Post by thread:absorption

try to enclose it in lead !! Stef Tony Smith wrote: {Quote hidden}>>Hi All, >> >>I have a small device that has a small motor moving a small mechanical >>structure. The device is very noisy when running, is there any way to >>shield >>the box so that the noise will be greatly reduced? >> >>Thanks in advance! >> >>John >> >> > > >Either move it somewhere else, bury it under your dirty laundry to muffle >the sound, or mount the motor (or whatever is rattling) on rubber to stop >the vibrations transferring to whatever it's bolted to. > >Another option is to use a bigger motor, and gear it down. A slow turning >high-torque motor is always quieter than a high-speed low-torque one. > >Tony > > >

>> I have a small device that has a small motor moving a small >> mechanical structure. The device is very noisy when running, >> is there any way to shield the box so that the noise will be >> greatly reduced ? What Jinx says. Plus: You need to identify the source of the noise and the noise transmission mechanism. eg is the motor per se noisy, is the structure acting as a noise transducer, is the noise coupled through the mountings etc It may be that mounting the unit on a "spongy" mount may assist greatly. Try some foam rubber of various stiffnesses and thicknesses. Not so stiff or so flexible that there is little damping. Critical damping is usually ideal - the system will stop in about a cycle if power is removed. Somewhat compliant rubber feet can make a vast difference to some devices. Acoustic insulation should be possible. This can again be foam of various sorts or something a little 'cleverer' with eg acoustic chambers with damping material coupled by holes to a box containing the noise source. A whole science in itself. Used in room dividers, acoustic tiles. vehicle mufflers and more. Lead has been mentioned. May in fact work BUT is probably too dense as is. People make spun lead fabrics which have excellent sound absorbent properties. A little more information would help people to help you. RM

http://www.treehugger.com/files/2008/01/smallscale_sola.php "For years we have been saying that solar powered air conditioning just makes sense- if you are boiling in Phoenix the sun is probably shining really hard. We have seen big units, evaporative units that won't work in humid climates, a few vaporware units and even home-made absorption chillers Now it looks like a Spanish company, Rotartica, has put it all together, by combining evacuated tube thermal collectors with a water-heated absorption chiller, and sized it at 4.5Kw (1.28 tons) for residential use, all packaged in a neat little box. http://schroderzimmerly.com/rotartica_technicalspecifications.html >From an operation point of view it is very simple: you put hot water in, you get cold water out, which you can run to a conventional fancoil. The hot water in can come from any source, but evacuated tube collectors, which used to be very expensive, are pretty affordable now. If you want to get more techie: In an absorption chiller unit the evaporator and condenser are the same as in conventional systems but the function of the compressor is performed by a chemical absorbent (LiBr) and a heat generator, with only a pump being required to provide the change in pressure. As there is no compressor, electricity consumption is reduced significantly." Two Rotartica Solar 045v are being tested in the U.S.A.: http://solar.uc.edu/solar2007/technology www.ornl.gov/sci/de_materials/documents/3rdQuarterFY07ReportApril-Jun e5.pdf I've been looking for something like this for years: http://techref.massmind.org/techref/other/spac.htm I've emailed them asking for P&A and will report if I hear back. James Newton: PICList webmaster/Admin spam_OUTjamesnewtonTakeThisOuTpiclist.com 1-619-652-0593 phone http://www.piclist.com/member/JMN-EFP-786 PIC/PICList FAQ: http://www.piclist.com

This is the answer I received to my question about P&A: In summary about $20,000 USD for the unit (not including the solar hot water heating system, cold water radiator / fan, plumbing or installation. But this is not bad for an item that is not being mass produced. If the price eventually drops to half that, it would be worth it to have A/C at little to no operational cost in the average home. Here is the text of the reply: "Unfortunately we do not have a set time-line for when the chillers will be readily available to home owners at a set retail price. Right now the cost of the Rotartica units range between $18,000 - $25,000 depending on exchange rates, availability from the manufacturer, and is subject to change. Because the unit is a new design, made in low production in Spain, Rotartica does not have a set retail price for the U.S.A. market. We will get back with you as soon as there is an established retail price. However, Rotartica is interested in potential emblematic projects that will display the new technology and help to gradually bring down the costs. The technology is new and requires an engineered system to obtain the proper performance; otherwise, more electrical power will be required than a standard mechanical compression system. It is not quite plug and play yet. However, this is part of bringing a new technology to the forefront and hopefully it will be very little time before everyone understands the power of absorption chilling. Currently there are two Rotartica Absorption Chiller models, the 045 and 045v. The 045v is a dry dissipation best used for radiant cooling and the 045 is a wet dissipation that is better suited for forced air especially when using geothermal as the dissipation circuit. The hydronic system with an absorption chiller requires a few electrically driven pumps: for water circulation through the collectors, to distribute the chilled water, and dissipation pump if using the 045. Schroder Zimmerly recommends and can provide Wilo Stratos high efficiency pumps, just recently made available in the USA. The chiller requires some electrical input as well to operate the motor for the rotary heat exchanger and controls for the unit. Rotartica intends to make larger units with less electrical consumption in the coming years. Please note the Rotartica units are not yet UL certified. Regarding further information about how the Rotartica unit works, please refer to this page on our website. There are several PDF linked on this page. Please take a look, and let us know if you have any further questions. http://schroderzimmerly.com/rotartica_technicalspecifications.html Thank you for your interest in absorption chilling. I hope this information gives you an understanding of the new technology, how you might learn more about it, and whether or not we can help you further with implementing a solar powered air conditioning system. We are glad to see communities like yours expressing interest and we are working hard to bring this technology to all home owners." {Original Message removed}