JPH0126461B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a temperature cycle between a high temperature state where the reversible reaction between the inorganic salt and the gas occurs and a low temperature state where the gas condenses and evaporates. The present invention relates to a chemical heat pump using a combination of the following. More specifically, we separate the location where the gas is decomposed and endothermicly reacted from the inorganic salt that has absorbed the gas corresponding to the high temperature state, and the location where the gas is absorbed into the inorganic salt and undergoes the exothermic reaction, and the inorganic salt and gas are separated between the two reaction locations. This invention relates to a chemical heat pump characterized by moving and circulating absorbed inorganic salts to continuously release and absorb energy.

Traditionally, absorption refrigerators have been used as chemical heat pump air conditioning systems that utilize solar heat, and in these systems, gases such as H ₂ O, CH ₃ OH, and NH ₃ are used as refrigerants, and LiBr, LiCl, and other absorbents are used as absorbents.
An aqueous solution of NaOH or a liquid such as H ₂ O is used.

As described above, all absorbents for conventional chemical heat pump type air conditioning systems use liquids because fluidity is required. However, the disadvantages of these liquids are their high vapor pressure and limited operating temperature.

In contrast, the present invention is characterized in that the absorbent is a solid inorganic salt, and its vapor pressure at operating temperatures is extremely low and can be ignored.

In addition, in chemical heat pumps using solid absorbents, metal hydrides are known as a method of circulating the solid absorbent between a high-temperature container and a low-temperature container. (Japanese Patent Publication No. 55-33588). However, one of the features of the present invention is that the inorganic salt absorbent is circulated between the gas decomposition reactor and the gas absorption reactor, and the gas is circulated between the high temperature side container and the low temperature side container. It is. Conventionally, chemical heat pumps using inorganic salt absorbents have been considered for long-term heat storage or seasonal heat storage applications, in which the same inorganic salt absorbent is fixed and stored separately in two containers. A method was used in which absorption reactions and decomposition reactions were alternately performed. That is, this method is a long-term intermittent operation, and the drawback of this method is that it cannot be operated continuously.

Furthermore, a feature of the present invention is that a carrier gas is used to transport gas and forced circulation is performed. This makes it possible to operate in a thermal equilibrium state and near normal pressure, thus making it possible to provide heating, cooling, and hot water supply with high efficiency and easy maintenance.

Next, the basic configuration and operating principle of the present invention will be described.

FIG. 1 shows a basic configuration diagram related to the implementation of the present invention. 1 is a gas decomposition reactor that has the function of thermally decomposing an inorganic salt that has already absorbed gas to generate gas and separating the generated gas from the decomposed inorganic salt; 2 is a gas decomposition reactor that allows the inorganic salt to absorb gas; At the same time, it is a gas absorption reactor that has the function of collecting the generated thermal energy and using it for heating, hot water supply, etc. The gas decomposition reactor 1 and the gas absorption reactor 2 are connected to an inorganic salt transfer device 3 and a gas absorption inorganic salt transfer device 4.
are connected by Here, either one of the inorganic salt transfer device 3 and the gas absorption inorganic salt transfer device 4 may utilize natural falling due to gravity. 5 is a condenser that has the function of cooling and condensing the high-temperature gas decomposed in the gas decomposition reactor 1 using outside cold air, underground cold water, etc., and 6 is an air conditioner for cooling the liquid condensed in the condenser 3. The condenser 5 and the evaporator 6 are connected by a connecting pipe 7 and a liquid transport device 8. Note that as the liquid transport device 8, a natural fall device using gravity can also be used. The gas decomposition reactor 1 and the condenser 5 are connected by a pair of connecting pipes 9 that transport gas from the gas decomposition reactor 1 to the condenser 5. In addition, in order to transport gas efficiently, a carrier gas is used, and as shown in FIG. The gas decomposition reactor 1 and the condenser 5 are connected by a pair of connecting pipes 9 to which the carrier gas is returned. Here, the carrier gas is transferred to the gas decomposition reactor 1 and the condenser 5.
A gas transport device 10 is used to circulate the gas between the two, and this gas transport device 10 is attached to either one of the pair of connecting pipes 9. 11 is a heat collector, which collects natural thermal energy such as solar heat, waste heat from factories, homes, etc., and functions as a heat supply source to the gas decomposition reactor 1; 12 is the gas decomposition reactor 1; a heat exchanger between the heat collector 11 and the heat collector 11;
3 is a heat exchanger for utilizing the thermal energy obtained in the gas absorption reactor 2 for heating and hot water supply; 14 is a heat exchanger between the condenser 5 and a natural cold body such as outside air or underground water; It is a heat exchanger between the evaporator 6 and the indoor air to be cooled (or underground water or outside air if cooling is not required).

Next, the operating principle of the present invention will be explained. The present invention uses a combination of the following two types of reversible processes.

M・X(S) Process A (endothermic) --------→ ←--------- Process D (exothermic) M(S) + X(g) X(g) Process B (exothermic) ――――――→ ←―――――― Process C (endothermic) , X(g) is a gas, and X(l) is a liquid.

The operation of the present invention consists of repeating the cycle of process A (gas generation) → process B (gas condensation) → process C (gas evaporation) → process D (gas absorption) → process A (gas generation).

In process A, M. The generated gas X(g) is transported to the condenser 5 through a pair of connecting pipes 9 that circulate the carrier gas, and at the same time, the inorganic salt M(S) after decomposing part or all of the gas X(g) is The inorganic salt transfer device 3 sends it to the gas absorption reactor 2 .

In process B, high-temperature gas X transported to condenser 5
(g) is cooled by the heat exchanger 14 and becomes liquid (l),
The liquid is sent to the evaporator 6 by the liquid transport device 8 .

In process C, the liquid X(l) carried to the evaporator 6 is supplied with thermal energy by the heat exchanger 15 and evaporated, and the evaporated low-temperature, low-pressure gas is sent to the gas absorption reactor 2 through the connecting pipe 16. 17 is a connecting pipe between the gas decomposition reactor 1 and the gas absorption reactor 2.

In process D, the inorganic salt M(S) transported to the gas absorption reactor 2 reacts with the low-temperature, low-pressure gas X(g), and returns to M.X(S) while releasing thermal energy.
The gas-absorbed inorganic salt M.

By continuously repeating the above steps A→B→C→D, the absorption of thermal energy within the evaporator 6 that occurs particularly in step C can be used for cooling.
Furthermore, the thermal energy released in the gas absorption reactor 2 occurring in step D can be used for heating or hot water supply. Moreover, they can be performed continuously.

This will be explained below using specific examples.

Calcium chloride (Call ₂ ) commercially available as an inorganic salt
We prepared commercially available methanol (CH ₃ OH) as a gas, and selected a combination of the following two types of reversible processes.

CaCl ₂・2CH ₃ OH(S) Process A -----→ ←--- Process DCaCl ₂ (S) +2CH ₃ OH(g) ... CH ₃ OH(g) Process B -----→ ←--- Process CCH ₃ OH(l) …… Equilibrium vapor pressure of reversible reactions such as CaCl ₂ −CH ₃ OH −
The temperature curve and the equilibrium vapor pressure-temperature curve of the condensation and evaporation process of methanol are shown in FIG. 2, respectively. 0.4 atm was chosen as the equilibrium pressure of methanol vapor on the high temperature side. At this time, the equilibrium temperature in the reversible reaction such as CaCl ₂ -CH ₃ OH is 110°C, and the equilibrium temperature in the methanol condensation and evaporation process is 41.5°C. On the other hand, the equilibrium pressure of methanol vapor on the low temperature side is 0.06
I chose atmospheric pressure. At this time, the equilibrium temperature of the reversible reaction such as _CaCl2 - _CH3OH is 70.6°C, and the equilibrium temperature of the methanol condensation and evaporation process is 5°C.

The decomposition reaction temperature of CaCl ₂ .2CH ₃ OH (S) in the gas decomposition reactor 1 in process A (gas generation process) was selected to be 120°C. The partial pressure of methanol vapor generated at this time is 0.5 atm. Generally, the operating point A of the decomposition reaction should be higher than the equilibrium temperature of 110° C. and the equilibrium vapor pressure of 0.4 atm. Thermal energy to be supplied from the heat collector 11 required for the decomposition reaction in process A (in the example, the supply is approximately 222 cal/g due to heater heating)
_CaCl2 .

The condensation temperature of methanol vapor in the condenser 5 in process B (gas condensation process) was selected to be 35°C. The partial pressure of methanol vapor at this time is 0.3 atm. Generally, the operating point B of condensation is the equilibrium temperature of 41.5
℃, equilibrium vapor pressure lower than 0.4 atm.

Heat exchanger 14 required for methanol condensation in process B
The thermal energy that should be pumped out to the outside (tap water is used in the example) is approximately 263 cal/g.
It is _CH3OH .

In process C (gas evaporation process), the methanol liquid at 35°C sent to evaporator 6 reaches operating point C (vapor Pressure 0.07 atm, temperature 10
℃), so it evaporates completely. Its heat of vaporization is approximately
265 cal/g CH ₃ OH, which is supplied through the heat exchanger 15 from the thermal energy in the room to be cooled. The cooling limit temperature is the temperature at the set operating point C.

In process D (gas absorption process), gas absorption reactor 2
In order to absorb the low temperature, low pressure vapor of methanol generated in process C into CaCl ₂ in the reactor, it is necessary to maintain the absorption reaction temperature (temperature at operating point D) below the equilibrium temperature of 70.6°C. That is, it is necessary to quickly take out the heat amount of about 222 cal/g CaCl ₂ released by the absorption reaction to the outside of the gas absorption reactor 2 through the heat exchanger 13. This released thermal energy is used for heating or hot water supply. However, their reaching limit temperature is the temperature of the set operating point D.

As an embodiment of the present invention, as shown in FIG. 1, if the carrier gas is circulated at high speed between the gas decomposition reactor 1 and the condenser 5 using a pair of connecting pipes 9 and a gas transport device 10, the It has been found that the higher the circulation rate, the closer the operating points A and B are to their respective equilibrium temperatures. Similarly, a pair of connecting pipes 16 are connected between the evaporator 6 and the gas absorption reactor 2.
It has been found that when the carrier gas is circulated at high speed using the carrier gas and the gas transport device 10, the higher the circulation speed, the closer the operating points C and D are to their respective equilibrium temperatures.

In this way, process A that combines the reversible reaction such as CaCl ₂ -CH ₃ OH and the condensation and evaporation process of CH ₃ OH→
By repeating B→C→D, it was possible to continuously perform cooling and heating or hot water supply at a very low partial pressure of methanol vapor of 1 atm or less.

As explained above, the present invention enables continuous operation (for example, heating and cooling while storing heat from the sun during the day), which was not possible with conventional fixed chemical heat pumps using solid absorbents. This also makes it possible to reduce the size and weight of continuous chemical heat pumps using conventional liquid absorbents (e.g. LiBr-
_However , in the present invention, the operating steam is less than 1 atm, and a carrier gas is used, so that the vapor pressure of the absorbent is not negligible. It can be used under pressure, has simple maintenance, and has excellent effects such as the vapor pressure of the absorbent can be almost ignored.

[Brief explanation of drawings]

Fig. 1 is a circuit explanatory diagram of a chemical heat pump type air-conditioning/heating water supply system according to an embodiment of the present invention;
The figure shows the CaCl ₂ −CH ₃ OH system and the vapor pressure of CH ₃ OH −
It is a temperature characteristic diagram. 1... Gas decomposition reactor, 2... Gas absorption reactor, 3... Inorganic salt transfer device, 4... Gas absorption inorganic salt transfer device, 5... Condenser, 6... Evaporator, 7,
9, 16, 17...Connection pipe, 10...Gas transport device.

Claims (1)

[Claims] 1. A chemical heat pump is installed that takes advantage of the reversibility of the gas absorption reaction (exothermic) into the inorganic salt and the gas decomposition reaction (endothermic) from the inorganic salt that has absorbed the gas, and the gas absorption reaction on the high reaction temperature side. A gas decomposition reactor, a device for moving inorganic salts and inorganic salts that have absorbed gas, a heat collector, a condenser on the low reaction temperature side, an evaporator, a device for moving liquid, and a device for moving the inorganic salts and gases on the high temperature side. The inorganic salt that has absorbed the gas is condensed in the condenser by the inorganic salt transfer device and the inorganic salt that has absorbed the gas is circulated between the gas absorption reactor and the gas decomposition reactor by the connecting pipe and the liquid transfer device on the low temperature side. a pair of connecting pipes, a gas transport device, and a pair of connecting pipes that transport the high-temperature gas generated in the gas decomposition reactor on the high-temperature side to the condenser on the low-temperature side using a carrier gas; A pair of connecting pipes that transport low-temperature gas generated in the evaporator to the gas absorption reactor on the high temperature side using a carrier gas, a gas transport device, and a heat transfer device between the collector and the gas decomposition reactor on the high temperature side. A chemical heat pump type air-conditioning/heating and hot water supply system equipped with a connecting pipe that circulates water.