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M. Falk: As a person with (minor) French ancestry, I am shocked and offended at your suggestion that the French do not bathe regularly. I challenge you to defend yourself in a duel of honor. Shampoo at fifty yards, the first one to achieve a glossy sheen to be declared the winner. I name as my seconds Vidal Sasoon and the Breck girl. If the first duel is not satisfactory, we will rinse and repeat. Prepare to meet your suds. M. Weaver Hakan Falk wrote: Tom, Do not worry, it must be other developed countries than US, this because US is using more gasoline than water. Cannot be the French either, since I saw some statistics that they only shower once every two weeks and that was the immigrants, according to a French guy I know. It is no sure numbers on how often the real French shower. They have however the best perfumes on the market.I feel a bit guilty here, because it is the Swedes who are using more water than gasoline and they shower several times a week. A very wasteful people, the Swedes, and they have a lot of water also. They should be ashamed to use so little oil, according to a well known oil company, who threatened to stop delivering oil. Hakan At 17:31 14/10/2005, you wrote:Hi Bob, You mean people heating their water with electricity aren't using flow limiting shower heads. Why I'm shocked to hear this. You must be talking about people who live in the third world not the first. Whew, I was really worried there for a minute. But wait I'm confused, most people living in developing countries don't have accress to electricity to heat their hot water. What's going on here. Tom Irwin ---------- From: bob allen [mailto:[EMAIL PROTECTED]] To: Biofuel@sustainablelists.org Sent: Fri, 14 Oct 2005 09:53:14 -0300 Subject: Re: [Biofuel] Grey water heat recovery and low tech Solar collectors???? Although my observations will offset in terms of net effects, a fifteen minute shower is a really really long shower in my experience. A few years ago I had students go out and calculate energy use for showers. average length 3 to 4 minutes, temperature around 40 C, and flow rate varied from 2 to 6 gallons per minute, average on the high end about 5 gal/min. this from a combination of dorms, apartments, and single family homes. Tom Irwin wrote:Hi Mike, Lets do a quick calc. Let's say flow is a gallon a minute for 15 minutes. Let's say you like really hot showers at about 45C. Let's say room temp is 20C giving us a differential of 25C. Mass x Temperature change x specific heat......... hmmmmm less than 6000 kilojoules. Yep, ridiculous, meaning I wouldn't waste may time or capital. Of course, I didn't really consider leaving the water in the bathtub. That will heat ya twice, once from the waste heat and again when you scrub the tub. Tom Irwin ------------------------------------------------------------------------ *From:* Michael Redler [mailto:[EMAIL PROTECTED]] *To:* Biofuel@sustainablelists.org *Sent:* Thu, 13 Oct 2005 10:31:05 -0300 *Subject:* Re: [Biofuel] Grey water heat recovery and low tech Solar collectors???? With all due respect Tom, when I see someone use the word "ridiculous" in threads like this, I usually think of the people who actually believe that the buck stops with them, every possible scenario has been explored and all possible conclusions made as to the potential of an idea (even if you put "seems" in front of it). It is presumptuous and discounts contributions made by people like John who present and argument and back it up with something other than conjecture. Although, I'm not convinced that the concept can work effectively, I think of the variables involved, like the energy necessary to heat the water from ambient, the amount of water being heated and the difference in temperature. "...bacteria that will definitely grow and clog heat exchange tubing." Fouling is a foregone conclusion in most heat exchanger applications and If clogging from bacteria were that severe, I suspect that most people would be taking baths, whether they want to or not. "...problems in trying to recover shower water at 40 or 45 C" Air conditioners are expected to function in similar situations. One thing about using heat pumps for generating heat is that inefficiency in the cycle is not necessarily a bad thing. After all, you are trying to generate heat. This is not a new idea. Below is an article from www.motherearthnews.com which talks about applying it to solar and geothermal systems. In addition, I know that it is used to recover heat from attics for domestic hot water. I think that heat recovery from waste water might also be an appropriate application. "Though solar energy is likely to be one of the most popular heat sources for the new absorption-cycle heat pump, the design is equally well suited to cogeneration systems using waste heat or geothermal heat sources." *<http://tinyurl.com/dxk4p>http://tinyurl.com/dxk4p *Mike */Tom Irwin > >/* wrote: Hi John, Just because graywater has some heat in it does not make it economically recoverable. Graywater is a wonderful breeding ground for fungi and bacteria that will definitely grow and clog heat exchange tubing. I think it will be a huge headache and a waste of capital and time. Think about the problems in trying to recover shower water at 40 or 45 C for a 10 or 15 minute period. That´s only a 20 or 25 C differential for a very small amount of time. It seems ridiculous to me. Tom Irwin ------------------------------------------------------------------------ *From:* John Hall [mailto:[EMAIL PROTECTED] ] *To:* Biofuel@sustainablelists.org *Sent:* Wed, 12 Oct 2005 23:16:44 -0300 *Subject:* Re: [Biofuel] Grey water heat recovery and low tech Solar collectors???? Jim, There are commercial grey water heat recovery systems out there. They recover 50% to 75% of the heat going down your drain, largely while taking showers. According to the DOE studies conducted. Check <http://www.gfxtechnology.com/>http://www.gfxtechnology.com/ There is one other company that makes a similar product for about the same price of $375 and there are tax incentives for these. I do not agree that they would not be worth it for the money since most homes use about 30% of their energy bill heating water. This should cut that about in half. Regards; John_______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/ |
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