JPS60226675A - Intermittent operation type multistage cooling device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a chemical heat pump device that utilizes heat generation and heat absorption in a reversible adsorption/desorption reaction of a working gas. It is for obtaining.

Conventional configurations and their problems Heat pump devices can be roughly divided into three types: compression type, absorption type, and chemical heat pump. The chemical heat pump according to the present invention has been attracting increasing attention in recent years from the viewpoint of effective energy utilization.

Chemical heat pumps are heat pumps that use adsorption and desorption reactions of substances or phase change reactions, and the working medium is metal hydrides or inorganic hydrates.

Organic substances, zeolites, etc. are considered as such materials. These working gases include hydrogen, water vapor, and ammonia.

A conventional general intermittent cooling cycle exhibits the temperature and equilibrium pressure characteristics shown in FIG. Two types of metal hydrides with different temperature equilibrium pressure characteristics are used, and the metal hydride (MHl) with a lower equilibrium pressure at the same temperature adsorbs hydrogen sufficiently.
When communicating with a metal hydride (MH2) with high equilibrium pressure at the same temperature that has desorbed sufficient hydrogen at TA degrees, the hydrogen in MHL moves to MH2 (state B). MH2 generates heat through an exothermic reaction, which is discarded into the atmosphere or into a heat sink. Next, when MHL is cooled in the atmosphere or the like and communicated with MH2, hydrogen in MH2 moves to MHL, and MH2 absorbs heat, so the temperature drops to Tc degrees (C state). On the other hand, since the MHI generates heat, it is discarded into the heat sink (state D) 0 Like this A→B
−) By repeating the process of C−+D, T
Cold heat at a temperature of Tc can be generated using heat from a heat source at a temperature of H degrees.

In this way, it is extremely useful because it can perform cooling using thermal energy, but when you want to further increase the temperature difference between the heat sink temperature and the resulting low temperature, as shown in Figure 2, it is possible to perform cooling using thermal energy. The equilibrium pressure is the MH mentioned earlier
Using MH3, which is even higher than 2, Fig. 2 +7) A
' -+ B' -+ C'-+ I) By forming a nof cycle, Tc' lower than the above-mentioned TO
However, at the same time, the heating temperature TH rises to TH' and the high pressure also rises from PH to PF6.

Therefore, this method cannot be used when the heat source temperature cannot be changed sufficiently.

Therefore, as shown in Fig. 3, with the combination of the same materials <, MHl, MH2, further
``, and the heat generation at B is A→B
-+ C-+ As in the D cycle, it is discarded into a TA degree heat sink, but the heat generated in D" is the same as the previous A→B→C-
A method has been invented which allows the temperature to be changed to a lower temperature equivalent to that of the A'→B'→C'→D' cycle without increasing the heating temperature TH6 streak by processing by the endotherm at C of +D psi. (Japanese Unexamined Patent Publication No. 58-99663). The difference between the low temperatures obtained by this and the previous methods and the heat sink temperature is considered to be less than twice the temperature difference for a single cooling cycle.

The biggest practical difficulty with either of these methods is that the difference between high and low pressure is from PH-PL to PF6-PL or PHPL'
(See Figure 2 or Figure 3).

Purpose of the Invention The purpose of the present invention is to combine two cooling cycles, make the heating temperature the same in the two cycles, and use the low temperature obtained in the first cycle to reduce the heat generated by absorption of the adsorption/desorption medium on the low temperature side in the second cycle. By combining the two cycles in such a way that the heat generated by the absorption of the adsorption/desorption medium on the high temperature side is discarded into the same heat sink as in the first cycle, the system operates with the same high and low pressure difference as in the case of one cycle, and The difference between the heat sink temperature and the low temperature output temperature is 6 for one stage.
The second step is to obtain a two-stage cooling device that achieves twice the efficiency.

Structure of the Invention The multi-stage cooling device of the present invention stores a working gas and two types of media capable of reversibly adsorbing and desorbing the working gas and having different temperature and equilibrium pressure characteristics, respectively, in a closed container divided into two chambers.
Heat generated during gas adsorption/desorption reactions.

This is a chemical heat pump device that utilizes heat absorption, in which the heat pump cycle adsorbs the adsorption to a high-temperature side adsorption/desorption medium consisting of at least two sets, discards the adsorption heat generated at that time to a heat sink such as the atmosphere, and then By cooling the desorption reaction medium to the heat sink temperature and causing the working gas from the low temperature side adsorption/desorption medium to be adsorbed again to the high temperature side adsorption medium, a cooling cycle is formed in which the temperature of the low temperature side adsorption medium is made to absorb heat below the heat sink temperature, Furthermore, in the second cooling cycle where the heating temperature is the same as that of
is the same as that of the first cycle, so that the heat generated by the adsorption of the adsorption/desorption medium on the low temperature side can be removed by the heat absorption on the low temperature side of the first cycle.

More preferably, in the combination of these two cycles, the adsorption and desorption pressures (high pressure and low pressure) in both cycles are configured to be the same, and even more preferably, the adsorption and desorption media on the high temperature side of both cycles are made of the same substance. Use materials with identical temperature equilibrium pressure characteristics.

Still in this cycle, combinations of metal and hydrogen to form metal hydrides are easily realized.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the multistage cooling device of the present invention is shown in FIG. 4, and a cycle diagram thereof is shown in FIG. 6. In addition, an explanation will be given using metal hydride as an example of a medium that can be adsorbed and desorbed. As shown in Figure 4, two types of metal hydrides with different temperature and equilibrium pressure characteristics are housed in two compartmented closed containers. I created two sets. In FIG. 5, MHl and MH2 form a first cooling cycle that operates at a relatively high temperature side, and MH1' and MH2' form a second cooling cycle that operates at a relatively low temperature side.
A cooling cycle was configured. In these two cooling cycles, the high temperature heating side with lower equilibrium pressure at the same temperature is MHL
and MH1'.

Next, the operation of the cooling device will be explained.

The metal hydride on the high-temperature heating side of the first cooling cycle is heated at TH degree by heat source 1, and the metal hydride on the low-temperature heating side (
When MH2) is cooled with outside air at TA degree and valve 2 is opened, hydrogen adsorbed in MHL moves to MH2. At this time, MH1 absorbs heat, and MH2 generates heat. This heat generation is discarded in the radiator 4 (hydrogen transfer from state A to B in Figure 6). After that, the valve 2 is closed to stop heating MHL, and the radiator 5 cools it to the TA temperature, and the valve 2 When I reopen the
Hydrogen in MH2 moves to MHL, causing an endothermic reaction in MH2.

The second cooling cycle is also heated by the heat source 1, and the high temperature heating side temperature TH is the same temperature as that of the first cycle. When valve 2' is now opened, hydrogen gas moves toward 9HenoMH2' and is adsorbed, but at this time heat is generated.

In accordance with this timing, the endothermic reaction in MH2 of cycle 1 is made to proceed, and the heat transfer means 3 is
If provided between H2 and MH2', MH2' is cooled at the cooling output temperature TC of MH2. Next, close valve 2' and MH
1' is cooled to atmospheric temperature by the radiator 6, hydrogen in cycle 2 moves from MH2' to MH1', and MH2'
cools down to 107 degrees, which is even lower than TC. This can be taken out from the output end 7.As a specific example of the present invention, a cooling device having the configuration and temperature-pressure cycle as shown in FIGS. 4 and 6 was prototyped, and the results of its evaluation will be described.

T 1 o as MHL, as Z ro, es Mn1.2
Cro, e Coo, 2MH2 as T 1 o, e Z r o, 4″11.4 C
rO, 4CuO, 2MH/ is the same as MHl 1o / MH2' as T 1 o , s Z ro , 2 Mn1.2 C
ro, 6Cuo, 2 Ti-Mn alloys
Kg each was filled into an apparatus having the configuration shown in Fig. 4. The metal hydride was prepared so that approximately 31 moles of hydrogen gas was transferred in each heat pump cycle.

By setting the temperature of the heat source 1 to 95°C and setting the heat radiation temperature to the heat sink in the first cooling cycle to 46°C, the temperature was reduced to about 20'C.

On the other hand, the second cooling cycle is heated at 96°C as well, and the heat generated by the adsorption of the adsorption/desorption medium on the low temperature side is cooled at the cooling output temperature of 20'C in the first cycle, and the heat generated due to the adsorption of the adsorption/desorption medium on the high temperature side is cooled. By dissipating heat at 46°C as in the first cycle, the temperature was reduced to about 2°C.

This experiment is an example of an experiment in which a low temperature is obtained under unfavorable conditions such as a relatively low-temperature heat source and a high heat sink temperature such as air cooling, but if the heat source temperature is high, a lower temperature can be obtained in the first cycle, and a lower temperature can be obtained in the second cycle. By choosing a material that matches the MH2' of the cycle, a lower temperature of 11/\- can be obtained.

Also, in the experiment mentioned above, the value obtained by dividing the output by the input, the so-called coefficient of performance, was obtained as 0.4.

In principle, the coefficient of performance for each cycle is C0P.
1. If C0P2 is assumed and the coefficient of performance of the two-stage cooling cycle of the present invention is CoP, then it is given by:

In this embodiment, MHL and MH1' are made of the same substance and designed so that high pressure and low pressure are the most convenient pressure ranges, but it is of course possible to use different substances as the working gas. However, in any case, it is preferable to use hydrogen gas as the working gas in at least one of each heat pump cycle, and to use a metal or an alloy thereof capable of forming a metal hydride as the adsorption/desorption reaction medium. The heat pump cycle using metal hydrides has a long lifespan due to the reversibility of the reaction and repeated operation.
(The cooling cycle shown in the example is a two-stage cooling cycle,
Using the same principle as the 3rd and 4th stages, a lower temperature can be obtained by repeating the cycle without increasing the heating temperature.

Effects of the Invention Conventionally, when trying to obtain a low temperature using an intermittent cooling cycle, it was necessary to raise the heating temperature higher to obtain a lower temperature, and when using solar heat etc., the heat source temperature Since very high temperatures could not be expected, the low temperatures that could be obtained were limited, making it impractical.

In response, methods have been invented that combine two cycles, but the biggest drawback is that the difference between high and low pressure increases. That is, when the cycle is stacked in two stages in the conventional method, the pressure ratio between high and low pressure is raised to the square of so, and depending on the difference between the heating temperature and the heat sink temperature, the pressure ratio becomes 5 to 10 times higher in one stage.

By the way, if the low pressure is significantly lower than 1 atm, it will be difficult to use due to pressure loss, and if the high pressure is significantly higher than 10 atm, problems will arise in terms of pressure vessel design and safety.

According to the method of the present invention, if the pressure loss required for the movement of gas between the two adsorption/desorption media is ignored, the pressure ratio does not change even if the number of stages is increased.

Also, the coefficient of performance of the two-stage refrigeration cycle of the present invention is given as described above, but the coefficient of performance of the conventional two-stage cycle shown in FIG. Since the value is smaller than 1, equation (1) is always larger than equation (2). Also, cycle 2 in Figure 3
In the second stage, the temperature difference between the top and bottom of each medium is large and the coefficient of performance is lower than in the first stage, whereas in the present invention
The coefficient of performance of each stage remains unchanged, and as a result, the method of the present invention is superior to the conventional two-stage method in terms of coefficient of performance.

14 heno

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle of a conventional intermittent cooling cycle, Figure 2 is a diagram showing a cycle for obtaining a lower temperature in a single cycle, Figure 3 is a diagram showing a conventional two-stage cooling cycle, and Figure 3 is a diagram showing a conventional two-stage cooling cycle. 4
The figure is a block diagram of a two-stage cooling device according to an embodiment of the present invention, and FIG. 6 is a diagram showing a cooling cycle in the two-stage cooling device. 1...Heat source, 2, 2', old...Valve, 3...
・Heat transport means, 4. 5, 5... radiator, 7.
...Output end.

Claims (2)

[Claims] (1) Two types of adsorption/desorption reaction media, which are substances that can reversibly adsorb and desorb working gases and have different temperature equilibrium pressure characteristics, are used, each medium is housed in a container, and the working medium is connected between the two media. At least the first chemical heat pump cycle utilizes heat generated and absorbed during movement. A second cycle is prepared, in which the low and high-temperature side adsorption/desorption reaction media at the same temperature and equilibrium pressure are heated by a heat source, and the working medium is adsorbed by the low-temperature side adsorption/desorption medium with a high equilibrium pressure. The heat of adsorption is dissipated into the heat sink, the high temperature side adsorption/desorption reaction medium is then cooled to the heat sink temperature, and the working gas from the low temperature side adsorption/desorption medium is adsorbed again to the high temperature side adsorption/desorption medium, thereby reducing the temperature of the low temperature side adsorption/desorption medium. is used as a cooling cycle that absorbs heat below the heat sink temperature, and the heating temperature and cooling temperature of the high temperature side adsorption/desorption medium in the second cycle are 2. An intermittent operating multistage cooling device that is the same as that of the first cycle, and is capable of removing heat generated by adsorption of the adsorption/desorption medium on the low temperature side of the second cycle by heat absorption on the low temperature side of the first cycle. (2) The intermittent operating multi-stage according to claim 1, in which hydrogen gas is used as the working medium in at least one of each cycle, and a metal or its alloy capable of forming a metal hydride is used as the adsorption/desorption reaction medium. Cooling system.