JPH0414258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an intermittent operating heat pump device based on the principle of a chemical heat pump that utilizes heat generation and heat absorption in a reversible adsorption/desorption reaction of a working gas.

BACKGROUND ART First, factors that influence the product coefficient, which indicates the performance of such an intermittent heat pump device, that is, the value obtained by dividing output energy by input energy, will be explained.

To make the explanation easier to understand, an example will be explained in which the adsorbent is a metal hydride and the working medium is hydrogen.

Now, the first container is filled with an alloy powder capable of forming one metal hydride, and the second container is filled with an alloy powder capable of forming one metal hydride.
Assume that the chamber is filled with an alloy powder that forms a metal hydride with a high equilibrium pressure at the same temperature, and the former is sufficiently hydrogenated.

Next, by connecting both containers with a pipe, hydrogen can move to the second container, but since the equilibrium pressure of the alloy hydride in the second container is higher, the hydrogen gas pressure in the first container is In order to make the pressure higher than 2, it is necessary to heat the first container. At this time, the second container shall be kept at room temperature. Furthermore, in order to desorb hydrogen gas, desorption heat is required, and this heat must be supplied. If this heat is Q _a1 and the amount of heat required to warm the container and its contents to a predetermined temperature is Q _s1 , then the input is Q _a1 + Q _s1 . Q _s1 is the product of the sum of the heat capacities of the container and its contents (C ₁ ) and the temperature rise width ΔT ₁ (this is called sensible heat loss).

Upon heating in this manner, hydrogen moves from the first container to the second container, the alloy in the second container becomes almost entirely metal hydride, and the contents of the first container become almost entirely the same as before. becomes an alloy.

Next, when the first container is returned to room temperature and the first and second containers are communicated again, the hydrogen in the second container is dissociated and the alloy in the first container is hydrogenated. An endothermic reaction occurs in the vessel, the temperature of the vessel and its contents decreases, and the endotherm continues at the equilibrium temperature of the metal hydride in the second vessel, which corresponds to the equilibrium pressure determined by the temperature of the first vessel. This heat absorption capacity is the cooling output, and the value of this cooling output is calculated from the total heat absorption Q _a2 generated by the reaction to the amount of heat Q _s2 required to lower the container and contents from room temperature to a temperature at which low-temperature endotherm persists. The value obtained by subtracting Q _a2 −Q _s2 is obtained.
Note that Q _s2 is the product of the heat capacity C ₂ of the second container and its contents and the temperature reduction width ΔT ₂ (sensible heat loss).

From the above considerations, the product coefficient (COP) is given by COP=Q _a2 −Q _s2 /Q _a1 +Q _s1 .

What is clear from this is that how small Q _s1 and Q _s2 are made is a factor in increasing COP.

From the above considerations, it is important to reduce the heat capacities C ₁ and C ₂ of the container, but it is also effective to reduce ΔT ₁ and ΔT ₂ .

FIG. 3 is a diagram schematically representing the basic configuration of an intermittent operation type heat pump device, and shows containers 1 and 2.
are filled with adsorption media 3, 4 and are connected by a support 5, between which a valve 6 is present.
Each container is provided with a heat exchanger 7,8.

First, the adsorption medium 3 in the container 1 is heated via the heat exchanger 7 to release the working medium, which then reaches the container 2 through the pipe 5 and is adsorbed by the adsorption medium 4. At this time, heat is generated, so it is cooled through a heat exchanger 8. At this time, the temperature of the adsorption medium 4 becomes higher than the temperature of the cooling water, and a thermal output is obtained from the heat exchanger 8. Let T _M be the temperature of the adsorption medium 4 at this time.

Next, the adsorption medium 3 is cooled through the heat exchanger 7,
When the valve 6 is opened, the working medium flows from the adsorption medium 4 to the same 3
At this time, heat absorption occurs in the adsorption medium 4, and its own temperature first drops to T _L , and then a cooling output of temperature T _L is obtained from the heat exchanger 8. Here, T _M − T _L is the above ΔT ₂
It is. In this way, the intermittent heat pump alternates between two phase states.

Considering a system that can be used for cooling and heating hot water, T _M = 50℃, T _L = 5℃, and ΔT = 45℃.
It becomes the rank.

Next, to explain the double effect, the product coefficient of each cycle is as explained above, but since the second cycle is driven by the waste heat of the first cycle, it is free, so to speak. You will be working. Productivity coefficient (COP) in this case
If the product coefficients of the first and second cycles are COP ₁ and COP ₂ , then it is given by COP=COP ₁ +COP ₂ , and the product coefficient is significantly improved.

Problems to be Solved by the Invention In principle, the formation coefficient should be greatly improved by creating a dual effect. The problem is that it's big.

In other words, since Δt ₁ is large, Q _s1 in the first cycle is large, and the product coefficient is not very large.
The effect of dual utility is not very effective.

Means for solving the problem Two sets of dual-effect chemical heat pump equipment, A and B, each having a first cycle and a second cycle are used. In this case, the second cycle is heated by the heat generated when the high temperature medium of the first cycle is adsorbed.

Here, a fluid passage capable of exchanging heat with the internal adsorption medium is provided in the storage container for the high temperature side medium of each cycle, and these passages are connected to the first group of A group, the first group B, the second group B, and the second group A. A circulation path is provided which is connected in sequence and finally returns to the first group of A, and a heat medium is sealed in this circulation path, and means such as a pump is provided along the way to circulate the heat medium in the above order or in the reverse order.

Furthermore, in this circulation path, valves that can be opened and closed are provided in the middle of the pipe connecting the first group A and the first group B, and in the middle of the pipe connecting the second group A and the second group B. 1,
A heat medium path having an on-off valve in the middle is provided between the other ends of the heat medium path of the high temperature side container of the second cycle that are not directly connected by the circulation path.

Function When operating as a heat pump, the valve in the circulation path is closed, and the heat medium circulation means is also stopped, so that it does not function at all.

Now consider a state where one cycle is about to end.

For example, assume that the first cycle of group A is heated from the outside, reaches a high temperature _T1 , and releases most of the internal hydrogen.

At this time, the first cycle of group B is lower than T ₁
It is absorbing hydrogen at a temperature of T ₂ and the reaction is almost complete. The heat generated at this time is then transferred by some means to the hot side medium container of the second cycle of group B, and this container and the medium therein are at a temperature approximately close to T ₃ but somewhat lower than that.
At T ₂ , the adsorption medium on the high temperature side in the second cycle of group B has released almost all hydrogen.
On the other hand, the second cycle of group A at this time absorbs hydrogen from the adsorption medium on the low temperature side of this cycle at a temperature of _T4 , which is even lower than _T3 , and the reaction is almost completed.

That is, A1 (the first cycle high temperature side adsorption medium of group A and its container, the same applies hereinafter) is T ₁ degree,
B1 is T ₂ degrees, A2 is T ₄ degrees, B2 is T ₃ degrees, and T ₁ > T ₂
>T ₃ >T ₄ .

Here, in the next phase state, the states of group A and group B are reversed, and A1 is T ₂ , B1 is T ₁ , A2 is T ₃ , and B2 is
At T ₄ degrees, the adsorption and desorption operations are reversed.

Therefore, upon this phase reversal, A1 becomes T ₁ - _{T 2}
, and B1 must increase in temperature by T ₁ - T ₂ .

Also, the temperature of A2 must be increased by T ₃ - T ₄ and the temperature of B2 must be decreased by T ₃ - _{T 4} .

This temperature difference multiplied by the specific heat of the container and adsorption medium is the sensible heat loss mentioned at the beginning, and is the cause of the decrease in the accumulation coefficient.

Therefore, when this phase is reversed, a state called the heat recovery phase is created. That is, the valve of the hydrogen passage between the containers of each cycle is closed to prevent it from moving to the next phase, and the above-mentioned circulation path is filled with A in the condition described.
The valves of the heat medium path are opened so that the heat medium can be circulated in the order of 1, B1, B2, and A2, and the pump as a heat medium circulation means is activated.

In this way, A1 at T ₁ degree will gradually cool down.
B1 at T ₂ degrees is gradually warmed, and the temperature of both is ideally T ₁ +T ₂ /2.

Also, B2 at T ₃ degrees is gradually cooled, and A2 at T ₂ degrees is gradually warmed, and ideally the temperature of both is
It becomes T ₃ +T ₄ /2.

After this, the next reverse phase state is entered, and when the hydrogen flow path valve is opened, hydrogen flows in the opposite direction to A1,
B1, A2, and B2 are T ₂ , T ₁ , T ₃ , and T ₄ degrees, respectively.

And when this phase is finished, close the hydrogen valve as before, and this time turn the heating medium into B1, A1, A2, B
When flowing in the order of 2, B1 and A1 are at the same temperature again.
At T ₁ +T ₂ /2, A2 and B2 become T ₃ +T ₄ /2.

In addition, during the operation phase as a dual-effect heat pump, between A ₁ and A ₂ of the heat medium circulation path, B ₁ and B ₂
At the same time, the valve on the side where heat needs to be transferred from the first cycle to the second cycle for double effect (for example, if this is between A1 and A2) is directly in the circulation path. If you open the valve of the pipe connecting the other end of the unconnected container heat medium passage, A1,
Since a heat medium circulation path is created between A2, heat can be transferred from A1 to A2 using this circulation path using the same heat medium and the same heat exchanger as in the previous sensible heat recovery.

Example FIG. 1 shows an embodiment of the present invention.

The left side of the figure is the A group, and the right side is the B group dual-effect chemical heat pump. All part numbers for the A group have a 1 in the single digit, and the B group has a 2 in the 1 digit. The same numbers were assigned to corresponding parts of the two sets.

11 (12), 21 (22), 31 (32), 4
1 (42) respectively indicate containers containing metal hydrides;
In this cycle, containers 31 and 41 form a second cycle, containers 11 and 31 are on the high temperature side of their respective cycles, and containers 21 and 41 are on the low temperature side of their respective cycles. The valves 51 and 61 are valves that open and close the hydrogen flow path of each cycle.

The pipe lines 101, 111 etc. provided in each container are
It is a heat medium passage (heat exchanger tube) that can exchange heat with the metal hydride that is the content, and the containers 21 (22), 4
1 (42) also requires a heat exchanger tube to take out the cold output, but it is omitted because it is not necessary for the explanation. Further, the heat transfer tubes used for cooling the high temperature side container 31 (32) in the second cycle will also be omitted.

In this way, in two sets of dual-effect chemical heat pump cycles, the pipes 101, 102, 11
2 and 111 are provided, pipes 15 and 16 are provided,
Pipe lines 101, 16, 102, 122, 112, 1
5, 111, 121, and then back to the pipe line 101, forming a circulation path. At this time, pipes 131 and 132
Valves 71 and 72 provided in are closed. Also, in this circulation path, there is a liquid pump 91 (92) having a bypass valve 81 (82), and when the pump 91 is operated, the bypass valve 81 is closed, and the bypass valve 82 is opened,
The heat medium circulates in the above-mentioned circulation path counterclockwise in the figure, and when the pump 92 is operated in the opposite direction to close the bypass valve 82 and open the bypass valve 81, the heat medium circulates clockwise.

Also, with the valves 13 and 14 closed, the pump 91
When the bypass valve 81 is closed and the valve 71 of the pipe line 131 is opened, heat exchange between the high temperature side adsorption medium container 11 of the first cycle of group A and the high temperature side adsorption medium container 31 of the second cycle is performed. conduct. heat exchanger tube 101,
The heat medium can be circulated through the circulation path of the pipe line 131, the heat transfer tube 111, and the pipe line 121. Said pump 9
If one digit of the number in the explanation below 1 is set to 2, exactly the same thing will be done in group B.

Figure 2 shows the opening and closing of the valves, pump operation, and presence/absence of heating by the external heat source on the high temperature side of the first cycle. If the phase is set to It exists, but it is operated between them.

The heat transfer in this system may be so-called sensible heat transfer using the temperature difference of the liquid, but it is even better to use so-called latent heat transfer due to evaporation and condensation. That is, for example, in counterclockwise circulation, the heat exchanger tube 10
Evaporates at 1, condenses at 102, evaporates at 112,
111 to condense. This is because there is a large temperature difference between the heat exchanger tubes 111 and 101, and in sensible heat transfer, the metal hydride 11 is cooled by this temperature difference.

Effects of the Invention As explained above, a phase of sensible heat regeneration is provided between the two phases of operation, and at this time, the heating medium flows through the four metal hydrides in a predetermined order. The medium and containers 101 and 102 on the high temperature side of the cycle have their average temperature (T ₁ +
T ₂ )/2, and the container 111 of the second cycle,
112 reaches a temperature of (T ₃ + T ₄ )/2 and then enters the next operation phase. Therefore, the temperature increase width of the next heated container is changed from the conventional T ₁ - _{T 2} or T ₃ - T ₄ to T ₁ −
(T ₁ + T ₂ )/2 = (T ₁ − T ₂ )/2, or (T ₃ −
T ₄ )/2, and the sensible heat loss mentioned earlier is also halved, so the product coefficient for each cycle is (Q _a2 − Q _s2 )/(Q _a1 + Q _s1 ) to (Q _a2 − Q _s2 )/
(Q _a1 +Q _s1 /2). When the latter is divided by the former to find the ratio, it is clearly larger than 1 as 1+Q _s1 /2/Q _a1 +Q _s1 /2. In other words, this indicates that the product coefficient increases.

Another important point here is that in the formula for the product coefficient shown in the prior art, if the numerator becomes 0, there is no possibility of improving the product coefficient by this method. That is, it must be noted that this method is not effective unless the heat capacities C ₁ and C ₂ of the first and second containers and their contents are made small.

The idea of a sensible heat circuit is not new;
There are already proposals based on this idea, but
In order to do this, a heat exchanger is installed in the metal hydride storage container to recover excess sensible heat, and separate heat carriers are used for each, so in reality, C ₁ and C ₂ are not as expected. The coefficient of performance is often close to 0 or negative.

Particularly in the case of the present invention, where the heat generated in one cycle is used to drive another cycle (double effect), an extra heat exchanger is required for this purpose, further increasing the heat capacity of the container.

The present invention relates to a configuration in which a heat exchanger for dual effect, a heat exchanger for sensible heat recovery, and _a heat medium can be used in common.
Since Q _s2 can be made small, the coefficient of performance without sensible heat recovery is improved, and the effect of sensible heat recovery is increased accordingly, as is clear from the above equation.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an intermittent heat pump device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the same device, and FIG. 3 is a basic block diagram of a general intermittent heat pump device. . 11, 21, 31, 41... Container, 101, 1
11... Pipe line, 91, 92... Heat medium pump, 5
1, 61, 81, 71, 13, 15... valve.

Claims (1)

[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 a working medium passage is provided to connect these containers. comprising a pump for transferring heat of the working medium between each cycle, the adsorption exothermic temperature of the hot side medium of the first cycle being higher than the thermal desorption temperature of the hot side medium of the second cycle; A and B groups of dual-effect chemical heat pumps are used to perform heating in the second cycle using heat generated in the first cycle, and are operated alternately in opposite phases, and an on-off valve is provided in the working medium passage. Groups A and B, 1st and 2nd
A heat exchanger tube that can exchange heat with the adsorption medium inside is installed in the high temperature side medium container of the cycle, and these are connected.
A circulation path is provided which returns to the first group A pipe line through each of the pipe lines of the first group, the first group B, the second group B, and the second group A, and a heat medium is sealed in the circulation path, and the heat medium is An intermittent operating heat pump device comprising means for circulating the medium in said order and in the reverse order.