JP2000234820A - Solar heat driven freezing machine and its operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar heat driven freezing machine capable of Increasing a yearly heat output amount than in the prior art. SOLUTION: A solar heat driven freezing machine is adapted such that there are switchably coupled first high temperature side section containers 11, 13 in which there is filled first high temperature hydrogen adsorption alloy MH1 having lower equilibrium hydrogen pressure than that of low temperature hydrogen adsorption alloy MH2, and second high temperature side reaction containers 81, 82 in which there is filled second high temperature hydrogen adsorption alloy MH3 having higher equilibrium hydrogen pressure than those of the low temperature hydrogen adsorption alloy MH2 and the first high temperature hydrogen adsorption alloy MH1, with respect to low temperature side reaction containers 12, 14 in which there is filled the low temperature hydrogen adsorption alloy MH2 having higher equilibrium hydrogen pressure. As a result, there is ensured migration of hydrogen gas between the low temperature side reaction containers 12, 14 and the one high temperature wide reaction containers 11, 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar-driven refrigerator for cooling a refrigeration load using solar heat as a heat source.

[0002]

2. Description of the Related Art The applicant has proposed a solar powered refrigerator as shown in FIG. In the solar powered refrigerator,
A heat collector (4) and an air / water heat exchanger (6) are switchably connected to a heat pump device (1) via a high-temperature side switching device (2), and a low-temperature side switching device (3). The air-water-cooled heat exchanger (5) and the freezer (7) are switchably connected to each other through the, and between the heat collector (4) and the high temperature side switching device (2),
A heat storage tank (9) is interposed.

[0003] The heat pump device (1) includes a first heat pump P1 and a second heat pump P2. The first heat pump P1 is a high-temperature side first reaction vessel (11) containing a hydrogen storage alloy MH1 having a low equilibrium hydrogen pressure.
And a low-temperature-side first reaction vessel (12) containing a hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure are connected to each other via a connection pipe (17), and a valve ( 15) intervenes. The second heat pump P2 includes a high-temperature second reaction vessel (13) containing a hydrogen storage alloy MH1 having a low equilibrium hydrogen pressure and a low-temperature second reaction vessel (14) containing a hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure. ) Are connected via a connecting pipe (18), and a valve (16) is interposed in the connecting pipe (18).

[0004] The high temperature side switching device (2) comprises a heat medium supply pipe (41) and a heat medium return pipe (42) extending from the heat storage tank (9).
A heating medium supply pipe (61) and a heating medium return pipe (62) connected to one of the reaction vessel (11) and the high temperature side second reaction vessel (13) and extending from the air / water cooling type heat exchanger (6). Is connected to the other reaction vessel, and a plurality of three-way valves interposed in the piping system. The low temperature side switching device (3) comprises a refrigerant supply pipe (51) and a refrigerant return pipe (52) extending from the air / water heat exchanger (5) and a low temperature side first reaction vessel (12) and a low temperature side second reaction vessel. A piping system for connecting to one of the reaction vessels (14) and connecting a refrigerant return pipe (71) and a refrigerant supply pipe (72) extending from the freezer (7) to the other reaction vessel; And a plurality of four-way valves interposed therebetween.

[0005] The heat collector (4) is constituted by a plurality of heat collection tubes having a heat pipe structure and can supply high-temperature water (heat medium) at about 140 ° C. The heat medium outlet pipe (43) and the heat medium inlet pipe (44) extending from the heat collector (4) are connected to the heat storage tank (9), and the heat medium outlet pipe (43) is connected to the three-way valve (91). Connected to the heat medium inlet pipe (44) through the heat medium outlet pipe (43) when the heat medium supplied from the heat collector (4) reaches about 140 ° C. Then, a high-temperature (about 140 ° C.) heat medium is supplied to the heat storage tank (9). As a result, sufficient heat is stored in the heat storage tank (9), and a heat medium at a constant temperature (about 140 ° C.) is supplied from the heat storage tank (9) to the heat pump device (1) via the heat medium supply pipe (41). Because

In the heat pump device (1), a heat collector
(4) is a heat source, an air-water-cooled heat exchanger (5) and an air-water-cooled heat exchanger (6) are radiating means, and a freezer (7) is a refrigeration load. →) is configured. For example, in the first heat pump P1, the heat collector (4) is connected to the high temperature side first reaction vessel (11), and the air / water cooling heat exchanger (5) is connected to the low temperature side first reaction vessel (12). When connected, the hydrogen storage alloy MH1 in the high temperature side first reaction vessel (11) is heated (→) to release hydrogen, and the released hydrogen is sent to the low temperature side first reaction vessel (12). And
It is absorbed by the hydrogen storage alloy MH2 (→: regeneration mode). Here, heat generated by the absorption of hydrogen by the hydrogen storage alloy MH2 is radiated from the air-water cooled heat exchanger (5).

Next, by switching the high temperature side switching unit (2) and the low temperature side switching device (3), the air / water heat exchanger (6) is connected to the high temperature side first reaction vessel (11), The freezer (7) is connected to the first side reaction vessel (12). Thereby, the hydrogen storage alloy MH in the high temperature side first reaction vessel (11) is
1 is set to the state temperature, and the low-temperature side first reaction vessel (12)
The hydrogen in the state absorbed in the hydrogen storage alloy MH2 in the inside of the low-temperature side first reaction vessel (12) due to the pressure difference from the state
And absorbed by the hydrogen storage alloy MH1 in the low temperature side first reaction vessel (12). Here, the hydrogen storage alloy MH2 in the low temperature side first reaction vessel (12) is cooled with the release of hydrogen (→: cold heat generation mode). This results in a freezer
The refrigerant supplied from (7) via the refrigerant return pipe (71) is cooled, and the low-temperature refrigerant is sent to the freezer (7) via the refrigerant supply pipe (72).

The above-described refrigeration cycle is connected to a first heat pump P
The first and second heat pumps P2 perform the operation with a phase difference of 180 degrees, so that a low-temperature refrigerant is continuously supplied to the freezer (7).
It is kept at a low temperature.

[0009]

The refrigeration efficiency of a solar-powered refrigerator depends on the product of the heat collection efficiency of the heat collector (4) and the heat efficiency of the heat pump device (1).
The heat collection efficiency of (4) decreases with increasing temperature, whereas
The heat efficiency of the heat pump device (1) increases with the temperature due to the characteristics of the hydrogen storage alloy, and the efficiencies of the heat collector (4) and the heat pump device (1) show opposite characteristics with respect to temperature. Here, the amount of solar radiation received by the collector (4) varies depending on the season,
The temperature of the heat medium supplied from the heat collector (4) changes. Conventionally, this change in temperature is determined by a three-way valve (91) and a heat storage tank as described above.
The heat medium was kept constant by (9) and was supplied to the heat pump device (1) at a constant temperature.

Therefore, in summer when the amount of solar radiation increases, the temperature is reduced to, for example, about 130 ° C., even though a high-temperature heat medium exceeding, for example, 140 ° C. is obtained from the collector (4). Since the heat is supplied to the heat pump device (1), the heat efficiency of the heat pump device (1) becomes lower than a value which should be originally obtained, and as a result, the refrigeration efficiency of the solar heat driven refrigerator becomes low. In winter, when the amount of solar radiation is small, the heat collection efficiency at 140 ° C. is low, and the required heat collection amount cannot be obtained. As a result, the refrigeration efficiency of the solar heat driven refrigerator has been low. As described above, sufficient refrigeration efficiency cannot be obtained for the solar-driven refrigerator throughout the year, resulting in a problem that the annual heat output is reduced.

It is an object of the present invention to provide a solar-driven refrigerator capable of increasing the annual heat output compared to the conventional one, and a method of operating the same.

[0012]

SUMMARY OF THE INVENTION A solar-powered refrigerator according to the present invention is a solar-powered refrigerator for cooling a refrigeration load using solar heat as a heat source, comprising a high-temperature hydrogen storage alloy having a low equilibrium hydrogen pressure. A heat pump that forms a refrigeration cycle by moving hydrogen gas between low-temperature hydrogen storage alloys with high equilibrium hydrogen pressure, and heat for circulating a heat medium between the heat source and the heat pump to heat the high-temperature hydrogen storage alloy. It is composed of a medium system and a refrigerant system for circulating the refrigerant between the heat pump and the refrigeration load to radiate the low-temperature hydrogen storage alloy. Here, the heat pump is filled with a low-temperature side reaction vessel filled with a low-temperature hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure and a first high-temperature hydrogen storage alloy MH1 having a lower equilibrium hydrogen pressure than the low-temperature hydrogen storage alloy MH2. The first high-temperature side reaction vessel, and the second hydrogen storage alloy MH2 having a lower equilibrium hydrogen pressure than the low-temperature hydrogen storage alloy MH2 and the first high-temperature hydrogen storage alloy MH1.
A second high-temperature side reaction vessel filled with the high-temperature hydrogen storage alloy MH3, wherein the first high-temperature side reaction vessel and the second high-temperature side reaction vessel are switchably connected to the low-temperature side reaction vessel; The transfer of hydrogen gas between the reaction vessel and any one of the high-temperature side reaction vessels was enabled.

Here, as the low-temperature hydrogen storage alloy, T
An alloy having a C14 type structure containing i, Zr, Mn, V, and Ni can be adopted. As the first and second high-temperature hydrogen storage alloys, La, Ni, Sn, and Al
Can be adopted as the alloy having a CaCu _5- type structure.

In the above-described solar-powered refrigerator of the present invention, in the low-temperature period including winter, the first high-temperature reaction vessel filled with the first high-temperature hydrogen storage alloy MH1 having a high equilibrium hydrogen pressure is supplied to the low-temperature side reaction vessel. Connect to container. Thereby, the first
Hydrogen gas moves between the high-temperature side reaction vessel and the low-temperature side reaction vessel, and a refrigeration cycle is configured. On the other hand, in the high temperature period including the summer, the second high temperature reaction vessel filled with the second high temperature hydrogen storage alloy MH3 having a low equilibrium hydrogen pressure is connected to the low temperature side reaction vessel. Thereby, the hydrogen gas moves between the second high temperature side reaction vessel and the low temperature side reaction vessel, and a refrigeration cycle is configured.

Therefore, in winter when the heat source temperature is low, it is possible to improve the heat collection efficiency by setting the heat medium supply temperature lower than the reference value. In summer when the heat source temperature is high, the heat medium can be improved. By setting the supply temperature higher than the reference value, it is possible to improve the heat efficiency of the heat pump. As a result, the refrigeration efficiency can be improved over the whole year.

[0016]

According to the solar-powered refrigerator and the method for operating the same according to the present invention, the refrigerating efficiency can be improved throughout the year, so that the annual heat output is larger than before.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. In the solar powered refrigerator according to the present invention, as shown in FIG. 1, a heat collector (4) and an air / water cooling type heat exchanger (6) are connected to a heat pump unit (8) via a high temperature side switching device (2). Are switchably connected, and the air / water heat exchanger (5) and the freezer (7) are switchably connected via the low temperature side switching device (3), and the heat collector (4) is connected to the high temperature collector (4). A heat storage tank (9) is interposed between the side switching devices (2).

The high-temperature side switching device (2) includes a heat medium supply pipe (41) and a heat medium return pipe (42) extending from the heat storage tank (9), and a high-temperature side first pipe.
A heating medium supply pipe (61) and a heating medium return pipe (62) connected to one of the reaction vessel (11) and the high temperature side second reaction vessel (13) and extending from the air / water cooling type heat exchanger (6). Is connected to the other reaction vessel, and a plurality of three-way valves interposed in the piping system. The low temperature side switching device (3) comprises a refrigerant supply pipe (51) and a refrigerant return pipe (52) extending from the air / water heat exchanger (5) and a low temperature side first reaction vessel (12) and a low temperature side second reaction vessel. A piping system for connecting to one of the reaction vessels (14) and connecting a refrigerant return pipe (71) and a refrigerant supply pipe (72) extending from the freezer (7) to the other reaction vessel; And a plurality of four-way valves interposed therebetween.

The heat collector (4) is constituted by a plurality of heat collector tubes having a heat pipe structure.
Supply of high-temperature water (heat medium). The heat medium outlet pipe (43) and the heat medium inlet pipe (44) extending from the heat collector (4) are connected to the heat storage tank (9), and the heat medium outlet pipe (43) is connected to the three-way valve (91). When the heat medium supplied from the heat collector (4) reaches a predetermined temperature, the heat medium outlet pipe (43) is connected to the heat medium inlet pipe (44).
A high-temperature heat medium is supplied to the heat storage tank (9) through the three-way valve (91). This stores enough heat in the heat storage tank (9),
A heat medium of a constant temperature is supplied from the heat storage tank (9) to the heat pump device (1) via a heat medium supply pipe (41).

The heat pump unit (8) includes a first heat pump P1 and a second heat pump P2. The first heat pump P1 includes a low-temperature side first reaction vessel (12) containing a low-temperature hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure, and a first high-temperature hydrogen storage having a lower equilibrium hydrogen pressure than the low-temperature hydrogen storage alloy MH2. A high temperature side first reaction vessel (11) containing an alloy MH1, and a high temperature containing a second high temperature hydrogen storage alloy MH3 having a lower equilibrium hydrogen pressure than the low temperature hydrogen storage alloy MH2 and the first high temperature hydrogen storage alloy MH1. A second reaction vessel (81), and a first reaction vessel (11) on the high temperature side and a second reaction vessel (8) on the high temperature side with respect to the first reaction vessel (12) on the low temperature side.
1) are connected via connecting pipes (17) and (83), respectively, and valves (15) and (19) are interposed in each connecting pipe (17) and (83). or,
A heating medium supply pipe (45) and a heating medium return pipe (46) branched from the heating medium supply pipe (41) and the heating medium return pipe (42) are connected to the high temperature side second reaction vessel (81). I have.

The second heat pump P2 comprises a low-temperature side second reaction vessel (14) containing the low-temperature hydrogen storage alloy MH2,
A high temperature side third reaction vessel (13) containing the first high temperature hydrogen storage alloy MH1, and a second high temperature hydrogen storage alloy MH3;
And a high-temperature third reaction vessel (13) and a high-temperature fourth reaction vessel (82) with respect to the low-temperature second reaction vessel (14). The connecting pipes (18) and (84) are connected to each other, and the connecting pipes (18) and (84) have valves (16) and (20) interposed therebetween. A heating medium supply pipe (65) and a heating medium return pipe (66) branched from the heating medium supply pipe (61) and the heating medium return pipe (62) are connected to the high temperature side fourth reaction vessel (82). Have been.

Incidentally, as the low-temperature hydrogen storage alloy, Ti,
Synthesis of C14 type structure containing Zr, Mn, V, and Ni
Gold, for example Ti_0.85Zr_0.15MnV_0.4Ni
_0.6It is possible to employ
The elementary pressure becomes 0.06 MPa at -20 ° C. In addition,
And the second high-temperature hydrogen storage alloys MH1 and MH3 are L
CaCu containing a, Ni, Sn, and Al₅Type structure
Alloy, such as LaNi_4.7Sn _0.2Al_0.1Take
In this case, the composition ratio of Sn and Al can be reduced.
To adjust the equilibrium hydrogen pressure to, for example, 14
When obtaining the first high-temperature hydrogen storage gold MH1 of 1 MPa at 0 ° C.
In both cases, the second equilibrium hydrogen pressure is, for example, 150 ° C. and 1 MPa.
High-temperature hydrogen storage alloy MH3 can be obtained.

In the above solar-powered refrigerator, the valve (15) of the first heat pump P1 and the valve (15) of the second heat pump P2 are used during a low temperature period including winter (for example, from October to May).
While (16) is opened, the valve (19) of the first heat pump P1 and the valve (20) of the second heat pump P2 are closed to operate.
The temperature of the heat medium supplied from the heat collector (4) to the heat medium supply pipe (41) is set lower than the conventional value (reference value), for example, 100 ° C. On the other hand, in a high temperature period including summer (for example, from June to September), the valve (15) of the first heat pump P1 and the valve (16) of the second heat pump P2 are closed, while the valve (1) of the first heat pump P1 is closed. 19) and the valve (20) of the second heat pump P2 is opened for operation. The temperature of the heat medium supplied from the heat collector (4) to the heat medium supply pipe (41) is set higher than a conventional value (reference value), for example, 140 ° C.

Thus, the heat collector (4) is a heat source, the air / water cooled heat exchanger (5) and the air / water cooled heat exchanger (6) are radiating means,
The freezer (7) becomes a refrigeration load, and a first refrigeration cycle (→→→→) shown in FIG. 2 is configured in a low temperature period, and a second refrigeration cycle (→→→) shown in FIG. ′
→ ′ → ′ →→ ′).

FIG. 3 is a graph obtained by calculating the relationship between the heat source temperature and the heat output of the refrigerator when the cooling water temperature is constant at 20 ° C. in the above-described solar heat driven refrigerator of the present invention. The solid line connects the high-temperature first reaction vessel (11) and the high-temperature third reaction vessel (13) to the low-temperature first reaction vessel (12) and the low-temperature second reaction vessel (14), respectively. The relationship when the first high-temperature hydrogen storage alloy MH1 is used,
The dashed line indicates that the high-temperature second reaction vessel (81) and the high-temperature fourth reaction vessel (82) are connected to the low-temperature first reaction vessel (12) and the low-temperature second reaction vessel (14), respectively. High temperature hydrogen storage alloy M
The relationship when H3 is used is shown.

As shown, in the range A where the heat source temperature is low,
A higher heat output is obtained when the first high-temperature hydrogen-absorbing alloy MH1 is used, but a range B in which the heat source temperature is higher.
In this example, a higher heat output was obtained when the second high-temperature hydrogen storage alloy MH3 was used. FIG. 4 shows the relationship between the cooling water temperature and the heat output when the heat source temperature is constant at 150 ° C. As shown, when the heat source temperature is high, a higher heat output is obtained when the second hydrogen storage alloy MH3 is used, regardless of the cooling water temperature.

Therefore, in the low temperature period including the winter season when the outside air temperature is low, the high-temperature side first gas filled with the first hydrogen storage alloy MH1 is used.
By using the reaction vessel (11) and the third reaction vessel (13) on the high temperature side, the supply temperature of the heat medium to be supplied to these reaction vessels (11) and (13) is set lower than 130 ° C. Heat output is obtained. On the other hand, in the high-temperature period including the summer time when the outside air temperature is high, the high-temperature second reaction vessel (81) and the high-temperature fourth reaction vessel (82) filled with the second hydrogen storage alloy MH3 are used. By setting the supply temperature of the heat medium to be supplied to the containers (81) and (82) to 130 ° C. or higher, a high heat output can be obtained. As a result, the annual heat output is increased more than before.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of a solar heat refrigerator according to the present invention.

FIG. 2 is a diagram illustrating a refrigeration cycle in the solar-powered refrigerator according to the present invention.

FIG. 3 is a graph showing a relationship between a heat source temperature and a heat output.

FIG. 4 is a graph showing a relationship between cooling water temperature and heat output.

FIG. 5 is a system diagram showing a configuration of a conventional solar-powered refrigerator.

FIG. 6 is a diagram illustrating a refrigeration cycle in a conventional solar-driven refrigerator.

[Explanation of symbols]

 (8) Heat pump unit MH1 First high-temperature hydrogen storage alloy MH2 Low-temperature hydrogen storage alloy MH3 Second high-temperature hydrogen storage alloy (11) High-temperature first reaction vessel (12) Low-temperature first reaction vessel (13) High-temperature side Third reaction vessel (14) Low temperature side second reaction vessel (81) High temperature side second reaction vessel (82) High temperature side fourth reaction vessel (2) High temperature side switching unit (3) Low temperature side switching unit (4) Heat collection (5) Air / water heat exchanger (6) Air / water heat exchanger (7) Freezer

Claims (3)

[Claims] 1. A solar heat driven refrigerator for cooling a refrigeration load using solar heat as a heat source, wherein a hydrogen is stored between a high-temperature hydrogen storage alloy having a low equilibrium hydrogen pressure and a low temperature hydrogen storage alloy having a high equilibrium hydrogen pressure. A heat pump that forms a refrigeration cycle by moving gas, a heat medium system that circulates a heat medium between the heat source and the heat pump to heat the high-temperature hydrogen storage alloy, and circulates a refrigerant between the heat pump and the refrigeration load. The heat pump is composed of a low-temperature side reaction vessel filled with a low-temperature hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure, and a low-temperature hydrogen storage alloy MH2. A first high-temperature side reaction vessel filled with a first high-temperature hydrogen storage alloy MH1 having a low equilibrium hydrogen pressure, a low-temperature hydrogen storage alloy MH2 and a first high-temperature hydrogen storage alloy MH1 A second high-temperature side reaction vessel filled with a second high-temperature hydrogen storage alloy MH3 having a lower equilibrium hydrogen pressure than the first high-temperature side reaction vessel and the second high-temperature side reaction vessel with respect to the low-temperature side reaction vessel. A solar-powered refrigerator characterized by being switchably connected so that hydrogen gas can be moved between a low-temperature side reaction vessel and one of the high-temperature side reaction vessels. 2. The low-temperature hydrogen storage alloy is Ti, Zr, M
a C14 type structure containing n, V, and Ni,
The solar heat driven refrigerator according to claim 1, wherein the second high-temperature hydrogen storage alloy has a CaCu _5- type structure containing La, Ni, Sn, and Al. 3. A method for operating a solar heat driven refrigerator for cooling a refrigeration load using solar heat as a heat source, wherein the solar heat driven refrigerator includes a high-temperature hydrogen storage alloy having a low equilibrium hydrogen pressure and a low temperature having a high equilibrium hydrogen pressure. A heat pump that constitutes a refrigeration cycle by moving hydrogen gas between the hydrogen storage alloys,
A heat medium system for circulating the heat medium between the heat source and the heat pump to heat the high-temperature hydrogen storage alloy, and a refrigerant for circulating the refrigerant between the heat pump and the refrigeration load to release the low-temperature hydrogen storage alloy. A low-temperature side reaction vessel filled with a low-temperature hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure, and a low-temperature hydrogen storage alloy MH2.
High temperature hydrogen storage alloy MH having a lower equilibrium hydrogen pressure than
1 and a second high-temperature reaction vessel filled with a second high-temperature hydrogen storage alloy MH3 having a lower equilibrium hydrogen pressure than the first and second high-temperature hydrogen storage alloys MH2 and MH1. A first high-temperature side reaction vessel and a second high-temperature side reaction vessel are switchably connected to the low-temperature side reaction vessel, and the low-temperature side reaction vessel and one of the high-temperature side reaction vessels are connected to each other. The first high-temperature reaction vessel filled with the first high-temperature hydrogen storage alloy MH1 having a high equilibrium hydrogen pressure is connected to the low-temperature side reaction vessel in the low-temperature period including the winter season. While the supply temperature of the heat medium to be supplied from the heat source to the first high-temperature reaction vessel is set lower than the reference value, during the high-temperature period including summer, the second high-temperature hydrogen storage alloy MH3 having a low equilibrium hydrogen pressure is used. Place the filled second high-temperature reaction vessel on the low-temperature side While connected to the container, the method operation of solar driven refrigerator and setting higher than the reference value the supply temperature of the heat medium to be supplied from the heat source to the second hot side reaction vessel.