JPH05340550A - Controller of refrigerant heater - Google Patents

Abstract

PURPOSE:To provide a controller of a refrigerant heater used for an air conditioning device by heating refrigerant with high temperature gas such as combustion gas, wherein when the refrigerant is overheated because of an insufficient refrigerant in a refrigerant heating portion, that can be immediately detected to normalize the operation of the system. CONSTITUTION:A controller 29 outputs an overheating signal when the temperature output of an overheating temperature detecting means 25 is more than the fixed value. And the controller 29 inputs the temperature output from the overheating temperature detecting means 25 for every fixed times, computes the difference of the before and after outputs in the controller 29, and outputs the overheating signal when the computed value is more than the fixed value. Accordingly, the device can be operated without any response delay because the controller 29 stops the drive of a burner 8 by outputting the overheating signal, and the protection of the device and the system operation can be normalized, moreover heat decomposition and deterioration of refrigerant do not occur, and a system having high reliability can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a refrigerant heater which heats a refrigerant such as water or cologne by a high temperature gas such as a combustion gas and uses the refrigerant in a cooling and heating device.

[0002]

2. Description of the Related Art A conventional refrigerant heating / heating machine as shown in FIG. 3 is used in which a refrigerant is used as a fluid to be heated and is heated by combustion gas to evaporate a liquid refrigerant to carry heat by latent heat for heating. There is. This connects the heat exchanger 1 for exchanging heat between the combustion gas and the refrigerant with the radiator 2 by the closed pipe 3 for circulation, and forcibly circulates the refrigerant by the refrigerant carrier 4 provided in the closed pipe 3. Is configured to. FIG. 4 shows a conventional example of the heat exchanger 1 (Japanese Patent Application Laid-Open No. 59-10).
No. 7167), a large number of fins 5 are provided on the inner peripheral surface of a cylindrical body extending in the horizontal direction along the longitudinal direction, and a pipe holding portion 6 and a pipe 7 through which a refrigerant flows in the axial direction of the outer peripheral surface. The combustion gas from the burner 8 is provided to flow horizontally in the horizontal direction along the inner surface of the cylinder, and is sent by the refrigerant carrier 4 to heat the refrigerant flowing in the pipe 7. 9
Is a temperature detector, which is attached to the surface between the pipe holding portions 6 and controls so that the heating is stopped when the temperature of the refrigerant is abnormally increased and the temperature detector 9 reaches a certain temperature or higher.

[0003]

However, in this heating system, the refrigerant carrier 4 as an external power is required to carry the refrigerant, and therefore it is desired to reduce the running cost during the heating operation.

In order to reduce the running cost during the heating operation, it is effective to transfer heat without power by eliminating the external power for transferring the refrigerant. When performing refrigerant heating and heating by non-powered heat transfer, the natural circulation force due to the buoyancy of the gaseous refrigerant generated by heating the liquid refrigerant is important.

However, in the above-described conventional structure, in the heat exchanger 1 for heating the refrigerant, the refrigerant flows in the pipe 7 extending in the horizontal direction, so that the gas component of the refrigerant which is heated and is in the gas-liquid two-phase mixed state smoothly exits. Since it does not flow toward the interior, stagnation of the refrigerant occurs, causing localized abnormal overheating. In addition, since the combustion chamber and heat exchange part in the cylinder are integrated, the amount of heat exchange becomes uneven depending on the combustion state, causing local overheating, thermal decomposition of the refrigerant, abnormal temperature rise of the device, etc. there were. In addition, when the temperature of the refrigerant rises to an abnormal temperature, the temperature of the refrigerant rapidly rises because the latent heat of the refrigerant changes and then the sensible heat of the refrigerant changes. Therefore, the response due to the heat capacity of the temperature detector is delayed. Therefore, the refrigerant is overheated to a high temperature to cause thermal decomposition, which causes a problem in reliability of equipment such as performance deterioration and corrosion.

In order to solve the above problems, the present invention enhances the natural circulation force of the natural circulation cycle of a refrigerant heater heated by a burner or the like to smoothly circulate the refrigerant to ensure unpowered heat transfer. , A high-temperature combustion gas is uniformly introduced from the combustion chamber to the heat exchange section to maintain a uniform temperature of the refrigerant, and a highly reliable system does not cause thermal decomposition of the refrigerant, and when the refrigerant heater lacks the refrigerant, etc. When is overheated,
Immediately detect this and protect equipment and normalize system operation.

[0007]

In order to achieve the above object, the present invention includes a heat exchange section communicating with a refrigerant inlet section and a refrigerant outlet section, a heat source section for heating the heat exchange section, and a heat exchange section. An overheat temperature detecting means is provided, and a control section that outputs an overheat signal when the temperature output of the overheat temperature detecting means is a certain value or more, and the control section keeps the temperature output of the overheat temperature detecting means constant. It is inputted every time, the difference between the temperature output before and after this is calculated, and when this value is equal to or more than a predetermined value, an overheat signal is output.

[0008]

According to the present invention, the refrigerant is
The refrigerant enters the heat exchange section, is heated by the heat source section in the heat exchange section, becomes high-temperature refrigerant gas, and exits from the refrigerant exit section and circulates. At this time, the refrigerant transfers heat by latent heat due to evaporation. Therefore, the heat exchange section balances the amount of heat that is heated from the heat source and the amount of heat that is released to the refrigerant, such as when the refrigerant leaks to the outside during operation, such as when the filling amount decreases or the circulation amount decreases, When the heat cannot be normally released to the refrigerant, the heat exchange section rapidly overheats to a high temperature, and the refrigerant and the refrigerating machine oil deteriorate at a high temperature. Further, as an abnormal condition, when there is no refrigerant in the heat exchanging portion at the start of operation, the heat exchanging portion is overheated by the heat source portion, and the temperature output of the overheat temperature detecting means rapidly rises. Therefore, when the temperature output of the overheat temperature detecting means exceeds a certain value, an overheat signal is output to the control section to normalize the protection of the equipment and the operation of the system.

Further, as another abnormal condition, when there is a refrigerant in the heat exchange section at the start of operation and the circulation of the refrigerant is stopped, the heat received by the heat exchange section by the heat source section is first converted to latent heat of vaporization of this refrigerant. Therefore, the response of the temperature output of the overheat temperature detecting means becomes slow. Therefore, the equipment is stopped by predicting that all the refrigerant in the heat exchange section will evaporate. That is, the temperature output of the overheat temperature detecting means is input at regular intervals, the temperature output before and after this is calculated, and when this value is equal to or greater than a predetermined value, an overheat signal is output, thereby The refrigerant disappears in the liquid phase, and a sudden rise due to sensible heat can be detected only in the gas phase, thus protecting the equipment and normalizing the system operation. Therefore, when the refrigerant overheats, such as when the refrigerant heater runs short, the temperature of the refrigerant can be immediately detected to normalize the equipment protection and system operation, and the thermal decomposition and deterioration of the refrigerant do not occur and are highly reliable. Become a system.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 1 and 2, reference numeral 10 denotes a cylindrical combustion chamber case in which a heat insulating material 23 is provided on the inner surface to form a combustion chamber 10a, and a burner 8 faces the bottom. The combustion chamber case 10 has an open end surface joined to the outer surface of a high temperature gas passage body 12a having a large number of vertical high temperature gas passages 12. The high temperature gas passage body 12a is vertically divided into two, and a horizontally long inlet 12b is formed between the two so that each high temperature gas passage 12 communicates with the gas outlet 13 of the combustion chamber 10a. Then, the high temperature gas passage body 12a is joined to the heat transfer partition wall 11, and the heat of the high temperature gas passage 12 and the heat are uniformly transferred to the heat transfer partition wall 11 through the large number of heat transfer fins 22. Reference numeral 14a denotes an exhaust case in which the tip of the combustion chamber case 10 is extended to form an exhaust chamber 14b surrounding the upper and lower outlet sides of each high temperature gas passage 12 of the high temperature gas passage body 12a and the left and right sides of the high temperature gas passage body 12a. The exhaust path 14 is provided at the upper part. 15 is a heat transfer partition 1
1 is a heat exchange part that is thermally joined to the outer surface of 1, and is provided with a large number of longitudinal refrigerant passages 16. 17 is a heat exchange unit 1
5, an inlet header pipe provided at the lower end of 5, a heat exchange section 15
Is an outlet header pipe provided at the upper end of the inlet header pipe 19 and the refrigerant outlet pipe 20 are respectively connected to the refrigerant circuit, and the other end of the inlet header pipe 17 is bent downward to form an oil. A vent pipe 21 is provided. The inlet header pipe 17 and the outlet header pipe 18 are communicated with each other by a vertical refrigerant passage 16. Reference numeral 22 is a heat transfer fin that is in thermal contact with the inside of the heat transfer partition wall 11, and is a large number. The combustion chamber 10a is provided with a heat insulating material 23 inside the combustion case 10 for covering the remaining outer surface which is not in contact with the high temperature gas passage 12. In a part of the heat transfer partition wall 11 of the high temperature gas passage 12,
A heat transfer tool 24 is provided in close contact with the heat transfer partition wall 11, and a temperature thermistor 25 as an overheat temperature detecting means is attached to the heat exchange section 15 at a position opposed to the heat transfer tool 24.

In this embodiment, the heat transfer tool 24 and the heat transfer fin 2 are used.
2. The heat transfer partition wall 11 and the heat transfer fin 2 are made of aluminum, and the heat transfer tool 24 is brazed to the heat transfer partition wall 11 while being fitted to the heat transfer fins 22.
A heat transfer tool 24 is provided in close contact with the second member 2. This heat transfer tool 24
A hole that penetrates through the heat transfer partition wall 11 and reaches the vicinity of the refrigerant passage 16 of the heat exchange section 15 is provided at approximately the center of the heat transfer section 15. The temperature thermistor 25 is coated with a heat conductive material and is inserted and held by the fixture 26. ing. The temperature sensitive portion of the temperature thermistor 25 is provided at the tip and is located near the refrigerant passage 16. Reference numeral 28 is a refrigerant temperature detecting means, and a holder 27 is provided on the outer wall surface of the outlet pipe 20.
It is a temperature thermistor bitten and attached by. Reference numeral 29 denotes a control unit, which is a control unit configured by a microcomputer or the like for controlling the system by calculating the detection outputs of the temperature thermistor 24 and the temperature thermistor 28 as inputs and controlling the system by the output of the results. The combustion output of the burner 8 is controlled by the detection output of the temperature thermistor 28.

FIG. 5 shows the operation when the refrigerant in the heat exchange section is reduced.
Shown in. The detection output of the temperature thermistor 25 is a certain value or more 9
When the temperature is 0 ° C., the control unit 29 outputs an overheat signal, and the control unit 29 inputs the detection output of the temperature thermistor 25 at regular intervals (for example, 30 seconds), and outputs the temperature before and after this. Is calculated, and this value is greater than or equal to a predetermined value (for example, 1
When it is 0 deg), an overheat signal is output. Then, in the refrigerant circuit, a heat exchanger or the like (not shown) for heat radiation is connected between the outward pipe 30 and the return pipe 31. Outgoing pipe 30, return pipe 3
1 is a refrigerant inlet pipe 19, a refrigerant outlet pipe 20 and a refrigerant receiving tank 3
2 are connected.

In the above structure, the fuel supplied by the fuel supply device is burned by the burner 8, and the high temperature gas generated in the combustion chamber 10a is divided into two parts, that is, from the combustion gas outlet 13 to the inlet 12b and above and below the high temperature gas passage body 12a. The hot gas flowing through each of the hot gas passages 12 and the heat transfer fins 22 and flowing from the upper outlet of the hot gas passage 12 to the exhaust chamber 14b, and the hot gas from the lower outlet of the hot gas passage 12 The high temperature gas flowing in the exhaust chamber 14b that surrounds the left and right sides of the passage body 12a merges in the upper exhaust chamber 14b and flows into the exhaust passage 14.

On the other hand, the liquid refrigerant that has passed through the refrigerant inlet pipe 19 and entered the inlet header pipe 17 is divided into a plurality of vertical refrigerant passages 16 from the lower portion of the heat exchange portion 15 and flows into the high temperature gas passage 12. Heat is transferred from the flowing combustion gas and the heat transfer fins 22 to the heat exchange section 15 via the heat transfer partition wall 11. Therefore, the refrigerant in the longitudinal refrigerant passage 16 of the heat exchange portion 15 is sufficiently heated from the lower portion near the inlet header 17. Then, the heated liquid refrigerant starts vaporization and evaporation, and becomes a gas-liquid two-phase state in which bubbles are generated in the liquid. Due to the buoyancy effect, the generated bubbles rise upward from below in the refrigerant passage 16 provided in the vertical direction. Particularly, the combustion gas leaves the combustion gas outlet 13 from the combustion chamber 10a, and then the heat transfer partition wall 1 from the high temperature gas passage 12.
Since the heat is transferred to the refrigerant via 1, the temperature and flow of the combustion gas are uniform, each part of the heat exchange section 15 can be uniformly heated, and the refrigerant is evaporated smoothly and uniformly, and the refrigerant is not locally overheated. The non-powered heat transfer is reliably performed, and the thermal decomposition of the refrigerant does not occur. Further, since the refrigerant passage 16 of the heat exchange section 15 can be uniformly heated, the flow rate of each of the refrigerant passages 16 becomes uniform and the resistance as a whole is reduced, the bubble rising force is strengthened and the natural circulation force is strengthened and the refrigerant is sent to the upper part. Bubble pump action occurs.

The refrigerant reaching the upper end of the refrigerant passage 16 flows into the outlet header pipe 18 and flows from the refrigerant outlet pipe 20 into the gas-liquid separation tank 32, and the separated gas refrigerant is discharged from the outward pipe 30 for heat dissipation (see FIG. It flows out toward (not shown). The temperature of the refrigerant is constantly detected by the temperature sensor 28 in response to the fluctuation of the heat radiation amount of the heat exchanger, and the combustion amount of the burner 8 is controlled by the control unit 29 so that the temperature becomes constant.

Further, the high temperature gas passage 12 is formed by the high temperature gas passage body 12a, and the double wall structure is constituted by the heat exchange portion 15 which is in close contact with the heat transfer partition wall 11, so that the refrigerant passage is formed from the inner wall through the heat transfer fins 22. Since the heat is transferred to the heat exchanger 16, heat transfer efficiency is increased, and the double wall structure constituted by the heat exchange section 15 having a perforated pipe structure prevents the refrigerant from leaking to the combustion gas portion, and the high temperature combustion chamber 10a and the refrigerant passage 16 are heated to a high temperature. Since the gas passage body 12a is completely separated, the refrigerant is not thermally decomposed or deteriorated due to local overheating, and the system has high reliability. Combustion chamber 10a
The inner surface of the combustion chamber case 10 that is not in contact with the high temperature gas passage 12 is covered with a heat insulating material 23 to prevent heat radiation.

During normal operation, the refrigerant returns to the return pipe 31,
From the refrigerant inlet pipe 19 to the inlet header pipe 17 to the heat exchange section 15
The refrigerant passage member 16 is heated by the burner 8 which is a heat source in the heat exchanging portion 15, becomes high-temperature refrigerant gas, flows out from the refrigerant outlet pipe 20 to the outward pipe 30, and circulates. Since the refrigerant is transported by latent heat due to evaporation, the temperature is always constant according to the pressure of the refrigerant, and the temperature of the refrigerant discharged from the heat exchange section 15 detected by the temperature thermistor 28 provided in the refrigerant outlet pipe 20 and the heat exchange section 15 are provided. The temperature of the heat exchange section detected by the temperature thermistor 25 becomes almost the same temperature, and the heat exchange section balances the heat quantity heated from the heat source section and the heat quantity released to the refrigerant to keep a constant temperature.

FIG. 5 shows the temperature of the heat exchange section at the time of abnormality. When heat cannot be normally released to the refrigerant, such as when the filling amount decreases or the circulation amount decreases such as the refrigerant leaking to the outside during operation, the heat exchange unit 15 causes the refrigerant to change from latent heat change to sensible heat change. Since the temperature of the refrigerant rapidly rises, the temperature thermistor 25 of the overheat temperature detecting means rapidly rises and detects without a response delay, and the control unit operates. Also, in the event of an abnormality,
Similarly, when there is no refrigerant in the refrigerant passage member 15 of the heat exchange section at the start of operation, the heat exchange section 15 is overheated by the burner 8 and the temperature output of the temperature thermistor 25 rapidly increases. Therefore, when the output of the temperature thermistor 25 exceeds a certain value, an overheat signal is output to the control unit 29, and the control unit 29 operates so as to immediately stop combustion, thereby protecting the equipment and normalizing the operation of the system. Then, as another abnormal condition, when the heat exchange section 15 has a refrigerant at the start of operation and the circulation of the refrigerant is stopped, as shown in FIG. 5, the heat received by the heat exchange section 15 by the burner 8 is initially Since it changes to the latent heat of vaporization of the refrigerant, the response of the output of the temperature thermistor 25 of the overheat temperature detecting means becomes slow. Therefore, the equipment is stopped by predicting that all the refrigerant in the heat exchange section 15 will evaporate. That is, when heating is started by the burner 8 and the refrigerant in the heat exchange section 15 begins to evaporate, at the same time, the output of the temperature thermistor 25 attached to the heat exchange section 15 gradually increases. The initial temperature rise of the temperature thermistor 25 is affected by the heat capacity of each part of the heat exchange section 15 and the ambient temperature, and the temperature rise curve changes slightly. The output of the temperature thermistor 25 is input to the control unit 29 at regular intervals (30 seconds), and the difference in temperature output before and after this is calculated. Then, when all the refrigerant in the heat exchange section 15 evaporates and the refrigerant disappears in the liquid phase state and heat transfer by sensible heat is started only in the gas phase, the temperature thermistor 25
Since the output of 1 increases sharply, the value of the difference between the temperature output before and after the calculation increases rapidly (10 deg). Therefore,
This abnormality can be predicted before the refrigerant in the heat exchange section 15 is completely consumed, and the temperature becomes the temperature shown by the broken line in FIG. Therefore, the heat exchange section 15 does not become abnormally high temperature due to the response delay, and the equipment is protected and the system operation is normalized. If the above control is performed at the start of operation when there is no refrigerant as described above, the heat stress of the heat exchange section 15 can be reduced as shown in FIG. As a result, when the refrigerant overheats, such as when the refrigerant heater runs short, the temperature of the refrigerant can be immediately detected to protect the equipment and normalize the operation of the system, and thermal decomposition and deterioration of the refrigerant do not occur and reliability is improved. It can be a high system.

The heating input amount of the burner 8 is kept constant by keeping the input amount constant for a certain period of time even if the input amount to be heated is at least from the start of heating. When vaporization starts, the temperature rise of the output of the temperature thermistor 25 of the heat exchange section 15 becomes a stable temperature rise curve, and malfunction does not occur even if the predetermined value determined by the output difference of the temperature thermistor 25 is set small. Therefore, it becomes possible to detect an abnormality more quickly, less overheat due to an abnormality of the device, less thermal stress applied to the heat exchanger, the refrigerant, etc., and reliability is improved in durability.

[0021]

As described above, according to the present invention, the heat exchange section communicating with the refrigerant inlet section and the refrigerant outlet section, the heat source section for heating the heat exchange section, and the overheat temperature detection provided in the heat exchange section are provided. And a control unit that outputs an overheat signal when the temperature output of the overheat temperature detection unit is equal to or higher than a constant value, and the control unit inputs the temperature output of the overheat temperature detection unit at constant time intervals, The difference between the temperature outputs before and after this is calculated, and when this value is equal to or greater than a predetermined value, an overheat signal is output, so that the following effects can be obtained. (1) When the refrigerant leaks to the outside during operation or the circulation amount decreases, when the temperature output of the overheat temperature detecting means exceeds a certain value, an overheat signal is output from the control unit to protect the equipment and prevent the system from operating. The operation can be normalized. Also, when there is a refrigerant in the heat exchange section at the start of operation, and even when the circulation of the refrigerant is stopped, the temperature of the refrigerant can be immediately detected without delay in response to normalize the protection of the equipment and the operation of the system, thermal decomposition of the refrigerant,
A highly reliable system can be obtained without deterioration. (2) The control unit sets the predetermined value of the output of the refrigerant heating temperature detection unit with high accuracy by setting the input amount for heating the heat source unit to a constant input amount for a certain period of time even if the heating is not started. It can be set and the abnormality can be detected earlier.

[Brief description of drawings]

FIG. 1 is a perspective view of a cross section of a main part of a chair heat exchanger according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a heat exchange part of the heat exchanger.

FIG. 3 is a circuit configuration diagram of a conventional refrigerant heater.

FIG. 4 is an external perspective view of a conventional refrigerant heater.

FIG. 5 is a temperature change diagram when the refrigerant in the heat exchanger decreases.

[Explanation of symbols]

 8 burner (heat source part) 15 heat exchange part 17 inlet header pipe (refrigerant inlet part) 18 outlet header pipe (refrigerant outlet part) 25 overheat temperature detecting means 29 control part

Claims (2)

[Claims] 1. A heat exchange section communicating with a refrigerant inlet section and a refrigerant outlet section, a heat source section for heating the heat exchange section, an overheat temperature detection means provided in the heat exchange section, and an overheat temperature detection means. A control unit that outputs an overheat signal when the temperature output is equal to or higher than a certain value is provided, and the control unit inputs the temperature output of the overheat temperature detecting means at regular time intervals and calculates a difference between the temperature output before and after the temperature output. The control device for the refrigerant heater, which outputs an overheat signal when this value is equal to or greater than a predetermined value. 2. The control device for a refrigerant heater according to claim 1, wherein the input amount for heating the heat source unit is a constant input amount for a certain period of time at least from the start of heating.