JPH0573984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a chemical heat pump device that ideally generates heat and absorbs heat through reversible adsorption and desorption reactions of working gas. It can be widely used as air conditioning, heating, and hot water equipment.

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 utilize adsorption and desorption reactions of substances or phase change reactions, and the working medium is thought to be made of metal hydrides, inorganic hydrates, organic substances, zeolites, etc. These working media include hydrogen, water vapor, and ammonia. Although the chemical heat pump devices known so far are expected to have many features such as energy saving, no noise, and no vibration, they have not reached the practical level of current compressor and absorption types.

The main reasons for this include relatively low performance as a heat pump device including coefficient of performance (COP), difficult usage conditions, and economic efficiency. Specifically, the heat exchanger occupies a larger proportion in terms of weight, volume, and heat capacity than the medium-filled container, and the heat exchanger requires pump power to circulate the heat medium during heat exchange. This includes expending extra energy and requiring additional piping to switch heat exchange loops. Therefore, improving performance and reducing costs are important issues for chemical heat pump devices.

Next, the configuration of a conventional heat pump device and its problems will be explained using a metal hydride as an example. A conventional general heat pump cycle exhibits the temperature/equilibrium pressure characteristics shown in FIG. Using two types of metal hydrides with different temperature and equilibrium pressure characteristics, the metal hydride MH1, which has a low equilibrium pressure at the same temperature, is heated to the TH temperature by inputting a high-temperature heat source (state A). MH1 is pressurized, and hydrogen can be transferred to the other metal hydride MH2, which has a higher equilibrium pressure, by using the pressure difference. The temperature obtained for MH2 at this time is TM. (State B). Next, if MH1 is maintained at temperature TM and communicated with MH2, MH2
hydrogen moves to MH1. At this time, MH2's temperature drops below room temperature due to an endothermic reaction (TL), while MH1 generates heat (C→D). By repeating the process of A→B→C→D in this way, a heat pump cycle of the heat acquisition type that obtains heat at the TM temperature due to the heat generated by the reaction in states B and D with the input of the high temperature heat source TH of A, In state C, it is possible to form a cold heat generation type heat pump cycle that obtains cold heat at the TL temperature due to the endothermic reaction of the reaction. In a heat pump cycle as shown in Figure 1,
During heating, when the COP is 1.0 or more, the output is greater than the input, and it is attracting attention as an energy-saving device, but when the COP is around 0.4 to 0.5 during cooling, the performance is relatively poor. In addition, in this heat pump cycle, when the input heat source temperature (TH) is set to a high quality, relatively high temperature, e.g. 200 to 300℃,
The problem is that the COP decreases. This cannot contribute to the effective use of high-quality high-temperature heat sources. In order to improve the low COP of such a simple cycle, there is an invention as disclosed in Japanese Patent Application Laid-Open No. 54-99095. Figure 2 is a diagram of the heat pump cycle. As shown in the figure, it is a multi-stage type using metal hydrides with different temperature and pressure characteristics. It can output hot heat, and in states C and E, it can output cold heat. In this case, the COP during cooling is 0.8
It can be expected to improve up to about 1.0. This cycle is made possible by increasing the input heat source temperature (TH), and is a method that effectively utilizes the high input heat source temperature. However, in this multistage heat pump cycle, the pressure range used in the cycle needs to be considerably expanded compared to the simple cycle shown in FIG. 1 in order to allow the hydrogen adsorption/desorption reaction to proceed smoothly. For this reason, if a high pressure range is selected, the pressure resistance of the container becomes important, which not only increases the cost but also increases the COP due to the increase in heat capacity.
On the other hand, if a low pressure region is selected, the specific volume will increase, the pressure loss during hydrogen transfer will be large, and the reaction rate of the entire cycle will be significantly reduced.

In this regard, a multiple effect heat pump cycle (Japanese Patent Application No. 125044/1982) has been proposed.
This has been solved in principle, but in this case, the adsorption reaction heat of the adsorption/desorption medium on the high temperature heating side of a heat pump cycle that operates at a relatively high temperature is transferred to the adsorption/desorption heat on the high temperature heating side of a heat pump cycle that operates at a relatively low temperature. The need arises to transfer it to a medium.

Conventionally, this purpose has been achieved by providing passages for the heat medium in both media containers and forcibly circulating the heat medium using a pump, resulting in unnecessary power consumption and
There were problems such as increased heat loss from pumps, piping, etc., increased heat capacity of the adsorption/desorption medium container, and a decrease in the coefficient of performance of the entire system.

Purpose of the Invention The present invention effectively utilizes a high-temperature heat source to provide a double (multiple) cycle in which the heat generated by the reaction of one cycle drives another cycle.
Downsizing of heat exchange container, reduction of heat exchange pump power,
By simplifying the heat exchange piping system, the aim is to create a structure that allows the cycle to operate more efficiently and in an energy-saving manner, allowing the cycle to run smoothly and with a high COP (coefficient of performance). .

Structure of the Invention The multiple effect heat pump device of the present invention has a working gas and a temperature at which the working gas can be reversibly adsorbed and desorbed.
This is a chemical heat pump device that stores two types of media with different equilibrium pressure characteristics in a sealed container divided into two rooms, and utilizes heat generation and heat absorption during adsorption and desorption reactions of gas, and the heat pump cycle consists of at least two sets. The adsorption reaction exothermic temperature of the adsorption-desorption reaction medium on the high-temperature heating side with a lower equilibrium pressure at the same temperature in a heat pump cycle where the adsorption-desorption reaction medium on the high-temperature heating side has a lower equilibrium pressure characteristic (operates on the relatively high-temperature side). The high-temperature heating side of the adsorption-desorption reaction medium has a higher equilibrium pressure characteristic (operates on the relatively low-temperature side) and the high-temperature heating side with lower equilibrium pressure at the same temperature of the heat pump cycle (operating on the relatively low-temperature side) has a higher desorption reaction heating temperature of the adsorption-desorption reaction medium. In a device that heats a heat pump cycle (which operates at a relatively low temperature side) using the adsorption reaction heat of a heat pump cycle (which operates at a relatively high temperature side), the heat pump operates at a relatively high temperature side. Adsorption/desorption reaction medium on the high temperature heating side of the cycle (hereinafter referred to as MH1)
(hereinafter referred to as container V1), and a medium that operates at a relatively low temperature side (hereinafter referred to as MH3).
A gravity natural circulation type heat pipe is provided as a connecting pipe line capable of heat exchange between the container filled with (hereinafter referred to as container V3), and a first heat exchange loop is formed. The adsorption reaction heat of the operating heat pump cycle is used to heat the heat pump cycle that operates at a relatively low temperature side, and as a connecting pipe that can exchange heat between the container V3 and the hot/cold output device. A gravity natural circulation heat pipe is installed to form a second heat exchange loop, and the heat generated by the adsorption reaction of the adsorption/desorption medium on the high temperature heating side of the heat pump cycle that operates on the relatively low temperature side is transferred to the pressure heat output device. Try to take it out,
Further, the first and second heat exchange loops are connected to the container V3.
The heat pipe is characterized in that the heat pipe also serves as a conduit in the heat pipe. Each of the heat pump cycles is capable of switching between the first and second heat exchange loops by operating a valve when performing intermittent operation. Furthermore, the same substance or a substance having almost the same temperature equilibrium pressure characteristics should be used for the adsorption/desorption reaction medium on the low temperature endothermic side, which has a high equilibrium pressure at the same temperature of the medium that can reversibly adsorb and desorb the working gas in each heat pump cycle. Further, the present invention is characterized in that hydrogen gas is used as a working gas in at least one of each heat pump cycle, and a metal or an alloy thereof capable of forming a metal hydride is used as an adsorption/desorption reaction medium.

DESCRIPTION OF EMBODIMENTS FIG. 3 shows a configuration diagram of an embodiment of the multi-effect heat pump device of the present invention, and FIG. 4 shows a heat pump cycle diagram thereof. Note that the description will be made using a metal hydride as an example of a medium that can be adsorbed and desorbed. Third
As shown in the figure, two sets of two types of metal hydrides with different temperature and equilibrium pressure characteristics were each housed in two compartmented closed containers. Figure 3
The first one operates on the relatively high temperature side between MH1 and MH2.
form a heat pump cycle, MH3 and MH
4 to form a second heat pump cycle that operates at a relatively low temperature. In these two heat pump cycles, MH1 and MH3 are on the high temperature heating side with lower equilibrium pressure at the same temperature. Then, container V1 filled with MH1 and MH3
A gravitational natural circulation heat pipe is provided between the container V3 filled with the container V3 to form a first heat exchange loop, a gravitational natural circulation heat pipe is provided between the container V3 and the heating/cooling output device, A second heat exchange loop was formed, and the heat exchange path inside the container V3 was configured so that the first and second heat exchange loops were also used.

Next, the operation of the heat pump device will be explained. The metal hydride MH1 on the high temperature heating side of the first heat pump cycle is heated using the waste heat source 1 having a relatively high temperature. Then, MH1 is heated and the pressure is increased to point A in FIG. When the hydrogen gas valve 2 is opened at this time, hydrogen moves to MH2 due to the pressure difference between MH1 and MH2, and MH2 generates heat accompanying the reaction. (Hydrogen transfer from state A to state B in Figure 4) After this, by stopping the heating from waste heat source 1 to MH1, the temperature of MH1 gradually decreases, and the equilibrium pressure becomes lower than that of MH2, so the reverse occurs. In addition, hydrogen can be transferred from MH2 to MH1 due to the pressure difference. (Hydrogen transfer from states B and C to D in FIG. 4) At this time, MH2 generates cold heat due to hydrogen release, and MH1 generates warm heat due to hydrogen storage.

As far as operation using MH1 and MH2 is concerned, it is no different from a conventional general heat pump. The present invention does not simply use the heat generated in MH1 as heat output (as in conventional heating) or radiate heat (as in conventional cooling), but instead uses it to heat MH3 in a separately configured second heat pump cycle. A gravity natural circulation type heat pipe is used as the heat source for heat exchange, and the heat exchange path inside the container V3 is also used to take out the adsorption reaction heat of MH3 to the thermal output device. The feature is that a heat exchange loop is formed using pipes. By using gravity natural circulation heat pipes in the heat exchange loop, the second heat pump cycle can transfer hydrogen in the order of A'→B'→C'→D' very smoothly, similar to the first heat pump cycle. can be moved to. When performing intermittent operation in each of the heat pump cycles described above, the heat exchange loops can be switched by simply operating a valve.

When transferring hydrogen from MH2 to MH1 in the first heat pump cycle, valve 5,
5' and close valves 6 and 6', MH1
MH3 is heated by the first heat exchange loop of the heat pipe, and when the adsorption heat generation of MH1 is completed, the valves 5 and 5' are closed and the first heat exchange loop is heated.
The heat transfer fluid in the heat exchange loop is transferred to the vessel V in the loop.
It is stored in a position other than the heat exchange path in the second heat exchange path.
In the heat pump cycle, MH4
When hydrogen is transferred to MH3, valves 6 and 6' are opened, valves 5 and 5' remain closed, and the heat generated in MH3 is transferred to the heat output device through the second heat exchange loop of the heat pipe. When the adsorption heat generation of MH3 is completed, the valves 6 and 6' are closed, and the heat medium fluid in the second heat exchange loop is stored in a position other than the heat exchange path in the container V3 in the loop. The heat transfer fluid used in the first heat exchange loop and the heat transfer fluid used in the second heat exchange loop may be the same type or different depending on the operating temperature.

As a specific example of the present invention, a heat pump device having a configuration as shown in FIGS. 3 and 4 and a temperature-pressure cycle was prototyped, and the results of its evaluation will be described. As MH1, Ti _0.3 Zr _0.7 Mr _1.2
Cr _0.6 Co _0.2 , Ti _0.6 Zr _0.4 Mr _1.2 Cr _0.6 as MH3
Cn _0.2 , Ti _0.9 Zr _0.1 Mr _1.4 Cr _0.4 as MH2 and MH4
Approximately 10 kg of Ti-Mn alloy having a V of _0.2 was charged into an apparatus having the structure shown in FIG. 3. Approximately 63 moles of hydrogen gas was adjusted as metal hydride to be transferred in each cycle of the first and second heat pump cycles. We then heated MH1 to approximately 200℃ and examined its performance as a heat pump.
As a result, the COP values are 1.56 (heating) and 1.01 (cooling)
This was a very good value, and the operation could be carried out smoothly and repeatedly. By the way, the performance of a heat pump using the conventional heat exchange method is 1.36 (heating)
and 0.91 (air conditioning). Therefore, since the above heat pump device employs multiple effects, there is no need to increase the COP, which has been a problem in the past. Note that it is preferable to use a substance that has the same temperature and equilibrium pressure for each heat pump cycle. By making the exothermic or endothermic temperature levels obtained by the reaction almost the same, the temperature level on the utilization side can be made constant, and the high and low pressures of the two cycles can be made almost the same. Further, 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. Heat pump cycles using metal hydrides not only have excellent reversibility of the reaction and long life performance due to repeated operation, but also have the advantage of extremely fast reaction rates. Furthermore, many of the materials for chemical heat pumps related to the present invention are capable of reacting at relatively high temperatures, and are not limited to the two heat pump cycles (double effect) shown in the examples, but can also be used to utilize even higher temperature heat sources. Therefore, triple or quadruple effect types are also possible.
It is also useful for the effective use of energy such as high-temperature waste heat. Furthermore, the medium filled in the container may be the same type of material or a mixture of different materials, especially in the case of metal hydrogenation.

Effects of the invention A dual-effect (multiple-effect) heat pump device uses the waste heat from the first stage to drive the second stage, so a high coefficient of performance is expected in principle, but there are various problems with the heat transfer method. It was hot. However, according to the present invention, conventional heat pump cycles require pump power to drive the heat exchange loop, which is disadvantageous in terms of energy and also generates noise, but in the present invention, pump power is not required. Therefore, it is energy saving and noiseless. During intermittent operation,
The heat transfer fluid can be switched only by valve operation.
Driving becomes very easy. Since the structure is such that the main flow paths of the two heat exchange loops are also used, the container can be smaller than the conventional structure, and therefore the heat capacity of the container is reduced. Since the heat exchange loop of the present invention can transport a large amount of heat with a small temperature difference, the difference between the heat radiation temperature of the first cycle and the heating temperature of the second cycle can be designed to be small. Accordingly, the heating temperature in the first cycle can be designed to be lower.

As a result, the cycle has a high coefficient of performance and high energy savings. Furthermore, the heat transfer loop of the present invention has many advantages such as a simple structure, no failures, and low cost.

[Brief explanation of the drawing]

Fig. 1 is a diagram of a single-effect heat pump cycle that is well known in the past, Fig. 2 is a diagram of an improved conventional multi-stage heat pump cycle, and Fig. 3 is a diagram of a multi-effect heat pump cycle of an embodiment of the present invention. , FIG. 4 is a heat pump cycle diagram of the heat pump device shown in FIG. 3. 1...Waste heat source, 2,2'...Hydrogen gas valve,
3...First heat exchange loop, 4...Second heat exchange loop, 5, 5'...First heat exchange loop operating valve, 6,6'...Second heat exchange loop operating valve, 7...Heat and cold output device, MH1~MH
4...Metal hydride.

Claims (1)

[Scope of Claims] 1. A chemical heat pump comprising at least two containers filled with a substance capable of reversibly adsorbing and desorbing a working gas to form containers having different temperature and equilibrium pressure characteristics, and a working medium being movably filled between the containers. A second heat pump operates at a relatively low temperature side, with the adsorption reaction exothermic temperature of the adsorption/desorption reaction medium on the high temperature heating side having the same temperature and low equilibrium pressure as the first heat pump cycle operating at a relatively high temperature side. The temperature is set higher than the desorption reaction heating temperature of the adsorption/desorption reaction medium on the high temperature heating side where the equilibrium pressure is lower at the same temperature of the cycle, and the second heat pump cycle is heated using the adsorption reaction heat of the first heat pump cycle. The adsorption/desorption reaction medium on the high temperature heating side of the heat pump cycle (hereinafter referred to as
MH1) and a container filled with MH1 (hereinafter referred to as container V1).
media that operate at relatively low temperatures (hereinafter referred to as
A gravity natural circulation type heat pipe is provided as a connecting pipe line capable of heat exchange between the container (hereinafter referred to as container V3) filled with MH3 (referred to as MH3), and a first heat exchange loop is formed. The adsorption reaction heat of the heat pump cycle is used to heat the second heat pump cycle, and a gravity natural circulation heat pipe is provided as a connecting pipe between the container V3 and the thermal output device to enable heat exchange. is provided to form a second heat exchange loop, and the heat generated by the adsorption reaction of the adsorption/desorption medium on the high temperature heating side of the second heat pump cycle is taken out to the thermal output device, and the first and second heat exchange loops are This is a multi-effect heat pump device, characterized in that the heat pipe also serves as a conduit in the container V3. 2. Claim 1, characterized in that when the first and second heat pump cycles perform intermittent operation, the first and second heat exchange loops can be switched by operating a valve. multi-effect heat pump device. 3. The multi-effect heat pump device according to claim 1, wherein a substance having substantially the same temperature and equilibrium pressure characteristics is used as the adsorption/desorption reaction medium on the low-temperature endothermic side with the same temperature and high equilibrium pressure in each heat pump cycle. 4. The multi-effect heat pump device according to claim 1, wherein hydrogen gas is used as a working gas in at least one of each heat pump cycle, and a metal or an alloy thereof capable of forming a metal hydride is used as an adsorption/desorption reaction medium.