Monthly Archives: April 2009

Simple Technologies That Can Help

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As we transition from hydrocarbon fuels to renewable sustainable energy sources one of the issues we have is that many sustainable energy sources are intermittent. The sun only shines during the day, wind blows when it wants to.

With hydrocarbon fuels, many power plants can’t be readily throttled to adjust to variable energy demand. Coal for example, the thermal mass of the units make it impossible to throttle them up and down rapidly. Yes, you can dissipate excess thermal energy in a cooling tower instead of generating electricity but you’re still burning the coal and producing carbon dioxide.

The variability of sustainable sources isn’t introducing a new problem even though the existing industry suggests that it is, because already the load varies considerably being about 3x greater in the day than in the night, and the grid accommodates that variability by wasting huge amounts of energy at night.

In the southern US and much of the industrialized world; much energy is used for air conditioning. A company called “Icebear” makes an air conditioning unit that has a 500 gallon water tank with copper coils. It runs the compressor at night, freezing the water, then pumps a coolant through the coils in the daytime to get rid of heat by melting the water. This shifts the electrical load from the day, when demand is high to night, when demand is low.

I can see where a similar strategy could be used for heating, using eutectic salts or some other phase change medium to store heat in a similar manner.

Now it occurred to me, if we could do this we could take it one step further with smart-grid technologies and have these things come on and “charge” if you will, whenever there is surplus power. That would allow a larger percentage of wind and solar power to power the grid by automatically kicking in demand when there is surplus and using stored energy when there is not.

Now I can also see how this could be accomplished for heating by using eutectic salts to store heat;

Category: Future