JP2692966B2 - Heat transfer device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer device that transfers heat to a use side by utilizing a pressure increase when heating a refrigerant.

2. Description of the Related Art In order to perform a heat-driven heat transfer method in which a refrigerant is heated by combustion heat from a burner or the like and the pressure of the evaporated refrigerant is circulated, the liquid refrigerant filled in the receiver is intermittently filled. To the refrigerant heater.

This intermittent supply cycle is limited by the physical property value of the refrigerant (for example, when the refrigerant is CFC and the upper pressure limit for heating operation is 30 kg / cm ² , the latent heat amount kcal per unit weight of the refrigerant is kcal). Since / kg decreases with increasing pressure), it was set according to the highest pressure in other heat transfer conditions, in other words, the highest temperature. That is, since the latent heat of the refrigerant becomes the minimum at the highest temperature in the use such as heating, in order to convey a predetermined amount of heat to the user side, the circulation flow rate kg / h of the refrigerant per unit time is the maximum at the upper use temperature. Become.
Therefore, the circulating flow rate of the refrigerant is determined at the highest temperature (or pressure) in the operating range of the system, and the number of times per unit time the liquid refrigerant is sent intermittently from the receiver to the refrigerant heater in accordance with this circulating flow rate. The liquid refrigerant is intermittently supplied to the refrigerant heater at the shortest cycle determined so as to be optimal for the highest temperature (or pressure) in the operating range of the system.

However, in the conventional system as described above, the latent heat of the refrigerant increases under the condition of low operating temperature (or pressure) of the system, so that the flow rate of the liquid refrigerant supplied to the refrigerant heater increases. On the other hand, the flow rate of the gas refrigerant that is heated and evaporated by the refrigerant heater decreases, the amount of liquid refrigerant in the refrigerant heater gradually increases, and the amount of liquid refrigerant staying in the radiator on the use side decreases.

At this time, the liquid refrigerant with poor heat transfer decreases in the radiator, the two-layer area with good heat transfer, which is a mixture of gas refrigerant and liquid refrigerant, increases, and the heat dissipation performance of the radiator increases, so the heat dissipation temperature decreases. At the same time, the pressure drops. However, when the amount of liquid refrigerant staying in the refrigerant heater further increases and the liquid level height in the refrigerant heater rises, a large amount of liquid refrigerant flows out together with the gas refrigerant that evaporates. As the amount of liquid refrigerant sharply decreases, the liquid refrigerant rapidly flows into the radiator on the use side, and the liquid refrigerant area in the radiator rapidly increases, leading to a decrease in heat dissipation performance, so the heat dissipation temperature rises and the pressure rises at the same time. . In this way, hunting may occur in which the temperature (or pressure) drops and rises periodically due to the imbalance between the amount of refrigerant entering the heater and the amount of refrigerant exiting the heater. Moreover, if this hunting is severe, a large amount of liquid refrigerant flows out of the refrigerant heater at one time along with the vaporized gas refrigerant, and local overheating may occur in the refrigerant heater that has run short of liquid refrigerant. In this case, there is a problem of system reliability such as thermal decomposition of the refrigerant and durability of the refrigerant heater.

The present invention solves the above-mentioned conventional problems, minimizes the occurrence of hunting regardless of the operating condition of the cycle, stably supplies the necessary liquid refrigerant to the refrigerant heater, and improves system reliability. It is an object of the present invention to provide a heat transfer device capable of improving the property.

Means for Solving the Problems In order to solve the above problems, the heat transfer device of the present invention is provided with an annular passage portion in which a refrigerant heater and a gas-liquid separator are connected by piping, and a liquid receiving device is provided above the gas-liquid separator. The vessel first
A drop pipe having a check valve and a pressure equalizing passage having an opening / closing valve are connected to the annular passage portion, and the gas-liquid separator, the radiator, the second check valve, and the liquid receiver are sequentially connected by piping. To form an annular heat transfer path, and the opening / closing operation cycle of the opening / closing valve is increased with the start of hunting of the temperature or pressure detected by the temperature detector or the pressure detector provided on the outlet side of the refrigerant heater in the previous period. When the hunting cycle is short, the opening / closing operation cycle is changed by a predetermined change width immediately before, and when the hunting cycle is short, the opening / closing operation cycle is changed immediately before the increase / decrease direction is reversed to change by a predetermined change width. Is provided.

Further, the change width of the opening / closing operation cycle is set to be large when the hunting cycle is short, and small when the hunting cycle is long, and variable control is performed by the hunting cycle.

Action With the above configuration, when the temperature detection or pressure detector installed on the outlet side of the refrigerant heater detects that hunting in which temperature or pressure repeatedly rises, falls, or falls and rises occurs, the opening / closing valve is opened and closed first. Hunting is mitigated by slightly increasing the operating cycle to reduce the number of switching operations per unit time to reduce the amount of refrigerant flowing into the refrigerant heater and bring the amount of refrigerant closer to the amount of refrigerant that is heated and flows out of the refrigerant heater. If the hunting cycle of temperature or pressure is longer due to the longer opening / closing operation cycle, the refrigerant inflow / outflow amount in the refrigerant heater tends to be balanced. repeat.

However, if the temperature or pressure hunting cycle is shortened by increasing the opening / closing operation cycle, the refrigerant inlet / outlet amount in the refrigerant heater tends to be out of balance. If the hunting cycle becomes longer by shortening it, the opening / closing operation cycle is shortened repeatedly.As a result, if the hunting cycle becomes shorter again, the direction of change of the opening / closing operation cycle is reversed and opening / closing is performed. The operation cycle is gradually lengthened.

In this way, in order to balance the amount of refrigerant flowing into the refrigerant heater with respect to the amount of refrigerant flowing out of the refrigerant heater, first make the opening / closing cycle a little longer, and if the hunting cycle becomes longer, open / close cycle immediately before. When the hunting cycle is shortened by changing the open / close operation direction by maintaining the same increasing / decreasing direction (longer if the opening / closing cycle is longer, shorter if shorter). The temperature or pressure hunting is changed by reversing the increasing / decreasing direction immediately before and after changing the opening / closing cycle (short if the opening / closing cycle is long, long if the opening / closing cycle is long) and changing it within a predetermined change width. Reduce.

Then, irrespective of the operating condition of the cycle, the amount of the refrigerant flowing from the refrigerant heater to the radiator is balanced with the amount of the refrigerant supplied from the liquid receiver to the refrigerant heater, and the temperature in the refrigerant heater is temporarily changed. By eliminating the occurrence of insufficient refrigerant, local abnormal overheating in the refrigerant heater is prevented, and stable refrigerant overheating operation improves system reliability.

Further, the change width of the opening / closing operation cycle of the opening / closing valve increases / decreases,
If the hunting cycle is short, the change width is large, and if the hunting cycle is long, the change width is small.
Hunting is converged in a shorter time, and stable refrigerant heating operation is realized in a short time, so that system reliability is further improved.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram of a heat transfer device showing an embodiment of the present invention. In FIG. 1, gas-liquid separator 1
Is arranged above the refrigerant heater 2 and is connected by the inlet pipe 3 of the refrigerant heater 2 and the outlet pipe 4 of the refrigerant heater 2 to form an annular passage portion.

Further, the liquid receiver 5 is arranged above the gas-liquid separator 1, and the liquid receiver 5 constitutes the annular passage portion.
To the refrigerant heater outlet pipe 4 forming an annular passage portion by a pressure equalizing passage 9 having an opening / closing valve 8. As a result, the liquid receiver 5 and the refrigerant heater 2 are connected.

The gas-liquid separator 1 and the radiator 10 are connected by a gas refrigerant outflow pipe 11, and the radiator 10 and the liquid receiver 5 are connected by a liquid refrigerant return pipe 13 having a second check valve 12.

As described above, the gas-liquid separator 1, the radiator 10, the second check valve 12, the liquid receiver 5 and the first check valve 6 form an annular heat transfer path sequentially connected by piping.

The temperature detector 14 is provided in the outlet pipe 4 of the refrigerant heater 2. Further, the control device 15 includes the open / close valve 8 and the temperature detector.
It is electrically connected to 14. The burner 16 is provided in the refrigerant heater 2 and heats the refrigerant. Reference numeral 17 is a blower provided in the radiator 10.

The pressure equalizing passage 9 connects the liquid receiver 5 and the gas-liquid separator 1 so as to eliminate the pressure difference and equalize pressure. In this embodiment, one end of the pressure equalizing passage 9 is connected to the liquid receiver 5. , The other end is connected to the outlet pipe 4 forming the annular passage portion, and the gas-liquid separator 1 is connected.
However, it goes without saying that the other end of the pressure equalizing passage 9 may be directly connected to the gas-liquid separator 1 forming the annular passage portion for communication.

 The operation of the above configuration will be described below.

In the refrigerant heater 2, the refrigerant heated by the combustion heat of the burner 16 flows into the gas-liquid separator 1 through the refrigerant heater outlet pipe 4 in a two-phase state in which gas and liquid are mixed, and the liquid refrigerant heats the refrigerant. After passing through the inlet pipe 3, it again flows into the refrigerant heater 2. On the other hand, the gas refrigerant of the two-phase refrigerant flowing into the gas-liquid separator 1 passes through the gas refrigerant outflow pipe 11 and the radiator 10
Then, by operating the blower 17, heat is radiated to the air on the use side to be condensed and liquefied, and further radiated to the air to become a supercooled liquid having a temperature lower than the saturation temperature and accumulated in the outlet side of the radiator 10 and the liquid refrigerant return pipe 13. .

Here, the supercooled liquid refrigerant that has been pushed by the pressure of the refrigerant that evaporates flows into the liquid receiver 5 as the opening / closing valve 8 closes. When the supercooled liquid refrigerant flows into the liquid receiver 5, the gas refrigerant in the liquid receiver 5 is cooled by the supercooled liquid refrigerant and liquefied to sharply reduce its volume, so that the pressure in the liquid receiver 5 sharply decreases. To do. Due to the synergistic effect of the sudden depressurization of the liquid receiver 5 and the pressure of the refrigerant evaporated in the cooling heater 2, the liquid refrigerant in the radiator 10 passes through the liquid refrigerant return pipe 13 and the second check valve 12 to receive the liquid. It flows into the container 5 all at once. At this time, since the pressure of the liquid receiver 5 cooled by the supercooled liquid refrigerant is lower than the pressure of the gas-liquid separator 1, the first check valve 6 is closed.

When the open / close valve 8 is opened in this state, the liquid receiver 5 and the gas-liquid separator 1 communicate with each other through the pressure equalizing passage 9 to be in a pressure equalizing state, and the liquid refrigerant in the liquid receiver 5 is gravitationally moved to the first reverse direction. Stop valve 6
Through which the liquid refrigerant flows into the gas-liquid separator 1 and is supplied to the refrigerant heater 2.

The time required for the liquid refrigerant in the liquid receiver 5 to finish flowing out is almost constant because the liquid refrigerant falls due to gravity (the specific weight of the liquid refrigerant changes slightly depending on the operating conditions, but its influence is slight. Therefore, the opening time of the on-off valve 8 can be set to be substantially constant.

Next, when the on-off valve 8 is closed again, the liquid receiver 5 is suddenly decompressed with the re-inflow of the supercooled liquid refrigerant, and is filled with the supercooled refrigerant all at once.

In this manner, the opening / closing valve 8 is opened to supply the liquid refrigerant in the liquid receiver 5 to the refrigerant heater 2, and the opening / closing valve 8 is closed to flow the liquid refrigerant into the liquid receiver 5 to be repeated sequentially to transfer heat. Continue driving.

Thus, the natural circulation cycle between the gas-liquid separator 1 and the refrigerant heater 2 is based on the evaporated refrigerant pressure, and the supply of the liquid refrigerant from the liquid receiver 5 to the gas-liquid separator 1 and the refrigerant heater 2 is opened and closed. This is an intermittent operation cycle depending on the opening / closing cycle of the valve 8.

In this intermittent operation cycle, the control device 15 changes the opening / closing operation cycle of the opening / closing valve 8 (in other words, increases / decreases the number of opening / closing operations of the opening / closing valve 8 per unit time), thereby supplying an appropriate amount of refrigerant to the refrigerant heater 2. can do.

Here, a temperature detector provided on the outlet side of the refrigerant heater 2
The case where the closing time τ _off of the opening / closing valve 8 is increased / decreased by the controller 15 according to the temperature detected by 14 and the opening time τ _on is made constant to change the opening / closing operation cycle (τ _off + τ _on ) is shown in FIG. explain.

In FIG. 2, when the closing time of the on-off valve 8 is operating at τ _off1 and the operating temperature θ of the cycle _hunts down, rises or rises and falls repeatedly in a short time at this time. First, the controller 15 discriminates the point A at which the temperature θ detected by the temperature detector 14 changes from a decrease to an increase to detect the start of hunting, and the closing time is increased by Δτ. After that, the hunting cycle f ₁ , f ₂ , f ₃ ... Is measured by the controller 15 at the valley portion where the hunting falls from rising to rising, and the closing time τ _off is compared by comparing the magnitudes of the hunting cycle f before and after. increase. That is, the hunting cycle f ₁ <f ₂ <f
₃ and the hunting cycle f increases, the control device 15 determines that the hunting is in the direction of convergence, and maintains the increasing / decreasing direction of the closing time (when the closing time is increased immediately before, Also, and if the closing time is decreased immediately before, the next is also decreased), and in this case, the hunting periods f _{1 to} f ₃ are sequentially increased, and therefore the closing time τ
_{It is} gradually increased by Δτ until _off5 .

However, if the previous hunting cycle started to decrease with f ₃ > f ₄ and the hunting cycle f ₄ , the direction of increase / decrease in the closing time is reversed (if the closing time is increased immediately before, the Then, if the closing time is decreased immediately before, it is increased next.) In this case, the closing time τ _off6 is reduced by Δτ from the previous value, and the closing time τ _off6 = τ _off5 −Δτ. further,
Since the hunting cycle f ₄ <f ₅ and the hunting cycle f ₅ are long, the closing time τ _off7 maintains the previous increasing / decreasing direction, and is decreased by Δτ from the previous value, and the closing time τ _off7 = τ _off6 −Δτ
And

As described above, first, the opening / closing time of the opening / closing valve 8 is increased with the start of hunting, but thereafter, the opening / closing time is increased / decreased so that the hunting cycle f becomes longer. In this way, the opening / closing operation cycle is increased / decreased to stably maintain the temperature or pressure of the cycle to prevent the local overheating of the refrigerant to improve the system reliability and also to improve the distance between the radiator 10 and the receiver 5. When the (pipe length) is long, or the radiator 10 and the receiver 5
Even if the flow resistance of the liquid refrigerant return pipe 13 increases due to the difference in the installation height between the and the like, stable heat transfer can be performed automatically and the degree of freedom in the installation of the system can be improved.

In this embodiment, the temperature detector 14 controls the opening / closing operation cycle of the on-off valve 8. However, the outlet side of the refrigerant heater 2 is in a two-phase state, and there is a constant relationship between temperature and pressure. As such, it is clear that the pressure detector can similarly control the opening and closing cycle.

FIG. 3 and FIG. 4 show another embodiment, in which the hunting cycles f ₁₁ , f ₁₂ , of the temperature detected by the temperature detector 14 are shown.
It is intended to change the size of the value of the variation .DELTA..tau _off to increase or decrease the closing time tau _off off valve 8 f _13, when when hunting period f is short variation .DELTA..tau _off is large, a long hunting period f Reduces the amount of change Δτ _off .

In Fig. 3, the hunting period increases (f ₁₁ <f ₁₂ <f ₁₃ )
However, this is the case where the increasing / decreasing direction of the closing time τ _off is maintained (in this case, the increasing direction), and the change amount Δτ _off becomes Δτ _off11 > Δτ _off12 > Δτ _off13 as the hunting period f becomes longer.
And shows the case where it becomes small.

By doing so, the cycle can be stabilized more quickly, the local abnormal overheating of the refrigerant can be prevented quickly, and the reliability of the system can be further improved.

Effects of the Invention As described above, according to the heat transfer device of the present invention, the opening / closing operation cycle of the on-off valve is increased with the start of the hunting of the temperature or the pressure detected by the temperature detector or the pressure detector, and the hunting cycle is further lengthened. If the hunting cycle is shortened, the increase / decrease direction by changing the opening / closing operation cycle is maintained, and if the hunting cycle becomes shorter, the increasing / decreasing direction by changing the opening / closing operation cycle is reversed. Regardless of the state, hunting can be minimized to maintain a stable state at all times, local abnormal overheating of the refrigerant can be prevented, stable refrigerant heating operation can be performed, and system reliability is improved. You can

Further, even if the pipe lengths are greatly different or the installation height is greatly different, the system can be automatically stabilized and operated, so that the installation flexibility of the system can be greatly improved.

Further, the change width of the opening / closing operation cycle is increased when the hunting cycle is short and is decreased when the hunting cycle is long, and variable control is performed according to the hunting cycle, so that the cycle operation can be stabilized more quickly. The reliability can be further improved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a heat transfer device showing an embodiment of the present invention, and FIG. 2 is a closing time control diagram of an on-off valve for explaining a system operation of the heat transfer device showing an embodiment of the present invention. FIG. 3 is a closing time control diagram of an opening / closing valve for explaining the system operation of a heat transfer device showing another embodiment of the present invention, and FIG. 4 is a characteristic diagram of the variation width of the closing time in FIG. is there. 1 ... Gas-liquid separator, 2 ... Refrigerant heater, 3 ... Inlet pipe, 4 ... Outlet pipe, 5 ... Liquid receiver, 6 ... First check valve,
7: drop pipe, 8: open / close valve, 9: pressure equalizing passage, 10 ...
… Radiator, 11 …… Gas refrigerant outflow pipe, 12 …… Second check valve,
13 ... Liquid refrigerant return pipe, 14 ... Temperature detector, 15 ... Control device.

Claims (2)

(57) [Claims] 1. An annular passage portion is provided in which a refrigerant heater and a gas-liquid separator are connected by piping, and a liquid receiver provided above the gas-liquid separator has a first check valve and a drop pipe and an on-off valve. A pressure equalizing passage is connected to the annular passage, and the gas-liquid separator, the radiator, the second check valve, and the liquid receiver are sequentially pipe-connected to form an annular heat transfer passage, and the opening / closing valve is opened / closed. The operation cycle is increased with the start of hunting of the temperature or pressure detected by the temperature detector or the pressure detector provided on the outlet side of the refrigerant heater, and when the hunting cycle becomes long, the opening / closing operation cycle is changed immediately before. A control device that changes the opening / closing operation cycle by a predetermined change width while maintaining the increase / decrease direction, and reverses the increase / decrease direction in which the opening / closing operation cycle was changed immediately before the hunting cycle becomes short and changes by a predetermined change width. Heat transfer provided Apparatus. 2. The heat transfer device according to claim 1, wherein the change width of the opening / closing operation cycle is increased when the hunting cycle is short and is decreased when the hunting cycle is long, and variable control is performed by the hunting cycle.