How is Ice cooling more efficient than air conditioning?
Answer:
Usually for cooling large amounts of water, an absorption unit is used instead of a compression unit. They work at a much closer temperature differential, thus, more efficient. Whereas a compression unit is used for the high pressure side, using an electrical motor, the absorption unit uses whats called a generator. It replaces the compressor in the cycle. It works by heating the coolant to expand and pressurize. There are many less parts to worry about, and these things run great for a long time without trouble. There are small versions of these units you can cool a house with. They have a much lower operating cost - unfortunately, they have a higher installation cost. But there is a pay back period, depending on natural gas and electric costs.
The key phrase in that article is "water is frozen in large silver tanks at night when power demands are low". The power consumption is the same or even greater, it is just moved to times when it is less of a problem.
I read exactly the same argument and thought exactly the same thing that you did. the main advantage seems to be one of timing. Ice is made using energy in an off peak time to offset potential use of energy during peak time.
It never hurts to market something as being green and having a negative carbon foot print these days.
edit - on further consideration, perhaps there is some benefit because the ambient temperature is lower at night. So if a unit of energy can lower the temperature from 100 degrees to 75 degrees, if the temperature at night were lower, say 60 degrees, the same unit of energy will lower it to 35 degrees. The scheme may be a way to use a "capacitor" to make the unit of energy be worth more the next morning. This entails the making of the ice and the latent heat that it involves to give the "capacitor" a large storage. Just guessing.
Again who knows - maybe it's just that commercial customers have different rates during day and night.
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