Review (distorted) on heat pumps and refrigerators machinery

[bolt]

The current yields (COefficient of Performance COP) of reversible air conditioners are 3 to 5 on average: I consume 1000W of electricity, I produce around 4000W of heating or cooling depending on the operating conditions; with the best systems, an average annual yield of 4 can be obtained.

hello Capt_Maloche
If you are a connesseur on this subject, I would like to have your point of view:

For small depth "geothermal energy" what is the best performance:

1) Geothermal probes without water withdrawal

2) Water drilling + pump which sends water into the heat exchanger of the heat pump

bolt

[Christophe]

For small depth "geothermal energy" what is the best performance:

1) Geothermal probes without water withdrawal

2) Water drilling + pump which sends water into the heat exchanger of the heat pump

bolt

I don't think he can answer your question precisely, it all depends on the parameters of the average temperature of the house, the depth of drilling, the temperature of water drilled ... etc etc. It is studied case by case and the study is more often different from reality ...

[Capt_Maloche]

if so, well water in general from 4m at a stabilized temperature at 12 ° C summer and winter (frost protection in the trench is usually at -0,80m)

PAC well water systems generally have the best yields because they allow evaporation of the fluid at approx + 7 ° C against -15 ° C on the air when it is -10 ° C outside

at + 7 ° C it is common to find COPs of 5 !! with R410
a little less with R407

The best system is well water, if you have an accessible tablecloth, otherwise the coil unwound in the garden more than 1m deep is a palliative; attention to the specific heat of the earth, to its conduction etc depending on the terrain, the exchange surface can go from simple to triple
In the case of aerated earth with a poor exchange, if a bad calculation is made, you can freeze your land and have to wait 1 whole season before being able to reuse your installation !!

Pascal

[bolt]

PAC well water systems generally have the best yields because they allow evaporation of the fluid at approx + 7 ° C against -15 ° C on the air when it is -10 ° C outside

If I understand correctly, the water from a well of T ° 12 ° C drops by 5 ° C in the evaporator by supplying it with its calories
ditto for air (from -15 ° C to -10 ° C) (in winter when it is most needed) and therefore the difference in yield depends mainly on the T ° available in the sampling medium
So "at the same time" the value of T ° that is used at the output of the heat pump also influences the COP (efficiency):
if you heat a heated floor (PER under the tiling for example) to 28°C max, this should make a big difference compared to heating the circuit of radiators from central heating to 50°C

If we take the extremes:
inlet 7 ° C outlet 28 ° C (difference: 21 ° C) = good COP
inlet -15 ° C outlet 50 ° C (difference: 65 ° C) = poor COP (65 ° C is this possible first?)

But often the COP of PACs with water withdrawal does not take into account the kw which are used to convey water to the PAC

ex: PAC consumes 2 kw, returns 10 kw = COP of 5
if the water pump consumes 1 kW the real result gives:
10 kw divided by (2 + 1) = COP of 3,33

at + 7 ° C it is common to find COPs of 5 !! with R410
a little less with R407

What are the differences between R134a; R407 and R410

With a probe system in a borehole without water withdrawal (advantageous by the compression of the pumping of this water) can have the same problem as a network buried at 0,80 m (freezing a whole mass of underground land to lapse a heat pump) (problem necessarily absent by water withdrawal)

bolt

[Capt_Maloche]

If I understand correctly, the water from a well of T ° 12 ° C drops by 5 ° C in the evaporator by supplying it with its calories
ditto for air (from -15 ° C to -10 ° C) (in winter when it is most needed) and therefore the difference in yield depends mainly on the T ° available in the sampling medium

Reversible or non-reversible refrigeration systems use 2 exchangers:
1 "hot" exchanger called condenser which serves to condense the fluid and evacuate the "calories" of condensation of this fluid
1 "cold" exchanger called evaporator which serves to evaporate the fluid and absorb the "calories" of evaporation of this fluid
The compressor and the expansion valve are used to compress and expand the fluid to suitable pressures and temperatures; we chose a refrigerant according to its characteristics

So-called Mollier diagram
See this well done site: http://www.cooling-masters.com/articles-4-0.html

http://www.univ-nancy2.fr/Amphis/images ... r%20pdf%22

for the brave
http://www-ipst.u-strasbg.fr/jld/machth.htm

http://pastel.paristech.org/bib/archive ... %20R410%22

The more the temperature of the medium (air or water) used to capture the "calories" of the evaporation of the fluid is close to the evaporation limits of this fluid at atmospheric pressure, the less the performance is good;
For example the R134 must have an evaporation pressure of -25 ° C at atmospheric pressure, it can be used for cold rooms at T ° 0 ° C, the fluid will work at an evaporation temperature of -10 ° C
Just as the condensation temperatures at the top of the Mollier diagram (sorry, we still cannot insert a file) from 50 to 70 ° C also make the yield drop, because the energy used for compression is greater.

If we take the extremes:
inlet 7 ° C outlet 28 ° C (difference: 21 ° C) = good COP
inlet -15 ° C outlet 50 ° C (difference: 65 ° C) = poor COP (65 ° C is this possible first?)

You understood everything, the relation PxV / T ° being constant, the less there is delta between the temperatures of evaporation and condensation, the less there is effort to provide for the compression of the fluid and the better the yield .
There are so-called high temperature heat pumps, but the efficiency is affected.

The ideal is indeed to use a heat pump on a floor heating at 28 ° C max with a sun supplement.

But often the COP of PACs with water withdrawal does not take into account the kw which are used to convey water to the PAC

ex: PAC consumes 2 kw, returns 10 kw = COP of 5
if the water pump consumes 1 kW the real result gives:
10 kw divided by (2 + 1) = COP of 3,33

Well yes, the more energy consuming equipment, the lower the efficiency,
a 1KW pump is still tough, unless you pump very deep

at + 7 ° C it is common to find COPs of 5 !! with R410
a little less with R407

What are the differences between R134a; R407 and R410

The T ° of evaporation at atmospheric pressure are different
-25 ° C for 134A
-45 ° C for R407
-52 ° C for R410

With a probe system in a borehole without water withdrawal (advantageous by the compression of the pumping of this water) can have the same problem as a network buried at 0,80 m (freezing a whole mass of underground land to lapse a heat pump) (problem necessarily absent by water withdrawal)

bolt

yes, it all depends on the nature of the earth and the exchange surface

I hope I have informed you
Hello

[bolt]

Thank Capt_Maloche

(that, at least, is not information with 2 bullets)

The main factor in the efficiency (COP) of a heat pump is the energy to run the compressor, but what is unfortunate is not being able to recover the energy from the regulator:

If I understood correctly, it only serves to relax the liquid fluid under pressure

If we imagine in place of the regulator, a small diesel engine: we cancel the intake valve,
the fluid to be expanded is made to arrive by a kind of pump injector replacing the injector
arrived at the top dead center we inject the liquid fluid under pressure

it relaxes by pushing back the piston (principle of the compressed air motor) and giving a driving force that could be recovered to help turn the main compressor
the exhaust of the expanded gas continuing its path in the condenser

The question is: how much energy could be recovered as a% of the driving energy injected into the rotation of the compressor

Eg. if it was 50% (I doubt it), a 2 kw compressor would run with a 1 kw motor only for the same efficiency:
If it had a COP of 5 with the 2 kw, it would have a COP of 10 by recovering the energy (pressure drop in the regulator)

bolt

[emlaurent]

Perhaps the most serious thing in history is:

For information I received this by email from a visitor (former professor of INSA ...) ...

Did this gentleman teach this state of mind to students of the INSA (National Institute of Applied Sciences) ??

[Capt_Maloche]

EH Bolt, you get it fast

If I understood correctly, it only serves to relax the liquid fluid under pressure

If we imagine in place of the regulator, a small diesel engine: we cancel the intake valve,

it could be an idea to exploit

But the regulator is a "controlled pressure drop" (calibrated orifice + evaporator filling control system, or capillary) which allows the pressure reduction of the fluid in phase. liquid only and the rate is relatively low compared to the gas phase
Although R410A a very high density in the gas phase, there will be around 40 10 ° C times less liquid phase flow.
It seems difficult to get some work connected with compressors that rotate 1500 and 3000tr / min.

Good try

Now, to increase the economic performance of the whole, I propose to operate a heat pump on a heated floor which will accumulate "calories" in off-peak hours.

See EDF tariff http://particuliers.edf.fr/article494.html

in order to save another 40% on the cost of the energy spent,
If the average COP was 4, it would economically fall to a COP of 6,6 compared to the price of electricity in peak hours.

It's funny, but I prefer solar ... when there is

[PITMIX]

Hello

I admit that the New fluids to obtain lower evaporation temperature pressure atmo in that a lower pressure in hp and thus a compressor that less force, but are t there a big difference to intensity absorbed to the compressor in this case?
From what I have observed the conso a compressor varies in 10 20% following fluid loading.
So the machine moves from one cop to 4 4,8 Cop but is it still valid if we do not take into account only the compressor capacity but the entire system?
Even taking into account the peak hours being given that Pac are calculated as accurately as their elevé price high power, turning the latter longer than traditional boilers. The calculation is valid ??
Bolt you trying to reinvent the perpetual motion machine !!!
This is the closed circuit principle take pleasure in fridges but unfortunately the energy reccuperé the pressure regulator how you never meant to allow trourner a compressor with enough force to compress the fluid.
It would have to invent the machine fridge that turns upside down.
A device that converts electric power fridge or mechanical energy.
Stirling product of eletricity or a driving force but the hot condenser and the evaporator of the cold they would be enough to run a stirling coupled to a compressor fridge ???
I imagine that others have already worked on it ...

[Other]

Hello,
In my system when I put an excess of freon the compressor draws more amperage or 28 to 30 amperes at 230volts in single phase, normally I keep it at 24 amperes.
The machine produces more heat, but it should not be forgotten that the freon passes over the motor winding and that this heat from the motor enters the system.
The compressor is 5 hp the whole system draws around 30 amperes

The best yield I have when the earth's water is 13c
and that I use the heat pump to heat my domestic water tanks when they are cold, in the cold and as the temperature rises in the tanks the yield crashes, at 50c it is not worth it to turn the system for heating domestic water, ok for heating the house.
it is my main heating of the house that provides even at -25c

What you need to know about the shallow water table (my case) the water in the earth fluctuates during the year it is in November after the first snowfall that it is at its highest, then in end of February it starts to kiss because of the return of cold water which is 10 meters from pumping, (it is enough to purge a 50 cubic meters and it goes back a few degrees) returned in April when the snow melts the temperature in the ground is at its lowest 9c, fortunately there is less need to heat it, the snow cover has a big influence on the temperature of the surface water (4 meters)

The water pump is 1 hp, the water passing through the pump gains 1c if the system is well constructed it lasts long enough I am close to 20 years of use, but the water collection hose would need cleaning .. the flow has decreased ..

in summer it is the most profitable air conditioning and heating of domestic water, the water forced to circulate in the exchanger sometimes rises to 62c, another exchanger takes over and sends the water to the sewer . (do not return hot water 37 c in the ground this causes many problems at the outlet grille.)

Andre