Wednesday, May 25, 2016

four degrees of separation...


The mercury finally kissed 100° outside today.  Good time to tweak around with Pepino.  Much to my surprise, running just 2 of the 4 fans produces cooler air coming in (although half the volume - 200CFM vs. 400CFM...my hut is about 750 cubic feet inside).  Number on the top in each photo is the inside temperature.  Number on the bottom is the temperature coming in through the swamp cooler.  Is the cooler temperature at a lower volume enough to keep in the inside temperature from rising?  Will 3 fans be the magic number?  89,100,76,0,B

8 comments:

Margery Bills said...

Step by step.

Carlos said...

The laws of thermodynamics won't be ignored. You'll have to quadruple the size of you absorption pad to allow allow the water to evaporate into that much more air. If you're indoor humidity is above 20%, the swamp cooler loses efficiency especially if the outside humidity is above 10%. Evaporative cooling is alot more complex than people think.


ybkdave said...

200 cfm x 1.08 x 6 degree temp rise= 1296 btu's/hr
400 cfm x 1.08 x 1.7 tr = 734 btu's/hr
if i'm not mistaken.
not an exact answer to your question, but you can take it fro here.

J said...

I don't understand why running fewer fans produces cooler air. Does it have to do with the heat produced by the fan motors?

J said...

...or maybe with four fans the air flow is greater than what the evaporator is capable of cooling, resulting in the higher temperature. I'll bet that the reason.

ybkdave said...

fewer cfm's are allowing much better heat transfer, but it only goes so far.
too slow and you have the same problem.

Larry G said...

does it matter - WHERE in the room the thermometer is?

George Alexander said...

We use a similar method to produce better humidity removal here in florida. When the blower motor slows down the air can sit on the evaporator coil longer which makes the air colder and in turn removes more humidity.

We install a lot of 2 stage systems with variable speed blowers that will lower the capacity of the system causing it to run longer in the lower stage to satisfy the thermostat and running longer allows it to remove even more humidity.

Makes sense that moving less air through the same size swamp cooler coil would allow for colder air. So if we increase the evap coil of your swamp cooler then we could increase the blower amount and accomplish colder air with more cfm? Makes sense? Neat stuff.

Or colder water over the same coil. Dig a deep hole, pump the colder water up and hmm should make colder air? geo thermal swamp cooler. neat project i would enjoy.

I wonder how digging a hole deep enough to get to an area where the temps were lower would work out there.