Thermal energy storage and heat pump

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chatelot16
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Thermal energy storage and heat pump




by chatelot16 » 05/09/09, 15:30

Hello

I have some idea given on the storage of thermal energy which I want to separate from the other subject already open

water is the best and cheapest: only fault, no phase change at constant temperature

the thing to invent is therefore above all the means of exploiting variable temperatures not necessarily adapted to what we want to do

it's already almost invented: heat pump
it only remains to make it really reversible: being able to serve sometimes as a heat pump sometimes as a heat engine to make electricity with a difference in temperature available

when in summer the heat rab will have been put in a tank of almost boiling water, for quite a long time the thermal machine will make almost free electricity by letting pass a little heat from hot water to low temperature heating

later when the water is too cold the heat pump will start to use a little electricity instead of producing it

when the tank is cold, as soon as there is sunshine to make boiling water, it should not be swayed stupidly in the cold water tank: it must also be passed through the thermal machine: production of 'electricity !

almost the same as a heat pump, so often criticized, once transformed into a heat engine would become the essential complement to a storage of hot water

we can do better with 2 managed tanks so that one is as hot as possible and the other as hot as possible: when there is sun and we do not need electricity we put solar heat in the hot tank

when there is sun and we want electricity we put in the warm tank with production of electricity by the engine

conversely when you want to heat without the sun: heating with the hot tank and production of electricity or direct heating without electricity with the warm tank

if there is other energy available in rab (wind turbine) we can also operate the heat pump to increase the temperature of the tank ...

the heat pump so criticized, once transformable into a heat engine becomes a good tool to use the sun
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dedeleco
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by dedeleco » 19/09/10, 02:43

Apparently no reaction to pump with a reversible heat pump in perfect engine with the maximum possible efficiency of Carnot !!
the thermal machine will make almost free electricity by letting some heat pass from hot water to low temperature heating

Unfortunately this yield for electricity is very low with temperatures of 13 ° C to 60 ° C typical !!
And "the little heat" is actually enormous, the necessary heat fluxes gigantic with very bulky exchangers to obtain a weak electrical work !!
http://en.wikipedia.org/wiki/Carnot_cycle
Electric work on heat exchanged as (60_13) / (273 + 60 ° = 1/7 !!
For 1KW electric obtained we waste 7KW in heat and not a little so perfect, but in reality the efficiency is 4 times less good so we lose 28 times in heat 28KW !!!
The tanks will not store the heat long enough in practice.

Worse result than storing this heat from summer underground to winter, losing half of it by thermal diffusion underground !!
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chatelot16
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by chatelot16 » 19/09/10, 11:03

if your underground storage works the reversible heat pump will be as useful as for storing it in a water tank

for example in summer the solar collectors make a temperature much higher on the ground to be heated: the difference will make mechanical energy at least to run the circulation pumps

the heat pump would not be profitable if it was only used for AC ... but it will also serve as a real heat pump if at the end of winter the thermal storage is no longer hot enough, and the more it will be cooled with the heat pump, the more it will make electricity when we want to heat it

the heat pump is precisely a way of experimenting with too small a heat storage

spending an astronomical sum on drilling to make sufficient thermal storage without a heat pump is not within my means ... especially since you still haven't convinced me that it works!

making a small compressor of 1kw reversible in engine is much more within my means, and will allow me to prove that we can approach much more the theoretical maximum cop than the current heat pumps

the current compressors are not optimized for performance, but for lightness!

a big improvement in the performance of steam locomotives has been to increase the diameter of the pipes to avoid pressure losses: the same must be done for heat pumps: all the passages are too small, including the valves
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by dedeleco » 19/09/10, 12:49

making a small 1kW motor reversible compressor is much more within my means, and will allow me to prove that we can get much closer to the theoretical maximum cop than current heat pumps

So you have to do it and prove it concretely but 10KW of heat will be lost for 1KW of electrical work recovered with a COP close to 1 and the adequate exchangers will be necessary.
It is certain that such a reversible heat pump motor with good efficiency close to the Carnot maximum will have immense practical applications if it is not too expensive !!!

We can make electricity with the temperature difference between outdoor air or sun and air in the earth, both in summer and winter but the necessary exchangers are huge.

Approaching Carnot's yield is difficult, full of traps.

But in my case, making simple little holes seems easier to me, although a little less creative.
Survey augers already exist to make cheap deep holes and their rental is not at an astronomical price.
It is not a question of making an oil well!
To make a small drilling robot, with commercial elements gathered, seems to me a project much less difficult and very useful, because with much less unknowns, instead of moving a whole garden to 3m deep to make a Canadian well often undersized .

For a very well insulated house like a house with straw, it seems to me much more possible to recover the heat of the summer for the winter, because dimensioned much smaller.
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