Hello Cathy, -----Original Message----- From: Cathy Colwell [mailto:colwell@mindspring.com] Sent: Friday, February 23, 2001 7:53 AM To: Lienesch, Gary W. (BP Solar) Subject: PV awnings - Mainland High School Project - update 1 Gary, I wrote to Richard. You received a cc. The kids are so excited to have a product! I am lost in size requirements. I know that Richard needed specific sizes but I don't know them. Are there standard window widths - 4 foot? How much vertical space would these awnings require when there are in the "winter" position? Are these details we need to find out - or can we just base our cost estimates on the "best sizes" for your modules? [Gary Lienesch] Any MSX-120 laminate is 38.6x43.2x1.9 inches. Any MST-43 laminate is 1219x657x50 mm. Richard knows standard window widths better than I would. As far as winter vertical space, that requires a bit of geometry - left as an exercise for the students! Play around with the laminate layout to make them protruding to the amount you desire. You alternately could have the lower support members straddling the windows if necessary. For me to size a system, you'd also have to tell me how many laminates are used in the demo site. If the laminates are 24V then you'll have 20 laminates in a string to get 480 VDC. Consequently your laminate count would be a multiple of 20. I can use system sizing software to tell you what your power out will be. It produces many nice charts and graphs. I'll need to know where the building is (city, country), the tilt angle(s) during each month and how the building (i.e. PV array(s)) is situated. Our latitude is 30º for Daytona Beach, Central Florida. [Gary Lienesch] Your tilt angles from the horizontal will be 15 deg during the summer and 45 deg during the winter. The target tilt angle relative to the horizontal for twice-a-year adjustments (on or about the equinox - March 21 and Sept 21) is latitude +15 degrees and latitude -15 degrees. I can provide the calculations that give this result. The larger angle is to target a winter sun lower on the horizon in the northern hemisphere. The standard product you would use would be either a 120W poly crystalline laminate or a 43W Millennia laminate. I can get dimensions. What would this cost? [Gary Lienesch] Figure $4.50 - $5.50/Watt PV modules only (BIPV, standard product, large quantities), Use ~10W/sq-ft for Polycrystalline modules. Get an estimate for the framing. Email Trace and ask them on the retail price of a PV-?? and an isolation transformer if required. Add 15-20% for installation labor. Just figure you'll have a monopolar PV array and assume you'll need an isolation transformer. I hope that I can continue to reach you through the weekend and early next week. I'll send you the page address for the product this afternoon. [Gary Lienesch] My home email address is lienesch@carr.org and we're always connected. Bless you! Cathy _______________________________________________________ ----- Original Message ----- From: "Lienesch, Gary W. (BP Solar)" To: Sent: Thursday, February 22, 2001 1:07 PM Subject: RE: RE: PV awnings - Mainland High School Project Kawneer makes BIPV framing systems for our modules. Contact Richard Braunstein mailto:richard_braunstein@kawneer.com (Richard is in engineering) to look over your drawings. You can tell him that I sent you. Just figure you'll have a monopolar PV array and assume you'll need an isolation transformer. You won't need to contact Trace. I hope this helps. -Gary- _______________________________________________________ -----Original Message----- From: colwell@mindspring.com [mailto:colwell@mindspring.com] Sent: Thursday, February 22, 2001 11:52 AM To: lienesgw@bpsolar.com Cc: colwell@mindspring.com Subject: Re: RE: PV awnings - Mainland High School Project Gary - I like your options but I am worried about time. We have to submit our site for judging at 5 PM, next Wed, February 28th. Is there time for all of these people to get involved? I'll write back again this afternoon and evening? Cathy _______________________________________________________ Good morning, Cathy! -----Original Message----- From: colwell@mindspring.com [mailto:colwell@mindspring.com] Sent: Wednesday, February 21, 2001 6:38 PM To: lienesgw@bpsolar.com Cc: colwell@mindspring.com Subject: PV awnings - Mainland High School Project Gary, We would like to pursue option #3. At today's meeting, the group unanimously voted to use this suggestion for our product. We are changing our technical application from Efficient Building Technology: Energy Windows to Efficient Building Technology: Building Integrated Photovoltaics. Very good. As a first step I would like your permission for one of my students to recreate your sketch in Illustrator. The next thing that we need is a reasonable estimate of its construction cost and power output. You have my permission. You are now the owner of the drawing/sketch. Let me think of how to estimate the construction cost. I may refer you to a sales person who works for a company that makes BIPV framing systems with our products. He could give the best estimate. (Maybe you can sell them the rights to manufacture your design!) I can use system sizing software to tell you what your power out will be. It produces many nice charts and graphs. I'll need to know where the building is (city, country), the tilt angle(s) during each month and how the building (i.e. PV array(s)) is situated. We would like the awning to be self-contained. The cost would need to include the mechanism to change the awning's position, the PV material required to cover its top surface, and the electronics to incorporate the electricity produced into the power grid for the building. We do not think that every window needs an inverter, but we do not know many would be necessary or how to link the awning outputs together. The target tilt angle relative to the horizontal for twice-a-year adjustments (on or about the equinox - March 21 and Sept 21) is latitude +15 degrees and latitude -15 degrees. I can provide the calculations that give this result. The larger angle is to target a winter sun lower on the horizon in the northern hemisphere. The standard product you would use would be either a 120W poly crystalline laminate or a 43W Millennia laminate. I can get dimensions. You need to design a framing system. Each module will be 24VDC and you will be stringing them together in series to get about 480VDC. Then you can connect these strings in parallel to get the required power. Go to www.tracetechnologies.com to shop for an inverter. They make some from 5 to 20 kW (PV-5 to PV-20) You'll put 480 VDC in and get 208VAC, three-phase out. You might need an isolation transformer for the output of the inverter to comply with NEC code (no DC current should be injected into the grid) if your array is configured as monopolar. If it is configured as a bi-polar array, you may not need it. Check with Trace. And that's it. It'll be a simple system that will pump its power into the building when there is sun. When the grid power is interrupted, there will be no backup capability. That's OK, you won't need to maintain batteries. Plus you get the benefit of solar thermal heating during the winter and less cooling costs during the summer for energy cost savings. Are there certain sizes of awnings for which your Millennia modules would be better suited? That is, could the cost of an awning be reduced by using a more standard size? The size of the laminate will dictate the dimensions you have to work with. You might be able to place them two deep from the wall, for example. Just use enough frame to support the laminate in high winds (Another potential feature is that in Florida, the system can be retracted during a hurricane. Or it could be lowered to cover the windows and secured to the lower sill.) Would glazings on the windows still be useful if the windows no longer have direct sunlight striking them? I don't think so. That would depend on whether Winter direct sun needs anything filtered out. You want the heat. Regular glass filters out UV. That would be an independent issue or option for the architect. We do not literally have to build the device, we only need to get your endorsement as to its feasibility. I can ensure it's electrical feasibility. Maybe you can get an opinion from the BIPV framing sales rep I can recommend to get his endorsement on the mechanical aspects. Let me know. -Gary- Gary, the end might just be within sight! Thank-you again, and again, and again! Cathy ----------------------------------------------------- (3) Another group of students is looking at placing solar cells on outside shutters that are fastened to the top of the window and can be louvered in and out. Keeping the integrity of the building's AC/heating. Different tilts could result in more electricity being collected from the shutter. [Gary Lienesch] I pictured your idea as attached. It's a PV awning. Tilt could be adjusted manually twice a year. I like your idea as it could use a standard PV product -- and doesn't require a massive R&D effort.