[EXTERNAL] Re: Why Water Source Heat Pump is not considered as Renewable Energy in LEED rating system? (UNCLASSIFIED)

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Fun facts and wild ideas.

If the Earth was the size of an egg, the Earth's crust would be 5 times thinner than the shell of the egg.

On this thin thin crust we dig/drill for oil, gas, coal and search for plants to burn for heat. Just below the crust is an unimaginable amount of thermal energy.

The purposed XL-pipe line is 1,179 miles. The Earth's crust is on average only 25 miles thick. Why are we looking to drill horizontal and not vertically?

It is almost comical that we work so hard to find different energy sources while floating around on a blob of molten rock while living on a thin layer of ash.


I haven't done any calculations, but in terms of "Global Cooling", how much energy would be have to extract to lower the average temperature of the Earth's core by 0.001 degrees? I'm guessing it would be several millions of times more energy than the entirety of all the energy used by humans in all of history (& prehistory).

Jeurek's picture
Joined: 2010-10-07
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You may also consider the fact that electricity used to power the heat pump generally comes from a thermal plant, coal-powered or otherwise. Efficiency of those plants is generally 33%, or 3:1 energy used to useful energy produced.

Geothermal heat pump with COP of around 3 (which is somewhat optimistic, if we factor in the pumping energy) combined with the thermal plant efficiency brings back the global efficiency to around 1.0, which is not much better than gas-fired condensing boiler (for heating), and worst than most air-conditioner (for cooling).

Hence, not a renewable energy system...



Genest, Frederic's picture
Joined: 2011-10-02
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While I agree with what you wrote about the thermal losses in electricity generation, I'm
puzzled by the comment that the overall efficiency of GSHP is worse than that of most
air-conditioners. Since both are powered by electricity, an A/C unit is no different in
terms of the losses for electricity generation. Therefore, in comparing the two the
only thing to consider are their relative COPs. From what I've heard, GSHPs perform
better because it's rejecting heat to the ground rather than the air.


Joe Huang
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Joe Huang's picture
Joined: 2011-09-30
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I'm confused too. Why you say HP is worse than AC? In summer, the air temperature is 90F, while the soil or ground water temperature could be 70F. So the condensing temperature of HP is lower than AC. So the efficiency of HP should be higher than AC in summer.


YangMo's picture
Joined: 2014-11-26
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