THIN FILM SOLAR PANELS

Archive for July, 2008

Our good friend Siel, also known as the world-famous Green LA Girl, is hosting a class tomorrow night that anyone in LA should check out. It’s on Green Apartment Living. Siel will be joined by fellow teachers Summer Bowen and Traci Reitz. The class will be held on Wednesday July 16 at the Santa Monica Synagogue starting at 8:30PM.  It’s free– just show up!

This is an issue SO many people are interested in– we tip our hat to these ladies at their class.  If you are interested in learning how to green your apartment, you can also read our feature on it here.

Here is what the class will cover:

“Summer will introduce you to the wonderful world of balcony gardening, by which I’ve personally benefited because I’ve gotten to eat the bounty — from corn to tomatoes! You’d be amazed to see what yummies you can grow, even if you don’t have a plot of land to call your own.

Traci will demystify eco apartment renovations — done frugally yet prettily! She’ll let you know what eco paints work and what don’t, what’s better to reuse and what’s better to replace.

Siel will talk about getting around, greenly. Apartment dwellers move around a lot, so my portion will cover how to pick an eco apartment, and how to use that apartment to green the way you get around the city. De-car-ing doesn’t mean sitting at home.

We’ll have a Q&A at the end — and will be going out for drinks afterwards. Join us!”

Does anyone know about classes like this happening in other cities?  Let us know in the comments section please!

Over the past few months we’ve noticed quite a bit of interest in geothermal heating and cooling amongst our site visitors, and in particular in geothermal heat pumps. We’ve also had many questions from people about exactly what they are and how/if they should consider them as an eco-friendly heating/cooling option. If this describes you, then read on - these systems ARE incredibly promising technologies to heat and cool your home, but they’re also more complicated than your typical AC or furnace unit. We’ll try to help clear the air!

We get into quite a bit of detail below, but before you get into that here’s a very quick summary of geothermal heat pumps:

• Geothermal (or ground source) heat pumps can be incredibly efficient, delivering 3-6x as much energy for heating and cooling as you use to power the equipment;
• They are in some ways a renewable energy system, since they use the heat contained in the earth to provide heating / cooling;
• They do require extensive installation work, including excavation or drilling to install subsurface pipes; and
• They are more expensive than traditional heating/cooling equipment, but the payback period is less than five years almost everywhere in the country due to their greater efficiency.

What is a Heat Pump?

First things first, though: what exactly is a heat pump? Well, just like it sounds, a heat pump moves heat from one place to another rather than creating heat or cooling by burning a fuel (like a furnace or boiler). They do this by taking advantage of the fact that liquid refrigerants absorb huge amounts of heat when they turn into gas via evaporation, and release that same heat when they are condensed back into liquids.

The most common kind of heat pump, called an air-source heat pump, uses the energy in outdoor air to heat and cool. To cool a warm space, a heat pump evaporates the liquid refrigerant in copper coils indoors and condenses it (via a compressor) in similar coils outdoors. To heat a cold room, a valve is activated that reverses the process: the gaseous refrigerant is condensed indoors where it gives off heat, and it evaporates in the outdoor coils, picking up heat from outdoors in the process. Air conditioners and refrigerators use the same exact process to deliver their cooling performance.

Why are they such great heating and cooling options? For one, heat pumps can be incredibly efficient: because they move rather than create heat, they can often deliver 3-4x more energy into your home than you use to power the heat pump (high efficiency air conditioners have the same benefit). Unlike air conditioners, heat pumps also provide both heating and cooling, meaning you don’t need two separate systems that only get used for half the year.

With all of these benefits, you might expect to see air source heat pumps everywhere, so what’s the catch? Well, because they are more complicated than typical air conditioners and furnaces, they’re a bit more expensive up front. And, they work best in relatively moderate and humid climates: the greater the difference between the indoor and outdoor temperatures, the harder they have to work. Once outdoor temperatures drop below 40 degrees or so, heat pumps are no longer efficient as heaters and you need some kind of auxiliary heating. In very hot climates with low heating needs, air source heat pumps are no more efficient than air conditioners but are more expensive.

The Joys of Geothermal

Fortunately, there’s a great way around these limitations on traditional air source heat pumps. In even the most extreme climate regions, the temperature several feet underground is between 45 and 75 degrees Fahrenheit. Enter the geothermal heat pump (also called GeoExchange heat pumps and ground source heat pumps). These heat pumps circulate a fluid through piping buried in the ground, discharging heat to the ground in summer and pulling it from the ground in winter. The heat pump coils are in contact with this fluid rather than the outside air as in a standard heat pump, thereby avoiding the huge temperature swings of our atmosphere. Geothermal heat pumps can be incredibly efficient, delivering from 3-6x the amount of energy used to power the pump’s compressor and fans/pumps.

There are several options for installing a ground source heat pump. The choice of which one makes sense in your area involves many factors, such as how much land you have available, what the underground conditions are like, and the skill / experience of installers in your area. As you scan these options you might think “wow, these must be expensive!”, but due to the incredible energy efficiency of these systems payback periods can often be less than five years.

Installation Options

The most cost-effective option for residential applications is called closed loop horizontal installation. In this type of installation, plastic pipe is laid in horizontal trenches at least four feet deep. The pipes can be installed straight or in loops resembling a big Slinkly - this requires deeper but shorter trenches, which can help in smaller yards. For a typical home, you might have to install 1,000 - 2,000 feet of tubing/piping, so this isn’t a small project!

A second option is called the closed loop vertical system, in which u-shaped sections of pipe are installed in borings drilled 150+ feet deep. These systems are more expensive because of the drilling costs, but they can be used in tighter places or where the soil is very rocky or difficult to dig in. Vertical systems have been employed in areas as densely populated as New York City.

A final common option is referred to as an open loop system. Here the heat exchange is done via groundwater withdrawn from a well rather than through a closed loop of piping. Heat is transferred from the water to the building via the heat pump, and then the water is reinjected into the groundwater aquifer via a second well some distance away. This can be the easiest approach from a technical standpoint (and can work in dense urban areas as well), but it can introduce some permitting hassles in areas where groundwater is used for drinking or is tightly regulated.

There are some other options (such as using a lake or pond as your heat source), but the three above are the most common options in most residential situations. There are also some interesting innovations in the technology of the heat pump equipment itself (such as using the waste heat for hot water, hooking the heat pump up to in-floor radiant heating systems, and other higher-tech approaches), but we’ll cover those in a separate posting.

Geothermal Heat Pumps Near You 

Clearly, finding a contractor skilled in this type of system is critical! We have a directory of geothermal heat pump installers around the country here. If you don’t find any in your area, then check out the installer lists provided by some of the top heat pump manufacturers:

• WaterFurnace;
• ECONAR installers;
• FHP Manufacturing;
• Earthlinked Technologies.

Oh, one more thing to note. A geothermal heat pump is NOT the same as geothermal heating, where you heat your house directly using hot water pulled from deep underground. There aren’t that many parts of the country with the necessary underground geothermal energy to do this (primarily in the West), and even in these places almost all systems are commercial-scale operations. So if you’re thinking of harnessing the earth’s energy for your heating / cooling needs, most likely a geothermal heat pump is the way to go!

Last Friday Tim Hurst wrote an article entitled ‘Soaring Fuel Prices Spur Aviation Industry to Explore Alternatives’, wherein he focused our attention on Rolls-Royce and British Airways attempts to search for alternative fuels. Though probably not entirely humanitarian in nature, it is nice to see another industry getting in to the alternative fuel game.

With the start of a new week however, I get to bring to your attention the efforts of France’s LISA Airplanes and solar cell maker Trinia Solar Ltd.

Read the rest of this entry »

Written by Michelle Bennett, courtesy of CleanTechnica.com

MIT has perfected a dye technology that could change the solar world as we know it.

The most efficient form of solar technology today is (arguably) extreme concentrated photovoltaics, essentially solar panels placed under a magnifying glass, but the problem with these systems is heat. Concentrated sunlight can melt silicon solar panels unless you include specialized cooling systems. Cooling technology costs money, and the panels require expensive tracking mechanisms to follow the sun through the day. MIT’s new solar system bypasses the heat and tracking problems all together.

Thin coatings of organic dyes absorb sunlight and redirect favored wavelengths into a pane of glass. The light is aimed and concentrated towards the edge of the pane where small solar panels are located. The concentrated light allows the panels to produce the maximum possible amount of energy all day, every day without cooling systems or complex tracking mechanisms.

The idea is not new, but its founders in the ’70s could not overcome technical challenges. The technology was abandoned when research funding dried up. Their dyes were unstable, and their optical experise was imperfect. Much of the light captured and concentrated into their glass or plastic was lost before it could reach the solar cells. MIT took tips from laser technology and organic light emitting diodes (OLEDs) to perfect the technology. Their expertise increased the distance light can travel through glass or plastic to reach the solar panels, boosting energy production.

“In addition, the focused light increases the electrical power obtained from each solar cell “by a factor of over 40.”” According to Marc A Baldo, an associate professor at MIT who helped lead the project. For more technical details, you may need an AAAS membership to read the Science article.

Three Reasons Why This Could Rock the Solar World:

1) It’s Easy: The technology is neither complex or difficult to manufacture.  All you need is a window frame laced with solar panels and an ordinary pane of glass or plastic.  Apply the proper ratios of organic dyes and you’re ready to go. The finished product looks like smoked glass and could be used on rooftops or solar farms.  Future improvements could bring them to ordinary windows.  Hopefully it will be competitive in price with other solar technologies.

2) Upgrade Existing Solar: This technology can be applied to existing photovoltaic panels to boost their efficiency by as much as 50% with minimal additional cost. Upgrading existing solar panels will not only boost their energy output, but shift their cost/energy ratios.  That means that even older, more expensive solar installations could become more competitive with non-renewable energy sources.

3) It’s Coming Soon: MIT claims this technology could be ready for commerical production within three years. A company has already been founded to capitalize on the technology, and it won two prizes at MIT’s Enterpreneurship Competition, totaling $30,000.  They will also seek more investment over the next few months.  Keep your eyes peeled for Covalent Solar.

But nothing is certain.  Like any new technology, this one has its challenges ahead.  The dyes, for example, have a demonstrated lifespan of ten years, but most solar panels come with twenty or twenty-five year warranties.  Covalent Solar must also run the gamut of any fledgling business to bring their product to market.  With so many improving and emerging solar technologies, they will face a lot of competition.

What makes this technology different is its implications for existing solar installations and expansion into new spaces. A window that helps power a building could become a powerful tool towards super-efficient or power-producing structures. The potential for low cost, high efficiency solar technologies has never been greater.

Related articles:

Learn about new thin-film solar applications.
Find solar installers near you.

MIT has perfected a dye technology that could change the solar world as we know it.

The most efficient form of solar technology today is (arguably) extreme concentrated photovoltaics, essentially solar panels placed under a magnifying glass, but the problem with these systems is heat. Concentrated sunlight can melt silicon solar panels unless you include specialized cooling systems. Cooling technology costs money, and the panels require expensive tracking mechanisms to follow the sun through the day. MIT’s new solar system bypasses the heat and traching problems all together.

Thin coatings of organic dyes absorb sunlight and redirect favored wavelengths into a pane of glass. The light is aimed and concentrated towards the edge of the pane where small solar panels are located. The concentrated light allows the panels to produce the maximum possible amount of energy all day, every day without cooling systems or complext tracking mechanisms. Read the rest of this entry »