Monday, April 26, 2010

What Factors Should I Consider When Installing Solar Cells to a Building?

      With all the new craze about turning more environmentally conscious, many people are looking into alternate energy devices in order to replace their current electricity grid. Installing solar cells can be an expensive undertaking so it is important to evaluate all information carefully to know what to quantitatively expect from your system. In order to determine if installing photovoltaic devices will be beneficial for you, there are three main factors that one should look into. These three factors include insolation, local electricity prices and incentive programs.
      Insolation refers to the amount of sunlight that any given area receives. This factor directly affects your decision because the less sunlight in your area gets, the less electricity will be produced. The map of the country below(1) gives a general idea of how much insolation is present in various regions. The higher the numbers are, the more insolation is available. More specific figures for isolation in various cities can be found at www.solarseller.com/solar_insolation_maps_and_chart_.htm
 
      The second factor to consider is the cost of grid electricity in your area. This will help determine the payback time of investing in a photovoltaic system. An investor would have been considered to break even when the initial set up costs for the solar grid equal the amount of money that would have been spent on purchasing electricity on the older system. As shown below, the cost of electricity varies by state. The map shows the cost for electricity in cents per kWh in all fifty states.

(http://www.think-energy.net/EIA%20Map_Average%20electricity%20cost%20by%20state_2007.jpg)
     The third concept to look into is incentives, including federal tax credit as well as local incentives. The Federal Government can give up to 30% tax credit for anyone that buys an alternative energy device. For example, the Local Rebate Program for installing photovoltaic systems in San Francisco, CA will give about $1000-$2,500 incentive for a residential installation. For a comprehensive list of all the incentives, check out http://www.dsireusa.org/
      After taking insolation, cost of grid electricity and incentives into consideration, you will have a clearer idea of what to quantitatively expect when installing solar cells onto your roof. Although installing an alternative energy system will ultimately benefit the environment, installing the current system may not end up being a beneficial investment to the consumer for monetary purposes. In this case, it is up to the consumer's discretion to decide if they feel that a photovoltaic system is still a necessary investment.

Other Sources:
1.)Howard, George S. ""Where Are We Now?"" The Greening of Business: Solar as a Bridge to Our Hydrogen-electricity Future. Notre Dame, Ind.: Academic Publications, 2009. 31-34. Print.

Thursday, April 8, 2010

What is the status DSCC in terms of technology and commercialization capability?

     One of the best ways to gauge the growth of Dye Sensitized Solar Cells, or DSSC's, in terms of technology would be to use the quarterly Clean Energy Patent Growth Index (CEPGI), published by Heslin Rothenberg Farley & Mesiti P.C., that tracks the number of patents that were earned for different clean energy technologies such as fuel cells, solar cells, hydroelectric and biofuels. These reports show the activity of each sector per quarter since 2002.
      According to the CEPGI report released on March 10,2010, the number of solar energy patents in general has increased by 60% from the year before to reach numbers near its value for 2003, as shown below1. Although there are a lot fewer solar patents in comparison to fuel cells, technologies are expected to highly increase and surpass the decreasing wind technology. Further analysis also shows that the United States plays a large role in these advancements by producing nearly half of these patents while Japan trails behind by making almost one third2
 
      When comparing the different generations of photovoltaics in specific, the first generation technology has showed the highest levels of efficiency resulting in a large flux of scientists entering the field but decrease in the number of patents may indicate dwindling of the technology itself3. Second generation technology has been reported to “[have] shown a fairly consistent decline through almost the entire period of [the] tracking”4. Third generation technology in general has been stably increasing in patents. 
 
     DSSC's are included in this promising 3rd generation of PV technologies. many important technical progresses have been made already. The current DSSC technology can provide unique features the regular SI cells cannot offer. However, the progresses are made in a gradual manner, among which it is hard to predict how fast or smooth this transition may be. For example, it took over twenty years for someone to solve the problems of how to improve various characteristics of the electrode and the cathode, but now that they have been found, there will surely be a huge increase in its application. 
     In my point of view, in 10-15 years, DSSC's will hopefully become a standard component of a residential hose. Or, it may still remain as a hobby of some scientists. many factors will play into the commercialization of this technique, similar to what happened to silicon cells. Some of these factors include politics, economy, strategy and technique. For example, some expensive technologies became commercialized, while other less expensive ones failed. For the latest progress in technique, you can refer to websites for larger scale companies such as Dye-Sol or 3G Solar.
  References:
1. "002a All Sectors by Year - 2009." Clean Energy Patent Growth Index. Web. 05 Apr. 2010. .
2. "204 World Solar 2009." Clean Energy Patent Growth Index. Web. 05 Apr. 2010 <http://cepgi.typepad.com/ .a/6a00e5502e87bf88330120a91b4c85970b-popup>.
3. "Solar008 1st Gen."  Clean Energy Patent Growth Index. Web. 05 Apr. 2010 <http://cepgi.typepad.com/ .a/6a00e5502e87bf8833012876b54fac970c-popup>.
4.  Clean Energy Patent Growth Index. Web. 05 Apr. 2010 <http://cepgi.typepad.com/heslin_rothenberg_farley_/>.

Thursday, April 1, 2010

What Is Excessive Belt Stretching and How Can I Prevent It?

Excessive belt stretching is a rather common problem among furnace users around the world . When a brand new belt is heated repeatedly inside the furnace, the intensive heat combined with the pulling force stretches the belt over time. Although it is normal for a belt to stretch over time, excessive belt stretch can create several problems.

After the belt stretches, the extra belt length under the furnace may get caught by other mechanical parts under the furnace. The extra length may also touch the floor and pick up dirt, oil or water on the ground. The belt length should be checked during regular maintenance so that the excess length can be removed if necessary. In some cases, the belt stretches so much that the width of the belt decreases. That means the usable surface on the belt is decreased and ultimately reduces the rate of production.

When a furnace belt stretches, the only solution is to replace the belt and it is a rather costly repair so here are a few tips to avoid excessive belt stretching:
1. Get the right material. Different processes with varying temperature ranges require specific materials. Consult with the engineers and let them know your process and operating temperature range so they can get the material that is right for you.
2. Know how much your product weighs and how many will you will be putting in the furnace at one time. Calculate how much weight is being loaded onto the furnace before you order a belt. Get a heavier gauge wire if the products are heavy. However, a thicker wire also mean more heat is absorbed during heating and released during cooling, and therefore, results in a lower efficiency.
3. Make sure the friction pulleys are parallel to each other and the belt is not slipping on the pulley. A belt that is not tracking correctly will deform unevenly and it will shorten the life span of the belt. A belt that is slipping on the friction pulley will creating groves on the plastic friction pulley over time and eventually creates pressure points on the belt. This problem also occurs if the cross wire going across the width of the belt is also deformed.
4. Do not stop the belt during cooling down of the furnace. If the belt is stopped during the cooling down process, one section of the belt ends up being heated for an extended period of time. This also shortens the life span of the belt. During the shut down process, keep the belt running until the temperature drops down to 300-400°C. After the furnace cools to 300-400°C, you can shut down the belt and the furnace together.