Review (distorted) on heat pumps and refrigerators machinery

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Review (distorted) on heat pumps and refrigerators machinery




by Christophe » 31/08/06, 12:46

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

Be careful i do not defend at all the words of this document (the author leaves false assumption on the 1st principle ... some of you will scream :D ) and passes it to you (as expected and after asking the author's authorization) by ... mmm ...curiosity about the human psychological!

I think that all those who have a minimum of thermodynamic culture will understand the dangerousness of such remarks.

Good reading !

ps: from the same "author": https://www.econologie.com/forums/l-effet-de ... t2246.html

THE HEAT PUMP


James Prescott JOULE, British physicist (Salford, near Manchester, 1818 - Sale, Cheshire, 1889). He studied the heat given off by electric currents in conductors and formulated the law, which bears his name (1841). He determined the mechanical equivalent of the calorie (1842). He stated the principle of energy conservation and studied with W. Thomson (Lord Kelvin), the expansion of gases in a vacuum. Using the kinetic theory of gases, he calculated the average speed of gas molecules.

He was a scientifically rigorous man as was lavished in the nineteenth century. Curiously, the following century, if it also knew, gave free rein to the worst pseudoscientific rantings among which we will note the perpetual movement, the greenhouse effect specific to certain gases in traces in the atmosphere and, supreme stupidity philosophical: the heat pump.

Thermodynamics is the physical science least assimilated by the human mind. The concept of energy does not manage to assimilate the fact that energy is an absolute value, like calorie. The latter introduces a notion of heat so "palpable" that it is sometimes necessary to speak of "Calorie" or "Frigorie", depending on whether one looks at one side or the other of the refrigerator. The ignorant need this to appear to have understood these notions of energy, whatever their level of apparent culture, consecrated by a diploma or an official position.

If the perpetual movement allowed to claim a performance equal to the unit, the heat pump claims to exceed the unit by far. The Industrial Property Institute, at the beginning of the century, refused patent applications relating to perpetual motion. From now on, it accepts all the rantings based on the principle of the heat pump. Tax services do the same.

The operation of the refrigerator transferred to a heat pump consists of a set of three elements:
A mechanical or electrical energy receiver which distributes its energy in two temperature exchangers: a hot exchanger called a radiator and a cold exchanger called an evaporator. Communication between these three elements is established in series and in a closed circuit.

In an atmosphere at a given constant temperature, let us place each of the exchangers in two identical calorimeters containing the same mass of water. Let “M” be the sum of the mass of water and the water equivalent of the calorimeter. Let “W” be the absorbed energy measured, for example, with an electric meter. In accordance with JOULE's law, called the law of conservation of energy, each of the two exchangers will receive, for one "W1" and for the other "W2" of energy such as:

"W" = "W1" + "W2"

Let t and t 'be the temperature variations in each of the calorimeters at any time chosen for the measurements.
In the evaporator, the potential energy acquired will be: Mt = "W1"
In the radiator, the potential energy acquired will be: M.t '+ c = "W2" where "c" represents the heat losses of the installation. We will finally have:

"W" = Mt + M.t '+ c

Note that these are absolute values ​​and that no philosophical reasoning on energy transfers finds its place in the application of Joule's law. Indeed, each of the two calorimeters will contain water whose temperature is different from that of the ambient medium considered to be infinite. This temperature difference can be converted into mechanical energy on both the cooled and the heated side. Consequently, there can be no transfer of energy between the two calorimeters and even less production of a quantity of energy greater than that which was supplied to the motor source.

It would be too good; We put two money in the bastringue and we get three, or even the Jack-Pot.

Plant performance

The “W” energy will suffer heat losses of about 20% or 0,2W. The two exchangers will share the rest either for each: 0,4W
If we consider the production of cold, the yield will be Mt / W = 0,4 (40%)
If we consider the production of heat: the efficiency will therefore be (M.t '+ c) = 0,6 (60%)

If equivalent electrical energy is used in a common resistance electric heater, the efficiency will be 100%.

The heat pump is a rant which is not scientific. It is a bit like pretending that geometry is the art of reasoning correctly on false figures. However, as for the greenhouse effect due to carbon dioxide, it is globally accepted by very great official scientists. All the press echoed these stupidities and, as a political leader said with humor:

“Since it is written in the newspaper; it’s true. "

Our tax departments take this into account in income taxation. All these people there therefore consider that James Prescott JOULE only said bullshit. However ... It may be because they have understood nothing about thermodynamics.
Last edited by Christophe the 31 / 08 / 06, 18: 26, 1 edited once.
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by Capt_Maloche » 31/08/06, 13:33

WOW, calm down!

I am a fluent engineer and I eat heat pumps, air conditioning and others every morning;

There is nothing magical in a heat pump or in a reversible air conditioning

It is an entire thermodynamic system which includes air or water as an exchange medium (ambient air or well water, drilling, etc.) and which uses a so-called "refrigerant" (R410 currently) in a closed circuit. vapor or liquid states to recover or absorb energy through exchangers; changes in fluid state allow large exchanges of what is called latent heat of vaporization or condensation.

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.
These 1000W electrics are used to compress the fluid in the gaseous state and supply the motors (fans or pumps) of the exchangers. Relaxation is mechanical, the rest of the energy balance is drawn from air or well water, we do not yet pay for ambient air :D

From the consumer's point of view it does not count against his invoice.

But the lifespan of this equipment is only ten, even 15 years max, and the price of electricity more expensive than fossil fuels. The purchase cost is also more expensive: zero balance since it is necessary to renew the equipment more often.

I am currently developing with an architect the ideal house (in energy of course):
Solar panels + heated floors + heat pump and insert for very cold periods
Bay windows south with deciduous trees
Canadian well
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OUCH, OUILLE, OUCH, AAHH! ^ _ ^
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by Targol » 31/08/06, 14:01

Capt_Maloche wrote:I am currently developing with an architect the ideal house (in energy of course):
Solar panels + heated floors + heat pump and insert for very cold periods
Bay windows south with deciduous trees
Canadian well


I have a pretty good knowledge of bioclimatic houses and lots of ideas on it Captain, if you want, we can discuss it ...
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by Bibiphoque » 31/08/06, 14:16

Hello,
It is dangerous indeed, but it is not wrong, in its example, it defines a CLOSED system because the calorimeters are instruments of ISOLATED measurement of the ambient air.
However in the case of an open system, such as an air conditioning or a fridge, it is wrong because the calories gained or lost are at the expense of the ambient air.

This example is to be classified in the "polemic / rhetorical" genre : Mrgreen: : Mrgreen:
@+
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This is not because we always said that it is impossible that we should not try :)
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by abyssin3 » 31/08/06, 14:50

Yes, what he forgets is that the earth (for the greenhouse effect) is not a closed system: we receive a considerable amount of energy from the sun, and not only in the form of visible radiation. The nucleus of the planet is also important, that said a volcanic eruption often results in a drop in temperature, the dust of the eruption blocking solar radiation.

And these are only a very small part of all the parameters. We could also take into account the composition of the atmosphere (including CO2) susceptible to change, atmospheric pressure (for example much stronger on other planets), or the speed of rotation of the earth, which translates also by an energy at the origin.
So it's a bit closed as a reasoning. Furthermore, it does not explain how temperature variations could have existed in recent millions of years. If this were true, how the early Earth could have cooled to such an extent :?: :?: :?:
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by Christophe » 31/08/06, 15:03

abyssin3 wrote:Yes, what he forgets is that the earth (for the greenhouse effect) is not a closed system: we receive a considerable amount of energy from the sun, and not only in the form of visible radiation. The nucleus of the planet is also important, that said a volcanic eruption often results in a drop in temperature, the dust of the eruption blocking solar radiation.

And these are only a very small part of all the parameters. We could also take into account the composition of the atmosphere (including CO2) susceptible to change, atmospheric pressure (for example much stronger on other planets), or the speed of rotation of the earth, which translates also by an energy at the origin.
So it's a bit closed as a reasoning. Furthermore, it does not explain how temperature variations could have existed in recent millions of years. If this were true, how the early Earth could have cooled to such an extent :?: :?: :?:


1 +!
I would add this: I have documents and calculations on the radiative forcing from CO2 with energy forecasts (solar collector) ... I will occasionally put on the site.

So if there is only one positive point in the greenhouse effect, it is surely that: solar will be more efficient and therefore more profitable ... but will it not be too late? : Evil:
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by nonoLeRobot » 31/08/06, 15:24

I think that the rant of the author of the email wanted to take stock of 2 often false ideas:

- Geothermal energy confused with geothermal energy. There is no typo, we use the same name twice for "free" energy from the underground at very great depth (most often reserved for the company because major works) and geothermal with pump. heat which limits the electrical consumption of heating but does not produce energy strictly speaking.

- using COP greater than 1 in no way indicates that more energy is produced than consumed, in any case the energy produced cannot be converted into mechanical energy.

For that he is right, that says an electric heating with consumes 5 times less than an electric heating therefore it is more advantageous all the same but as Capt_Maloche rightly said it is not magic or revolutionary (what we try to make believe actually wrong) and can be hardly altarpiece given the investment ... That said if it allows to save energy I do not see why it would be scandalous to tax it
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by Capt_Maloche » 31/08/06, 17:11

Targol wrote:
I have a pretty good knowledge of bioclimatic houses and lots of ideas on it Captain, if you want, we can discuss it ...


Gladly :D
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by Targol » 31/08/06, 17:15

Capt_Maloche wrote:
Targol wrote:
I have a pretty good knowledge of bioclimatic houses and lots of ideas on it Captain, if you want, we can discuss it ...


Gladly :D


So, either we discuss it in MP, or by email, or we create a new subject because there, we are a little off topic.

Christophe, are you interested in having a Topic on this ???
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by Christophe » 31/08/06, 17:32

Capt_Maloche wrote: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.


Annual average of 4 I find that a lot, so we will say: with the best heat pumps and in the best conditions of use :).

Otherwise for the COP we agree ... However the author of the article in question speaks of COP from 0.6 to 0.4 .... and this is what I condemn ...
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