High-efficiency waste cold and warm heat recycling heat exchange device

Abstract

In the waste hot and cold energy recycling heat exchange device of the present invention, the refrigerant circulates between the evaporator 10 and the condenser 20 forming a closed loop, the condenser 20 is provided with a digital sensor 45 for detecting the internal refrigerant pressure and temperature and inputting the detection values ​​to the control device 50, the liquid refrigerant pipe 40 is provided with a liquid transfer pump 46 and a solenoid valve 47 for pushing the liquid refrigerant to the evaporator 10 side, and the control device 50, which receives the detection value of the digital sensor 45, controls the operation of the liquid transfer pump 46 and the solenoid valve 47 according to the detection value to adjust the flow rate of the liquid refrigerant flowing through the refrigerant pipe 40. As a result, the amount of refrigerant circulation can be automatically adjusted according to the degree of heat equilibrium and pressure equilibrium generated in the evaporator 10 and the condenser 20, and thus it is possible to achieve not only stable refrigerant circulation but also highly efficient optimization of waste hot and cold energy recovery.

Description

Technical Field

[0001] The present invention relates to a waste cooling and heating recycling heat exchange device that forms a closed loop between an evaporator and a condenser and recovers and recycles waste cooling heat or waste warm heat lost in various energy-consuming devices including an air conditioner by using a circulating refrigerant.

Background Art

[0002] In a heat exchange device using an evaporator and a condenser, when the temperature difference between the refrigerants passing through the evaporator and the condenser becomes large, evaporation and condensation phenomena of the refrigerant occur respectively.

[0003] Evaporation and condensation of the refrigerant generate a pressure difference between the evaporator outlet and the condenser inlet and between the condenser outlet and the evaporator inlet. Therefore, a thermosiphon action occurs in which the refrigerant flows along the pressure gradient of the refrigerant pipe connecting the evaporator and the condenser and circulates without separate power.

[0004] The basic principle of a conventional heat exchange device using the thermosiphon action (hereinafter referred to as a "thermosiphon heat exchange device") is introduced in Korean Registered Patent No. 10-1294939.

[0005] Such a thermosiphon heat exchange device has the advantage of being able to circulate the refrigerant by itself and transfer heat without separate external power. Therefore, it is widely used as a waste cooling and heating recycling heat exchange device attached to devices that generate waste cooling heat or waste warm heat such as existing air conditioners to improve thermal efficiency.

[0006] However, in the conventional thermosiphon heat exchange device, if the temperature difference between the refrigerants passing through the evaporator and the condenser is small, a thermal equilibrium and a pressure equilibrium state are likely to occur in the liquid refrigerant pipe and the gas refrigerant pipe connecting the evaporator and the condenser. In this case, the flow of the refrigerant stops, so there is a problem that the effect of recovering waste cooling and heating by the circulation of the refrigerant that repeats evaporation and condensation cannot be expected.

[0007] After a heat balance and a pressure balance state occur in the refrigerant pipe, usually, the liquid refrigerant on the evaporator side where the temperature and pressure become high flows in the reverse direction toward the condenser side, and a problem of losing the function as a heat exchange device also occurs.

[0008] Due to such problems, there is also a heat exchange device that adds a refrigerant compressor, a reheater, etc. to a thermosiphon heat exchange device to forcibly eliminate the heat balance and pressure balance states of the refrigerant and prevent the refrigerant from flowing in the reverse direction.

[0009] By the way, compared with the fact that existing thermosiphon heat exchange devices have been freely installed in various heat exchange devices and waste heat generation locations, in the case of a thermosiphon heat exchange device that has to consider the positions of a refrigerant compressor power supply device for a refrigerant compressor and a heat source device for a reheater due to the refrigerant compressor and the reheater, there are many restrictions on the installation application environment.

[0010] In addition, in order to operate a refrigerant compressor, a reheater, etc., a very large amount of external energy is further consumed, so there is a problem of losing the inherent advantage that a thermosiphon heat exchange device hardly consumes external energy. As the device becomes more complex, the failure rate increases, and problems such as an increase in the production cost and maintenance cost of the product also occur.

[0011] On the other hand, the inventor of the present invention improved the conventional thermosiphon heat exchange device and applied for the thermosiphon heat exchange device illustrated in FIG. 1, which was published as Korean Patent Publication No. 10-2018-0029474.

[0012] The thermosiphon heat exchange device illustrated in FIG. 1 is provided with check valves 31 and 41 that allow the refrigerant to pass only in one direction when a difference equal to or greater than a predetermined pressure occurs in the refrigerant pipes 30 and 40 that connect between the outlet of the evaporator 10 and the inlet of the condenser 20 and between the outlet of the condenser 20 and the inlet of the evaporator 10. An expansion valve 44 is installed between the outlet of the check valve 41 for passing the liquid refrigerant and the inlet side of the evaporator 10 so as to obtain a throttling effect of the refrigerant.

[0013] Therefore, in the case of the thermosiphon heat exchange device illustrated in FIG. 1, if a thermal equilibrium and a pressure equilibrium state occur in the gas refrigerant pipe 30 and the liquid refrigerant pipe 40, the flow of the refrigerant stops due to the check valves 31 and 41, and the reverse flow thereof is prevented. Thereafter, if the thermal equilibrium and the pressure equilibrium state are sufficiently eliminated, the forward refrigerant circulation through the check valves 31 and 41 is performed again.

[0014] As described above, the thermosiphon heat exchange device of Korean Patent Publication No. 10-2018-0029474 can solve the phenomenon that a thermal equilibrium and a pressure equilibrium state occur in a thermosiphon heat exchanger without a conventional check valve and the flow direction of the refrigerant is reversed, without using a separate power device for eliminating the refrigerant thermal equilibrium and pressure equilibrium state.

[0015] However, in the case of the thermosiphon heat exchange device of Korean Patent Publication No. 10-2018-0029474, when the temperature difference between the refrigerants passing through the evaporator 10 and the condenser 20 is small, there is a problem that a thermal equilibrium and a pressure equilibrium state easily occur in the liquid refrigerant pipe 40 and the gas refrigerant pipe 30, and the flow of the refrigerant stops. Until the pressure difference recovers to a level sufficient to pass through the check valve, there still remains a problem that the effect as a heat exchange device for recovering waste cooling heat cannot be expected.

Prior Art Documents

Patent Documents

[0016]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0017] The present invention is devised to solve the problems of the prior art, and even if a refrigerant heat balance and a pressure balance occur between the outlet of the evaporator and the inlet of the condenser and between the outlet of the condenser and the inlet of the evaporator, it is an object to provide a configuration of a highly efficient waste cold and heat recycling heat exchange device that can maintain a stable refrigerant circulation action with only a minimum external energy input.

[0018] In addition to this, another object is to provide a configuration of a highly efficient waste cold and heat recycling heat exchange device that can automatically adjust an appropriate amount of refrigerant introduced into the evaporator during waste cold and heat recycling operation.

[0019] Also, another object of the present invention is to provide a configuration of a highly efficient waste cold and heat recycling heat exchange device that enables the work of filling the optimal amount of refrigerant to be easily performed during the trial operation stage.

Means for Solving the Problems

[0020] To achieve the above object, the present invention installs a gas refrigerant pipe connecting between the evaporator outlet and the condenser inlet, and a liquid refrigerant pipe connecting between the condenser outlet and the evaporator inlet, so that a refrigerant forms a closed loop and circulates between the evaporator and the condenser. A digital sensor for detecting the internal refrigerant pressure and temperature of the condenser and inputting the detected value to a control device is installed in the condenser. A liquid transfer pump for pushing the liquid refrigerant in the direction of the evaporator is installed on the liquid refrigerant pipe. The control device that receives the input of the detected value of the digital sensor is configured to control the operating operation of the liquid transfer pump according to the detected value and adjust the flow rate of the liquid refrigerant flowing through the refrigerant pipe.

[0021] Also, a solenoid valve is further installed on the liquid refrigerant pipe of the present invention, and the control device that receives the input of the detected value of the digital sensor can be configured to adjust the flow path opening rate of the solenoid valve according to the detected value.

[0022] Then, after the control device performs control to stop the operation of the liquid transfer pump first, and after a predetermined time has elapsed, it determines whether the refrigerant pressure and temperature detection values inside the condenser detected by the digital sensor satisfy a specified change value. If the specified change value is not satisfied, it can be configured to perform adjustment control of the flow path opening rate of the solenoid valve.

Advantages of the Invention

[0023] In the waste cold and heat recycling heat exchange device of the present invention, even if refrigerant heat balance and pressure balance occur between the evaporator outlet and the condenser inlet and between the condenser outlet and the evaporator inlet, the liquid transfer pump can be controlled to stably maintain the circulation action of the refrigerant. In particular, since the refrigerant circulation amount can be automatically adjusted according to the degree of the generated heat balance and pressure balance, not only a stable refrigerant circulation but also an operation that achieves high-efficiency optimization of waste cold and heat recovery is possible.

[0024] Also, in the present invention, after the initial installation of the device, even an operator with low proficiency can easily confirm whether the appropriate amount of refrigerant has been filled during the trial operation stage or the refilling process during maintenance. Therefore, there is an advantage that the installation and maintenance of the device are facilitated.

[0025] And, the waste cold and heat recycling heat exchange device of the present invention can be installed in the front or rear stage of the heat exchanger for air conditioning or separately installed with the evaporator or condenser in a place for waste heat utilization without being restricted by the form of the existing air conditioner. Therefore, it has an advantage that it can be applied to the site where losses occur in various forms of energy consumption devices, and can actively and freely recycle waste cold and heat.

[0026] That is, the waste cold and heat recycling heat exchange device of the present invention can be very usefully utilized for a constant temperature and humidity device that requires a reheating process after pre-cooling, for strengthening the dehumidification function of an existing air conditioner, for free cooling and free heating of a high-temperature and dehumidifying drying device, and for recycling the exhaust waste heat of a ventilation duct.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0028] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the high-efficiency waste cold and heat heat exchanger of the present invention will be described in detail.

[0029] The terms used for the description of the present invention may include terms defined in consideration of the functions in the present invention. Since the terms used in the present invention may be expressed by other terms according to the intentions or conventions of other designers and users, the substantial definitions of such terms should be made with reference to the contents described throughout this specification.

[0030] Also, in the description of the present invention, directional terms such as "upper", "lower", "front side", "rear side", "front", "rear", "left", "right", "tip", and "rear end" used are based on the orientation of the disclosed drawings. However, since the components of the embodiments of the present invention can be positioned in various orientations, the directional terms are used for illustrative purposes and do not limit this.

[0031] When it is described that the components used in the present invention are "connected", "coupled", or "fastened" to each other, it should be understood to include cases made by an indirect method through an intermediate component.

[0032] And, in the description of the present invention, detailed descriptions of well-known functions and configurations that may obscure the gist of the invention are omitted.

[0033] FIG. 2 shows a schematic diagram of a heat exchanger in which a refrigerant circulation cycle for recycling waste cold and heat operates as an embodiment of the present invention.

[0034] As shown in FIG. 2, the heat exchanger of the present invention includes an evaporator 10 that absorbs external heat and evaporates a liquid refrigerant into a gas, a condenser 20 that condenses the gaseous refrigerant discharged from the evaporator into a liquid by heat dissipation, and a gas refrigerant pipe 30 that connects the outlet of the evaporator 10 and the inlet of the condenser 20, and a liquid refrigerant pipe 40 that connects the outlet of the condenser 20 and the inlet of the evaporator 10, so as to form a closed loop for the refrigerant to circulate. This is based on a configuration that forms a closed loop, which corresponds to a general configuration seen in a known thermosiphon heat exchanger.

[0035] And in the present invention, a swing-type check valve 31 is further installed in the gas refrigerant pipe 30, and a ball-type check valve 41 is further installed in the liquid refrigerant pipe 40. Such an installation configuration of the check valve is the same as that disclosed in Korean Patent Publication No. 10-2018-0029474 referred to as the prior art (see FIG. 1).

[0036] The check valve 31 is opened so that the gas refrigerant flows into the condenser 20 if the refrigerant pressure on the outlet side of the evaporator 10 is higher than a specified pressure difference from the refrigerant pressure on the inlet side of the condenser 20. The check valve 41 is opened so that the gas refrigerant flows to the evaporator 10 side if the refrigerant pressure on the outlet side of the condenser 20 is higher than a specified pressure difference from the refrigerant pressure on the inlet side of the evaporator 10.

[0037] Referring to the illustration in FIG. 2, as a preferred embodiment of the present invention, a liquid transfer pump 46 and a solenoid valve 47 are further installed on the liquid refrigerant pipe 40.

[0038] The liquid transfer pump 46 is a device that forcibly pushes the liquid refrigerant on the liquid refrigerant pipe 40 into the evaporator 10, and is a device that is completely different in function, action, and effect from a "compressor" that compresses a gas refrigerant at high temperature and high pressure in a normal heat exchanger and discharges it to the condenser side.

[0039] As described above, if the temperature difference between the refrigerant passing through the evaporator 10 and the condenser 20 becomes small, the heat balance and pressure balance states between the liquid refrigerant pipe 40 and the gas refrigerant pipe 30 will be approached. As a result, the flow of the refrigerant in the closed loop becomes too weak, and almost no recovery efficiency of waste cold heat can be expected.

[0040] In the present invention, when the flow of the refrigerant thus becomes extremely weak, the liquid transfer pump 46 is used to forcibly push the liquid refrigerant to maintain the refrigerant circulation cycle. Therefore, it is a device different in purpose and function from a compressor that compresses gas refrigerant at high temperature and high pressure in a normal heat exchange device.

[0041] And, since the liquid transfer pump used in the present invention only needs to have a liquid transfer capacity to the extent of simply inducing the flow of the liquid refrigerant, a small-capacity one may be used.

[0042] That is, in the thermosiphon heat exchanger of the present invention, it was confirmed that when the liquid transfer pump generates a fluid pressure of about 0.5 kgf / cm 2 a normal flow of the liquid refrigerant starts. Therefore, the liquid transfer pump of the present invention is adopted to generate a pressure rise of at least 0.5 kgf / cm 2 or a slightly higher pressure rise in the passed liquid refrigerant compared to before passing.

[0043] And, the solenoid valve 47 can be installed between the liquid transfer pump 46 and the evaporator 10 for the purpose of intermittently controlling the liquid refrigerant discharged from the liquid transfer pump 46. The solenoid valve 47 is installed in case the refrigerant outflow from the liquid transfer pump 46 is not accurately performed only by stopping the operation of the liquid transfer pump 46, so as to more surely implement the interruption of the flow of the liquid refrigerant.

[0044] In the present invention, a digital sensor 45 and a control device 50 are installed to control the liquid transfer pump 46 and the solenoid valve 47.

[0045] The digital sensor 45 is installed on the condenser 20 side using one that can detect temperature and pressure. Preferably, as shown in FIG. 2, it is installed on the lower side where the liquid refrigerant accumulates in the liquid-only header 22 on the outlet side of the condenser 20 to detect the temperature and pressure of the liquid refrigerant.

[0046] And a control device 50, which is a device that generates a signal for controlling the operation of the liquid transfer pump 46 and the solenoid valve 47 in response to the input of the detected values of the temperature and pressure detected by the digital sensor 45, is installed at a predetermined position.

[0047] As the control device 50, an MCU (Micro Controller Unit) can be used, which controls the operation of the liquid transfer pump 46 and the solenoid valve 47 according to the liquid refrigerant state in the condenser 20 to automatically adjust the flow rate of the liquid refrigerant flowing through the refrigerant pipe 40.

[0048] That is, in the control device 50, it is determined whether the detected values of the temperature and pressure detected by the digital sensor 45 exceed or fall short of a specified range to a certain extent, and by controlling the operating operation of the liquid transfer pump 46 in proportion to the magnitude of the excess value or the shortfall value, the refrigerant discharge amount can be adjusted or the discharge can be completely stopped.

[0049] Also, the control device 50 can generate and control a signal to increase, decrease, or close the flow path opening rate of the solenoid valve 47, and can also control it in an organic linkage with the control of the liquid transfer pump 46.

[0050] The expansion valve 44 is a means for obtaining a throttling effect on the liquid refrigerant. The liquid refrigerant passing through the expansion valve 44 is throttled and the pressure drops. However, if the pressure drop is excessive and it drops below the saturation pressure, a part of the liquid refrigerant may evaporate to generate flash gas. Since this flash gas absorbs the latent heat of evaporation from the liquid refrigerant, the temperature of the liquid refrigerant drops.

[0051] In view of the heat capacity of the heat exchanger and the like, the expansion valve 44 can be installed as an electronic or sensitive expansion valve, and can also be alternatively selected and installed from devices that can cause a throttling action such as a capillary tube or a globe valve.

[0052] The pressure gauges 32 and 42 shown in Fig. 2 are installed in the refrigerant pipes 30 and 40 on the inlet side of the check valves 31 and 41, and measure and display the pressure of the gas refrigerant or liquid refrigerant passing through the refrigerant pipes. It is preferable to further install pressure gauge intermittent valves 33 and 43 that can interrupt the flow of the refrigerant between the refrigerant pipes 30 and 40 and the pressure gauges 32 and 42.

[0053] In the embodiment of the present invention shown in Fig. 2, a distributor 11 is installed at the inlet side of the evaporator 10 where a number of distribution tubes 12 branch off.

[0054] The distributor 11 functions to distribute a small amount of flash gas and low-temperature and low-pressure liquid refrigerant transmitted through the refrigerant pipe 40 after passing through the expansion valve 44.

[0055] Since the distribution tubes 12 are respectively separated and joined to the ends of the heat exchange tubes of the evaporator, the refrigerant flowing in from the liquid refrigerant pipe 40 is evenly distributed to the entire evaporator through the distributor 11 and the distribution tubes 12 and then flows in.

[0056] And a gas-only header 13 and 21 are respectively installed at the refrigerant outlet of the evaporator 10 and the refrigerant inlet of the condenser 20, and a liquid-only header 22 is installed at the refrigerant outlet of the condenser 20.

[0057] The header functions to assist the smooth inflow or outflow of the refrigerant between the refrigerant pipe and the evaporator or condenser.

[0058] In the embodiment of the present invention, the blower fan 23 blows external air (or the air at the waste heat generation location) to the heat exchange tube side of the condenser 20 to heat it into hot air and let this hot air flow into the room.

[0059] In the following, with reference to FIG. 2, an example will be given of a case where the present invention is used as a waste heat recycling heat exchanger that supplies heated air into a room such as a high-temperature drying chamber by using the waste heat at a location where there is a waste heat source that discharges cold air, and its operation will be described.

[0060] Generally, in a normal heat exchanger, the refrigerant flowing into the evaporator is in a low-temperature / low-pressure liquid state. In the evaporator, the refrigerant exchanges heat (absorbs heat) with the outside air and vaporizes, thereby becoming a low-temperature / low-pressure gas state and being discharged. This low-temperature / low-pressure gaseous refrigerant is compressed into a high-temperature / high-pressure superheated gas state through a compressor, and then enters the condenser to exchange heat (release heat) with the outside air, thereby becoming a high-temperature / high-pressure liquid state and being discharged. This high-temperature / high-pressure liquid refrigerant is throttled by an expansion valve to become a low-temperature / low-pressure liquid state, and further flows into the evaporator to perform the refrigerant circulation cycle.

[0061] In the above normal heat exchanger, since the pressure on the condenser side is higher than the pressure on the evaporator side, without a compressor, the low-temperature / low-pressure gaseous refrigerant discharged from the evaporator cannot be transferred to the condenser side.

[0062] By the way, in the present invention, the evaporation action in which the refrigerant vaporizes in the evaporator 10 is continuously performed for a predetermined time or more, so as to increase the amount of vaporization of the refrigerant, and the low-temperature / low-pressure gaseous refrigerant generated from the evaporator 10 is made to become a high-temperature / high-pressure state by itself.

[0063] That is, in the present invention, since the pressure of the gaseous refrigerant discharged from the evaporator 10 can be made higher than a pressure determined to be higher than the pressure on the inlet side of the condenser 20, even if there is no separate process of making the gaseous refrigerant into a high-temperature / high-pressure state by a compressor, it can be transferred to the condenser 20 side.

[0064] If the outlet pressure of the evaporator 10 thus becomes larger than the inlet pressure of the condenser 20, the swing-type check valve 31 installed in the gas refrigerant pipe 30 opens toward the condenser due to the pressure difference, and the gaseous refrigerant automatically flows into the heat exchange tube of the condenser 20 along the path of the check valve 31 and the gas dedicated header 21 through the gas refrigerant pipe 30.

[0065] Subsequently, the high-temperature / high-pressure gas refrigerant flowing into the condenser 20 exchanges heat (releases heat) with the outside air, causing a condensation effect, so the state changes to a high-temperature / high-pressure liquid refrigerant in the condenser 20.

[0066] In the present invention, a digital sensor 45 is installed on the lower side of the liquid-only header 22 located on the outlet side of the condenser 20, and the control device 50 receives the temperature and pressure information of the liquid refrigerant in the condenser detected by the digital sensor 45.

[0067] The control device 50 determines whether the pressure of the liquid refrigerant detected by the digital sensor 45 is within a predetermined pressure range (for example, if the liquid refrigerant pressure in the condenser is in the range of 0.5 to 1.5 kgf / cm 2 it can be determined that it is normal), and controls the operation of the liquid transfer pump 46 and the intermittent operation of the solenoid valve 47 according to the result value.

[0068] In the present invention, when the liquid refrigerant in the condenser 20 rises to a pressure outside the predetermined pressure range (for example, a pressure exceeding the range of 0.5 to 1.5 kgf / cm 2 ), there is a possibility that the pressure difference between the evaporator outlet and the condenser inlet is very small, or the condenser inlet side is in a higher pressure state.

[0069] In this case, the pressure of the gas refrigerant flowing from the evaporator to the condenser side cannot be increased enough to open the swing check valve 31, and the flow of the gas refrigerant will be blocked by the check valve 31 and stop.

[0070] Therefore, in the present invention, when it is detected by the digital sensor 45 that the liquid refrigerant in the condenser 20 exceeds the predetermined pressure range (for example, 0.5 to 1.5 kgf / cm 2 or more), the control device 50 operates the liquid transfer pump 46 and controls the solenoid valve 47 to be in an open state to perform forced circulation of the refrigerant. As a result, the high-temperature / high-pressure gas refrigerant discharged from the evaporator can be continuously made to flow into the condenser 20.

[0071] And if the forced refrigerant circulation state continues, the high-temperature / high-pressure liquid refrigerant discharged from the condenser 20 continuously flows into the evaporator 10, and the pressure of the gaseous refrigerant generated in the evaporator 10 gradually increases.

[0072] Eventually, the pressure of the gaseous refrigerant discharged from the outlet of the evaporator 10 rises until it is almost the same as the internal pressure of the condenser 20, and the pressure difference between them becomes less than or equal to a defined pressure difference (for example, when the internal pressure of the condenser is detected by the digital sensor 45 to be within the range of 0.5 to 1.5 kgf / cm 2 range).

[0073] In this case, the control device 50 that receives the input of the detection signal from the digital sensor 45 controls to stop the liquid transfer pump 46, and eventually, the refrigerant circulation stops.

[0074] And in the state where the refrigerant circulation has stopped in this way, the gaseous refrigerant remaining in the condenser 20 continues to exchange heat with the outside air, so condensation further progresses and the refrigerant pressure in the condenser 20 may gradually decrease. On the contrary, the liquid refrigerant remaining in the evaporator 10 also continues to exchange heat with the outside air and evaporation further progresses, and the refrigerant pressure in the evaporator 10 may gradually increase.

[0075] Here, if, despite the control device 50 stopping the operation of the liquid transfer pump 46, a leak of liquid refrigerant occurs in the refrigerant pipe 40 from the liquid pump and a small amount of liquid refrigerant circulation continues, the rate of increase in the refrigerant pressure in the evaporator 10 may become excessively slow.

[0076] Therefore, if the control device 50 cannot satisfy the specified change values of the refrigerant pressure and temperature detection values inside the condenser 20 detected by the digital sensor 45 after stopping the operation of the liquid transfer pump 46 and a predetermined time has elapsed, it can be determined that there is a leak of liquid refrigerant from the stopped liquid pump, and control can be performed to adjust the flow path opening rate of the solenoid valve 47 between 0% and 100%.

[0077] When the above control is carried out and a predetermined time has elapsed, since the digital sensor 25 installed in the condenser detects that the liquid refrigerant in the condenser 20 has entered a predetermined pressure range, the control device 50 that receives the input of this detection signal controls to operate the liquid transfer pump 46 to open the solenoid valve 47, and the swing check valve 31 of the gas refrigerant pipe 30 opens, so that the refrigerant will further carry out a circulation cycle in the closed circuit.

[0078] Next, referring to the embodiment of FIG. 2, the expansion valve 44 installed on the refrigerant pipe 40 between the solenoid valve 47 and the inlet side of the evaporator 10 throttles and expands the high-temperature / high-pressure liquid refrigerant transmitted from the condenser 20 through the refrigerant pipe 40, cools it to a low-temperature / low-pressure state, and discharges it to the distributor 11 side installed at the inlet of the evaporator 10.

[0079] And since the distributor 11 installed at the inlet of the evaporator 10 and the distribution tubes 12 branched and led out here are connected to each end of the heat exchange tubes of the evaporator 10, the refrigerant flowing in through the distributor 11 is evenly dispersed throughout the evaporator, so that the evaporation action in the evaporator 10 can be carried out more efficiently.

[0080] In the evaporator 10 into which the liquid refrigerant in a low-temperature / low-pressure state has flowed in by the expansion valve 44 in this way, the evaporation action of exchanging heat (absorbing heat) with the outside air to vaporize the refrigerant is maintained for a predetermined time or more and discharged so as to become a high-temperature / high-pressure gas state, so that continuous circulation of the refrigerant is carried out.

[0081] On the other hand, in the present invention, the digital sensor 45 installed so as to be able to detect a predetermined pressure in the liquid-only header 22 installed on the outlet side of the condenser 20 can be used for the purpose of easily checking the refrigerant filling state at the initial installation or during maintenance.

[0082] That is, conventionally, when injecting refrigerant for the first time after installing a heat exchanger or when replenishing refrigerant from a maintenance perspective, the operator has to measure the pressure of the injected refrigerant using a separate pressure gauge and perform the work, which requires a certain level of proficiency.

[0083] However, in the present invention, since the digital sensor 45 accurately detects and displays the refrigerant filling state inside the condenser 20, when injecting refrigerant, the operator can simply look at the digital sensor 45 and complete the work by injecting until a predetermined set pressure is displayed. Therefore, even if the proficiency of the operator decreases, the refrigerant injection work can be accurately and easily carried out.

[0084] Those with ordinary knowledge in the technical field to which the present invention pertains can improve or change the technical idea of the present invention in various forms. Therefore, the embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. That is, if the above improvements and changes are easy for those with ordinary knowledge, they will fall within the protection scope of the present invention.

Claims

【Claim 1】 A gas refrigerant pipe (30) connecting between the outlet of the evaporator (10) and the inlet of the condenser (20), and a liquid refrigerant pipe (40) connecting between the outlet of the condenser (20) and the inlet of the evaporator (10) are installed so that the refrigerant forms a closed loop and circulates between the evaporator (10) and the condenser (20). A digital sensor (45) for detecting the internal refrigerant pressure and temperature of the condenser (20) and inputting the detected values to the control device (50) is installed in the condenser (20). A liquid transfer pump (46) for pushing the liquid refrigerant toward the evaporator (10) side is installed on the liquid refrigerant pipe (40). The control device (50) that receives the input of the detected value of the digital sensor (45) controls the operation of the liquid transfer pump (46) according to the detected value to adjust the flow rate of the liquid refrigerant flowing through the refrigerant pipe (40). A solenoid valve (47) is further installed on the liquid refrigerant pipe (40). The control device (50) that receives the input of the detected value of the digital sensor (45) adjusts the flow path opening rate of the solenoid valve (47) according to the detected value. The control device (50) After performing control to stop the operation of the liquid transfer pump (46) first, After a predetermined time has elapsed, it is determined whether the detected values of the refrigerant pressure and temperature inside the condenser (20) detected by the digital sensor (45) satisfy a specified change value. When the specified change value is not satisfied, the control device (50) performs adjustment control of the flow path opening rate of the solenoid valve (47). A highly efficient waste cold and heat exchange device is characterized by this.

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