Hi David
Boy, I don't have a clue about what you are talking. A cubic centimeter (cc) also called a milliliter (ml) takes one calorie to raise its temperature one degree centigrade also called one degree Celsius. To raise one cc one hundred degrees Celsius takes one hundred calories and to raise one thousand cc or ml i.e. one liter takes one hundred times one thousand and is equal to one hundred thousand calories. Since one calorie is equal to 4.184 Joules, it takes 418,400 Joules (0.4184 MJ) to raise one liter of water one hundred degrees Celsius. These are your assumptions about the temperature increase. If we add this to the 2.2 or 2.26 mega Joules we get 2.26 + 0.4184 MJ or 2.6784 MJ. If you put this on an exam, depending on what was being taught, you would probably fail because 1. you are assuming that everything is linear which it isn't and 2. there are far too many digits in the answer when we aren't even sure about the 2.2 MJ per liter. Ken Gotberg --- On Sat, 8/7/10, David G. LeVine <[email protected]> wrote: From: David G. LeVine <[email protected]> Subject: Re: [Gasification] Can use some help with stoves To: "Discussion of biomass pyrolysis and gasification" <[email protected]> Date: Saturday, August 7, 2010, 10:17 AM Ken, Let's ask some questions: 1. Is this for use in the Philippines? I will assume so. 2. Aren't the Philippines relatively high humidity and warm? 3. How many MJ/l would it take to condense the water from the air? My gut feel is that you will need to reject 2.26 MJ/L and cool it from 30° C to 20° C for it to be useful, which means 420 KJ/L or 2.7 MJ/L. To boil water will take 2.26 MJ/L and to to raise it to 130° C from 30° C will take 4.2 MJ/L. So heating it seems to need 6.5 MJ/L, then returning it to 20° C will take rejection of of about 7 MJ/L. 4. Might it be worth looking at another technology to pull the water from the air? We are talking putting in about 2 KWH/L and rejecting a bit more heat for 1 liter of water, 4 liters (not an unreasonable amount for a 70 KG man who works 1 hour per day) means needing 8 KWH/day per person who only works 1 hour per day. Working 8 hours/day in a warm climate means probably 16-32 KWH/day/person. 5. We receive an average of 164 W/M^2 per day from the sun, this implies about 100 meters^2/person just for water at 100% efficiency, and solar collection is well under 100% efficiency. Did I miss something here? Biomass for a family of four would to be 400 m^2 per day to supply water if 100% of the sunlight is harvested, and plants use a narrow band of energy, so collection is less than 100% efficient. It sounds like a poor choice, there may be a better way to spend the energy. _______________________________________________ Gasification mailing list [email protected] http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org http://gasifiers.bioenergylists.org http://info.bioenergylists.org
