Nov 24, 2013 ELV Systems
Happy Memorial Day, from all of us here at Home Controls.
As a notice, our San Diego store will be closed on Memorial Day.
HomeControls.com will still be open for orders.
All web orders will be processed Tuesday morning.
As always, thank you for your business.
The original post is created by: Home Controls
Jason Karp an electrical engineering Ph.D. student at the University of California, San Diego and his colleagues at the UC San Diego Jacobs School of Engineering are developing an inexpensive optical concentrator and assembly to offset the high cost of very efficient solar cells. The development should lead to solar concentrators that are less expensive and require fewer photovoltaic cells than existing solar concentrators or photovoltaic solar cell panels.
The design is an optical innovation. After the surface lenses focuses the light with a two-dimensional lens array a secondary optic, multimode slab waveguide is used as a secondary to collect and homogenize the sunlight.
Reflective facets fabricated on the backside of the waveguide act as fold mirrors to couple sunlight into the waveguide at angles, which exceed the critical angle for total internal reflection. These facets occupy a small fraction of the total waveguide surface and enable high geometric concentrations despite decoupling loss if light strikes a subsequent coupling region.
This geometry yields a thin, flat profile for moderate concentration systems that may be fabricated by low-cost roll manufacturing. The analyses of tradeoffs show optimized designs can achieve 90% and 82% optical efficiency at 73x and 300x concentration, respectively.
Karp and his group may be in the money – for concentrator photovoltaic (CPV) to be cost-effective, the complete cost of the optics, assembly and mechanical tracking must not exceed the cost savings gained from using small area PV cells. The team gets it; the place to shave expense is in the collection of the light, saving a big share with reduced photovoltaic cell counts.
Sunlight collected by each aperture of the arrayed primary collector is coupled into a common slab waveguide using localized injection features such as prisms, gratings or scattering surfaces. Rays that exceed the critical angle defined by Snell’s Law propagate via total internal reflection (TIR) within the waveguide to the exit aperture, typically at the edge of the slab. TIR is a complete reflection with negligible spectral or polarization-dependent losses, which enables long propagation lifetimes. The waveguide transports sunlight collected over the entire input aperture to a single PV cell placed at the waveguide edge. PV alignment becomes trivial since comparatively large cells are cemented to the waveguide edge(s). Fewer PV cells reduce connection complexity and allow one heat sink to manage the entire system output.
As illustrated, the innovation is going beyond a lens that concentrate an area to a PV, Karp’s waveguide collects several lenses to one or more PVs. This has to dramatically cut costs and allow budgeting for extremely efficient PVs.
The goal was to design a concentrator optic, which could be fabricated at an extremely low cost per unit area. Constraining the design to be compatible with a continuous roll process-manufacturing platform, as opposed to injection molded and assembled elements, maximizes the cost advantage of CPV. Roll processing can perform a range of functions on rigid or flexible substrates such as embossing of refractive or diffractive structures, dielectric and metallic deposition and the joining of multiple processed layers.
The team’s paper, in the January 2010 issue of the journal Optics Express, available in a pdf download, covers in detail concentrator geometry, coupling the waveguide, optimizing the system, and the building of a prototype. The paper also discusses the method Karp and his team use to self align the concentrator during fabrication. At 12 pages and lucid for the non-optic expert, it’s a worthwhile read.
The team took their prototype outdoors for testing to find the prototype system reached 90% of its maximum optical efficiency with ± 1° angular acceptance. The optical efficiency of the prototype system was significantly lower than the optimized simulations using custom optical elements. Despite its relative inefficiency the experimental measurements were in close agreement with the optical model and support the notion that optimized designs would also perform with high efficiency. The team is currently pursuing variations of the basic structure to increase both concentration and optical efficiency.
The team has demonstrated self-aligned fabrication using off-the-shelf components to create a 37.5x prototype concentrator with 32.4% optical efficiency. Systems with greater than 80% efficiency are expected when using a custom lens array with a 100% fill factor and minimal aberrations. A CPV with multimode waveguides opens a new design space for large-scale concentrator optics with the added benefits of flux uniformity and fewer PV cells in a thin, planar geometry.
OK. That’s all real technical. But it works, the lens array and the waveguide beneath can be roll to roll process manufactured. Mount some photovoltaic cells along the selected edge and you have a low cost high efficiency solar panel. One has to like this, especially if the savings can justify the cost of a solar tracking system to keep the panel squarely facing the sun.
Something has to be done about solar panel costs – it looks like Karp and his team have a very good shot at helping build a much larger market.
The original post is created by: New Energy and Fuel
Sep 29, 2013 HVAC
A vocational course in heating, ventilation, and air conditioning technology (HVAC) can be a great career option for you if you are mechanically or electrically inclined. This course will teach you how to plan, design, and operate building ventilation, heating and air conditioning system. In San Diego HVAC College, students can learn their trade in a comprehensive and truly outstanding manner.
A San Diego air conditioning college enables students to choose from several certificate programs and degree programs to find what best fits their needs. Certificate programs take a shorter time to complete, while associate’s degree programs take longer. This is because completing an associate’s degree program teaches students more which generally qualifies them for more positions. Additionally, associate’s degree programs qualify graduates to take the test for EPA certification. Since EPA certification is necessary to work with many refrigerants, this is very important.
Why join HVAC College?
A HVAC course will help you along the path towards bagging a secure career, where you will be able to provide comfortable and healthy conditions for residential and commercials buildings. These courses from San Diego air conditioning colleges will not only benefit HVAC technicians, but also design engineers, plant managers, architects and so on.
The great thing about a career in this field is that the demand for HVAC technicians is expected to keep increasing in future. In fact, by 2014, some think the demand could grow by 18% to 26%. This is because the increases in population mean that there will be more and more demand for office space and building of all types. This in turn entails that people would require the latest climate control technology, within the short span of time. Thus, many expect that there will be no shortage of work for HVAC technicians in years to come.
What will the coursework include?
Those who study in a San Diego AC school will learn to service and troubleshoot HVAC and refrigeration systems. Not only this, but they will also learn about air distribution, psychometrics, thermal comfort and other facets of the HVAC industry as well. Some of the other detailed coursework that may be available includes HVAC piping systems / ductwork, energy management, and HVAC control systems.
How much will it pay?
As with any vocational course, you would like to know what a HVAC technician job pays. The US Department of Labor Bureau of Labor Statistics reports that the hourly salary for an HVAC technician is $17.43. However, for a skilled and experienced technician, the pay will be much higher – over $27.11 per hour. Obviously wages will vary from location to location, but with the right training and experience you can hope for these wages. So if you are interested in building a carrier in this field, make sure you check out the courses offered in a San Diego HVAC College. It can be what gets you on a path towards a better life.
Sep 14, 2012 Sponge
Save $100 on the RIS Marketing & Sales Class and the RIS Design and Hands-on Technical Class if you register by July 8! That’s a $200 savings when you enroll in both classes!
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Here is the original: Home Controls