New heat pump concept

[raymon]

On agoravox I saw this new concept of heat pump, could you tell me what you think?

http://www.agoravox.fr/actualites/techn ... che-130895
Heat pump with dissolution and crystallization.
The idea below has been published through researchdisclosure under the number 581002: it is therefore part of the public domain and is accessible to anyone wishing to make a prototype to determine the coefficient of performance and optimize it.

1. INTRODUCTION.

Existing heat pumps (compression or absorption) use compression (mechanical or thermal) of a vapor or gas, which involves a significant amount of energy to be supplied to the system (in the form of electricity or heat).

In contrast, a system for dissolving and crystallizing a solid in a liquid that does not use a vapor phase requires less energy to be supplied and results in a higher coefficient of performance.

2. BASIC CONDITIONS AND CHOICE OF SOLUTE AND SOLVENT.

(a) The case under examination is that in which the solution is exothermic and the solubility increases with temperature: for example, the dissolution of caustic soda (NaOH) in water fulfills these conditions and releases a large quantity of heat.

(b) By analogy, the case where the dissolution is endothermic can be examined mutatis mutandis.

c) On the other hand, the following reasoning is based on a single tank, but one can imagine two tanks, one for the dissolution, the other for the crystallization, an Archimedes screw connecting the two tanks at the bottom of the tank. these, allowing the displacement of solid NaOH from the crystallization tank to the dissolving tank.

d) A vortex in the zone of dissolution and a hydrocyclone in the zone of crystallization upstream of the filter appear essential.

e) The addition of a freezing point depressant compound may be useful, as may any means of lowering the viscosity.

3. DESCRIPTION.

The assembly consists of a tank traveled from bottom to top by an aqueous NaOH solution, the circulation being provided by a pump (Figure 1).

I can not post the plan

The poor solution, after being preheated (A), enters the bottom of the tank, where it is enriched in NaOH (stirrer and excess NaOH) with increasing temperature (B), (the dissolution of NaOH is exothermic and the solubility increases as the temperature increases).

After supplying calories to the hot source (C), this rich solution preheats the poor solution, cools (D) and enters the crystallization zone where it is depleted in NaOH with a drop in temperature (the crystallization is endothermic and solubility decreases as temperature decreases).

After supplying calories from the cold source, it passes through a filter that retains the formed crystals (E).

This filter must allow the poor solution to maintain its concentration of NaOH and therefore its cold temperature, to ensure the cooling of the rich solution and the beginning of crystallization.

It is possible that this filter is not essential: tests performed at different flow rates will make it clear.

A spray boom rotating around the axis of the tank would clean the filter continuously: it would be supplied either in lean solution (possibly heated to reduce the viscosity at the filter), or air from the top of the tank (also allows to reduce the viscosity under certain conditions).

Controlling the exchange rates with the hot source and the cold source and the flow rate inside the tank must make it possible to regulate the assembly.

4. EXAMPLE.

Based on the following data (Figure 2):


- upper cycle temperature: 80 ° C,
- lower t °: - 20 ° C,

- mass proportion:
20% for the poor solution, namely: 0,250 Kg NaOH per Kg of water,
- 40% for the rich solution, ie: 0,667 Kg NaOH per Kg of water,
amount of dissolved (or crystallized) NaOH: 0,417 Kg NaOH per Kg of water,
mean enthalpy of dissolution of NaOH: 37 KJ / mole, ie: 925 KJ / Kg,
- enthalpy of the solution calculated as follows: i = 4,19 xmxt,
t (D): 17 ° C.


1. The heat released by the dissolution serves to heat the solution from A to B:

By Kg of solvent (water):
0,417 x 925 = 4,19 x 1,667 x 80 - 4,19 x 1,250 xt (A),

Hence t (A) = 33 ° C.

2. After exchange with the hot source, the heat (from C to D) remaining serves to preheat the poor solution (from E to A):

4,19 x 1,667 xt (C) - 4,19 x 1,667 x 17 = 4,19 x 1,250 x 33 - 4,19 x 1,250 x (- 20).

Hence t (C) = 57 ° C.

3. Amount of heat exchanged with the hot source: from B to C:
4,19 x 1,667 x 80 - 4,19 x 1,667 x 57 = 160,65 KJ per Kg of water.


Taking as an example:
- inner diameter of the tank = 50 cm,
- section = 3,14 x 2,5 x 2,5 = 19,625 dm²,
- heating system of 125.000 KJ / hr.

Rich solution flow per hour: (125.000 / 160,65) x 1,667 = 1.297 Kg / hr,
about 900 liters of solution per hour or 15 liters per minute,
or a speed in the tank (in areas without exchanger) of about 8 cm per minute, which would be the speed at the inlet of the filter, slow enough to limit this main source of pressure drop.

[Did67]

Not very young, the idea. See this text from the beginning of the 80 years:

http://hal.archives-ouvertes.fr/docs/00 ... _245_0.pdf

[raymon]

Yes indeed it dates a little, but do you know a little more, do you think that the system can work?

Apparently he's looking for people wanting to try to replicate the system.

So I sent, by e-mail and regular mail, the address of my blog to researchers and managers in the field concerned.
I got only one answer: a professor in a university who explained that all the research programs had been distributed, but that he could possibly ask a student, as a thesis subject, crystallization study in the targeted case.
No action has so far been given; I did not insist, considering that a minimum of motivation is needed.

I would like to put you to work: if you know a researcher or a leader or a professor in the field, could you ask him if he finds the idea interesting?
Thank you for your participation.

[chatelot16]

Existing heat pumps (compression or absorption) use compression (mechanical or thermal) of a vapor or gas, which involves a significant amount of energy to be supplied to the system (in the form of electricity or heat).

In contrast, a system for dissolving and crystallizing a solid in a liquid that does not use a vapor phase requires less energy to be supplied and results in a higher coefficient of performance.

big mistake from the beginning: the maximum heat pump is perfectly defined by carnot: only defined by the cold or hot temperature

the compression system makes it possible to get very close to the theoretical maximum if we put the means ... the heat pumps of the current trade are only half or a third of the theoretical maximum ... they can do much better with compressor better and bigger exchangers

I am not convinced that a salt dissolution system is better in principle: show us results obtained

[raymon]

the compression system makes it possible to get very close to the theoretical maximum if we put the means ... the heat pumps of the current trade are only half or a third of the theoretical maximum ... they can do much better with compressor better and bigger exchangers

I pretty much agree I just installed a reversible toshiba air conditioning that has a compressor has 2 floors so a very large area when only one part of the compressor is running right now it consumes 250 w instant its power is 4kw crete.

I am not convinced that a salt dissolution system is better in principle: show us results obtained

It was a question, I think the interesting idea is that a circulator pump consumes much less than a compressor.