KR20240036271A - Bypass valve for heat exchanger for considering heating and cooling performance - Google Patents

Abstract

The present invention relates to a bypass valve used in a heat exchanger considering cooling and heating performance. The purpose of the present invention is to solve the problem that cooling performance and heating performance are conflicting depending on the number of passes, and to introduce a heat exchanger considering cooling and heating performance that introduces variable passes, so that the passes can be appropriately varied in an appropriate temperature range. The aim is to provide a bypass valve designed to do so.

Description

Bypass valve for heat exchanger for considering heating and cooling performance}

The present invention relates to a bypass valve used in a heat exchanger, and relates to a bypass valve used in a heat exchanger considering cooling and heating performance by introducing a variable pass to solve the problem that cooling performance and heating performance are formed differently depending on the number of passes. will be.

Generally, in the engine room of a vehicle, there are not only driving parts such as the engine, but also various heat exchangers such as radiators, intercoolers, evaporators, and condensers to cool each part of the vehicle such as the engine or to control the air temperature inside the vehicle. are provided. Such heat exchangers generally have a heat exchange medium distributed inside them, and cooling or heat dissipation is achieved by heat exchange between the heat exchange medium inside the heat exchanger and the air outside the heat exchanger.

A typical refrigeration cycle essentially includes a condenser and evaporator. The condenser is a heat exchanger responsible for condensation in the main refrigeration cycle of a vehicle air conditioning system, and serves to condense high-temperature, high-pressure gaseous refrigerant into a liquid state. The evaporator is a heat exchanger responsible for evaporation, and unlike the condenser, it evaporates liquid refrigerant into gaseous state. In a general cooling mode, the condenser releases condensation heat generated as the refrigerant condenses inside to the outside, while the evaporator absorbs evaporation heat from the outside as the refrigerant evaporates inside. Cooling is achieved by blowing the air around the evaporator into the room, taking advantage of the fact that the air around the evaporator loses heat and is cooled. Meanwhile, in the heating mode, in addition to the method of directly heating the air, a heat pump method is used to blow the air around the condenser into the room by applying the method described above in reverse. In fact, since the cooling mode and heating mode are based on the same principle, the system is designed so that the flow direction of the refrigerant is variable, and one heat exchanger operates as an evaporator in the cooling mode and as a condenser in the heating mode, thereby providing cooling and heating with a single heat exchanger. Systems that allow both to be performed are also widely used.

Meanwhile, such a heat exchanger is generally formed in a form that includes a plurality of tubes arranged in parallel with each other through which refrigerant flows, and a pair of header tanks provided at both ends of the tube row composed of the tubes. The simplest and easiest form of refrigerant flow in this heat exchanger is a single path in which the refrigerant flowing into one header tank exchanges heat while passing through the entire tube row and is then discharged through another header tank. The refrigerant flow in the heat exchanger also basically adopts this single path. However, as the pressure drop varies depending on the length of the refrigerant passage in the heat exchanger, there are various problems such as the refrigerant flow rate being not uniformly distributed. Accordingly, designs that allow heat exchangers to have two or four paths instead of a single path are being widely introduced. For example, a variety of heat exchanger technologies with multiple passes are known, such as a dual-pass condenser disclosed in Korean Patent Registration No. 2103951 (“Refrigerator,” April 17, 2020).

Figure 1 shows the refrigerant flow of a 4-pass heat exchanger, and Figure 2 shows the refrigerant flow of a 2-pass heat exchanger. All of the 4-pass/2-pass heat exchangers 40 and 20 shown in FIGS. 1 and 2 respectively include a plurality of tubes 41 and 21 arranged in parallel with each other through which refrigerant flows, and the tubes 41 and 21 respectively. ) includes a pair of header tanks (42) (22) provided at both ends of a tube row consisting of. The heat exchanger in FIGS. 1 and 2 is basically a heat exchanger used as a condenser, and a receiver dryer (10) is connected to one header tank (42) (22). The header tank (42) (22) is provided with inlets (43) (23) and outlets (44) (24) through which refrigerant flows in and out. Additionally, in order to create a desired refrigerant flow direction, baffles 45 and 25 are provided at appropriate positions within the header tanks 41 and 21.

Referring to FIG. 1, the refrigerant flow in the 4-pass heat exchanger 40 will be described in detail as follows. As shown, the refrigerant flowing into the inlet 43 sequentially flows in a L-shape along passes (1), (2), and (3) and is gradually condensed. The refrigerant that has passed the (3) pass enters the receiver dryer (10) to undergo gas-liquid separation, and the liquid refrigerant separated in the receiver dryer (10) flows back into the (4) pass of the 4-pass heat exchanger (40). (4) The refrigerant that has been subcooled while passing through the pass is finally discharged through the outlet (44).

Referring to FIG. 2, the refrigerant flow in the two-pass heat exchanger 20 will be described in detail as follows. The refrigerant flowing into the inlet 23 is condensed as it passes through pass (1), as shown. The refrigerant that has passed the (1) pass enters the receiver dryer (10) to undergo gas-liquid separation, and the liquid refrigerant separated in the receiver dryer (10) flows back into the (2) pass of the 2-pass heat exchanger (20). (2) The refrigerant that has been subcooled while passing through the pass is finally discharged through the outlet (24).

When the 4-pass/2-pass heat exchanger (40) (20) of FIGS. 1 and 2 operates as a condenser in cooling mode, the 4-pass heat exchanger (40) has excellent heat transfer performance, solving the system high pressure problem and compressor It has the advantage of improving system COP (coefficient of performance) by reducing power consumption. On the other hand, the two-pass heat exchanger 20 has a relatively simple flow path structure, so heat transfer performance is relatively low and there is a problem in that system high pressure problems occur. In addition, compressor power consumption increases due to high system pressure, resulting in lower system COP. More specifically, it is known that in the cooling mode, the 2-pass heat exchanger 20 generates a high pressure of about 4 bar or more and the COP decreases by about 8% compared to the 4-pass heat exchanger 40.

Meanwhile, as described above, a system that operates one heat exchanger as a condenser in cooling mode and as an evaporator in heating mode has been widely introduced. However, in the cooling mode, as described above, the performance of the 4-pass heat exchanger 40 is much better than the performance of the 2-pass heat exchanger 40, while the opposite tendency occurs in the heating mode. That is, when the 4-pass/2-pass heat exchanger (40) (20) operates as an evaporator in the heating mode, the heating performance deteriorates because the refrigerant flow rate in the system is small due to the complex flow path structure of the 4-pass heat exchanger (40). On the other hand, the two-pass heat exchanger 20 has a small refrigerant flow resistance due to its simple flow path structure, and therefore has a relatively large refrigerant flow rate, thereby improving heating performance. More specifically, it is known that in the heating mode, the 2-pass heat exchanger (20) has a refrigerant flow rate of 4 to 14 kg/hr higher than the 4-pass heat exchanger (40), and the heating discharge temperature is superior by about 1 to 3 degrees. .

In this case, when one heat exchanger operates as a condenser in cooling mode/operates as an evaporator in heating mode, with the current heat exchanger structure, if it shows excellent performance in one of the cooling and heating modes, it tends to show poor performance in the other mode. This is confirmed. Therefore, there is a need to develop a heat exchanger that can provide excellent performance in both cooling and heating modes.

1. Korean Patent Registration No. 2103951 (“Refrigerator”, 2020.04.17.)

Therefore, the present invention was created to solve the problems of the prior art as described above, and the purpose of the present invention is to introduce a variable pass to solve the problem that cooling performance and heating performance are formed differently depending on the number of passes. It is introduced into a heat exchanger considering cooling and heating performance, and provides a bypass valve designed to vary the pass appropriately in an appropriate temperature range.

The bypass valve 160 used in the heat exchanger 100 considering the cooling and heating performance of the present invention to achieve the above-mentioned purpose is a tube in which a plurality of bypass valves 160 are arranged in parallel to form a core area through which the refrigerant flows. (110); A pair of header tanks provided at both ends of the tubes 110; A plurality of baffles provided in the header tank; In the bypass valve 160 used in the heat exchanger 100 including, in the heat exchanger 100, a plurality of passes are formed sequentially in the core area by the plurality of baffles, On one or both sides of a pair of header tanks, the bypass valve 160, which selectively bypasses some of the plurality of passes, is formed in communication, and the bypass valve 160 is opened and closed according to the refrigerant temperature. This can be formed to bypass the refrigerant when opened.

At this time, the bypass valve 160 includes a wax portion 176 that changes phase into a liquid or solid phase depending on temperature, and performs a valve stroke according to expansion or contraction according to the phase change of the wax portion 176. ) can be formed so that opening and closing occurs.

In addition, the bypass valve 160 operates as a condenser in the cooling mode, and as the heat exchanger 100 operates as a condenser, the refrigerant is formed at a relatively high temperature, and the wax part 176 becomes liquid, expanding in volume and causing the bypass valve ( 160) is closed, and in the heating mode, as the heat exchanger 100 operates as an evaporator, the refrigerant is formed at a relatively low temperature, and the wax part 176 becomes solid, thereby shrinking in volume and causing the bypass valve 160 to open. It may be formed to be open.

In addition, the bypass valve 160 is closed in the cooling mode, so that the refrigerant passes through the entire path of the heat exchanger 100 as designed, and in the heating mode, the bypass valve 160 is closed. As it is opened, refrigerant or additional refrigerant may be formed to pass through a portion of the path of the heat exchanger 100.

At this time, when the bypass valve 160 assumes that the wax portion 176 expands to its maximum volume and the valve stroke reaches 100% as valve operation completion, the wax portion 176 The valve operation completion temperature, which is the temperature, can be formed to correspond to the average refrigerant temperature in cooling mode.

In addition, in determining valve operation completion, the bypass valve 160 may determine the valve operation completion point at which the bypass flow rate of the refrigerant becomes 2.5% or less of the total flow rate when the valve stroke is near 100%.

Additionally, the valve operation completion temperature of the bypass valve 160 may be formed to be lower than the refrigerant saturation temperature at the refrigerant pressure level determined by the load that varies depending on the average temperature of the outside air.

In addition, the bypass valve 160, when the refrigerant used in the heat exchanger 100 is R1234yf, the valve operation completion temperature is 10 kg/cm ² G, which is the lowest limit of the refrigerant pressure level under low-load cooling conditions in spring and fall. It can be formed lower than the refrigerant saturation temperature.

Additionally, the bypass valve 160 may be formed so that the valve operation completion temperature is 40°C or lower.

In addition, the bypass valve 160 shrinks the wax portion 176 to its minimum volume and assumes that the valve stroke reaches 0% as the start of valve operation. When the valve operation starts, the wax portion 176 The valve operation start temperature, which is the temperature, can be formed to correspond to the average refrigerant temperature in the heating mode.

Additionally, in determining the start of valve operation, the bypass valve 160 may determine the point at which the valve stroke becomes 0.1 mm or more as the start time of valve operation when the valve stroke is near 0%.

Additionally, when the refrigerant used in the heat exchanger 100 is R1234yf, the bypass valve 160 may be formed so that the valve operation start temperature is 20°C or higher.

In addition, the bypass valve 160 has a first communication passage 161 connected to the heat exchanger 100 through which refrigerant flows, and a second communication passage connected to the bypass path of the heat exchanger 100 through which refrigerant flows. (162), a valve part that performs opening and closing operations is accommodated, a main space part 163 in communication with the first communication passage 161, and formed to communicate with the main space part 163, the main space part It has a cross-sectional area smaller than (163), the communication with the main space 163 is opened or closed by the operation of the valve unit, and may include a subspace 164 in communication with the second communication passage 162. You can.

At this time, the valve unit extends in the direction of extension of the main space 163 and includes a guide pin 171 provided in the main space 163, and one side of the guide pin 171 is connected to the main space 163. ), a valve cap 172 fixed to one side, a case 173 formed in the form of a container with one end open to accommodate the guide pin 171, and whose inner wall is formed to be spaced apart from the outer surface of the guide pin 171 ), an elastic portion 174 provided to surround the guide pin 171, a cover portion 175 formed to be movable along the guide pin 171 and sealing the open end of the case 173, The wax part 176, which is filled in the space between the elastic part 174 and the case 173 and changes phase into a liquid or solid state depending on the temperature, is provided on the other side of the case 173 and includes the main space part 163, and It may include a valve plate 177 that opens or closes communication of the subspace portion 164.

In addition, as the refrigerant is formed at a relatively high temperature in the cooling mode, the wax portion 176 changes phase into a liquid phase and increases in volume to press the elastic portion 174, and the elastic portion 174 As the guide pin 171 is squeezed by pressure, the case 173 moves, and the valve plate 177 moves between the main space 163 and the sub space 164. It is formed to close the communication, and as the refrigerant is formed at a relatively low temperature in the heating mode, the wax part 176 changes phase to a solid state and its volume decreases, so that the case 173 is restored to its original position, and the valve plate is (177) may be formed to open communication between the main space 163 and the sub space 164.

In addition, the valve part includes a main spring 178, both ends of which are supported on one side of the valve plate 177 and the case 173 to absorb excess expansion of the wax part 176, and both ends of the valve plate 177. And it may include a restoration spring 179 that is supported on the other side of the subspace portion 164 and assists in restoring the case 173 to its original position.

Additionally, the valve unit and the case 173 may be formed of a metal material.

According to the present invention, by introducing a design that allows the number of passes in the heat exchanger to be varied as needed, there is a great effect of fundamentally solving the problem that cooling performance and heating performance are formed in conflict with each other depending on the number of passes. To explain in more detail, 4-pass/2-pass heat exchangers have been widely used in the past, and it is known that the 4-pass heat exchanger shows excellent performance when used as a condenser, and the 2-pass heat exchanger shows excellent performance when used as an evaporator. In the present invention, by using a bypass valve in one heat exchanger to vary the refrigerant path, it is possible to obtain all the advantages by operating as a 4-pass heat exchanger in cooling mode / as a 2-pass heat exchanger in heating mode. At this time, in particular, in the present invention, the path is varied using a bypass valve while leaving the configuration of the heat exchanger itself almost the same, which has the great effect of excellent compatibility with existing heat exchangers.

In particular, in the present invention, by making the bypass valve a thermal bypass valve, the refrigerant path is varied by sensitive to the refrigerant temperature, so that an optimized path for each cooling and heating mode is formed. Accordingly, the heat exchanger path can be easily changed without the use of separate electrical signals or power, and excellent performance can be achieved in both cooling and heating modes.

In addition, according to the present invention, the bypass valve is manufactured from a material selected by optimal design in consideration of the temperature range formed by the refrigerant in the cooling mode / heating mode, so that the cooling mode / heating mode pass variable can be realized much more effectively. It has a big effect.

1 shows refrigerant flow in a 4-pass heat exchanger.
Figure 2 shows refrigerant flow in a two-pass heat exchanger.
Figure 3 shows the refrigerant flow in the cooling and heating mode of the first embodiment of the heat exchanger using the bypass valve of the present invention.
Figure 4 shows the refrigerant flow in the cooling and heating mode of the second embodiment of the heat exchanger using the bypass valve of the present invention.
Figure 5 shows the refrigerant flow in the cooling and heating mode of the third embodiment of the heat exchanger using a bypass valve of the present invention.
Figure 6 shows the refrigerant flow in the cooling and heating mode of the fourth embodiment of the heat exchanger using the bypass valve of the present invention.
Figure 7 shows the refrigerant flow in cooling and heating mode of the fifth embodiment of the heat exchanger using a bypass valve of the present invention.
Figure 8 shows the operating principle of the thermal valve.
Figure 9 is a cross-sectional view of the bypass valve of the present invention.
Figure 10 is an operational cross-sectional view of an embodiment of the bypass valve of the present invention.
Figure 11 is a graph of the saturation temperature and saturation pressure of R1234yf refrigerant.
Figure 12 is a basic design of the valve operating range based on low load in spring/autumn/interseasonal.
Figure 13 is a design for improving the valve operating range based on low load in spring/autumn/interseasonal.

Hereinafter, a bypass valve used in a heat exchanger considering cooling and heating performance according to the present invention having the above-described configuration will be described in detail with reference to the attached drawings.

[1] Basic configuration of a heat exchanger equipped with the bypass valve of the present invention

3 to 7 show various embodiments of the bypass valve 160 installation location of a heat exchanger to which the bypass valve 160 of the present invention is applied, particularly the refrigerant flow in the cooling mode/heating mode. FIG. 3 is the first embodiment, FIG. 4 is the second embodiment, FIG. 5 is the third embodiment, FIG. 6 is the fourth embodiment, and FIG. 7 is the fifth embodiment, and each embodiment shows the bypass valve 160. There is a difference in the installation location and number. This will be described in more detail later, and first, the basic configuration of the heat exchanger 100 of the present invention will be described.

The heat exchanger 100 of the present invention basically has a similar configuration to a 4-pass heat exchanger. That is, a plurality of tubes 110 are arranged in parallel to form a core area through which refrigerant flows, a pair of header tanks provided at both ends of the tubes 110, and a plurality of baffles provided within the header tank. and a plurality of paths sequentially arranged in the core area are formed by the plurality of baffles.

As previously explained, the 4-pass heat exchanger has superior performance compared to the 2-pass heat exchanger when it operates as a condenser in cooling mode, but when it operates as an evaporator in heating mode, there is a problem of poor performance due to the complicated path. Considering this, in the present invention, the heat exchanger 100 is operated as a 4-pass heat exchanger in the cooling mode, but in the heating mode, a portion of the refrigerant flows through a simpler path using the bypass valve 160. This solves the problem caused by path complexity in the conventional 4-pass heat exchanger. That is, in the heat exchanger 100 of the present invention, a bypass valve 160 that selectively bypasses some of the plurality of paths is connected to one or both sides of the pair of header tanks. In particular, at this time, the heat exchanger 100 further includes a receiver dryer 200, and the bypass valve 160 can be opened and closed according to temperature.

The configuration of the heat exchanger 100 will be described in more detail as follows. One of the pair of header tanks is called the first header tank (121), and the other is called the second header tank (122). The first header tank 121 is provided with an inlet 130 through which refrigerant flows in and an outlet 140 through which refrigerant is discharged. In addition, first and third baffles 151 and 153 are provided in the first header tank 121, and second and fourth baffles 152 and 154 are provided in the second header tank 122. The 1st, 2nd, and 3rd baffles 151, 152, and 153 are provided at sequentially spaced apart positions to form the first, second, and third passes (①) (②) (③), and the third and fourth baffles ( 153)(154) are provided at the same location to form the fourth pass (④). That is, the core area is separated by the baffles and the first, second, third, and fourth passes (①) (②) (③) (④) are formed to be sequentially arranged. Meanwhile, the receiver dryer 200 is connected to one of the header tanks and receives the refrigerant that has passed through the first, second, and third passes (①) (②) (③), separates gas and liquid, and flows the liquid refrigerant into the fourth pass (①) (②) (③). It is equipped to discharge to ④).

To explain more clearly, the first baffle 151 is provided at a position between the inlet 130 and the outlet 140 in the first header tank 121, and the second baffle 152 is provided in the first header tank 121. It is provided at a position between the first baffle 151 and the outlet 140 within the second header tank 122. The third baffle 153 is provided at a position between the second baffle 152 and the outlet 140 within the first header tank 121, and the fourth baffle 154 is located within the second header tank 121. It is provided in the same position as the third baffle 153 within (122). Accordingly, the area separated by the first baffle 151 forms the first path ①, and the area between the first baffle 151 and the second baffle 152 forms the second path. (②) is formed, and the area between the second baffle 152 and the third and fourth baffles 153 and 154 forms the third path (③), so that the refrigerant flows through the first, second, and As you sequentially pass through the 3 passes (①), (②) (③), a L-shape is drawn. The areas separated by the third and fourth baffles 153 and 154 form the fourth path (④), that is, the fourth path (④) is substantially the first, second, and third path (①). )(②) is completely isolated from (③). Meanwhile, the inlet 130 is formed in a position communicating with the first path ①, and the outlet 140 is formed in a position communicating with the fourth path ④. At this time, since the receiver dryer 200 connects the third pass (③) and the fourth pass (④) to each other, the refrigerant flows into the inlet 130 and then flows into the first, second, and third passes. It sequentially passes through the passes (①) (②) (③), the receiver dryer (200), and the fourth pass (④), so that it can be smoothly discharged through the outlet (140).

This configuration itself is substantially the same as the flow path configuration of the 4-pass heat exchanger 40 illustrated in FIG. 1. However, in the present invention, as described above, the bypass valve 160 is used to allow the refrigerant to flow through 4 passes as it is or to bypass it appropriately depending on the cooling and heating mode, thereby improving performance in each mode. .

In the present invention, by arranging the bypass valve 160 at an appropriate position, the problem of insufficient refrigerant flow in the heating mode is solved by additional supply of refrigerant or simplification of the path. Now, the differences in configuration of the bypass valve 160 between the first, second, third, fourth, and fifth embodiments will be described in more detail.

In the first embodiment, when the bypass valve 160 is closed, the refrigerant passes through the receiver drier 200 (see the upper view of FIG. 3), and when the bypass valve 160 is opened, additional refrigerant passes through the receiver drier 200. It is formed to further pass through (see lower view of FIG. 3). At this time, the bypass valve 160 is provided at the inlet 130 so that additional refrigerant can flow smoothly. More specifically, when the bypass valve 160 is opened, additional refrigerant is supplied to additionally pass through the third and fourth passes (③) and (④). Accordingly, in the first embodiment, the problem of insufficient refrigerant flow is solved by additional supply of refrigerant.

In the second embodiment, when the bypass valve 160 is closed, the refrigerant passes through the receiver drier 200 (see the upper view of FIG. 4), and when the bypass valve 160 is opened, the refrigerant passes through the receiver drier 200. It is formed so as not to pass through (see the lower view of FIG. 4). At this time, the bypass valve 160 is provided between the inlet 130 and the outlet 140 so that the refrigerant can be smoothly discharged during the process, and the bypass valve 160 is connected to the outlet 140. More specifically, when the bypass valve 160 is opened, the refrigerant is supplied through only the first and second passes (①) and (②). Accordingly, in the second embodiment, the problem of insufficient refrigerant flow is solved by simplifying the path.

The third embodiment is substantially the same as the second embodiment, but in the second embodiment, the heat exchanger 100 is left and right with the first and second header tanks 121 and 122 as shown in FIG. 4. The tubes 110 are spaced apart and arranged horizontally, and in the third embodiment, the heat exchanger 100 has the first and second header tanks 121 and 122 spaced apart from each other, as shown in FIG. 5, so that the tubes The difference is that (110) is arranged vertically. That is, the only difference is whether the refrigerant flow direction in the core area is horizontal or vertical, but the role and operating principle of the bypass valve 160 are the same as those of the second embodiment.

In the fourth embodiment, one bypass valve 160 is provided on the receiver side, but when the bypass valve 160 is closed, the refrigerant does not pass through the receiver dryer 200 (see the upper view of FIG. 6), and the bypass valve 160 is closed. When the valve 160 is opened, the refrigerant is formed to pass through the receiver dryer 200 (see the lower view of FIG. 6). At this time, considering the location of the path to be bypassed, etc., the bypass valve 160 is provided on the upper side of the receiver dryer 200.

In the fifth embodiment, the bypass valve 160 installed on the receiver side and the bypass valve 160 installed on the distribution port side are provided, and when the bypass valves 160 are closed, the refrigerant flows into the receiver dryer 200. Instead of passing through the refrigerant (see the upper view of FIG. 7), when the bypass valves 160 are opened, a portion of the refrigerant passes through the receiver dryer 200, and the remaining portion passes through only a portion of the heat exchanger 100 (Fig. 7 (see bottom drawing). To explain in more detail, the flow of part of the refrigerant according to the opening and closing of the bypass valve 160 is the same as in the fourth embodiment, but the flow of the remaining part of the refrigerant according to the opening and closing of the bypass valve 160 is of the heat exchanger 100. Route simplification is realized by allowing only a portion of the route to pass through. At this time, considering the location of the path to be bypassed, etc., one bypass valve 160 is provided on the upper side of the receiver dryer 200, and the other bypass valve 160 is formed in the header tank. It is provided between the inlet 130 and the outlet 140.

That is, as shown in the upper drawings of FIGS. 3, 4, 5, 6, and 7, when the bypass valve 160 is closed, in all of the first, second, third, fourth, and fifth embodiments, the refrigerant flows into the first, second, and fifth embodiments. Pass all 3 and 4 passes (①)(②)(③)(④). The fact that the refrigerant passes through all of the first, second, third, and fourth passes (①) (②) (③) (④) means that the heat exchanger 100 is operated as a four-pass heat exchanger. As described above, in the cooling mode, the 4-pass heat exchanger is advantageous in terms of performance, and this advantage can be obtained by closing the bypass valve 160 in the cooling mode.

Meanwhile, as shown in the lower view of FIG. 3, when the bypass valve 160 is opened, in the case of the first embodiment, the refrigerant basically flows through the first, second, third, and fourth passes (①) (②) (③) (④). ), but allow additional refrigerant to pass through the third and fourth passes (③) (④) (see FIG. 4), that is, more refrigerant than the amount of refrigerant passing through the first and second passes (①) (②). It is formed so that the amount of refrigerant passing through the third and fourth passes (③) (④) is large. In addition, as shown in the lower views of FIGS. 4, 5, 6, and 7, when the bypass valve 160 is opened, in the case of the second, third, fourth, and fifth embodiments, the refrigerant flows through the first, second, third, and fourth passes ( Only two passes selected from ①)(②)(③)(④) pass. What is different in each embodiment is the difference in which two passes it passes through. More specifically, the refrigerant passes through the first and second passes (①) (②) in the second and third embodiments, and through the first and second passes (①) (②) in the fourth embodiment. In the 1st and 4th passes (①) (④), in the 5th embodiment, some of the first and 2nd passes (①) (②) / and the remaining part of the first and 4th passes (①) (④). passes through

That is, when the bypass valve 160 is opened, the additional refrigerant (first embodiment) or the entire refrigerant (second, third, fourth, and fifth embodiments) passes through two optional passes, as if the heat exchanger It can be said that machine 100 is operated as a two-pass heat exchanger. As previously explained, in the heating mode, the two-pass heat exchanger is advantageous in terms of performance, and this advantage can be obtained by allowing the bypass valve 160 to be opened in the heating mode.

Additionally, in the present invention, there are slight differences depending on the embodiment, such as the location where the bypass valve 160 is provided or the number of bypass valves 160 may be one or two, and the bypass valve 160 Due to considerations such as the physical distance between the pass and the desired pass location, detours and detours are further included. Specifically, when the bypass valve 160 is provided on the distribution port side, the heat exchanger 100 includes the distribution port side bypass port 131 provided in the first header tank 121, and the bypass valve 160 installed on the distribution port side. It may include a distribution port side bypass 132 that is connected to the valve 160 and diverts the refrigerant when opened. In addition, when the bypass valve 160 is provided on the receiver side, the receiver side bypass port 141 provided in the second header tank 122 is connected to the bypass valve 160 installed on the receiver side, and when opened, the refrigerant It may include a receiver side bypass circuit 142 that bypasses. The refrigerant flow according to the location of the bypass port and bypass path, whether the bypass valve 160 is opened or closed, etc. can be confirmed in Figures 3 to 7.

[2] Detailed configuration of the bypass valve of the present invention

As explained in paragraph [1], in the heat exchanger 100 of the present invention, the path changes as the bypass valve 160 is opened or closed depending on the mode, forming an optimal path for each mode. At this time, an electronic circuit may be provided in the bypass valve 160 to control opening and closing by applying a control signal. However, in the present invention, the bypass valve 160 mechanically controls opening and closing according to the refrigerant temperature, thereby further improving system efficiency by eliminating the addition of unnecessary parts and control algorithms.

First, the operating principle of the valve that is controlled to open and close according to temperature will be briefly explained. Figure 8 is a diagram for explaining the operating principle of the thermal valve. As shown in Figure 8, the thermal valve is provided with a piston surrounded by an elastic body within a housing, and the space between the housing and the elastic body is filled with expansion wax. Expanding wax changes phase into a liquid or solid phase depending on the temperature, but when the temperature is low, it exists in a solid phase and its volume decreases. The left diagram of FIG. 8 shows the state of the thermal valve in a low temperature state. On the other hand, when the temperature environment rises to a high temperature, the expansion wax changes phase into a liquid phase and its volume increases. Since the space volume within the housing is fixed, pressure is applied to the elastic body as the volume of the expanding wax increases. The pressure applied to the elastic body in this way so-called “squeezes” the piston inserted into the elastic body. Accordingly, the piston moves in a direction pushed out of the housing as shown in the right side view of FIG. 8. When the temperature environment goes back to low temperature, the volume of the expansion wax decreases and it naturally returns to the state shown on the left side of FIG. 8.

If the end of the piston is designed to block any passage hole in the state of the right drawing of FIG. 8, the thermal valve of FIG. 8 will operate by closing the passage hole at high temperature and opening the passage hole at low temperature. Of course, by designing the flow path in a different way, it can be operated by opening the flow path at high temperatures and closing the flow path at low temperatures. In this way, the thermal valve does not require any electronic circuits or control signals at all, and can control opening and closing solely on a purely mechanical operating principle using only the surrounding temperature environment.

Figure 9 shows a cross-sectional view of the bypass valve of the present invention. First, to elaborate, the bypass valve 160 shown in FIG. 9 is according to the first embodiment, and accordingly, the inlet 130 is shown formed on the bypass valve 160. However, in the case of the second, third, fourth, and fifth embodiments, the inlet 130 is not formed in the bypass valve 160, so it can be understood that the inlet 130 is deleted from the drawing.

By applying the principle of the thermal valve illustrated in FIG. 8, the bypass valve 160 of the present invention shown in FIG. 9 is capable of being opened and closed solely based on a purely mechanical operating principle. That is, the bypass valve 160 is formed to open and close according to the refrigerant temperature, so that in the cooling mode, it is closed as the refrigerant is formed at a relatively high temperature, and in the heating mode, it is opened as the refrigerant is formed at a relatively low temperature. It is formed as much as possible. First, the configuration of the bypass valve 160 will be described in detail with reference to FIG. 9, and then the movement of each part during opening and closing will be described in more detail with reference to FIG. 10.

The bypass valve 160 is connected to a path position as needed, such as the receiver side bypass port 141 or the distribution port side bypass port 131, so that the refrigerant can flow in, and the refrigerant can be divided and discharged as needed. As shown in FIG. 9, it includes a first communication path 161 and a second communication path 162.

The first communication passage 161 is connected to the heat exchanger 100 to distribute refrigerant, and the second communication passage is connected to a bypass path of the heat exchanger 100 to distribute refrigerant. Specifically, the first communication path 161 is located at a location in communication with the second header tank 122 or the first header tank 121, and more specifically, at the receiver side bypass port 141 or the distribution port side. It is formed at a position connected to the bypass port 131, and the second communication path 162 is formed at a position connected to the receiver side bypass circuit 142 or the distribution port side bypass circuit 132. As described above, in the present invention, the bypass valve 160 is closed in the cooling mode so that the refrigerant flows through the first, second, third, and fourth passes (①) (②) (③) (④). ), and in the heating mode, the bypass valve 160 is opened so that the refrigerant or additional refrigerant is discharged after passing only two selective passes. That is, the first communication passage 161 is always open, and the second communication passage 162 is formed to be opened and closed as needed.

To do this, first, a main space 163 and a sub space 164 are formed in the bypass valve 160. The main space 163 communicates with the inlet 130 and the first communication passage 161, and also accommodates a valve unit that performs opening and closing operations. The sub space 164 is basically formed to communicate with the main space 163 and has a smaller cross-sectional area than the main space 163. That is, a step is formed at the connection part between the main space 163 and the sub space 164 as shown in FIG. 9, and the valve part is formed to open and close this part. That is, the communication between the subspace 164 and the main space 163 is opened or closed by the operation of the valve unit. At this time, since the subspace portion 164 communicates with the second communication passage 162, the opening and closing of the second communication passage 162 is consequently controlled by the operation of the valve unit.

The operating principle of the thermal valve previously described with reference to FIG. 8 is applied to the valve unit. The valve part basically includes a guide pin 171, a valve cap 172, a case 173, a cover part 175, an elastic part 174, a wax part 176, and a valve plate 177, as shown. It includes a main spring 178 and a sub spring 179 for smoother operation.

The guide pin 171 extends in the extension direction of the main space 163 and is provided within the main space 163, and corresponds to the “piston” in FIG. 8. However, in the bypass valve 160 of the present invention, the guide pin 171 itself is fixed without moving, so the name is different.

The valve cap 172 fixes one side of the guide pin 171 to one side of the main space 163. It is preferable that a sealing ring 172a in the form of an O-ring is provided between the valve cap 172 and the inner wall of the main space 163 to prevent leakage. Additionally, it is preferable that a snap ring (172b) is provided on the top of the valve cap (172) to prevent the valve cap (172) from coming off.

The case 173 is formed in the form of a container with one end open to accommodate the guide pin 171, and the inner wall is spaced apart from the outer surface of the guide pin 171. That is, the case 173 corresponds to the “housing” in FIG. 8. Meanwhile, as described above, the guide pin 171 corresponding to the “piston” in FIG. 8 is fixed to one side of the main space 163 by the valve cap 172. In the thermal valve of FIG. 8, the “housing” is fixed, so the “piston” moves relative to the “housing” according to temperature changes, but in the bypass valve 160 of the present invention in FIG. 9, the guide pin 171 ) is fixed, so the case 173 moves relative to the guide pin 171 according to temperature changes. Meanwhile, as can be seen from the thermal valve operation principle of FIG. 8, since the valve operation is realized by the wax changing phase according to the surrounding temperature environment, heat transfer must be actively performed between the surrounding temperature environment and the wax. Therefore, the case 173 is preferably made of a metal material that conducts heat well, for example, brass.

The elastic portion 174 is provided to surround the guide pin 171 and corresponds to the “elastic body” in FIG. 8. The elastic portion 174 is preferably made of a material that changes elasticity easily so as to effectively press the guide pin 171, and is preferably made of, for example, rubber.

The cover portion 175 is formed to be movable along the guide pin 171 and serves to seal the open end of the case 173. At this time, as shown in FIG. 9, a structure is formed in which the upper part of the elastic part 174 is fitted inside the lower part of the cover part 175. In order to prevent foreign substances from entering between the elastic part 174 and the guide pin 171, a sealing plate 175a is provided between the cover part 175 and the elastic part 174 as shown. It is desirable to be

The wax portion 176 is filled in the space between the elastic portion 174 and the case 173 and changes phase into a liquid or solid phase depending on temperature, and corresponds to the “expanded wax” in FIG. 8. In general, it is known that the refrigerant flowing into the condenser in cooling mode is about 81 degrees or higher, and the refrigerant flowing into the evaporator in heating mode is about 64 degrees or lower. In consideration of this, it is preferable that the wax portion 176 be made of a material that becomes liquid at temperatures above about 81 degrees and in solid at temperatures below about 64 degrees. As a specific example, the wax portion 176 is preferably a paraffin-based wax with a changeable characteristic temperature range of 45 degrees to 120 degrees.

The valve plate 177 is provided on the other side of the case 173 and serves to open or close communication between the main space 163 and the sub space 164. At this time, so that the valve plate 177 can be firmly fixed to the case 173, it is preferable that a fixing ring 177a that is assembled by press-fitting is provided on the lower side of the valve plate 177.

The main spring 177 is supported at both ends on one side of the valve plate 177 and the case 173, and serves to absorb excess expansion of the wax portion 176. Although it can operate as a thermal valve with just the structure from the guide pin 171 to the valve plate 177, the valve operation can be performed more stably by providing the main spring 177.

The restoration spring 179 is supported at both ends on the other side of the valve plate 177 and the subspace portion 164, and serves to assist in restoring the case 173 to its original position. Even without the restoration spring 179, the position of the case 173 is restored as the wax part 176 changes to a solid state, but the valve operation is improved as the restoring force of the restoration spring 179 assists. This can be done more smoothly.

Figure 10 shows an operational cross-sectional embodiment of the bypass valve of the present invention, where the upper view of Figure 10 shows the cooling mode and the lower view of Figure 10 shows the heating mode. FIG. 9 shows the bypass valve 160 in the first embodiment of FIG. 3 in which the inlet 130 is formed on the bypass valve 160, but FIG. 10 shows the second embodiment of FIG. 4. 5 shows the bypass valve 160 in the third embodiment, etc., and the inlet 130 is not formed on the bypass valve 160. Figure 10 shows an embodiment in which the bypass valve 160 is provided on the distribution port side, so the first communication passage 161 is connected to the distribution port side bypass port 131, and the second communication passage (162) is formed to be connected to the distribution port side bypass 132. The distribution outlet side bypass 132 is connected to the outlet 140.

In the cooling mode, that is, when the refrigerant is at a high temperature, the bypass valve 160 operates to close, and the valve plate 177 closes the second communication passage 162. Therefore, the path through which the refrigerant flows directly to the outlet 140 is blocked, and the refrigerant that has passed through the first and second passes (①) (②) flows back to the third and fourth passes (③) (④) as before. It flows. In the heating mode, that is, when the refrigerant is at a low temperature, the bypass valve 160 operates to open, and the valve plate 177 opens the second communication passage 162. Therefore, the refrigerant that has passed through the first and second passes (①) (②) can flow directly to the outlet (140) through the bypass path (132) along the open second communication passage (162) and be discharged. do. Accordingly, the refrigerant does not flow through the third and fourth passes (③) and (④), making it possible to greatly simplify the flow path. In Figure 10, an example is given in which the bypass valve 160 is provided on the distribution side, but even when the bypass valve 160 is provided on the receiver side, it operates the same, but only the device or path through which it passes as a result is different. Therefore, detailed explanation is omitted.

[3] Optimization of the bypass valve material of the present invention

As described above, the bypass valve of the present invention is provided in a heat exchanger and is formed to change the open and closed state depending on the temperature, so that the number of passes through which the refrigerant flows can be smoothly varied depending on the cooling mode/heating mode. am.

First, as well explained in [1] , in the present invention, the bypass valve is closed in the cooling mode, allowing the refrigerant to pass through all 4 passes, so that the heat exchanger is operated as a 4-pass heat exchanger, and in the heating mode, the bypass valve is closed. is opened to allow refrigerant (or additional refrigerant) to pass through two passes, allowing the heat exchanger to operate as (almost) a two-pass heat exchanger. In other words, in summary, the bypass valve 160 of the present invention is configured to bypass the refrigerant when opened by opening and closing depending on the refrigerant temperature.

In addition, as well explained in [2] , the bypass valve of the present invention is a thermal valve, and is formed so that the opening and closing of the valve changes as the expansion wax expands or contracts depending on the ambient temperature. In the cooling mode, the heat exchanger operates as a condenser, so the refrigerant is formed at a relatively high temperature. In the heating mode, the heat exchanger operates as an evaporator, so the refrigerant is formed at a relatively low temperature. In the explanation in [2] , it was explained that the expansion wax of the thermal valve expands as it becomes liquid at high temperature and contracts as it becomes solid at low temperature. That is, when the bypass valve of the present invention is provided in a heat exchanger, the expansion wax expands and the valve closes when the refrigerant is relatively high temperature (=when in cooling mode), and when the refrigerant is relatively low temperature (=when in heating mode), the bypass valve of the present invention closes. ) The valve can be opened as the expansion wax contracts. The bypass valve 160 of the present invention shown in FIG. 9 is designed to operate just like that. When the refrigerant is relatively high temperature and the wax part 176 expands, the valve plate 177 is pushed out and opens the second communication passage 162. By closing, the bypass valve 160 itself is in a closed state, and when the wax portion 176 shrinks due to the relatively low temperature of the refrigerant, the valve plate 177 returns and opens the second communication passage 162, thereby closing the bypass valve. (160) itself becomes open.

In other words, in summary, the bypass valve 160 of the present invention includes a wax portion 176 that changes phase into a liquid or solid phase depending on temperature, and the valve expands or contracts according to the phase change of the wax portion 176. A valve stroke occurs to enable opening and closing. At this time, in the cooling mode, as the heat exchanger 100 operates as a condenser, the refrigerant is formed at a relatively high temperature, and the wax part 176 becomes liquid, expanding in volume and closing the bypass valve 160, As the bypass valve 160 is closed in this way, the refrigerant passes through the entire path of the heat exchanger 100 as designed. In addition, in the heating mode, as the heat exchanger 100 operates as an evaporator, the refrigerant is formed at a relatively low temperature, and the wax part 176 becomes solid, thereby shrinking in volume and opening the bypass valve 160. As the bypass valve 160 is opened, refrigerant or additional refrigerant passes through a portion of the path of the heat exchanger 100.

In this way, the bypass valve 160 adopts a thermal valve configuration and the heat exchanger 100 selectively performs pass operation depending on whether the bypass valve 160 is opened or closed, so that the heat exchanger 100 uses the refrigerant itself. It is well designed so that the cooling mode/heating mode changes naturally depending on the temperature. In the case of general winter/summer, the difference between the refrigerant temperature and the surrounding environment (outside air) temperature is clearly formed when operating in the cooling mode/heating mode, so the bypass valve 160 in the form of a thermal valve operates smoothly. It can be done.

However, in medium temperature environments such as spring, fall, or between seasons, the operation of these thermal valves may not be performed somewhat smoothly. In this medium temperature environment, the refrigerant pressure applied to the heat exchanger 100, which functions as a condenser, during operation in the cooling mode is significantly lowered, which means that the refrigerant saturation temperature in the condenser is lowered. If the wax portion 176 fails to react to this relatively low refrigerant saturation temperature, the bypass valve 160 cannot form a completely closed state, and some of the refrigerant may leak through the bypass path. In this case, there is a risk that refrigerant in a two-phase state that is not subcooled may flow into the expansion valve. In this case, refrigerant bubbles pass through the hole of the expansion valve, causing hiss noise.

Considering these matters, it can be seen that there is a need to properly design at what temperature the wax portion 176 begins to melt or harden, that is, how to set the temperature at the start and completion of the valve operation. In particular, compared to cases where the difference between the refrigerant temperature and the surrounding environment (outside air) temperature is clear, such as in the winter/summer, it must be designed to ensure smooth operation even in medium-temperature environments such as the spring/autumn/inter-season.

As described above, the load on the heat exchanger 100 varies depending on the outside temperature, the refrigerant pressure changes depending on the load, and as a result, the refrigerant saturation temperature changes. Figure 11 is a graph of the saturation temperature and saturation pressure of the R1234yf refrigerant. It is desirable to design an appropriate valve operating range based on the physical properties of the refrigerant.

Figure 12 shows the basic design of the valve operating range based on low load in spring/fall/interseasonal on the refrigerant saturation temperature/pressure graph of Figure 11. In spring/interseasonal low-load cooling conditions, the heat exchanger 100 operates as a condenser, and at this time, the refrigerant pressure level applied to the heat exchanger 100 is known to be 10 kg/cm ² G. Referring to the refrigerant saturation temperature/pressure graph in FIG. 11, the refrigerant saturation temperature at this time is 42.4°C. That is, the bypass valve 160 must already be closed (i.e., the valve operation must be completed) at at least 42.4°C. Also, considering the physical properties of typical wax, in order for the bypass valve 160 to close at 42.4°C, the wax portion 176 must start reacting at 35°C (that is, the valve must start operating). However, if the valve operation completion/start temperature is set exactly to the boundary value, various problems as described above may occur, so it is necessary to set the temperature more safely.

Figure 13 shows the valve operating range improvement design based on low load in spring/fall/interseasonal on the refrigerant saturation temperature-pressure graph of Figure 11. In the valve operation range of FIG. 13, the valve operation completion temperature is set lower than the valve operation range of FIG. 12, so that problems such as the generation of supercooled refrigerant caused by the valve operation completion temperature being set at the boundary value can be safely excluded. . Below, the valve operation completion/start point will be defined more clearly, and the temperature setting principle accordingly will be explained in more detail.

First, regarding the completion of the valve operation, most strictly, it can be assumed that the valve operation is completed when the wax portion 176 expands to its maximum volume and the valve stroke reaches 100%. That is, the complete closure of the bypass valve 160 is referred to as valve operation completion, and at this time, the heat exchanger 100 operates as a condenser in cooling mode. Therefore, at this time, the valve operation completion temperature, which is the temperature of the wax portion 176, should be set to correspond to the average refrigerant temperature in the cooling mode.

However, in a real environment, it is difficult to clearly determine the status of “valve stroke is completely 100%.” In other words, rather than setting the valve operation completion point very strictly as “valve stroke is completely 100%,” it is determined slightly more loosely, so that application in the actual environment can be performed more smoothly. In the present invention, when determining the completion of valve operation, it is defined that when the valve stroke is near 100%, the point when the bypass flow rate of the refrigerant is less than 2.5% of the total flow rate is judged as the time when the valve operation is complete.

Meanwhile, as shown in the example of the improved design in FIG. 13, it is preferable that the valve operation completion temperature is lower than the refrigerant saturation temperature at the refrigerant pressure level determined by the load that varies depending on the average temperature of the outside air. That is, as in the examples of FIGS. 11 to 13, when the refrigerant used in the heat exchanger 100 is R1234yf, the valve operation completion temperature is 10 kg/cm ² G, which is the lowest limit of the refrigerant pressure level under low-load cooling conditions in spring and fall. It is preferable that it is formed lower than the refrigerant saturation temperature. More specifically, it is preferable that the valve operation completion temperature is set to 40°C or lower.

Now, regarding the start of the valve operation, most strictly, it can be assumed that the wax portion 176 is contracted to the minimum volume and the valve stroke reaches 0% as the start of the valve operation. That is, the complete opening of the bypass valve 160 is called the start of valve operation, and at this time, the heat exchanger 100 operates as an evaporator in heating mode. Therefore, at this time, the valve operation start temperature, which is the temperature of the wax portion 176, should be set to correspond to the average refrigerant temperature in the heating mode.

In this case as well, since it is difficult to clearly determine the state of “valve stroke being completely 100%” in a real environment, the valve operation start time can be determined somewhat loosely, just like the valve operation completion time. In the present invention, in determining the start of valve operation, when the valve stroke is near 0%, the point at which the valve stroke becomes 0.1 mm or more is defined as the time to start valve operation.

In reality, the valve operation completion temperature described above is more important in solving problems such as preventing the generation of supercooled refrigerant, and the valve operation start temperature is relatively less important. In addition, setting the valve operation completion temperature means that the wax is mixed to have such physical properties, and in this case, the valve operation start temperature is also determined to some extent accordingly. Therefore, it is natural to first determine the valve operation completion temperature, mix the wax accordingly, and determine the valve operation start temperature as a result. As a specific example, as in the previous description, when the refrigerant used in the heat exchanger 100 is R1234yf, it is preferable that the valve operation start temperature is set to 20°C or higher.

The present invention is not limited to the above-described embodiments, and its scope of application is diverse, and anyone skilled in the art can understand it without departing from the gist of the invention as claimed in the claims. Of course, various modifications are possible.

100: heat exchanger 110: tube
121: 1st header tank 122: 2nd header tank
130: inlet 140: outlet
131: Distribution port side bypass 132: Distribution port side bypass
141: Receiver side right circuit 142: Receiver side right circuit
151: 1st baffle 152: 2nd baffle
153: 3rd baffle 154: 4th baffle
160A~D2: Bypass valve
161: 1st communication path 162: 2nd communication path
163: main space part 164: sub space part
171: Guide pin 172: Valve cap
172a: sealing ring 172b: snap ring
173: Case 174: Elastic portion
175: cover part 175a: sealing plate
176: wax part
177: Valve plate 177a: Fixed ring
178: main spring 179: sub spring

Claims (17)

A plurality of tubes are arranged in parallel to form a core area through which refrigerant flows; A pair of header tanks provided at both ends of the tubes; A plurality of baffles provided in the header tank; In the bypass valve used in a heat exchanger comprising,
The heat exchanger has a plurality of passes sequentially arranged in the core area by the plurality of baffles, and a bypass that selectively bypasses some of the plurality of passes on one or both sides of the pair of header tanks. The valve is formed to communicate,
The bypass valve is formed to bypass the refrigerant when opened by opening and closing depending on the refrigerant temperature.
The method of claim 1, wherein the bypass valve is:
It includes a wax portion that changes phase into a liquid or solid phase depending on the temperature,
A bypass valve, characterized in that it is formed to open and close by generating a valve stroke according to expansion or contraction according to a phase change of the wax portion.
The method of claim 2, wherein the bypass valve is:
In the cooling mode, as the heat exchanger operates as a condenser, the refrigerant is formed at a relatively high temperature, and the wax part becomes liquid, expanding in volume and closing the bypass valve,
In the heating mode, as the heat exchanger operates as an evaporator, the refrigerant is formed at a relatively low temperature, and the wax part becomes solid, thereby shrinking in volume and opening the bypass valve.
The method of claim 3, wherein the bypass valve is:
In the cooling mode, as the bypass valve is closed, the refrigerant passes through the entire path of the heat exchanger as designed,
A bypass valve, characterized in that as the bypass valve is opened in the heating mode, refrigerant or additional refrigerant is formed to pass through a portion of the pass of the heat exchanger.
The method of claim 3, wherein the bypass valve is:
When it is assumed that the valve operation is completed when the wax part expands to the maximum volume and the valve stroke reaches 100%,
A bypass valve, characterized in that the valve operation completion temperature, which is the temperature of the wax portion when the valve operation is completed, is formed to correspond to the average refrigerant temperature in the cooling mode.
The method of claim 5, wherein the bypass valve is:
In determining valve operation completion, when the valve stroke is near 100%,
A bypass valve characterized in that the valve operation completion point is determined when the bypass flow rate of the refrigerant becomes less than 2.5% of the total flow rate.
The method of claim 6, wherein the bypass valve,
A bypass valve, wherein the valve operation completion temperature is formed lower than the refrigerant saturation temperature at the refrigerant pressure level determined by the load that varies depending on the average temperature of the outside air.
The method of claim 7, wherein the bypass valve is:
If the refrigerant used in the heat exchanger is R1234yf,
A bypass valve, characterized in that the valve operation completion temperature is lower than the refrigerant saturation temperature when the lowest limit of the refrigerant pressure level is 10 kg/cm2G under low-load cooling conditions in spring and fall.
The method of claim 8, wherein the bypass valve is:
A bypass valve, characterized in that the valve operation completion temperature is formed at 40 ℃ or less.
The method of claim 5, wherein the bypass valve is:
When assuming that the valve operation starts when the wax part shrinks to the minimum volume and the valve stroke reaches 0%,
A bypass valve, characterized in that the valve operation start temperature, which is the temperature of the wax portion when the valve operation starts, is formed to correspond to the average refrigerant temperature in the heating mode.
The method of claim 10, wherein the bypass valve is:
In determining valve operation start, when the valve stroke is near 0%,
A bypass valve characterized in that the valve operation start point is determined when the valve stroke becomes 0.1 mm or more.
The method of claim 11, wherein the bypass valve is:
If the refrigerant used in the heat exchanger is R1234yf,
A bypass valve, characterized in that the valve operation start temperature is formed at 20°C or higher.
The method of claim 1, wherein the bypass valve is:
A first communication passage connected to the heat exchanger through which refrigerant flows,
A second communication path connected to the bypass path of the heat exchanger and through which refrigerant flows,
A main space portion that accommodates a valve portion that performs opening and closing operations and is in communication with the first communication passage,
A subspace portion formed to communicate with the main space portion and having a smaller cross-sectional area than the main space portion, the communication with the main space portion being opened or closed by the operation of the valve portion, and communicating with the second communication passage.
A bypass valve comprising a.
The method of claim 13, wherein the valve unit,
A guide pin extending in the extension direction of the main space and provided within the main space,
A valve cap that secures one side of the guide pin to one side of the main space,
A case formed in the form of a container with one end open to accommodate the guide pin, but the inner wall is formed to be spaced apart from the outer surface of the guide pin,
An elastic portion provided to surround the guide pin,
A cover portion that is movable along the guide pin and seals the open end of the case,
The wax portion filled in the space between the elastic portion and the case and changing phase into a liquid or solid phase depending on temperature,
A valve plate provided on the other side of the case to open or close communication between the main space and the sub space.
A bypass valve comprising a.
The method of claim 14, wherein the valve unit,
As the refrigerant is formed at a relatively high temperature in the cooling mode, the wax part changes phase into a liquid state and increases in volume, pressing the elastic part, and the guide pin receives a squeezing force due to the pressure of the elastic part, thereby causing the case moves so that the valve plate closes communication between the main space and the sub-space,
As the refrigerant is formed at a relatively low temperature in the heating mode, the wax portion changes into a solid phase and its volume decreases, so that the case is restored to its original position, and the valve plate is formed to open the communication between the main space and the sub space. A bypass valve characterized by being
The method of claim 14, wherein the valve unit,
A main spring, both ends of which are supported on one side of the valve plate and the case, to absorb excess expansion of the wax portion,
A restoration spring whose both ends are supported on the other side of the valve plate and the subspace portion to assist in restoring the case to its original position.
A bypass valve comprising a.
The method of claim 14, wherein the valve unit,
A bypass valve, characterized in that the case is formed of a metal material.

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