On 4 September 2013 00:51, Henner Zeller <h.zel...@acm.org> wrote: > On 3 September 2013 23:54, Lucas González <lucas.gonzalez...@gmail.com> wrote: >> Interested. Would evaporative cooling work _at all_ in humid climates? > > If you are close to 100% humidity: no. In particular since you want to > cool down the air, you need to look at the amount of humidity in the > _target_ temperature range; if you already have a pretty humid > climate, then this might already be oversaturated at the target > temperature, so nothing can be evaporated more. Swamp coolers are only > useful in dry climates. > > It is relatively simple: you really just need to calculate the partial > gas pressure of water vapor in the given target temperature (colder > air can hold less water), and how much more could 'fit in' given the > dryness of the climate (how much water vapor is already there per m^3 > and how much more you can add). This looks like a useful resource: > http://www.engineeringtoolbox.com/water-vapor-saturation-pressure-air-d_689.html > With that, you can calculate the amount of water you can evaporate > into a given volume. > Given the required target temperature and knowing how much heat energy > is supplied every second (estimate energy intake by the yurt area in > sun in Joule (<< 1000 J/(m^2 * s) (1000W energy of sun per m^2, but > most of it is reflected with aluminum covered sheets, hence the 'much > less than' sign) + number of people * 100 J/s (typical heat 'exhaust' > of a human is 100W)
+ temperature gradient outside/inside and energy flow due to that depending on the insulation of your insulation material. > and the amount of energy taken by the water->steam > transition (2260 J/g water evaporation heat) - you can calculate the > grams water you need to evaporate per time unit (to fit the energy > bill) and flow rate (to keep the air dry enough to be able to take on > this mass of water per time-unit). > > -h > >> Perhaps with some modifications? I think not but haven't tried. >> Sleepbreeze.com.uk does seem to work, but that's one body, not one room. >> >> Thanks, >> >> Lucas >> >> El 04/09/2013 08:32, "ken winston caine" <ken.winston.ca...@gmail.com> >> escribió: >> >>> David is right. You definitely need to have an exhaust vent. Swamp cooling >>> cools by moisture evaporating in dry air -- not by creating increasingly >>> swampy air. You must draw fresh dry air in, and let the moist air out. >>> >>> Since the moist, cooler air falls to the floor, it is best not to depend >>> upon a roof exhaust vent. A mid-height window, or open door will do the >>> trick. >>> >>> RE: your test. You didn't tell us WHERE, what region, you were conducting >>> the test in. Were you in a region with 30% or less relative humidity? If so, >>> your test would be a good indicator of the effectiveness of the evaporative >>> cooling, once you have the intake and exhaust set up correctly. If you were >>> in a higher humidity zone, there is no point in running the test. It simply >>> won't give you any indication of how the evaporative cooling will work in >>> low-humidity, desert conditions. >>> >>> Hope that helps. >>> >>> ken winston caine >>> >>> >>> On Tue, Sep 3, 2013 at 11:41 PM, David Kelso <david+goo...@kelso.id.au> >>> wrote: >>>> >>>> A swamp cooler needs to be constantly moving fresh air in, humid air >>>> out in order to keep cool. So you should aim to have a directional >>>> airflow path. It can go up to the roof, or out to the door. You need >>>> to make sure the outlets are big enough that the fan isn't fighting >>>> any extra pressure inside the yurt. An outlet fan would help with that >>>> but isn't strictly necessary >>>> >>>> The major factor in swamp cooler effectiveness is fan speed. Which fan >>>> were you using? >>>> >>>> For anecdotal evidence, last year I was in a 6ft stretch and was >>>> getting at least 30 degree F cooling throughout the whole yurt. >>>> >>>> On Tue, Sep 3, 2013 at 10:19 PM, Jason Adams >>>> <jasonadamspriv...@gmail.com> wrote: >>>> > So I setup an H12, with two swamp coolers, with insulated ducts into >>>> > opposite ends of my Yurt. Just cut a hole for the ducts. >>>> > >>>> > Its going to be hard to describe, but I still felt like the swamp >>>> > coolers or >>>> > the yurt wasn't really cooling much. I felt like being out in the sun, >>>> > but >>>> > in the breeze was way more cooling that in a h12 with two swamp coolers >>>> > running. The airflow really close to the duct holes was nice, but once >>>> > you >>>> > got more than a foot away from duct, you didn't really feel it. >>>> > >>>> > It also felt hot inside, maybe thats just the moisture or sticky icky >>>> > feeling you get from releasing that much moisture in the air. >>>> > >>>> > It's definitely nice not having the intense light on you, the yurt >>>> > certainly >>>> > kept alot of that sun off the ground , probably getting a cooling >>>> > ground >>>> > effect, but I feel like I was missing some comfort. >>>> > >>>> > I feel like my options are to basically vent the yurt, or do a fan >>>> > exiting >>>> > air at the top of the yurt. Which would ideally get more airflow in the >>>> > yurt >>>> > -- however I feel like that would lose some of the effect of the swamp >>>> > cooling (after all I'm sealing the bottom to keep the cool air in >>>> > right?). >>>> > >>>> > Maybe what I really needed was some type of airflow in the yurt, either >>>> > up >>>> > the power of the swamp cooling fans -- or hang a big fan from the top >>>> > of the >>>> > yurt. >>>> > >>>> > Just trying to figure out how to make this thing more comfortable, >>>> > because I >>>> > honestly felt cooler under a shade structure, with some pillows and the >>>> > breeze coming through. >>>> > >>>> > Thoughts? >>>> > >>>> > -- >>>> > You received this message because you are subscribed to the Google >>>> > Groups >>>> > "hexayurt" group. >>>> > To unsubscribe from this group and stop receiving emails from it, send >>>> > an >>>> > email to hexayurt+unsubscr...@googlegroups.com. >>>> > To post to this group, send email to hexayurt@googlegroups.com. >>>> > Visit this group at http://groups.google.com/group/hexayurt. >>>> > For more options, visit https://groups.google.com/groups/opt_out. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google Groups >>>> "hexayurt" group. >>>> To unsubscribe from this group and stop receiving emails from it, send an >>>> email to hexayurt+unsubscr...@googlegroups.com. >>>> To post to this group, send email to hexayurt@googlegroups.com. >>>> Visit this group at http://groups.google.com/group/hexayurt. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "hexayurt" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to hexayurt+unsubscr...@googlegroups.com. >>> To post to this group, send email to hexayurt@googlegroups.com. >>> Visit this group at http://groups.google.com/group/hexayurt. >>> For more options, visit https://groups.google.com/groups/opt_out. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "hexayurt" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to hexayurt+unsubscr...@googlegroups.com. >> To post to this group, send email to hexayurt@googlegroups.com. >> Visit this group at http://groups.google.com/group/hexayurt. >> For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "hexayurt" group. 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