JPH0571887A - Heat accumulation method - Google Patents

Abstract

PURPOSE:To make it possible to accumulate heat even if it is a low temperature heat source by installing a mechanical booster (steam compressor) between a heat accumulation reactor and a condenser. CONSTITUTION:There is installed a mechanical booster 9 from a pipeline which connects a heat accumulation reactor 1 to a condenser 6 which cools, condenses and returns aqueous vapor generated by a dehydrating reaction by way of valves 10 and 11. This mechanical booster 9 is provided with a capacity to compress a pressure which exceeds a suction pressure of aqueous vapor by a constant value, which lowers a dehydration and regeneration temperature and raises a condensation temperature. This construction makes it possible to accumulate heat even if it is a low temperature heat source, which results in an increase in the degree of freedom about the heat source temperature in a heat accumulation process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage method utilizing the heat of hydration reaction of a solid inorganic compound or a chemical heat pump which is an application technique of this heat storage method. More specifically, the solid inorganic compound is used as a heat storage medium, The present invention relates to a heat storage process of a heat storage system in which heat is stored by subjecting a heat storage medium in a hydrated state to a dehydration reaction, and heat is released by subjecting a partially or completely dehydrated heat storage medium to a hydration reaction with water vapor.

[0002]

2. Description of the Related Art First, the principle of a heat storage system utilizing the heat of hydration reaction of a solid inorganic compound will be described with reference to FIGS. FIG. 1 is a device diagram of a conventional heat storage method, and FIG. 2 is a graph showing a saturated vapor pressure curve of water and an inorganic hydrate in the conventional heat storage method. The heat storage system includes a heat storage process and a heat dissipation process.

(Heat Storage Process) A.nH ₂ O (solid) + Q1 (heat) on the reactor (1) side → A. (N−a) H ₂ O (solid) + aH ₂ O (gas) (1) Condenser (6) Side aH ₂ O (gas) → aH ₂ O (liquid) + Q2 (heat) (2) In FIG. 1, A · nH ₂ O (solid) which is a heat storage medium filled in the reactor (1) Solid inorganic hydrate represented by (2)
_Is heated to T _E1 ° C by flowing a heat source fluid (4) having a temperature T _S1 through a heat exchange section (3) provided in the reactor (1). At this time, the heat storage medium A · nH ₂ O (solid) exhibits the equilibrium steam pressure P _E1 of T _E1 ° C shown in FIG. On the other hand, this pressure P _E1 is T _C1
Equivalent to saturated water vapor pressure of water in ° C, reactor (1) and condenser
Open the valve (5) provided in the pipe (12) connecting (6), and in the heat exchange part (7) on the condenser (6) side, T _W1 ℃ lower than T _C1 ℃
When the cooling water of (2) is flowed, the water vapor is cooled, condensed and condensed by the reaction of Eq. (2), so the water vapor on the right side of the reaction equation of (1) decreases and the reaction of Eq. (1) proceeds to the right. Become. Reactor
The heat storage process ends if the valve (5) is closed while a mole of water vapor is dehydrated from A.nH ₂ O (solid) in (1).

The heat storage process described here corresponds to a regeneration process in the case of a chemical heat pump.

(Heat dissipation process) Evaporator (6) side aH ₂ O (liquid) + Q 2 (heat) → aH ₂ O (gas) (3) Reactor (1) side A · (na) H ₂ O ( Solid) + aH ₂ O (air) → A ・ nH ₂ O (solid) + Q1 (heat) (4) When dissipating the stored heat, separate water in the condenser (6) separated during heat storage is provided. To the designated evaporator,
Or use the condenser (6) as it is as an evaporator,
When the auxiliary heat source fluid (usually water) of T _W2 ℃ (8) is flown into the heat exchange section (7) of the evaporator (6), the reaction of equation (3) causes the P P equivalent to the saturated vapor pressure of T _C2 ℃. Generates _E2 water vapor. valve
Open (5) and introduce this steam into the reactor (1)
Since the reverse reaction of the equation (1), that is, the reaction of the equation (4) occurs, the original inorganic hydrate A · nH ₂ O (solid) is generated and the hydration reaction heat Q1 is generated. Heat having a temperature of T _S2 ° C is recovered by the heat recovery fluid (4) through the heat exchange section (3). At this time, the temperature of the heat storage medium rises to the equilibrium temperature T _E2 corresponding to P _E2 .

The above is the principle of the heat storage system using the inorganic hydrate, and when recovering a temperature higher than the heat source temperature at the time of heat storage by using heat of a slightly high temperature as the auxiliary heat source fluid, a temperature rising type chemical is used. It becomes a heat pump.

The difference between the saturated water vapor pressure curve of water and the saturated water vapor pressure curve of inorganic hydrate shown in FIG. 2 is represented by a temperature difference (for example, T _E1 -T _C1 , T _E2 -T _C2 ). Generally, it is called a temperature rise range, but the temperature rise range naturally depends on the type of the inorganic hydrate and has a unique value.

In this heat storage system, the larger the temperature rise, the higher the temperature at which heat can be stored, but conversely, heat cannot be stored or the inorganic compound cannot be regenerated without a high-temperature heat source. For example, when A · nH ₂ O in the formula (1) is CaBr ₂ · 2H ₂ O and A · (na) H ₂ O is CaBr ₂ · H ₂ O, CaBr ₂ · 2H ₂ O T _E1 and T _C1 have a relation of approximately T _E1 = 1.24 × T _C1 +87 (5). Therefore, the temperature rise width ΔT is ΔT = T _E1 −T _C1 = 0.24 × T _C1 +87 (6). When this heat storage method is put into practical use, normally cooling tower circulating water is often used as cooling water, and T _C1 is about 40 ° C. in the summer. Therefore, from equation (5), T _E1 is 1
37 ° C, and if the heat transfer temperature difference is 10 ° C, 147
In principle, heat cannot be stored unless the heat source has a temperature of ℃ or more.

[0009]

If the condensation temperature of the dehydrated water vapor is determined in this manner, the temperature required as a heat source for heat storage or regeneration will be determined, and therefore the heat storage reaction by a heat source at a temperature lower than this or the construction of a chemical heat pump. I couldn't.

Further, since the heat source temperature is high as described above, there is a problem in the material of the heat storage reaction device. That is, lightweight aluminum has a corrosion resistance limit temperature of 150 ° C. For example, when CaBr ₂ · 2H ₂ O is used as a heat storage medium, aluminum is conventionally used as a device material because of its corrosive property. Instead, stainless steel was used. Therefore, it has been desired to reduce the weight of the device.

An object of the present invention is to improve the drawbacks of such a heat storage method and to provide a method capable of storing heat even at a lower temperature heat source.

As a result of earnest research, the present inventors have found means for achieving the above object.

[0013]

Means for Solving the Problems That is, the present invention uses a solid inorganic compound as a heat storage medium, and the heat storage medium in a hydrated state is subjected to a dehydration reaction to perform heat storage, and a part or all of the heat storage medium is dehydrated. In the heat storage process of the heat storage system that radiates heat by subjecting water to hydration reaction with water vapor, the heat storage reactor (1) that heats the heat storage medium under reduced pressure to regenerate dehydration and cools the steam generated by the dehydration reaction. The heat storage method is characterized in that a mechanical booster (9) is provided between the condensers (6) that condense and condense water to lower the dehydration regeneration temperature and raise the condensation temperature.

In the present invention, a mechanical booster
(9) is the vapor compressor (9).

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention.

[0016]

EXAMPLE FIG. 3 is an apparatus diagram of the heat storage method of the present invention, and FIG. 4 is a graph showing a saturated vapor pressure curve of water and an inorganic hydrate in the heat storage method of the present invention.

In FIG. 3, the heat storage reactor (1) and the condenser
A vapor compressor (9) called a mechanical booster is installed from a pipe (12) connecting (6) through valves (10) and (11). This mechanical booster (9) has the ability to compress by ΔP (mmHg) than the water vapor suction pressure. Other configurations in the figure are similar to those in FIG.

(Heat Storage Process) On the side of the condenser (6), the same cooling water of T _W1 ° C. as described in FIG. 1 is flown, and the valves (10) and (11) are opened while operating the mechanical booster (9).
On the reactor (1) side, a heat source fluid having a temperature T _{S1 '} ° C is flown. T _C1
Assuming that water vapor is condensed at ℃, the pressure in the condenser (6) shows P _C1 , which is the same as the pressure P _E1 on the reactor side in the example of FIG. 1, but the mechanical booster (9) 4, the pressure P _{E1 ′} on the reactor (1) side becomes P _{E1 ′} = (P _C1 −ΔP) (mmHg) as shown in FIG. Therefore, the heat storage medium on the reactor side causes a dehydration reaction at an equilibrium temperature T _{E1 ′} ° C. corresponding to P _{E1 ′} . That is, the dehydration reaction temperature is lowered by (TE1-T _{E1 '} ) = ΔT _D.

Therefore, the temperature T of the heat source fluid flowing in the reactor is
_{S1 '} ℃ needs to be a temperature slightly higher than T _E1' ℃, and heat can be stored at a temperature lower than the heat source temperature T _S1 ℃ in the case shown in Fig. 1 where the mechanical booster (9) is not provided. Becomes

For example, assuming that T _C1 = 40 ° C., P _C1 = 5
It becomes 5.3 (mmHg), but ΔP = 17 (mmHg)
When the mechanical booster (9) of No. 1 is interposed, the pressure P _{E1 '} on the suction side (reactor (1) side) becomes P _E1' = 55.3-17 = 38.3 (mmHg), and T _C1 = 33. This is the same as condensing at 3 (° C). Therefore, T _{E1 ′} = 1.24 × 33.3 + 87 = 121.5 (° C.), and the heat transfer temperature difference is 10 ° C. as in the case described in FIG.
Then, the required temperature of the heat source fluid for heat storage is 132 ° C,
The temperature can be lowered by 15 ° C compared to the case where no mechanical booster (9) is interposed.

(Heat dissipation process) The valves (11) and (10) are closed,
The valve (5) is opened to radiate heat in the same way as described in FIG.

[0022]

According to the method of the present invention, since a mechanical booster is provided, heat can be stored even in a low temperature heat source. As a result, the degree of freedom of the heat source temperature in the heat storage process is increased, and the heat storage reaction or the chemical heat pump can be designed corresponding to each heat source temperature.

Further, since the method of the present invention can store heat even at a low temperature heat source, aluminum can be used as a material for the heat storage reaction device, and the weight of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a device diagram of a conventional heat storage method.

FIG. 2 is a graph showing an operation diagram of a conventional heat storage method.

FIG. 3 is a device diagram of a heat storage method of the present invention.

FIG. 4 is a graph showing an operation diagram of the heat storage method of the present invention.

[Description of symbols] (1)… Reactor (2)… Solid inorganic hydrate (3)… Heat exchange section (4)… Heat source fluid (5)… Valve (6)… Condenser (7)… Heat exchange Part (8)… Auxiliary heat source fluid (9)… Mechanical booster (10) (11)… Valve (12)… Pipeline

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Yasuda 5-328 Nishi Kujo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd. (72) Yoshinori Wakiyama 5-3-28 Nishijojo, Konohana-ku, Osaka Within Hitachi Shipbuilding Co., Ltd. (72) Toshihiko Yasuda, 5-3-28 Nishikujo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd. (72) Yoshihide Kawamura, 5-3-28 Nishikujo, Konohana-ku, Osaka Hitachi Shipbuilding Co., Ltd. Within the corporation

Claims (1)

[Claims] 1. A solid inorganic compound is used as a heat storage medium,
In the heat storage process of the heat storage system, the hydrated heat storage medium is subjected to a dehydration reaction to store heat, and the partially or completely dehydrated heat storage medium is subjected to a hydration reaction with steam to release heat. By installing a mechanical booster (9) between the heat storage reactor (1) that heats and recycles water under reduced pressure and the condenser (6) that cools and condenses the steam generated by the dehydration reaction to condense water, A heat storage method characterized by lowering the dehydration regeneration temperature and raising the condensation temperature.