Process for producing cold by solid-gas reaction and device pert

Details Process for producing cold by solid-gas reaction and device pert Process for producing cold by solid-gas reaction and device pert

1989-03-22

1990-07-31

King, Lloyd L.

Refrigeration

Processes

Evaporation induced by sorption

62480, F25B 1500

Patent

active

049441590

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to a process for producing cold by solid-gas reaction.
The invention also relates to the device for implementing this process.
At present, plants for producing cold make use almost exclusively of compression cycle (compressor--condenser--expansion valve--evaporator).
The advantages of these plants lie chiefly in the fact that they make use of a very well known and proven technique, and make it possible to obtain a good performance (approximately 2 in air conditioning), 1.5 at about 0.degree. C., below 1 in the case of very low temperatures).
The disadvantages of these plants are linked with the presence of the compressor, which presents problems of maintenance and, obviously, with the need to have mechanical energy available (generally in electric form).
The absorption cycle is based on the affinity of one fluid for another. A cycle of this kind comprises an evaporator, an absorber, a separator boiler, a condenser and an expansion valve.
In the case of low temperatures, the formula which is generally adopted is the ammonia/water solution. The advantage of the absorption cycle is that it requires only heat energy (waste heat, gas, lean gas etc.) and that it does not employ essential mechanical parts.
The disadvantages of this cycle are: a relatively low performance (below 0.5-0.8) and the fact that it demands the circulation of a large quantity of solution.
Other known devices for producing cold are gas expansion (airplane air-conditioning), the Peltier effect, and solid sorption systems, which are described hereinafter.
The solid-gas systems make use of adsorption or reaction phenomena. They involve chiefly the following systems:
the zeolite water (Z water) system, limited to a temperature above 0.degree. C.,
the active carbon-methanol (AC-methanol) system
the hydride systems
the salt/ammonia or ammonia derivative systems.
The development of the first three systems above has encountered the following difficulties:
low energy density (Z-water, AC-methanol)
rare products and the presence of hydrogen (hydrides)
system under very low pressure (Z-water)
difficulties of management in the case of divariant systems (Z-water, AC methanol).
The development of salt/ammonia or derivative systems has long been held back by the low powers obtained. Studies carried out on transfers (of mass and of heat) and on kinetics-transfers couplings, have led to the investigation of a binder permitting these transfers to be improved.
The research carried out has made it possible to produce reaction mixtures which under certain conditions produce powers of several kW/kg of salt. This power level makes it possible to design systems whose performance is comparable to the conventional compression systems employed at present.
The basis of the system for producing cold by solid-gas reaction will be recalled below. Under given temperature and pressure conditions, certain solids can react with certain gases: this reaction results in the formation of a defined, generally solid, chemical compound and is accompanied by a heat release. When, under other temperature and pressure conditions, heat is introduced into the compound thus formed, a gas release and the formation of the initial solid product are observed.
The operation of the system takes place, therefore, in two stages which are offset in time, illustrated by FIG. 1, and explained below:
In the first stage, known as an "evaporation-synthesis stage", evaporation of a refrigerant fluid and reaction of the gas thus formed with the solid take place simultaneously:
The fluid F1 supplies the heat .DELTA.HL to the evaporator E. The liquid [G] evaporates and the gas formed is fixed in the reactor R on the solid <S> to give the compound <S,G>. In the reactor R, the reaction is accompanied by a release of heat .DELTA.HR, the latter being removed by the fluid F2. The cold source is therefore the evaporator E, the cold being used directly or indirectly starting with the fluid F1.
In the second stage, called a "decomposition - condensation stage", decomposi

REFERENCES:
patent: 1808056 (1931-06-01), Mitchell
patent: 1932492 (1933-10-01), Smith
patent: 4165952 (1979-08-01), Bennett
patent: 4319626 (1982-03-01), Papazian et al.
patent: 4610148 (1986-09-01), Shelton
patent: 4623018 (1986-11-01), Takeshita et al.
patent: 4637218 (1987-01-01), Tchernev
patent: 4694659 (1987-09-01), Shelton
patent: 4713944 (1987-12-01), Januschkowetz
patent: 4765395 (1988-08-01), Paeye et al.

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