Saturday, May 5, 2012

Night Air Thermal Mass Cooling Using Water Barrels

This is a scheme that I am experimenting with to cool my shop.  It basically blows cool night time air over a collection of 50 gallon barrels filled with water to store "coolth" in the water. 

The idea is to cool the barrels down during the night hours, and then use the stored "coolth" in the barrels for space cooling during the daytime.  This requires a climate in which the night temperatures drop down to low levels even though the daytime highs are uncomfortably warm -- this is true for much of the western US.

While I am using the scheme in my shop, it could be used to cool any interior space.  Note that we use a variation on this cooling scheme to cool our house ...  The basic question is: does it make sense to use a fan forced flow of cool night air over thermal mass to store "coolth" for later use in daytime cooling?

Logger plot of water barrel storage and shop temperatures
with fan forced outside air flow over barrels at night.

This is definitely a work in progress, and I'm looking for any ideas people might have to make it work better.  I think that it has the promise to deliver good cooling performance for near negligible energy consumption (SEER 150 ish).   

This scheme only works for climates in which the night time temperature drop to relatively low levels even when the day temperatures are hot -- typical of a lot of the US west.

All the details and questions on night air cooling of water barrel thermal mass...

Water barrels for storing night time "coolth"

Rough prototype cooling tunnel to direct fan forced night time
airflow over the water barrels for good heat transfer.
In this particular scheme, the same water barrels are used to both store heat in the winter and store "coolth" in the summer!

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