Manufacturing Solar Cells - Assembly & Packaging

By Ken Kuang, Joyce Zhang and Bill Ishii, Torrey Hills Technologies, LLC, San Diego, CA 

The trend in packaging has shown a serious shift: attendance at assembly and packaging conferences has been dwindling over the past few years whereas solar power shows have increased in popularity. More and more electronics assembly and packaging companies are appearing at solar expos. There are significant opportunities for electronics engineers in the rapidly expanding solar business.

Solar cells are derived from the 1839 discovery of the photovoltaic effect by French physicist A. E. Becquerel. However, it was not until 1883 that the first solar cell was built by Charles Fritts, who coated the semiconductor selenium with an extremely thin layer of gold to form the junctions. The device was only about 1 percent efficient. A Russian physicist named Aleksandr Stoletov then built the first solar cell based on the outer photoelectric effect (discovered by Heinrich Hertz earlier in 1887). Also, Albert Einstein explained the photoelectric effect in 1905 for which he received the Nobel Prize in Physics in 1921. Finally, Russell Ohl, who worked on the series of advances that would lead to the transistor, developed and patented the junction semiconductor solar cell in 1946. 

Modern solar cells can be described as the co-existence of three different generations: crystalline silicon, thin film, and  dye. Along with the development of solar cells, there has also been a parallel development of solar cell manufacturing technologies. Assembly and packaging engineers have played a significant role in developing these manufacturing techniques, creating incredible potentials in every generation of the solar business.


First Generation

Elemental or crystalline silicon is the principal component of most semiconductor devices, most importantly integrated circuits or microchips. Silicon's ability to remain a semiconductor at higher temperatures has made it a highly attractive raw material for solar panels. Silicon's abundance, however, does not ease the challenges of harvesting and processing it into a usable material for microchips and silicon panels. At least three standard manufacturing processes mean that there are technical opportunities for assembly and packaging engineers.

1. Phosphorus diffusion. There are two main layers that are essential to the solar cell's function. One is a p-type layer, which means that the wafers are boron doped, and an n-type layer created by introducing phosphorus. The silicon wafer usually already starts off by already being doped with boron. In order to form the n-type layer, phosphorus has to be introduced to the wafer at high temperatures of around 870°C for 15-30 minutes in order for it to penetrate the wafer. The excess n-type material is then chemically removed.

These diffusion processes are usually performed through the use of a batch tube furnace or an in-line continuous furnace. According to BTU, detailed cost of ownership models have shown that in-line diffusion can deliver per wafer costs of as low as one third the cost of a batch diffusion furnace. The basic furnace construction and process are very similar to the process steps used by packaging engineers.

2. Silicon wafer metallization.Electrical contacts are formed through squeezing a metal paste through mesh screens to create a metal grid. This metal paste (usually Ag or Al) needs to be dried so that subsequent layers can be screen-printed using the same method. As a last step, the wafer is heated in a continuous firing furnace at temperatures ranging from 780 to 900°C. This completes the metallization process, removes solvent and binder, and forms electrical contacts. Metallization is the most critical step. The challenge of reducing wafer thickness for higher efficiency has created stringent requirements for both the equipment and the process itself.

3. Solar module assembly. Solar module assembly usually involves soldering cells together to produce a 36-cell string (or longer) and laminating it between toughened glass on the top and a polymeric backing sheet on the bottom. Frames are usually applied to allow for mounting in the field, or the laminates may be separately integrated into a mounting system for a specific application such as integration into a building. The basic process is very similar to the SMT process assembly that packaging engineers are already familiar with, albeit on a larger scale. The packaging industry's lean manufacturing methodology can be applied directly to solar module assembly.

Second Generation 

Second generation solar cell, also known as thin-film solar cell (TFSC) or thin-film photovoltaic cell (TFPV), is made by depositing one or more thin layers (thin films) of photovoltaic material on a substrate. The most advanced second-generation thin film materials in use today are amorphous silicon (aSi), cadmium telluride (CdTe), and copper indium gallium selenide (CIGS). The thickness range of such a layer is wide and varies from a few nanometers to tens of micrometers. Is thin-film now the way to go? There are certainly many good reasons for moving to thin films for the solar cell manufacturing process.

1. Thin film deposition. Copper indium gallium selenide (CIGS) is used for the thin film active layers in CIGS solar cells, commonly formed using sputter deposition. During this vacuum-based process, a plasma of electrons and ions is created from inert argon gas. These ions dislodge atoms from the surface of a crystalline material which is then deposited to form an extremely thin coating on a substrate. Depositing thin film by sputtering is the same process used in semiconductor manufacture and in packaging.

2. Thin film annealing. After sputtering, the thin film needs to be annealed to achieve optimum results. It is also possible to inject additional chemicals during the annealing process. An annealing furnace is similar to the brazing furnace commonly used in packaging industries. The muffle is typically made of SUS 316L material to ensure good corrosion resistance for the thin film solar panel's corrosive environment. A typical belt furnace can anneal up to 600 x 1200mm (23.6 x 47.2-in.) thin film solar panels after thin film deposition.

3. Metallization. Like its first generation cousin, the manufacture of thin film solar cells need Al or Ag screen printing metallization, originally invented for the thick film process. Such metallization pastes or inks can be used on both rigid (glass, silicon) and flexible (polyimide, polyester, stainless steel) substrates. The metallization can be accomplished through either thermal curing or firing.

The electrochemical dye solar cell was invented in 1988 by Professor Graetzel of Lausanne Polytechnique, in Switzerland. The "Graetzel" dye cell uses dye molecules adsorbed in nanocrystalline oxide semiconductors, such as TiO_2, to collect sunlight. Dye cells employ relatively inexpensive materials such as glass, Titania powder, and carbon powder.

Graetzel's cell is composed of a porous layer of titanium dioxide nanoparticles, covered with a molecular dye that absorbs sunlight, like the chlorophyll does in green leaves. The titanium dioxide is immersed in an electrolyte solution, above which is a platinum-based catalyst. As in a conventional alkaline battery, an anode (the titanium dioxide) and a cathode (the platinum) are placed on either side of a liquid conductor (the electrolyte). Sunlight passes through the cathode and the conductor, and then withdraws electrons from the anode, at the bottom of the cell. These electrons travel through a wire from the anode to the cathode, creating an electrical current.

 
Similar to Semiconductors

The basic dye cell manufacturing steps also resemble the approaches taken by the semiconductor and packaging industry. For example, a screen printer is typically used to apply titania and other layers to the Transparent Conductive Optical (TCG or TCO) glass. Nanocrystalline TiO₂ pastes are screen printed onto the TCO glass, then dried and fired in a continuous belt furnace. The sintering process allows the titanium dioxide nanocrystals to partially "melt" together, in order to ensure electrical contact and mechanical adhesion on the glass. All these furnaces are typically modified from standard thick film furnaces.

After dye staining and anode side application of proprietary current collectors, platinum catalyst is obtained by using the Pt-Catalyst T/SP product which can either be squeegee printed or screen-printed using a polyester mesh of 90. The solar cell needs to be dried at 100°C for 10 minutes before being fired at 400°C for 30 minutes. During the assembly, sealing and filling processes, TCO glass with the completed Titania layer is mated to the cathode current collector, protective glass plate, sealed, busbar attached to the cell and then the cell is filled with electrolyte. Custom designed, fully automated and efficient cell assembly, sealing and electrolyte filling machine sets are required for these production steps.

At one time, Torrey Hills Technologies sold in-line continuous furnaces mostly for thick film and brazing applications. Several years ago, in response to the growing demands of the solar manufacturing industry, the company's engineers reinvented the original technology and adjusted it to different types of solar cell processing. A critical step in solar cell manufacturing is metallization through screen printing. By changing the specifications of thick film drying and firing furnaces, the company stepped comfortably into the solar cell market.

Solar technologies have created compelling technical challenges and business opportunities for assembly and packaging engineers. The traditional thick film, thermal treatment and assembly techniques play key roles in solar cell manufacturing. Many skill sets possessed by electronics engineers can be easily reinvented and applied to the solar cell industry. 

 Contact: Torrey Hills Technologies, LLC

6370 Lusk Blvd., Suite F111, San Diego, CA 92121 

858-558-6666 fax: 858-630-3383

 E-mail: info@torreyhillstech.com 

Web: http://www.torreyhillstech.com

Chain slippage in belt furnace

    At Torrey Hills Technologies we attempt to satisfy customer's needs to the best of our capabilities. In regards to troubleshooting problems, we recently received the following email which displays a customer's concern about chain slippage in the belt furnace

    Belt slipping can occur over a period of time when the belt is stretched (thus thinner), wear on the belt surface or wear on the rubber drive pulley. This is normal after a period of use and under most case, no new belt is required.

    The solution is rather simple, by applying more pressure on the drive rubber pulley. There is a metal roller on top of the rubber pulley used to push the belt against the rubber to creat friction. You can decrease the distance between the two pulleys in order to increase the friction. Adjust the screw on both sides of the pulley with the same number of turns and that should ensure the belt is running in the same alignment as before. Try 2-3 turns each time and observe if the belt is slipping, apply more if needed.

Create Your Own Dye Sensitized Solar Cell

     Understanding the production of a Dye Sensitized Solar Cell may seem seem far from a walk in the park for many people. Every description throws out seemingly cryptic technical names of components, such as a 'photoelectrode composed of a transparent conducting oxide', or various processes, such as utilizing a firing furnace, that will not make sense to or may not be available to anyone that is not an engineer. This may, in turn, intimidate people from learning more about this innovative invention.

     So how can one learn more about these cells in layman's terms? By creating one at home! The video below teaches people how to make a Dye Sensitized Solar Cell at home using readily available parts.

Video by Solar Blogger

      Now that you have seen how to make a cell, it will be easier to understand its components and production. So instead of looking confused the next time you hear someone use the phrase 'photoelectrode composed of a transparent conducting oxide', you will be able to smile back and know exactly what part they are referring to!

National Annual Solar Energy Report for Utilties in 2009

     The Solar Electric Power Association (SEPA) released its report on the 2009 Utility Solar Rankings across the United States. SEPA is a non profit organization that focuses on research, education and utility outreach. For the last three years, they have released an annual report with the Top Ten rankings for “Solar Megawatts” overall and “Solar Watts per Customer”, which have been quantified nationally as well as been broken down by region, utility type and meter configurations. Here is a closer look at the national rankings for utilities according to annual solar megawatts, annual solar megawatts per customer, and cumulative solar megawatts.

     According to the report, “photovoltaics made up 98% of the installed megawatts”*, even though only two new solar power projects started this year, one in California and the other in Hawaii. Of the national top ten utilities providing annual solar megawatts, five of them were located in California. The top top two utilities were Pacific Gas & Electric (CA) and Southern California Edison (CA). Third place, which was previously held by San Diego Gas & Electric, was replaced by Public Service Gas & Electric (NJ).

      The top three utilities for annual solar watts-per-customer were Sulphur Springs Valley Electric Co-op (AZ), providing 56.0 watts per customer, Maui Electric Co (HI), providing 33.8 watts per customer, and Hawaii Electric Light Co. (HI), providing 31.4 watts per customer. All three of these were customer based distributed projects, as compared to Southern California Edison which was due to centralized photovoltaic plants that were constructed. Overall, the median watts per customer increased from an average of 15 watts per customer last year to about 20 watts per customer this year.

(Third Annual 2009 Utility Solar Rankings- figure 3) 

       Surprisingly, the cumulative solar megawatts rankings for 2009 went unchanged from 2008. This keeps Southern California Edison (CA) at number one, Pacific Gas & Electric Co. (CA) at number two, and NV Energy (NV) at number three. Of the top ten cumulative solar megawatt utilities, five of them were in California.

      Of all of the solar energy that has been captured, over two thirds of it was accumulated through rooftop distributed projects. The remaining one third was through concentrating solar power projects that will become more prominent throughout the coming years. 

 *Third Annual 2009 Utility Solar Rankings. Rep. no. 01-10. Solar Electric Power Association, 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.

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. 

 

All Sector Patents By Year 2002-2009

      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. 

 

Third Generation Photovoltaics By Quarter

     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_/>.

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.

Three Common Problems With Your Furnace and How to Fix Them

Drying or firing a product in a belt furnace is often a very important step in manufacturing cells and packages. If there is a problem with the furnace, it can result in a huge set back in production as well as quality. It can create defective products and even compromise the name and credibility of the company you have worked so hard to build. Here are three common problems that one might face when using a furnace and how to quickly and easily fix them.


1. What do I do if the temperature in one zone increases very slowly or does not reach the set temperature for an extended period of time?
a. Check the temperature control in that zone to make sure if the indicator light on the controller is on or not. If the light is not on, reset the setting in the controller.
b. If the temperature controller is on, check the heating board to see if there are any open circuits. Disconnect the heating broad wiring and use a multi-meter to check if the coils are burnt out. You will easily be able to tell if your coils are burned out by using a multi-meter because it will show a infinite resistance. If the heating board is burn out, replace it. When a new heating board is installed, 1-2 days of drying is needed before the furnace can be set at higher temperatures.
c.If the heating board does not have an open circuit, check the solid state relay for that zone. Replace it with a spare or one from a working zone and see if the problem still exists.


2. What if the temperature in one of the zones climbs over 100C or goes higher than the temperature I had originally set?
a. Check the temperature controller in that zone to see if the controller indicator light is on or off. If the controller light is on, reset the setting in the controller.
b. If the controller light is off, the solid state relay is probably bad. Replace the solid state relay and test it again.


3. The products seem to have oxidized during the process. Why did this happen and how can I prevent this from happening again?
a. Oxidation is caused by high oxygen content in the muffle. This can be checked by the O2 analyzer. Double check for leaks on the nitrogen/hydrogen piping by turning on all of the gas flow meters and by using soapy water to check for bubbles.
b. Next, check for leaks in the gaskets in muffle connections. Tighten all the bolts that hold the muffles together to ensure they are not loose. Also, check the condition of the gasket itself and replace if necessary.


If these nifty tips do not seem to solve the problem, absolutely do not hesitate to call the furnace manufacturer in order to receive more model-specific instructions to fix your furnace. Good luck and merry manufacturing!

Why Settle for One?- The New HSH3003-0406 Hybrid Drying and Firing Furnace

      After years and years of sleepless nights and fruitless days, you finally hit the jackpot! You figured it out! You finally have devised the perfect way to increase dye sensitized solar cell efficiency while keeping the costs at all all time low. Now all you have to try it out.

      But how? You know exactly which differing types of furnaces you need to fulfill each step. Where? Your lab doesn't have too much extra space, but that is something you are going to have to work with. Being a small lab based research and development group, you also do not have the money to burn on costly machinery. So what are you going to do? The answer: the compact HSH3003-0406 Hybrid Drying and Firing Furnace.
 

HSH3003-0406 Hybrid Drying and Firing Furnace Design

     This new hybrid furnace was design especially for the firing and drying of nano-sized titanium oxide particles in DSSC to fit the needs of smaller scale research and development. It can operate in temperatures varying from room temperature up to 650°C from which it acts as a dryer below 200°C and functions as a firing furnace at higher temperatures. It also comes equipped with an industrial computer system in order to switch between drying and firing modes. Its compact size optimizes its minimal space requirements as well increases cost efficiency in order to please any budget. In addition, its unique technology has customizable options in order to fit precise needs.

      This hybrid, produced exclusively by Torrey Hills Technologies, has been manufactured in the hopes that innovative researchers are not limited by potentially restricted resources, whether it be space or money. Various universities and research companies worldwide have already taken advantage of what this furnace can offer.

     Torrey Hills technology strongly supports research in DSSC applications in order to promote a greener way of life encompassing more efficient, as well as affordable, eco-friendly practices.

Patent 12/161,289 Review- Dye Sensitized Solar Cell and Dye Sensitized Solar Cell Module

      On January 21, 2010, a new patent was approved in the United States for a new type of dye sensitized solar cell and module that aims at improving performance, enhance short circuit current and reduce costs. This patent was filed by Ryohsuke Yamanaka, Nobuhiro Fuke and Atsushi Fukui on December 12, 2006.  

      Prior to filing for their patent, Yamanaka, Fuke and Fukui looked into the reasons why Dye Sensitized Solar Cells were inefficient. They were able to conclude that all of of the current solar cells consumed a lot of energy during their drawn out processes while not giving enough output, and were not able to be created on a larger scale. They also noticed that their heavy weight restricted its usage. Their new patent focuses on fixing all of these problems.

      Yamanaka et. al were able to pinpoint where the flaws in the current DSSC's were. In dealing with large scale replication, a solar cell that is created with a surface area as large as 1 m would highly reduce in efficiency due to an increase in solar resistance. This, in turn, reduces the fill factor and the short circuit current conversion. In order to counter this, the new patent proposes to have multiple DSSC's that can be connected into a series. Secondly, DSSC's were believed to be made in a very costly manner by utilizing a large amount of varying and expensive components, thereby having an intricate process in which to manufacture the cells. Yamanaka et. al were able to fix this problem by using by using less materials, such as thinner photoelectric conversion layers, as well as better manufacturing processes, such as firing furnaces, and therefore, use less energy to combine these materials.

      In doing this, the combined efforts of Yamanaka, Fuke and Fukui were able to create a new patent for a more cost effective and efficient dye sensitized solar cell. Although no official statistics have been claimed yet, we look forward to seeing how much of an improvement these changes can actually create.

The Green Machine- HengLi Creates a More Environmentally Friendly Furnace

      As the cost for crude oil and energy consumption increases, many companies are looking for ways to cut down on their costs. One way to do so is to focus on taking their highest energy intensive equipment, such as furnaces, and making them more environmentally, as well as wallet, friendly. In order to tackle this challenge, HengLi devised a simple math problem to not only to reduce energy consumption, but reduce the amount of materials used as well.

HengLi's Green Furnace- HSK 3505-0711 

      In order to evaluate a problem as large as high energy consumption, one must step back and take a more holistic view of the problem. One must consider not only how much energy is being used but why that much is being used. For that reason, the idea reducing energy consumption in furnaces gets broken down into two separate categories- dealing with materials and processes, or changing the equipment itself. 

      The material used and processes to create them highly depend on the end product's desired qualities and well as quantity. The process used within a furnace itself varies. Two of the most common processes include low firing temperature techniques and a fast fire method, each with their own benefits. The low firing technique is able to use less heat, and therefore less energy and resources in order to create a product. The fast fire furnaces ad able to decrease the time materials spend in the furnace and are able to conserve energy in that manner. The materials themselves can be altered in order to decrease furnace time. For example, using a glass powder and clay mix can reduce energy consumption by up to 40%!

      The manufacturers of HengLi furnaces have also looked into ways of improving energy efficiency within the furnace. Improvements in their furnaces are based off of the Simplified Model of Furnace Heat Loss that they developed which consists of the following variables:
          P: energy consumption of the furnace
          T: relative temperature of the heating elements to the surrounding environment
          T₁: relative surface temperature of the furnace body to the surrounding                        environment 
          R₁: insulation layer’s thermal resistant
          R₂: thermal resistance between furnace body and the surrounding environment
          C: system thermal capacity, which includes all the insulation and construction           material
          I₁: heat loss due to the load and its fixture or carrier
          I₂: other heat losses besides I1, like those from insulation layers, door and T.C           holes etc. 

      Through manipulating these variables in a series of simple mathematical equations, HengLi was able to develop a series of principles for energy saving. One of the many equations is:

P=T(T/(R₁+ R₂)+ I₁+I₂) + f(C,t)= (T-T₁)2/R₁+T₁²/ R₂+T(I₁+I₂)+f(C,t)

where f(C,t) is the rate of energy absorption of the furnace system and is set to approach zero over time. This also relays the information that R2 is directly proportional to the furnace's surface area and inversely proportional to the air's thermal conductivity. Another equation that was derived using these variables is one determining the difference between the energy consumptions of various furnaces, as follows:

P_s-P_c=(T-T₁)²/R₁+T₁ ²(R_2s+T(I₁+I₂)+f(Cs, t)-(T-T₁)²/R₁+T₁ ²(R_2s+T(I₁+I₂)+f(C_c, t)

=T₁²(1/R_2s-1/R_2c)+f(C_s,t)-f(C_c, t)

where the subscript s refers to the green furnace while the subscript c refers to a conventional furnace. After plugging in value for various models, the total equals a value below zero, inferring that the energy consumption of the green furnaces are lower than those of e furnace that are not.

      These resulted in a few main goals- to reduce the the total surface area (by increasing insulation) and to reduce the heat capacity of the furnace as well as the energy needed for each furnace to reach working temperature. After applying these principles, on-site testing proved that the new furnaces could save up to 20% energy for continuous furnaces and up to 40% for batch furnaces. 

 Sectional view of the mouth of the improved furnaces

      In addition to these main factors, one must also pay close attention to the specific furnace they are working with. For example, in larger furnaces, one must also look at variables such as heat lost from between insulation layers, the furnace door and the T.C. hole and therefore efficiency can be increased based on specific sizes and models. 

     Contact your nearest HengLi representative for more specific details on how to obtain or update your furnace to a more environmentally friendly furnace. 

Kyocera's Kazuo Inamori Takes Over Japan Airlines

     Last month, the highly esteemed entrepreneur Kazuo Inamori was asked by the Japanese government to take over the position of Chief Executive of Japan Airlines and save it from potential bankruptcy as well as threatening buy outs from other companies. The Japanese government bestowed this exciting opportunity upon him in hopes to revive the company and essentially stimulate the economy of the country.

     Kazuo Inamori is one of the most well known businessmen in the industry. He has already built many successful companies up from the ground, including the well known Kyocera Corporation and KDDI Corporation that serve in a variety of industries and employ over 66,000 people.

 

 

Kazuo Inamori of Kyocera (left) and Ken Kuang (right) CEO of Torrey 

Hills Technologies at Kyocera's 40th anniversary celebration

     Inamori was born on Januray 30, 1932 in Kagoshima, Japan. By 1955, he had graduated from Kagoshima University with a Bachelors of Science degree in applied chemistry. By the age of 27, he had already set up Kyoto Ceramics Co., Ltd, the company that later became known as Kyocera. 
     In addition be being a successful business man, Inamori is also well known for his generous philanthropic efforts. In 1984, he set up the non-profit Inamori Foundation that offers the Kyoto Prize, a distinguished prize that honors significant contributors in the fields of Basic Science, Advanced Technology, and Arts and Philosophy.

     By the time he retired from Kyocera in 1997, Inamori was ordained as a Zen Buddhist priest in the Rinzaishu sect of the Myoshinji lineage. He was given the title of “Daiwa” meaning “great harmony”.

     Although he is 77 years old and retired, he is still very active and holds many posts outside of his company as well as running Seiwajyuku, a prestigious private management school. Overall, we wish Kazuo Inamori good luck on this magnanimous endeavor he has undertaken and hope for his continued success in all of his ventures.

Hyundai Goes Green With Their New Hybrid Blue-Will

    Hyundai debuted their latest creation, Blue-Will, at the Detroit Auto Show earlier this week. This new hybrid sports a sleek body with unbelievable performance capabilities. It is stocked with features such as roof mounted Dye Sensitized Solar Cells, drive-by-wire steering and LED displays with touch screen control. It is also has the ability to be powered by either a Lithium Ion Polymer battery pack or a  four cylinder, 1.6 liter engine.
    In addition to its fuel saving techniques, it is also green friendly in the materials it uses. The cars makers used recycled PET soft drink bottles to make the headlamp bezels and bio-plastics for the interior and engine cover.
    Hyundai still has to decide on a few different options for Blue-Will. One interesting option that remains open is whether the car will be a plug-in hybrid or a regular hybrid. The plug in version is believed to be able to go as far as 40 miles on a single charge without using any gas. The down side is that this option would be more expensive than the regular hybrid.
    This new creation brings us one step closer to creating a transportation system that is fuel free by utilizing the beauty of DSSC's and solar energy.


(Information provided by iAfrica.com, Jalopnik, and USAToday)

DSSC Technology Has Reached New Depths- Within the Body

    A new type of technology that is being developed today revolves around creating various biological nanodevices that can be used for attaining a diagnosis and for varying therapeutic interventions. One huge problem that occurs when designing these types of biotechnologies is that they need to be wireless to ensure unrestricted access to parts of the body. In order to accomplish this, there needs to be a continual source of electrical energy that can be utilized in unusual environments such as the human body.
    Previous efforts to accomplish this includes the development of a direct current nano generator that uses ultrasonic waves. This breakthrough was made by Dr. Zhong Lin Wang, who is a COE distinguished professor and director of the Center for Nanostructure Characterization at Georgia Tech. Dr. Wang's research resulted in the creating of a nanogenerator that was able to take hydraulic energy from within the human body, such as a heart beat or blood flow, and convert it into electrical energy. Although this was an amazing find, improvements needed to be made in order to make it more practical for real life applications.
    Recent developments from researchers from the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials at Donghua University located in in Shanghai, China and the Max Planck Institute for Colloids and Interfaces in Potsdam, Germany include building a 980 nm laser driven Dye Sensitized Solar Cell that can function even when it is covered by a thick layer of biological tissue. This is possible because these tissues have a high transparency to this specific frequency of light. This  photovoltaic cell is created by utilizing rare nanophosphors that absorb light and then send out a glow that, in turn, excites solar cells to make electricity. It is capable of providing a maximum output of  0.28 to 0.02 mW of energy, even after being covered with 1 to 6 layers of pig intestine that averaged about 1 mm thick each. This amount of energy is enough to power a large variety of biotechnology.
    This development is in its primary stages of research and scientists are still looking for ways to improve. Some of these desired improvements include making all of the components more biologically compatible, improving conversion efficiency, and making the cell even smaller in order to increase it application.


(Information was Provided by Nanowerk-Nanoscale Power Plants and Nanowerk- Photovoltaic Cells to Power Biological Nanorobots Inside the Body)

What is a Dye Sensitized Solar Cell (DSSC)?

    The Dye Sensitized Solar Cells, also known as Grätzel cells,  are a type of third generation solar cell that is low in cost, easy to manufacture and simpler to adjust in order to suit a large variety of applications. This was accomplished by using lower costing materials than the previous silicon based product as well as a simpler production process. Recent studies have shown that the Dye Sensitized Solar Cells can  produce up to 11% efficiency and continued researched shows a possibility for it to become even more  effective.  


 What is a DSSC? 


    Essentially, DSSC's are based on a wide bandgap semiconductor such as TiO2, that has been made highly receptive to light through the use of a layer of dye. The cell consists of four main parts including a photoelectrode composed of a transparent conducting oxide with a layer of TiO2 film,  a counter electrode encompassing another transparent conducting oxide with a platinum catalyst deposited on it, a layer of dye that can be excited by light, and an electrolyte to fill in the voids of the inner cell.

How are they made?
    The first step to manufacture a DSSC on glass it to prepare the photoelectrode. This is accomplished by taking a glass substrate coated with a transparent conducting oxide, such as SnO2:F, and depositing a layer of  TiO2 through the process of screen printing using a firing furnace at about 500° C. This process will remove excess organic residue and create electrical contact. The photoelectrode is then submerged in a light sensitive dye. Simultaneously, a counterelectrode is prepared where another glass substrate coated in a transparent conducting oxide gets infused with a platinum catalyst.   Next, the dyed photoelectrode is sealed to the counterelectrode using a thermoplastic thin film that is placed in between. These three components are then heated at about 150° C and placed under pressure. Once sealed, the voids in the device are filled with an electrolyte through holes in the counterelectrode. To ensure longevity, the cell's holes are filled and the whole cell is covered with glass.


(Information Provided by The Energy Research Centre of the Netherlands, Wikipeida and Dyesol)

Autonomy from the Outlet- Living a Chord-Free Life

     After years and years of being imprisoned indoors to charge all of the electronics we really so heavily on, break free from the confines of the chords and the order of the outlet! A light shines on an opportunity to get out and to not be constrained by limited battery life- a solar light. Recently, a new line of backpacks and bags have been released that have Dye Sensitized Solar Cells, or DSSC's,  built right into them that can be used to charge electronics. These cells are not only cheap to make but are also flexible and can be utilized in a wide variety of products including clothing, tents, awnings and even windows in the future.
     This product has shown over a 12% efficiency rate and can store up to 0.5W of power. What is even more appealing about the DSSC 's in this product is that they can also absorb other forms of artificial light in order to charge itself.
     As of right now, further studies are being done to increase the efficiency of these cells by attempting to incorporate nonvolatile electrolytes and organic dyes. These alterations could further reduce costs and increase efficiency.
     Even though this is a huge breakthrough, since product like these have not been made available before, many people are skeptical of the actual efficiency and effectiveness that these products will be able to provide for the general public.
     The first shipment of these bags has already been sent to Hong Kong. It is expected that these bags will be available for commercial sale by December 2009.
     With these new innovations in mind, we can strive to live in a world where there will be no carbon foot print and runs purely off renewable solar energy. Now it is easy to see what a huge impact these developments can make in our lives. It is safe to say that these Dye Sensitized Solar Cells are here to stay!

(Information provided by Gizmag)

Helpful Housing- Fixing Global Warming, One House at a Time

     Everyone has heard of the huge and clunky solar cell that can rest on top of houses to create energy but a new and more stylish technology is making its way out into the housing market. SRS Energy has created a product called the Solé Power Tile in which each clay shingle can act like a powerhouse for energy. Each single has the ability to continually create energy that can be stored for the building to use at its convenience.
     Due to SRS Energy's creativity and innovation, it was awarded the “Best of What's New” award in the Home Technology category in 2009 from Popular Science Magazine for its Solé Power Tile because they not only created a roofing product that can harvest energy, but also incorporated a stylish design that can be blended into any Mission-Style roofing system without lowering the building's aesthetic value.
     Clay solar tile technology is categorized under Building Integrated Photovoltaic (BIPV) which are usually based off of either Thick Film cells (silicon based wafers) or Thin Film cells ( such as DSSC's). BIPV systems have been integrated into different aspects of the architecture of the buildings themselves in order to create a more environmentally friendly property. Photovoltaic technology has been incorporated into different parts of buildings such as walls, awnings, windows, roofs and more.
     Each BIPV system comes equipped with a photovoltaic module, a charge controller to regulate power, an energy storage system, power conversion equipment, backup power supplies and all of its respecting mounting and wiring hardware.
     It is hoped that in the long run, different forms of BIPV such as the Solé Power Tiles will be used increasingly amongst all house holds and will significantly decrease, if not eliminate the use of other more harmful methods of obtaining energy.
     Now just because a house can create its own energy, it does not mean that we should be stuck inside it. Coming soon is a look at how we can live a better life outdoors.


(Information provided by CleanTechnica)

Return of the Rainbow- Who Said Solar Cells Had to Look Boring?

     The Korean Institute of Technology has introduced a new method that allows a solar cell to absorb more light, making it more efficient than its previous amount of 11%. This development was lead by researcher Park Nam-Gyu who claims that this new discovery will improve power consumption by at least 50% making it more efficient and even more cost effective than it was before.
     Typically, a dye sensitized solar cell (DSSC) is a semiconductor that has been created from a photosensitized anode and an electrolyte. The cell is made of porous TiO2 particles that are covered with a specific dye that interacts with its respective electrolyte.
     Nam-Gyu's team was able to improve this design by finding a way to have the TiO2 particles take in different colors of dyes that allow the cell to absorb a wider spectrum of light, which will, in turn, increase efficiency.
     This was achieved by copying a scientific method of chromatography that involves separating chemical compound from mixtures. This process works in two phases, including the stationary phase and the mobile phase. In order to form the different layers, the team was able to control the release and settling of the dyes. As a result they were able to vertically align yellow, red and green dyes within the TiO2 film. This alignment was validated by an electron probe micro-analyzer.
     It is expected that when the DSSC reaches a higher efficiency, they will become commercialized. This will cause a huge shift in the solar market from silicon based thick film solar cells into lighter dye sensitized solar cells that are expected to reach equivalent efficiencies at a significantly lower cost of production.
     Next up is a more homely approach to solar cell usage.


(Information provided by  PV-Tech)