Swamp cooler; fresh air or not?

[adnedarn]

Since i am gonna use my whole back yard as a green house, i wonder if anyone has a swamp cooler running inside the greenhouse. meaning not sucking fresh air. I know it's said that for the cooler to work it must get fresh air, seams to me that's becuase we don't feel comforable with all that humidity. BUT, since our plants like it... will it be ok? please someone say they are doing it!!
Thanks,
Andrew

 

[Tony Paroubek]

I think it is more of an effectiveness issue. For an evaporative 'swamp' cooler to work best the air entering should be low in moisture. The lower it is the greater the temperature drop. If you put it inside where humid air is sucked through the pads the amount of cooling will drop dramatically.
Tony

 

[adnedarn]

hmmm... since i live in an area of low humidity (lower than 15 unless a storm is brewing) does really humid air heat as much or as fast as dry air? we can easily hit 110 degree in the shade...

Also, the "g/h" is just a closed in patio, so there is air exchange. perhaps this may keep the humidity low enough for the cooler to work
Thanks so much Tony!

 

[agustinfranco]

Hi all:

I would like to ask Tony what is the temperature drop using a swamp cooler in a greenhouse. Is it enough to achieve the necessary temperature changes that highlanders require?? or is it still far from ideal??

Agustin

 

[adnedarn]

When using fresh air, the adverage drop is 30 degrees when the humidity is low (up to 30%) anything above that and the cooling gets worse. But no, even in the best of all conditions.... you couldn't use it for highlander application. I just had a conversation with Tamlin about using a swamp cooler and he didn't even know what i was talking about (lives on the east coast) so here is a simular site i used to explain it to him... it also shows temp drop in relation to humidity levels... here
Andrew

 

[Tony Paroubek]

In the Northeast where normal relative humidity is fairly high during the day (50-70%) you can achieve about a 10-15 degree drop over ambient air temperature. Other parts of the country where humidity is much less can get up to a 25 degree drop. This is enough to keep highland plants happy during the day. (temps in fahr.)

I have not tried running an evaportive cooler during the night. Our night time humidity reaches near 100% when the air cools naturally. I suspect that at most the evaportive cooler would not give any additional cooling below ambient air temperature. Other parts of the country that still have a fairly low humidity during the night might be able to get some additional cooling. I suspect though that it would not be enough for picky highland plants. Fortunately our summer night time temperatures are near satisfactory for most highland plants so it has not been a major issue for me.
Tony