JP2647990B2 - Operation control device for chemical heat pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chemical heat pump operation control device for efficiently operating a chemical heat pump utilizing an adsorption action, an absorption action, or a chemical reaction.

[Conventional technology]

FIG. 13 is a configuration diagram showing an operation control device of a conventional chemical heat pump in a cooling system using an adsorption refrigerator described in, for example, Proceedings of the Society of Solar Energy Society of Japan, 1988, p. 118. In the figures, 1 is a cylindrical body, 2 is a solid adsorbent filled in the body 1, 3
Is a heat exchanger as a first heat exchanger for heating / cooling the solid adsorbent 2 in the body 1 and adsorbed on the solid adsorbent 2 is a refrigerant 4 such as water. Heating
This is a heat exchanger as a second heat exchanger for cooling. These 1 to 5 constitute a chemical heat pump.

6 to 13 are cold / hot water switching valves attached to the entrances of the heat exchangers 4 and 5, 14 is a heat source water tank as a heat source water supply system, and 15 is a switching valve 12, 13 and a heat source water tank 14. A heat source water pipe to be connected, 16 is a cooling tower as a cooling water supply system, 17 is a cooling water pipe connecting the switching valves 8, 9, 10, 11 and the cooling tower 16, and 18 emits cool air to cool the room. A chilled water supply system as an output chilled and heated water system including a fan coil unit and the like, 19 is a chilled water pipe connecting the chilled water supply system 18 and the switching valves 6 and 7, 20, 21 and 22
Are pumps attached to the pipes 19, 17, and 15, respectively. twenty three
Is a temperature sensor attached to the inflow side of the cold water pipe 17, and 24 is an arithmetic control unit which receives a detection signal of the temperature sensor 23 and controls switching of the switching valves 6 to 13.

 Next, the operation will be described.

The operation of the adsorption refrigerator includes a regeneration (desorption) step of desorbing the refrigerant 3 from the solid adsorbent 2 and an adsorption step of adsorbing the refrigerant 3 on the adsorbent 2 and obtaining cooling output by heat of vaporization of the refrigerant liquid. . FIG. 13 shows the operation in the regeneration step of the cooling system. In this regeneration step, the switching valves 6, 7, 10, 11 are closed, the switching valves 8, 9, 12, 13 are opened, and the heat source water (from the heat source water tank 14) is supplied to the heat exchanger 4 of the solid adsorbent 2. Hot water) flows, and cooling water from the cooling tower 16 flows to the heat exchanger 5 of the refrigerant 3. The solid adsorbent 2 is heated by the heat source water and the desorption of the adsorbed refrigerant proceeds. Further, since the heat exchanger 5 is cooled by the cooling water, the refrigerant 3 evaporated by the desorption is used.
Condensation and liquefaction occur. The liquefied refrigerant 3 is held around the heat exchanger 5. As described above, in the regeneration step, the solid adsorbent 2 is regenerated, and an operation of storing the refrigerant 3 around the heat exchanger 5 is performed. In this regeneration step, when a certain time calculated by the calculation control unit 24 elapses, the open / close of the switching valves 6 to 13 is switched by the output signal of the calculation (the line for the output signal is not shown). The adsorption step is performed.

FIG. 14 shows the operation in the suction step. In this adsorption step, the switching valves 8, 9, 12, 13 are closed, the switching valves 6, 7, 10, 11 are opened, and the cooling water from the cooling tower 16 is supplied to the heat exchanger 4 of the solid adsorbent 2 by the refrigerant. Cold water flows from a cold water supply system 18 such as a fan coil unit in the room to the heat exchanger 5 of No. 3. Since the solid adsorbent 2 is cooled by the cooling water, adsorption of the refrigerant 3 occurs. As a result, the refrigerant 3 evaporates around the heat exchanger 5, and the cold water flowing through the heat exchanger 5 is cooled by the endothermic heat of vaporization, so that a cooling output can be obtained. In the adsorption step in which a cooling output is obtained by the solid adsorbent 2 adsorbing the refrigerant 3, the switching valves 6 to 13 are switched by an output signal from the arithmetic and control unit 24 after a certain period of time, and the regeneration step is performed again. Done.

The control of the output of the adsorption type refrigerator performing the above-mentioned operation is performed, for example, by the Japan Refrigeration Association Academic Lecture Meeting, "Non-fluorocarbon Refrigeration and Air Conditioning System" Symposium, 1989, p. 25
As shown in 0, the cold water inlet temperature is detected by a sensor,
This is performed by changing the number of adsorption / desorption cycles per unit time according to the refrigeration load condition. For this,
As shown in FIGS. 13 and 14, the chilled water supply system 18 and the switching valve 6,
A temperature sensor 23 for detecting a chilled water inlet temperature is installed in the middle of a chilled water pipe 19 connecting the chilled water pipe 19 to the chemical heat pump, and a detection signal of the temperature sensor 23 is input to the arithmetic and control unit 24. An operation control device for controlling the switching valves 6 to 13 is provided.

In the operation control device including the arithmetic control unit 24 and the timer, control is performed according to, for example, a flowchart shown in FIG. First, upon receiving a detection signal from the temperature sensor 23 detected in step ST1, the cold water inlet temperature is input in step ST2. Next, in step ST3, the state of the refrigeration load from the chilled water supply system 18, such as a fan coil unit, is detected from the value of the chilled water inlet temperature, a change in the temperature, and the like.
Next, when the refrigeration load is known, step ST is performed based on the information.
In step 4, the number of cycles per unit time, that is, the time from the regeneration step is calculated, and the resulting time is referred to as step ST.
The timer is set in 5 and the opening and closing of the switching valves 6 to 13 is controlled in step ST6 based on the operation of the timer.

[Problems to be solved by the invention]

As described above, the conventional chemical heat pump operation control device is configured to calculate only the inlet temperature of the cold water chemical heat pump as an input and to control the cold / hot water switching valves 6 to 13, so that the above adsorption type The performance of the refrigerator is
For example, as shown in FIG. 16, even if the inlet temperature of the cold water is constant, it changes depending on the inlet temperature of the heat source water (hot water) or the cooling water. Therefore, the conventional control device cannot control the opening and closing time of the valve to maximize the performance in response to the change of the inlet temperature of the heat source water or the cooling water, and the performance of the chemical heat pump is reduced. There were challenges.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a chemical heat pump operation control device that can control a chemical heat pump in accordance with the inlet temperature of cold water, cooling water, and heat source water. .

[Means for solving the problem]

The operation control device for a chemical heat pump according to the present invention is configured such that a plurality of temperature sensors for detecting each inlet temperature of the heat source water, the cooling water, and the output cold / hot water are attached to each pipe, and a detection signal of each temperature sensor is sent to the arithmetic control unit. An input is provided to control a plurality of cold / hot water switching valves.

(Operation)

The operation control device for a chemical heat pump according to the present invention receives the inlet temperatures of the heat source water, the cooling water, and the output cold / hot water, and calculates the switching time of each switching valve corresponding to these temperatures, thereby switching the cold / hot water. Control the valve.

(Example of the invention)

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 101 denotes a reaction vessel. The reaction vessel 101 includes a solid reaction material 2 and a heat exchanger 4 through which cold and hot water flows.
And is stored. The solid reaction material 2 includes, for example, calcium chloride (CaCl ₂ ). Reference numeral 102 denotes a liquid container, in which a refrigerant 3 reacting with the solid reaction material 2 is sealed, and a heat exchanger 5 in which cold and hot water flows is contained. The refrigerant 3 is, for example, methylamine (CH ₃ NH ₂ ). 103 is the above reaction vessel 101
And a connection pipe connecting the liquid container 102 and the liquid container 102. 100 is 101,10 above
This is a chemical heat pump composed of 2,103,2,3,4,5 members. In addition, 6 to 24 are the same as those in FIG. 13 and FIG. 14, and the description thereof is omitted.

Reference numeral 25 denotes a temperature sensor attached to the cooling water pipe 17 on the inflow side to the chemical heat pump 100, and reference numeral 26 denotes a temperature sensor attached to the heat source water pipe 15 on the inflow side to the chemical heat pump 100.

 Next, the operation will be described.

In the chemical heat pump 100 according to this embodiment, the reaction between calcium chloride and methylamine represented by the following formula (1) proceeds in the reaction vessel 101, and the liquid vessel
In 102, the evaporation and condensation of methylamine represented by the following formula (2) proceeds.

_{CaCl 2 · 2CH 3 NH 2 +} 4CH 3 NH 2 ( _{gas) CaCl 2 · 6CH 3 NH 2} + ΔH ...... (1) CH 3 NH 2 ( gas) CH ₃ NH ₂ (liquid) + ΔH '...... (2), where , ΔH represents heat of reaction, and ΔH ′ represents latent heat of evaporation.

Calcium chloride (Ca
(Cl ₂ · 6CH ₃ NH ₂ ) decomposes and the reaction proceeds from right to left in equation (1), regeneration operation in which methylamine gas condenses, and methylamine evaporates to generate gas and methyl Amine gas is calcium chloride (CaCl ₂・ 2CH ₃ N
H ₂ ) and output operation that reacts. FIG. 1 shows the operation during the regeneration operation. In this regeneration operation,
The switching valves 6, 7, 10, 11 are closed, the switching valves 8, 9, 12, 13 are opened, and the heat source water is cooled to the heat exchanger 4 of the reaction vessel 101 and cooled to the heat exchanger 5 of the liquid vessel 102. Water flows. Calcium chloride (CaCl ₂ · 6CH ₃ NH ₂ ) is heated by the heat source water, and the decomposition reaction proceeds from right to left in equation (1) to generate methylamine gas. The methylamine gas is cooled in the liquid container 102 through the connecting pipe 103, condensed, and stored as a liquid of the refrigerant 3.

As described above, in the regeneration operation, the operation of regenerating calcium chloride as the solid reaction material 2 in the reaction container 101 and the operation of storing methylamine as the refrigerant 3 in the liquid container 102 are performed. In this regeneration operation, after a predetermined time calculated by the arithmetic and control unit 24 has elapsed, the arithmetic and control unit 24 outputs an output signal to switch the open / close of the switching valves 6 to 13, and shifts to the output operation.

FIG. 2 shows the operation in the output operation. In this output operation, the switching valves 8, 9, 12, and 13 are closed, the switching valves 6, 7, 10, and 11 are opened, and the cooling water is supplied to the heat exchanger 4 of the reaction vessel 101 and the liquid vessel 102
The cold water from a cold water supply system 18 such as a fan coil unit flows to the heat exchanger 5. In this output operation, calcium chloride (CaCl ₂ · 2CH ₃ NH ₂ ) as the fixed reaction material 2 proceeds from left to right in the equation (1) and reacts with methylamine gas as the refrigerant 3. Thereby, the liquid container 102
The above-mentioned methylamine evaporates, the cold water flowing through the heat exchanger 5 is cooled by the endothermic heat of vaporization at this time, and the cooling output is taken out. The output operation in which the cooling output is obtained by the reaction between the calcium chloride and methylamine is performed by a switching valve 6 based on an output signal from the arithmetic control unit 24 after a certain period of time.
The regeneration operation is performed again by switching .about.13.

Next, a control method of the chemical heat pump 100 according to this embodiment will be described. First, the chemical heat pump 10
The following three different control modes can be considered for the control of 0. The optimal operation is an operation that best matches each control target, and therefore differs depending on the control mode.

A. Control mode for obtaining the maximum capacity B. Control mode for obtaining the maximum coefficient of performance C. Control mode for obtaining a constant capacity Here, the capacity is the amount of output heat obtained per unit time, and in this embodiment, one hour. It represents the amount of heat for cooling (kcal / hr) obtained per unit. The coefficient of performance represents the ratio of the amount of output heat to the amount of input heat, and the larger the coefficient of performance, the greater the amount of output heat can be obtained with less energy input.

In the operation control apparatus for a chemical heat pump according to this embodiment, in each of the control modes A, B, and C, as shown in FIGS.
7. The temperature sensors 23, 25, and 26 that detect each inlet temperature are installed in the middle of each inflow side pipe of the heat source water pipe 15, and the detection signals from these three temperature sensors 23, 25, and 26 are calculated and controlled. The switching valves 6 to 13 are configured to be connected so as to be able to input to the switching valve 24 and to be controlled.

In the operation control device including the arithmetic control unit 24 and the timer, control is performed according to, for example, a flowchart shown in FIG. First of all, control mode in step ST1
A, B and C are selected. Next, upon receiving the detection signals of the respective temperature sensors obtained in steps ST2, ST3 and ST4, step ST5
, The cold water inlet temperature, the cooling water inlet temperature and the heat source water inlet temperature are input. Thereafter, in step ST6, the optimum operation time is calculated in accordance with the control mode selected based on the three temperature data, and the regeneration operation time and the output operation time are determined. As a result, the determined operation time is set in the timer in step ST7. Then, in step ST8, the switching of the switching valves 6 to 13 is controlled based on the signal of the elapsed time from the timer.

In order to show that the use of the operation control device of the present invention enables more optimal operation as compared with the conventional operation control device, a device of the same type as that shown in FIGS. 1 and 2 was prototyped. Experiments were performed and calculations were performed using a thermal model. 1.5 kg of calcium chloride (CaCl ₂ ) was used as a solid reaction material in the experiment. In addition, methylamine (CH ₃ NH ₂ ) was used as a refrigerant, and 2.1 kg was sealed in the device.

FIG. 4 shows the change over time of the reaction rate during the regeneration operation. Here, the reaction rate is a reaction that shifts from the right side to the left side of the above equation (1), and calcium chloride (CaCl ₂ .6) reacted with methylamine
CH ₃ NH ₂ ) is decomposed and regenerated to the extent that calcium chloride (Ca
Cl ₂・ 2CH ₃ NH ₂ ) or the ratio. The higher the reaction rate value, the better the regeneration was. FIG. 4 shows that the higher the heat source water inlet temperature, the higher the reaction rate in a shorter time, and the faster the regeneration. In addition, as described in FIG. 16, even when the cold water inlet temperature is constant, the reaction time during the regeneration operation changes depending on the heat source water or cooling water inlet temperature, so that the optimal operation time for each control mode varies. It is thought to be.

In order to determine the optimal operation time, a thermal model of the chemical heat pump 100 was created. This thermal model calculates the heat balance, such as the amount of heat generated and absorbed by the reaction in the chemical heat pump 100, the amount of latent heat associated with the evaporation and condensation of the refrigerant, the sensible heat of the solid reaction material and the refrigerant, and the container, and the amount of heat released to the outside air. This is represented by several relational expressions. In the following, description will be made based on the results of calculations made by putting the speed of reaction as shown in FIG. 4 into the above-mentioned thermal model as data.

The optimal operation time in the control mode to obtain the maximum capacity was obtained as follows. FIG. 5 is a diagram showing the values of the output operation time and the regeneration operation time at a heat source water inlet temperature of 70 ° C., a cooling water inlet temperature of 30 ° C., and a cold water inlet temperature of 10 ° C. Solid line of equivalent capacity is 20 kcal / h from 0 kcal / hr to 100 kcal / hr
It is drawn in r increments. The optimum operation time for obtaining the maximum capacity was obtained by obtaining the capacity at that time while changing the output operation time and the regeneration operation time. The operation indicated by a dot in FIG. 5 is the optimum operation. In the figure,
The performance at each point is shown in FIG. From FIG. 6, the calculation results by the thermal model and the experimental results obtained by operating the experimental apparatus were in good agreement, and it was clarified that the maximum performance was obtained by operating at points.

In the same manner as above, the heat source water inlet temperature is 80 ° C or 60 ° C.
The optimum operation time when the temperature changes to ° C is required. On the other hand, in the conventional control method, the operation is performed for a fixed operation time regardless of a change in the heat source water inlet temperature. Therefore, FIG. 7 shows the capacity at the optimum operation and the capacity when the operation time is fixed to the optimum operation time at the heat source water inlet temperature of 80 ° C. For example, when the heat source water inlet temperature is 60 ° C, the capacity during optimal operation is 60 kc
al / hr, but 52kca when the operation time is fixed
Only l / hr capacity can be obtained. As is apparent from this result, it is possible to obtain a larger capacity by controlling the operation to be optimal according to the temperature of the heat source water. The same can be said for not only the change in the temperature of the heat source water but also the change in the temperature of the cold water or the cooling water inlet. In addition, there is the same difference in the control mode for obtaining the maximum coefficient of performance among the control modes. Furthermore, in the case of a conventional operation control device that detects the temperature of the chilled water inlet, it was not possible to perform control so as to obtain a constant capacity.

On the other hand, in the control method according to the present invention, it is possible to use a diagram as shown in FIG. 5 to control the capacity to be constant corresponding to each inlet temperature of the cold water, the cooling water, and the heat source water. In this case, control can be performed by obtaining the operation time with the largest coefficient of performance on the isocapacity line in FIG. For example, FIG. 8 shows the sum of the output operation time and the regeneration operation time with respect to the change in the heat source water inlet temperature when the capacity is fixed at 50 kcal / hr. Thus, by appropriately changing the operation time in accordance with the inlet temperature of the heat source water, the capacity can be controlled to be constant.

As described above, in order to optimally operate the chemical heat pump 100 in each control mode, as shown in the present invention, the inlet / outlet temperature of each cold / hot water is detected, and the output / regeneration operation is performed in accordance with those inlet temperatures. It is necessary to determine the time and control the opening and closing of the switching valve for the cold and hot water. By the way, in the above embodiment, the configuration and operation of the operation control device when the chemical heat pump 100 is applied to the cooling system that cools the room has been described. The operation control device according to the present invention can obtain the same effect. When applied to a heating system, a chemical heat pump that produces hot water at a higher temperature than the heat source water temperature (referred to as a heating type), and a hot water that has a lower temperature than the heat source water temperature, but can output more heat There is a chemical heat pump (called a heating type).

FIGS. 9 and 10 show a configuration and an operation example of the operation control device for the heat increasing type chemical heat pump. FIG. 9 shows the state of the regeneration operation, in which the reaction material 2 in the reaction vessel 101
Is regenerated by the heat source water, the refrigerant 3 is condensed in the heat vessel 102, and the latent heat (heat generation) at that time is used for heating as an output. FIG. 10 shows an output operation, in which the coolant 3 in the liquid container 102 is heated and evaporated by the cooling water, and reacted with the reaction material 2 in the reaction container 101. Then, the reaction heat at that time is taken out as an output for heating. The operation control unit consists of temperature sensors 26, 25, 23 attached to the inflow side of each pipe 15, 17, 19 for heat source water, cooling water and hot water as output, and an arithmetic control unit.
24, timer, etc., three temperature sensors 26, 25, 23
The cold / hot water controls the switching time of the switching valves 6 to 13 on the basis of the temperature data from the control unit.

FIGS. 11 and 12 show an embodiment of a control device for a heat-up type chemical heat pump. FIG. 11 shows the operation during the regeneration operation, and FIG. 12 shows the operation during the output operation. The operation control device also includes temperature sensors 23, 25, 26 attached to the inlet side of each cold / hot water pipe, an arithmetic control unit 24, a timer, and the like in this embodiment, and switches valves 6 to 13 in accordance with the control mode. Control.

Further, in the above-described embodiment, the operation in the case of performing the optimal operation has been described. However, the same configuration can also serve as a protection device for ensuring the safety of the chemical heat pump. For example, in FIG. 1, the pressure of the refrigerant gas in the reaction vessel 101 and the liquid vessel 102 is determined by the temperature at which the refrigerant 3 condenses or evaporates, and the temperature of the condensation and evaporation of the refrigerant 3 is the cooling water flowing through the heat exchanger 5. Or cold water temperature. Therefore, the inlet temperatures of the chilled water and the chilled water are detected by the temperature sensors 23 and 25, and when the vapor pressure calculated from these temperatures exceeds the pressure that the reaction vessel 101 and the liquid vessel 102 can withstand, the switching valves 6 to By performing control to block 9, breakage of the container can be prevented.

Further, in each of the embodiments, the case where calcium chloride (CaCl ₂ ) is used as the solid reaction material 2 and methylamine (CH ₃ NH ₂ ) is used as the refrigerant is not limited thereto, but the solid adsorbent is zeolite, silica gel, Activated carbon or the like, or a solid reaction material such as an inorganic compound or a hydrogen storage alloy, or a liquid reaction material composed of an absorbing solution such as an aqueous solution of lithium bromide can be used. , Water, ammonia, hydrocarbons, alcohols, chlorofluorocarbon and the like can be used.

〔The invention's effect〕

As described above, according to the present invention, the operation control device of the chemical heat pump is provided with a temperature sensor for detecting each inflow temperature of the heat source water, the cooling water, and the output cold / hot water, and an arithmetic control unit to which detection signals of the respective temperature sensors are input. Therefore, in the control for maximizing the capacity, the control for maximizing the coefficient of performance, or the control for setting the constant capacity, there is an effect that the optimum operation corresponding to each cold / hot water inlet temperature can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a regeneration operation state of an operation control device of a chemical heat pump according to one embodiment of the present invention, FIG. 2 is a block diagram showing an output operation state of the device, and FIG. FIGS. 4 and 5 are characteristic diagrams of the chemical heat pump, FIGS. 6 and 7 are explanatory diagrams illustrating experimental results of the chemical heat pump, and FIGS.
FIG. 9 is a characteristic diagram showing an experimental result of the chemical heat pump, FIG. 9 is a configuration diagram showing a regeneration operation state of the operation control device of the chemical heat pump according to another embodiment of the present invention, and FIG. 10 is an output operation state of the device. FIG. 11 is a block diagram showing a regeneration operation state of a chemical heat pump operation control device according to still another embodiment of the present invention, FIG. 12 is a block diagram showing an output operation state of the device, FIG. Is a configuration diagram showing a regeneration process of a conventional chemical heat pump operation control device, FIG. 14 is a configuration diagram showing an adsorption process of the device, FIG. 15 is a flowchart showing an operation of the device, and FIG. It is a characteristic view of a chemical heat pump. 2 is a solid reaction material, 3 is a refrigerant, 4 is a first heat exchanger, 5
Is a second heat exchanger, 23, 25, and 26 are temperature sensors, 24 is an arithmetic and control unit, 100 is a chemical heat pump, 101 is a reaction vessel, 10
2 is a liquid container, 103 is a connecting pipe. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazunari Nakao 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Inside the Central Research Laboratory of Mitsubishi Electric Corporation (72) Inventor Masatake Ikeuchi 8-chome Honcho Tsukaguchi Amagasaki City, Hyogo Prefecture No. 1 Mitsubishi Electric Corporation Central Research Laboratory (56) References JP-A-61-225561 (JP, A)

Claims (1)

(57) [Claims] 1. A reaction vessel provided with a first heat exchanger filled with a solid adsorbent, a solid reaction material or a liquid reaction material and flowing cold and hot water, adsorbed on the solid adsorbent, or provided with a solid reaction material or A liquid container provided with a second heat exchanger filled with a refrigerant that reacts with the liquid reaction material and flowing cold and hot water, and a connecting pipe connecting the reaction container and the liquid container; Hot water is supplied to the first heat exchanger and cooling water is supplied to the second heat exchanger. During output operation, cooling water is supplied to the first heat exchanger and the second heat exchanger is supplied. A heat sensor for detecting the temperature of the cold water supplied to the second heat exchanger, wherein the temperature sensor detects the temperature of the cold water supplied to the second heat exchanger.
A temperature sensor for detecting a temperature of the cooling water supplied to the heat exchanger or the second heat exchanger, a temperature sensor for detecting a temperature of the hot water supplied to the first heat exchanger, An operation control unit for controlling the regeneration operation time and the output operation time based on a detection signal from each temperature sensor.