come!
  4. Install Low-Flow shower heads and 1 gallon per flush toilet. Whether you are a landlord or a homeowner, your water bill has probably skyrocketed in the last couple of years. Mine definitely has gone up 30% in last 3 years.

Have a Cool Roof installed

While most heat loss in the winter occurs through the windows, in the summer, most of the heat gain occurs through your roof. Most homes in the US have an asphalt shingles roof, which is not only bad for the environment, but also contributes 90% of the solar heat gain. Even light-colored asphalt shingles attract solar radiation, transfer it into the attic and also act as thermal mass, by storing most of the heat gained during the day, and keeping your attic steaming hot at night, making the AC work around the clock.



Whether you do or do not plan to have a Solar PV system installed (be it on the roof of your house or a ground-mounted array), your first concern must be to reduce your energy use. This is especially true if you actually plan to have a solar electric system installed. A cool roof can reduce your Cooling cost by 25% or more and can help you trim your solar PV system requirements by as much as 1 kW. At $10 to 12 per watt of solar PV system, you are looking to save $10,000 to 12,000 before any incentives or tax credits.

Choices of Cool Roofing for Residential and Commercial use

A good example of a cool roof would be a Metal Roof coated with Kynar 500 Cool-Roof certified reflective coating. You have a variety of architectural styles and choices of metal available to you. From Standing Seam to Aluminum shingles, to Steel Slate or Tile impression to Heavy Cedar shake, Spanish Tile, etc. As for material, your two basic choices are Steel and Aluminum, with Zinc and Copper being the more exotic, as well as the more expensive options. If you are looking to integrate Uni-Solar Thin Film laminates to Standing Seam metal roofing, you want to go with a steel panel, as aluminum’s expansion/contraction ratio is more than that of Uni-Solar’s PV modules.

If you own a home or building with a low pitch or a flat roof, the most economical and greenest choice for you is to use a IB CPA/PVC single-ply membrane, which has a Cool roof acrylic coating, featuring over 90% solar reflectance. IB roof is also a long lasting membrane that features hot-air welded seams. The welded seams create a permanent bond between two sheets of membrane, effectively eliminating the possibility of a leak.

Planning a Solar PV system

Solar electricity is probably the most expensive form of electricity, yet it is very popular due to some constraints associated with other forms of renewable energy. Wind power for example requires an adequate amount of land and the turbine must be located above the trees and surrounding structures. This limits the use of wind turbines mostly to rural areas. Small hydro-electric systems require a water stream or a river near your house or building, which also limits its use to certain locations. Solar on the other hand can be installed almost everywhere, as long as there is unshaded southern exposure and an adequate installation area. Solar PV can be installed on the ground, on the roof of a house, barn/garage, skyscraper or a warehouse. It can be installed in an urban environment – grid-tied, as well as on a remote unpopulated island – off-grid.



$5 Heating Oil – Are You Ready?

I know it’s May 1st, and you are thinking about the beach, sun-tan and barbecues, but now is the prefect time to start thinking about the next winter season, which is not that far away. By the time it comes, it is in your best interest to be ready. Especially if your home is not yet fuel efficient.

Why $5 heating oil? Well, look at the diesel price today. Here in Massachusetts (which has some of the lowest fuel prices across the United States, and is second only to NJ, which has no gas-tax, and thus has nation’s lowest gas price) the price of diesel in most places is above $4.45 per gallon, and given that gas jumped 35 cents in last two weeks, it is safe to assume the $4-plus gas and above $5 diesel/heating oil by the fall / winter time.
Thank you Mr. Bush. Oh, and it is such a pity that Exxon-Mobil missed their earning expectation and made only $10.89 BILLION in net profits, instead of $11.65 billion projected by analysts.

Any way, enough sarcasm, we need to make our homes use less energy. The first thing you can and should do, is replace those old, drafty windows.

Despite the fact that this is Green & Solar site, I’m going to recommend Vinyl windows. That is right, not the wood-green-built but vinyl. Why? It is simple. Remember the Practical Approach thing? The carbon-footprint of vinyl windows is less than that of wooden windows, if you include the heat loss accumulating over time, and the fact that vinyl windows are cheaper and more fuel efficient – therefore they are Practical!

Alside UlrtraMaxx triple-glaze windows with6.7 r-value save you money on heating and cooling Here I’ll discuss a specific type of vinyl windows – Alside UltraMaxx line, that comes with triple glazing, double low-e and two argon packets. Combined together, UltraMaxx gives you 6.67-r value. Bear in mind that standard and well-built double-glaze, low-e argon window has an R-value of less than 4.

Why Alside UltraMaxx? Well, this is not a commercial paid for by Alside. I just love those windows, and had personally installed many of them. They are very-well built, and have the most durable and sturdy frame of all other Alside lines.

You may ask why not Anderson or Harvey or Pella windows? Well, none of those actually make triple glaze windows, so my choice is Alside.