catouni wrote:Hello, I'm not a scientist and I have to explain to young children how a heat pump works which recovers heat from the basement to heat homes.
hello catouni
how old are the children, because you have to put yourself at their level of understanding
To start: the definition of a pump (pumping a fluid: liquid or gaseous): take from a place (possibly suck) by means of a hose, to go put elsewhere by means of another hose (hose delivery)
example 1: water pump which sucks in a well to water the garden.
example 2: the housewife's vacuum pump pumps the air close to the ground by taking the dust in the passage to discharge this air (after it has passed through the dust bag filter) into the atmosphere
example 3: the air compressor, at the garage, which is used to re-inflate the tires of cars, pumps the ambient air with force to manage to introduce it inside the tires (or of a soccer ball)
a heat pump is an abuse of language if we take it word for word:
a water pump leads from the
water from one place to another
an air pump driven from the
air from one place to another (fan)
but if the air is hot this air pump could be called a pump
heat (by circulating the air heated by a fire to the other rooms of the house)
Described like that, it seems logical, and yet a heat pump as we speak has a much more complicated principle, the main advantage of which is to be able to use a place A from which we take calories (heat ) to go put them in a place B (house)
knowing that location A is colder than location B
To do this, the heat pump sends a cooler fluid than the place (1 meter deep in the garden for example) in which it must take calories (heat): this very cold fuid will heat up by its simple passage in the garden soil, and will come back to the slightly less cold heat pump
but still colder than the temperature inside the houseand this is where the heat pump has its interest: it very strongly compresses the gaseous fluid (which returns from the garden less cold than it had left but even colder than the house), which warms it strongly ( compression of a gas increases its temperature)
(there is a compressor in a heat pump, exactly the same principle as in example 3 cited above)and this fluid in the gaseous state, once compressed and very hot, is pushed (always being compressed therefore hot) towards the place which must be heated: this place (the interior of the house) is therefore heated, and at the same time it cools (by pricking calories) the fluid still still compressed
then, this fluid always compressed, as it is cooling, it passes from the gaseous state to the liquid state, because, (and this is due to the nature of the fluid used), by being compressed s' it goes below a certain temperature threshold, it liquefies
the liquefaction of a gas gives a lot of calories, and for these calories to be useful, it is necessary to choose a gas which, combined with a given pressure, liquefies at a temperature higher than the temperature necessary for, for example, heating a House then the fluid now in the liquid state leaves the place it has heated (in fact the hot compressed fluid and the place to be heated have shared their heat
(exchanged is often said, but it is a bit of an abuse of language because exchanging hot with cold cannot be cold and hot but only lukewarm)once this place left, it goes through a pressure reducer (sort of narrow place where the fluid passes with difficulty: which, in fact, kept the fluid compressed
and at the same time very hot before crossing this regulator)
after the expansion valve, the fluid changes from the liquid state to the gaseous state
it evaporates and this action cools it very strongly, so much so that it becomes much colder than the temperature of the basement of the garden where it is going to repeat a little lap to warm up again
the fluid used by a heat pump has somewhat the same properties as water, only the boiling temperature is different
for info: the water boils at 100 ° C at atmospheric pressure
it takes about 100 calories to pass 1 gr of water from 0 ° C liquid to 100 ° C liquid
but it takes about 540 calories to pass 1 gr of water from 100 ° C liquid water to 100 ° C steam water (gas) always at atmospheric pressure
we see that it takes more than 5 times the amount of calories needed to increase the water by 100 ° C
to only evaporate the waterit is easy to imagine the large amount of heat produced by the simple liquefaction of water vapor,
while remaining around 100 ° Ccatouni wrote:1. Apparently we place pipes filled with liquid 1m deep?
there are 2 systems for these pipes: 1 with glycol water whose calories are recovered via an exchanger, 1 with the direct refrigerant
catouni wrote:3. Does it allow underfloor heating?
yes, and it is the most efficient
catouni wrote:4. Are heat pumps used for ONE dwelling or can they be used to heat an entire building?
yes, provided you have a
large garden
bolt
