A heat pump heating system and a control method thereof

Abstract

The application discloses a heat pump heating system and a control method thereof. The heat pump heating system is provided with a heating flow channel, a cooling flow channel and a fluid recovery device. The heating flow channel is sequentially divided into an inlet section, a heating section and a use section. The inlet section is divided into a first flow channel and a second flow channel. The first flow channel is used for connecting external fluid. The second flow channel is communicated to the use section to connect the second fluid recovered by the use section. The inlet end of the cooling flow channel is communicated to the fluid recovery device to connect the first fluid. The heat pump heating system comprises an evaporator, a compressor, a first condensing assembly and a second condensing assembly. The evaporator, the compressor, the first condensing assembly and the second condensing assembly are sequentially and circularly communicated. The evaporator is located in the cooling flow channel. The first condensing assembly is located in the heating section. The second condensing assembly is located in the first flow channel. The technical scheme can improve the heating process of the existing heating system, which has the problems of more air leakage and liquid leakage, and low overall energy efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump heating, in particular to a heat pump heating system and a control method thereof. BACKGROUND

[0002] In the field of industrial waste heat recovery and heat supply, there are many heating processes with more air leakage and liquid leakage, for example, in the lithium battery drying process, there is a large gap between the ovens, and there are large air leakage openings at the beginning and end of the production line, which increases the amount of new air and heat that needs to be supplemented. Since the assembly line must pass through each oven, it is difficult to overcome air leakage and other situations. In order to supplement the new air and maintain the oven temperature of the production line, electric heating must be used to supplement heat in the absence of additional heat recovery. The overall energy efficiency is low in the traditional drying process using electric heating. There is an urgent need for a new solution that can not only recover heat from other heat sources, but also improve the energy efficiency of the heating system such as drying. SUMMARY

[0003] The embodiments of the present application provide a heat pump heating system and a control method thereof, aiming to improve the problem of low overall energy efficiency caused by the heating process with more air leakage or liquid leakage in the existing heating system.

[0004] To this end, the first aspect of the embodiments of the present application provides a heat pump heating system, which is provided with a heating flow channel, a cooling flow channel and a fluid recovery device, wherein the fluid recovery device is used to collect waste first fluid with high-temperature waste heat, the heating flow channel is divided into an inlet section, a heating section and a use section in sequence along the flow direction of the fluid, the inlet section is divided into a first flow channel and a second flow channel, the first flow channel is used to access external fluid, and the second flow channel is connected to the use section to access second fluid with waste heat recovered by the use section, and the inlet end of the cooling flow channel is connected to the fluid recovery device to access the first fluid.

[0005] The heat pump heating system comprises an evaporator, a compressor, a first condensing assembly and a second condensing assembly, the evaporator, the compressor, the first condensing assembly and the second condensing assembly are sequentially connected in a refrigerant circulation mode, and the evaporator is located in the cooling flow channel, the first condensing assembly is located in the heating section, and the second condensing assembly is located in the first flow channel.

[0006] Optionally, in some embodiments of the present application, the first condensing assembly comprises a first condenser and a first throttling valve, the first condenser is located in the heating section, one end of the first condenser is connected to the compressor through a first pipeline, and the other end of the first condenser is connected to the second condensing assembly through a second pipeline provided with the first throttling valve.

[0007] Optionally, in some embodiments of the present application, the second condensing assembly comprises a second condenser and a second throttling valve, one end of the second condenser is arranged in communication with the first condenser through the second pipeline, and the other end of the second condenser is arranged in communication with the evaporator through a third pipeline provided with the second throttling valve.

[0008] Optionally, in some embodiments of the present application, a one-way valve is further arranged on the third pipeline, and the one-way valve is arranged between the second throttling valve and the second condenser.

[0009] Optionally, in some embodiments of the present application, a fourth pipeline provided with a refrigerant bypass valve is further arranged in communication between the second pipeline and the third pipeline, the communication between the fourth pipeline and the second pipeline is located between the first condenser and the first throttling valve, and the communication between the fourth pipeline and the third pipeline is located between the one-way valve and the second throttling valve.

[0010] Optionally, in some embodiments of the present application, the second condenser comprises a gas-liquid separator and a heat exchanger body, the heat exchanger body is provided with a two-phase heat exchange flow channel and a single-phase heat exchange flow channel, the inlet of the gas-liquid separator is arranged in communication with the second pipeline, the gas outlet of the gas-liquid separator is in communication with the two-phase heat exchange flow channel, the liquid outlet of the gas-liquid separator is in communication with the single-phase heat exchange flow channel, and the outlet of the two-phase heat exchange flow channel and the outlet of the single-phase heat exchange flow channel are both in communication with the third pipeline.

[0011] Optionally, in some embodiments of the present application, the cooling flow channel is divided into a main flow channel and a bypass flow channel, the evaporator is located in the main flow channel, and a first fluid bypass valve for controlling the opening and closing ratio of the inlet of the bypass flow channel is arranged at the inlet of the bypass flow channel.

[0012] Optionally, in some embodiments of the present application, the heat pump heating system further comprises an auxiliary heating bag and a second fluid bypass valve, the auxiliary heating bag is arranged in the heating section to assist in heating the fluid in the heating section, and the second fluid bypass valve is arranged at the separation between the first flow channel and the second flow channel to control the ratio between the fluid flowing from the first flow channel to the heating section and the fluid flowing from the second flow channel to the heating section.

[0013] In addition, the second aspect of the embodiments of the present application provides a control method of a heat pump heating system, which is applied to the heat pump heating system described above, the compressor is a variable frequency machine, and the control method comprises the following steps:

[0014] obtaining an actual temperature of the fluid in the heating section, and comparing the actual temperature with a target temperature;

[0015] if the actual temperature is greater than the target temperature, and a first difference between the actual temperature and the target temperature is greater than a first threshold, then the actual temperature is reduced by first reducing the frequency of the compressor until the first difference is less than or equal to the first threshold, and when the frequency of the compressor is reduced to a minimum value, and the first difference is still greater than the first threshold, the second fluid bypass valve is adjusted until the first difference is less than or equal to the first threshold;

[0016] if the actual temperature is less than the target temperature, and a second difference between the target temperature and the actual temperature is greater than a second threshold, then the actual temperature is increased by first increasing the frequency of the compressor until the second difference is less than or equal to the second threshold, and when the frequency of the compressor is increased to a maximum value, and the second difference is still greater than the second threshold, the auxiliary heating package is started until the second difference is less than or equal to the second threshold.

[0017] In addition, the third aspect of the embodiments of the present application provides a control method of a heat pump heating system, which is applied to the heat pump heating system described above, the compressor is a fixed frequency machine, and the control method comprises the following steps:

[0018] an actual temperature of the fluid in the heating section is obtained, and the actual temperature is compared with a target temperature;

[0019] if the actual temperature is greater than the target temperature, and a first difference between the actual temperature and the target temperature is greater than a first threshold, then the second fluid bypass valve is adjusted until the first difference is less than or equal to the first threshold;

[0020] if the actual temperature is less than the target temperature, and a second difference between the target temperature and the actual temperature is greater than a second threshold, then the auxiliary heating package is started until the second difference is less than or equal to the second threshold.

[0021] The heat pump heating system and the control method thereof provided by the technical scheme of the present application, the heat pump heating system thereof forms a refrigerant circulation system through an evaporator, a compressor, a first condensing assembly and a second condensing assembly, and is reasonably arranged in a cooling flow channel, a heating section of a heating flow channel and a first flow channel of the heating flow channel. At this time, since the inlet end of the cooling flow channel is communicated with a fluid recovery device, the first fluid with high-temperature waste heat collected by the fluid recovery device can be connected, so that the refrigerant circulation system formed by the above structure arrangement can recover the heat of the first fluid to the fluid in the heating flow channel, so that the heat pump heating system can realize the heating effect of the fluid itself through the heat recovery of other heat sources. At the same time, in the refrigerant circulation system formed by the above structure arrangement, in addition to the first condensing assembly arranged in the heating section of the heating flow channel for main heating (i.e., the first condensing assembly is used to heat the fluid in the heating section to the required temperature through heat exchange), the second condensing assembly for auxiliary heating is arranged in the first flow channel of the heating flow channel (i.e., the second condensing assembly is used to recover as much heat as possible in the refrigerant to the fluid in the first flow channel through heat exchange without heating the fluid in the first flow channel to a specific temperature), so that the first condensing assembly and the second condensing assembly form a double-throttling heat exchange design to greatly improve the energy efficiency of the heat pump heating system. In addition, the heat pump heating system directly connects the second fluid with waste heat recovered from the use section through the second flow channel, so that the fluid with waste heat used in the use section of the heating flow channel is effectively reused, i.e., the heat is returned to the fluid in the heating section, to further improve the energy efficiency of the heat pump heating system. It can be seen that the present technical scheme can effectively improve the problem of low overall energy efficiency caused by the heating process of the existing heating system with more air leakage or liquid leakage. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 The structural schematic diagram of the heat pump heating system of the present application embodiment;

[0024] Figure 2 The pressure enthalpy characteristic comparison diagram of the high-temperature refrigerant and the conventional refrigerant of the present application embodiment;

[0025] Figure 3 The structural use state schematic diagram of the second condenser of the heat pump heating system of the present application embodiment;

[0026] Figure 4Another structure using state schematic view of the second condenser of the heat pump heating system of the embodiment of the present application;

[0027] Figure 5 The first flow chart of the control method of the heat pump heating system of the embodiment of the present application.

[0028] Figure 6 The first flow chart of the control method of the heat pump heating system of the embodiment of the present application.

[0029] Explanation of reference numerals:

[0030] 100, heat pump heating system; 110, heating flow channel; 111, inlet section; 1111, first flow channel; 1112, second flow channel; 112, heating section; 113, using section; 120, cooling flow channel; 121, main flow channel; 122, bypass flow channel; 130, evaporator; 140, compressor; 150, first condensing assembly; 151, first condenser; 152, first throttling valve; 160, second condensing assembly; 161, second condenser; 1611, gas-liquid separator; 1612, two-phase heat exchange flow channel; 1613, single-phase heat exchange flow channel; 162, second throttling valve; 171, one-way valve; 172, refrigerant bypass valve; 173, first fluid bypass valve; 174, auxiliary heating bag; 175, second fluid bypass valve; 11, first pipeline; 12, second pipeline; 13, third pipeline; 14, fourth pipeline.

[0031] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0034] In addition, the descriptions involving "first", "second", etc. in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0035] In one embodiment, as shown in Figure 1 The present application provides a heat pump heating system 100, which can be specifically provided with a heating flow channel 110, a cooling flow channel 120 and a fluid recovery device (not shown), wherein the fluid recovery device is used to collect waste first fluid with high-temperature waste heat, the heating flow channel 110 is divided into an inlet section 111, a heating section 112 and a use section 113 along the flow direction of the fluid in sequence, the inlet section 111 is divided into a first flow channel 1111 and a second flow channel 1112, the first flow channel 1111 is used to access external fluid, and the second flow channel 1112 is communicated to the use section 113 to access the second fluid with waste heat leaked from the use section 113, and the inlet end of the cooling flow channel 120 is communicated with the fluid recovery device to access the first fluid. The heat pump heating system 100 comprises an evaporator 130, a compressor 140, a first condensing assembly 150 and a second condensing assembly 160, the evaporator 130, the compressor 140, the first condensing assembly 150 and the second condensing assembly 160 are sequentially and circularly communicated, and the evaporator 130 is located in the cooling flow channel 120, the first condensing assembly 150 is located in the heating section 112, and the second condensing assembly 160 is located in the first flow channel 1111.

[0036] It can be understood that the heat pump heating system 100 mentioned in the present application can not only be applied to a gas heating system such as a lithium battery drying device, but also can be applied to a liquid heating system. That is, the fluid mentioned above can be a gas or a liquid. As Figure 2As shown, according to the characteristics of the high-temperature refrigerant, the higher the condensing temperature, the more the two-phase region capacity that can be utilized decreases sharply, which makes the high-temperature heat pump COP using the high-temperature refrigerant lower than the conventional refrigerant when the exhaust gas superheat is lower than the conventional refrigerant. However, if the refrigerant after the first condensation is throttled first, the same pressure ratio can be used without increasing the frequency of the compressor 140 under sufficient waste heat resources, further increasing the condensing heat, which is the most direct and effective way to improve the overall COP of the high-temperature heat pump. Since the first condensing component 150 can only utilize a portion of the heat after throttling, for the case where heating to a higher temperature is not required, increasing the second condensing component 160 for secondary throttling can theoretically increase the compressor 140 frequency and power, thereby increasing the compressor 140 heating capacity and improving the COP. Therefore, the heat pump heating system 100 in the example of the present application preferably uses a high-temperature refrigerant. The above-mentioned heating flow channel 110 is divided into an inlet section 111, a heating section 112, and a use section 113 in the flow direction of the fluid, which refers to a virtual division. The inlet section 111, the heating section 112, and the use section 113 are not actually separated and remain in communication with each other. The inlet section 111 is divided into a first flow channel 1111 and a second flow channel 1112, which means that the first flow channel 1111 and the second flow channel 1112 are actually separated and remain independent of each other, and the flow direction of the first flow channel 1111 and the second flow channel 1112 is the same, both of which make the fluid flow to the heating section 112.

[0037] In addition to the above-mentioned external fluid, which refers to the fluid newly supplemented from the outside, it is not the fluid recovered from the original heating flow channel. The above-mentioned first fluid with high-temperature waste heat, in addition to a large part of which can be the waste fluid with high-temperature waste heat collected from other heat sources, a small part of which can be the leaked fluid collected from the side of the heating section 112 of the heating flow channel 110 of the heat pump heating system, to further reduce the heat loss caused by the leaked fluid, and to further improve the energy efficiency of the heat pump heating system 100. The above-mentioned first fluid with high-temperature waste heat specifically refers to a liquid at 30-80°C, or a gas at 30-150°C.

[0038] The sequential refrigerant circulation communication of the above-mentioned evaporator 130, compressor 140, first condensing assembly 150 and second condensing assembly 160 means that the refrigerant flows along the path of the evaporator 130, compressor 140, first condensing assembly 150 and second condensing assembly 160 in sequence, and then returns to the evaporator 130 for the next cycle. The whole refrigerant working process of the heat pump heating system 100 is as follows: the refrigerant in the evaporator 130 absorbs waste heat from the cooling flow channel 120 with a higher temperature to evaporate, and the dryness of the refrigerant is increased, and the refrigerant evaporates from a low-temperature and low-pressure gas-liquid mixed state to a low-pressure superheated state. Then, the low-pressure superheated refrigerant enters the compressor 140 and is compressed from a low-pressure superheated state to a high-pressure superheated state. Then, the high-pressure superheated refrigerant enters the first condensing assembly 150 and exchanges heat with the medium-temperature fluid in the heating section 112, and the refrigerant condenses from a high-pressure superheated gas state to a high-pressure subcooled liquid state, and at the same time, the medium-temperature fluid in the heating section 112 is heated to become a high-temperature fluid of a required temperature, which is sent to a required use place through the use section 113. Then, the high-pressure subcooled liquid refrigerant from the first condensing assembly 150 enters the second condensing assembly 160 for further subcooling, and the further subcooled liquid refrigerant heats the low-temperature fluid of the first flow channel 1111 to become a medium-temperature fluid. Finally, the further subcooled liquid refrigerant becomes a low-temperature and low-pressure low-dryness gas-liquid mixed state again, and reenters the evaporator 130 for the next cycle.

[0039] In this way, through the above structural arrangement, the heat pump heating system 100, through the refrigerant circulation system formed by the evaporator 130, compressor 140, first condensing assembly 150, and second condensing assembly 160, is rationally arranged in the cooling channel 120, the heating section 112 of the heating channel 110, and the first channel 1111 of the heating channel 110. Since the inlet end of the cooling channel 120 is connected to a fluid recovery device, the first fluid with high-temperature waste heat collected therein can be connected. Thus, the refrigerant circulation system formed by the above structural arrangement can recover the heat of the first fluid into the fluid in the heating channel 110, enabling the heat pump heating system 100 to achieve its own heating effect on the fluid through heat recovery from other heat sources. Meanwhile, in the refrigerant circulation system formed by the above-mentioned structural configuration, in addition to the first condensing component 150 for main heating (i.e., the first condensing component 150 is used to heat the fluid in the heating section 112 of the heating channel 110 to the required temperature through heat exchange) is provided, a second condensing component 160 for auxiliary heating is also provided in the first channel 1111 of the heating channel 110 (i.e., the second condensing component 160 is used to recover as much of the remaining heat in the refrigerant as possible to the fluid in the first channel 1111 through heat exchange, without having to heat the fluid in the first channel 1111 to a specific temperature). This makes the first condensing component 150 and the second condensing component 160 form a double throttling heat exchange design, so as to greatly improve the energy efficiency of this heat pump heating system 100. In addition, the heat pump heating system 100 is directly connected to the second fluid with residual heat recovered from the use section 113 through the second flow channel 1112, so that the fluid with residual heat after use in the use section 113 of the heating flow channel 110 is effectively reused, that is, the heat is returned to the fluid in the heating section 112, so as to further improve the energy efficiency of the heat pump heating system 100.

[0040] In some examples, such as Figure 1 As shown, the first condensing assembly 150 may specifically include a first condenser 151 and a first throttling valve 152. The first condenser 151 is located in the heating section 112. One end of the first condenser 151 is connected to the compressor 140 via a first pipe 11, and the other end of the first condenser 151 is connected to the second condensing assembly 160 via a second pipe 12 equipped with the first throttling valve 152. It can be understood that the first condenser 151 may specifically be a heating-side heat exchanger performing two-phase heat exchange, including but not limited to finned tube heat exchangers, shell-and-tube heat exchangers, etc., to effectively heat the fluid in the heating section 112 in conjunction with the first throttling valve 152, thereby obtaining a high-temperature fluid at the desired temperature. Thus, through the above structural arrangement, a good heating effect on the fluid in the heating section 112 can be ensured.

[0041] In some examples, such as Figure 1As shown, the second condensing assembly 160 may specifically include a second condenser 161 and a second throttling valve 162. The second condenser 161 is located in the first flow channel 1111. One end of the second condenser 161 is connected to the first condenser 151 via a second pipe 12, and the other end of the second condenser 161 is connected to the evaporator 130 via a third pipe 13 with the second throttling valve 162. It can be understood that the second condenser 161 may specifically be a heating-side heat exchanger for two-phase heat exchange, including but not limited to finned tube heat exchangers, shell-and-tube heat exchangers, etc., to cooperate with the setting of the second throttling valve 162 to effectively preheat the fluid in the first flow channel 1111. Thus, through the above structural arrangement, a good preheating effect can be ensured for the fluid in the first flow channel 1111. Further, as... Figure 1 , Figure 3 and Figure 4 As shown, the second condenser 161 specifically includes a gas-liquid separator 1611 and a heat exchanger body. The heat exchanger body is provided with a two-phase heat exchange channel 1612 and a single-phase heat exchange channel 1613. The inlet of the gas-liquid separator 1611 is connected to the second pipeline 12, the gas outlet of the gas-liquid separator 1611 is connected to the two-phase heat exchange channel 1612, and the liquid outlet of the gas-liquid separator 1611 is connected to the single-phase heat exchange channel 1613. The outlets of both the two-phase heat exchange channel 1612 and the single-phase heat exchange channel 1613 are connected to the third pipeline 13. Thus, with the above structural arrangement, when the fluid is a gas, the low-temperature fresh gas... Figure 3 As indicated by the arrow, the fluid first passes through the single-phase heat exchange channel 1613 and then enters the two-phase heat exchange channel 1612. The heat exchange process between the two channels is cross-flow heat exchange. When the fluid is a liquid, the new liquid at a low temperature... Figure 4 As indicated by the arrow, the fluid first undergoes co-current heat exchange in the single-phase heat exchange channel 1613, and then counter-current heat exchange in the two-phase heat exchange channel 1612, thus ensuring sufficient heat exchange in the two-phase heat exchange channel 1612. This ensures that the fluid in the first channel 1111, whether gas or liquid, has a good preheating effect.

[0042] In some examples, such as Figure 1 As shown, a one-way valve 171 is also installed on the third pipeline 13, and the one-way valve 171 is located between the second throttle valve 162 and the second condenser 161. In this way, the one-way valve 171 can controllably ensure that the refrigerant in the second condenser 161 flows only in one direction to the second throttle valve 162.

[0043] In some examples, such as Figure 1As shown, the second pipeline 12 and the third pipeline 13 are also communicated with the fourth pipeline provided with the refrigerant bypass valve 172, the communication between the fourth pipeline and the second pipeline 12 is located between the first condenser 151 and the first throttling valve 152, and the communication between the fourth pipeline and the third pipeline 13 is located between the one-way valve 171 and the second throttling valve 162. In this way, the refrigerant from the first condenser 151 can be controllably bypassed around the second condenser 161 through the refrigerant bypass valve 172, so as to adjust the refrigerant flow of the second condenser 161, and further control the heat exchange capacity of the second condenser 161.

[0044] In some examples, as Figure 1 As shown, the cooling flow channel 120 is divided into the main flow channel 121 and the bypass flow channel 122, the evaporator 130 is located in the main flow channel 121, and the bypass flow channel 122 is provided with the first fluid bypass valve 173 for controlling the opening and closing ratio of the inlet of the bypass flow channel 122. It can be understood that the division of the cooling flow channel 120 into the main flow channel 121 and the bypass flow channel 122 means that the main flow channel 121 and the bypass flow channel 122 are actually separated and kept independent of each other, and the fluid flow directions of the main flow channel 121 and the bypass flow channel 122 are kept the same, and both can access the second fluid with residual heat leaked from the side of the heating section 112. In this way, the recovered heat of the evaporator 130 can be adjusted through the setting of the first fluid bypass valve 173. Simply, the recovered heat of the evaporator 130 can be adjusted by directly controlling the opening and closing of the first fluid bypass valve 173, that is, closing the first fluid bypass valve 173 can increase the heat recovery fluid flow of the main flow channel 121, and further increase the heat recovery amount, and vice versa, opening the first fluid bypass valve 173, the flow resistance of the bypass flow channel 122 is smaller than that of the main flow channel 121, and part of the fluid does not flow through the evaporator 130 of the main flow channel 121, so that the heat recovery fluid flow of the main flow channel 121 is reduced, and the heat recovery amount is reduced. Complexly, the recovered heat of the evaporator 130 can be more finely adjusted by controlling the opening and closing ratio of the first fluid bypass valve 173, that is, by adjusting the first fluid bypass valve 173, the opening size of the bypass flow channel 122 changes correspondingly, the heat recovery fluid flow entering the bypass flow channel 122 is controlled, and the purpose of adjusting the recovered heat of the evaporator 130 is achieved.

[0045] In some examples, as Figure 1As shown, the heat pump heating system 100 further comprises an auxiliary heating package 174 and a second fluid bypass valve 175. The auxiliary heating package 174 is arranged in the heating section 112 to provide auxiliary heating to the fluid in the heating section 112. The second fluid bypass valve 175 is arranged at a partition between the first flow channel 1111 and the second flow channel 1112 to control the proportion of the fluid flowing from the first flow channel 1111 to the heating section 112 and the fluid flowing from the second flow channel 1112 to the heating section 112. In this way, the heating capacity of the fluid in the heating section 112 can be enhanced by the auxiliary heating of the auxiliary heating package 174. The heat exchange capacity of the second condenser 161 can be adjusted by controlling the proportion of the fluid flowing from the first flow channel 1111 to the heating section 112 and the fluid flowing from the second flow channel 1112 to the heating section 112 through the second fluid bypass valve 175.

[0046] In one embodiment, as shown in Figure 5 The embodiments of the present application also provide a control method of a heat pump heating system. The control method is applied to the heat pump heating system 1 in the above embodiments. The control method can specifically include the following steps.

[0047] Step S110: obtaining the actual temperature of the fluid in the heating section and comparing the actual temperature with the target temperature.

[0048] Step S120: if the actual temperature is greater than the target temperature and a first difference between the actual temperature and the target temperature is greater than a first threshold, the actual temperature is first reduced by reducing the frequency of the compressor until the first difference is less than or equal to the first threshold. If the first difference is still greater than the first threshold after the frequency of the compressor is reduced to the lowest value, the second fluid bypass valve is adjusted until the first difference is less than or equal to the first threshold.

[0049] Step S130: if the actual temperature is less than the target temperature and a second difference between the target temperature and the actual temperature is greater than a second threshold, the actual temperature is first increased by increasing the frequency of the compressor until the second difference is less than or equal to the second threshold. If the second difference is still greater than the second threshold after the frequency of the compressor is increased to the highest value, the auxiliary heating package is started until the second difference is less than or equal to the second threshold.

[0050] It can be understood that in the heat pump heating system in the above embodiment, the compressor used has two types, namely a variable frequency compressor and a fixed frequency compressor. Compared with the working frequency of the fixed frequency compressor, the working frequency of the variable frequency compressor can be adjusted to adjust the heat exchange capacity of the condenser, so as to adjust the actual temperature of the fluid in the heating section. Therefore, the method steps are mainly applied to the heat pump heating system in which the compressor is a variable frequency compressor. At this time, if the actual temperature of the fluid in the heating section is greater than the target temperature, and the first difference between the actual temperature and the target temperature is greater than the first threshold, the working frequency of the compressor is adjusted to adjust the heat exchange capacity of the condenser, so as to adjust the actual temperature of the fluid in the heating section. That is, the frequency of the compressor is first reduced to reduce the heat exchange capacity of the condenser, so that the actual temperature is reduced, until the first difference is less than or equal to the first threshold. However, since the working frequency of the compressor has a certain working range, when the frequency of the compressor is reduced to the minimum value and the first difference is still greater than the first threshold, the proportion between the fluid flowing through the first flow channel to the heating section and the fluid flowing through the second flow channel to the heating section can be further adjusted by adjusting the second fluid bypass valve, so as to adjust the heat exchange capacity of the condenser to reduce the actual temperature, until the first difference is less than or equal to the first threshold. Similarly, if the actual temperature of the fluid in the heating section is less than the target temperature, and the second difference between the target temperature and the actual temperature is greater than the second threshold, the working frequency of the compressor is adjusted to adjust the heat exchange capacity of the condenser, so as to adjust the actual temperature of the fluid in the heating section. That is, the frequency of the compressor is first increased to increase the heat exchange capacity of the condenser, so that the actual temperature is increased, until the second difference is less than or equal to the second threshold. However, since the working frequency of the compressor has a certain working range, when the frequency of the compressor is increased to the maximum value and the second difference is still greater than the second threshold, the auxiliary heating bag can be started to assist in increasing the actual temperature, until the second difference is less than or equal to the second threshold.

[0051] In addition, when the auxiliary heating bag is working, the output power of the auxiliary heating bag can be adjusted according to the temperature difference, so that the second difference is less than or equal to the second threshold as soon as possible. The first threshold and the second threshold mentioned above can be arbitrarily valued according to the actual heating precision, and the values of the two thresholds can be the same or different.

[0052] In this way, by the above method steps, the heat pump heating system can quickly and accurately heat the corresponding fluid to the required temperature to meet the user's related fluid heating needs.

[0053] In one embodiment, as shown in Figure 6 The control method of the heat pump heating system provided by the embodiment of the present application is applied to the heat pump heating system 1 in the above embodiment, and can specifically include the following steps:

[0054] Step S210: Obtain the actual temperature of the fluid in the current heating section, and compare the actual temperature with the target temperature.

[0055] Step S220: If the actual temperature is greater than the target temperature, and a first difference between the actual temperature and the target temperature is greater than a first threshold, adjust the second fluid bypass valve until the first difference is less than or equal to the first threshold.

[0056] Step S230: If the actual temperature is less than the target temperature, and a second difference between the target temperature and the actual temperature is greater than a second threshold, start the auxiliary heating package until the second difference is less than or equal to the second threshold.

[0057] It can be understood that the method steps are mainly applied to a heat pump heating system in which the compressor is a fixed-frequency compressor. Based on the above description, the working frequency of the fixed-frequency compressor cannot be adjusted, so the heat exchange capacity of the condenser cannot be adjusted by adjusting the working frequency of the compressor to adjust the actual temperature of the fluid in the heating section. At this time, if the actual temperature of the fluid in the heating section is greater than the target temperature, and a first difference between the actual temperature and the target temperature is greater than a first threshold, the proportion between the fluid flowing to the heating section through the first flow passage and the fluid flowing to the heating section through the second flow passage is controlled by adjusting the second fluid bypass valve, so as to reduce the actual temperature by adjusting the heat exchange capacity of the condenser until the first difference is less than or equal to the first threshold. Similarly, if the actual temperature of the fluid in the heating section is less than the target temperature, and a second difference between the target temperature and the actual temperature is greater than a second threshold, the actual temperature is assisted to rise by starting the auxiliary heating package until the second difference is less than or equal to the second threshold.

[0058] In addition, when the auxiliary heating package is working, the output power of the auxiliary heating package can be adjusted according to the temperature difference, so that the second difference is less than or equal to the second threshold as soon as possible. The first threshold and the second threshold mentioned above can be arbitrarily valued according to the actual heating precision, and the values of the two thresholds can be the same or different.

[0059] In this way, by the above method steps, the heat pump heating system can quickly and accurately heat the corresponding fluid to the required temperature to meet the user's related fluid heating needs.

[0060] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made according to the contents of the specification and drawings, or direct / indirect application in other related technical fields within the inventive concept of the present application is included in the patent protection scope of the present application.

Claims

1. A heat pump heating system, characterized in that, The heat pump heating system is provided with a heating flow channel, a cooling flow channel and a fluid recovery device, wherein the fluid recovery device is used for collecting the waste first fluid with high-temperature waste heat, the heating flow channel is sequentially divided into an inlet section, a heating section and a use section along the flow direction of the fluid, the inlet section is divided into a first flow channel and a second flow channel, the first flow channel is used for accessing external fluid, the second flow channel is communicated to the use section to access the second fluid with waste heat recovered by the use section, and the inlet end of the cooling flow channel is communicated to the fluid recovery device to access the first fluid. The heat pump heating system comprises an evaporator, a compressor, a first condensing assembly and a second condensing assembly, the evaporator, the compressor, the first condensing assembly and the second condensing assembly are sequentially and communicatively connected for refrigerant circulation, and the evaporator is located in the cooling flow channel, the first condensing assembly is located in the heating section, and the second condensing assembly is located in the first flow channel.

2. The heat pump heating system of claim 1, wherein, The first condensing assembly comprises a first condenser and a first throttling valve, one end of the first condenser is communicatively connected to the compressor through a first pipeline, and the other end of the first condenser is communicatively connected to the second condensing assembly through a second pipeline provided with the first throttling valve.

3. The heat pump heating system of claim 2, wherein, The second condensing assembly comprises a second condenser and a second throttling valve, the second condenser is located in the first flow channel, one end of the second condenser is communicatively connected to the first condenser through the second pipeline, and the other end of the second condenser is communicatively connected to the evaporator through a third pipeline provided with the second throttling valve.

4. The heat pump heating system of claim 3, wherein, A one-way valve is further arranged on the third pipeline, and the one-way valve is arranged between the second throttling valve and the second condenser.

5. The heat pump heating system of claim 4, wherein, A fourth pipeline provided with a refrigerant bypass valve is further arranged in communication between the second pipeline and the third pipeline, the communication position of the fourth pipeline and the second pipeline is between the first condenser and the first throttling valve, and the communication position of the fourth pipeline and the third pipeline is between the one-way valve and the second throttling valve.

6. The heat pump heating system of claim 3, wherein, The second condenser comprises a gas-liquid separator and a heat exchanger body, the heat exchanger body is provided with a two-phase heat exchange flow channel and a single-phase heat exchange flow channel, the inlet of the gas-liquid separator is communicatively connected to the second pipeline, the gas outlet of the gas-liquid separator is communicated to the two-phase heat exchange flow channel, the liquid outlet of the gas-liquid separator is communicated to the single-phase heat exchange flow channel, and the outlet of the two-phase heat exchange flow channel and the outlet of the single-phase heat exchange flow channel are both communicated to the third pipeline.

7. The heat pump heating system of claim 1, wherein, The cooling flow channel is divided into a main flow channel and a bypass flow channel, the evaporator is located in the main flow channel, and a first fluid bypass valve for controlling the opening and closing ratio of the inlet of the bypass flow channel is arranged at the inlet of the bypass flow channel.

8. A heat pump heating system as claimed in any one of claims 1-7, characterized in that, The heat pump heating system further comprises an auxiliary heating package arranged in the heating section to assist heating the fluid in the heating section, and a second fluid bypass valve arranged at a partition between the first flow channel and the second flow channel to control the proportion between the fluid flowing from the first flow channel to the heating section and the fluid flowing from the second flow channel to the heating section.

9. A control method of a heat pump heating system, characterized by, The control method is applied to the heat pump heating system as claimed in claim 8, wherein the compressor is a variable frequency compressor, and the control method comprises the following steps: acquiring an actual temperature of the fluid in the heating section, and comparing the actual temperature with a target temperature; if the actual temperature is greater than the target temperature, and a first difference between the actual temperature and the target temperature is greater than a first threshold, then the actual temperature is lowered by lowering the frequency of the compressor until the first difference is less than or equal to the first threshold, and when the frequency of the compressor is lowered to a minimum value and the first difference is still greater than the first threshold, the second fluid bypass valve is adjusted until the first difference is less than or equal to the first threshold; if the actual temperature is less than the target temperature, and a second difference between the target temperature and the actual temperature is greater than a second threshold, then the actual temperature is raised by raising the frequency of the compressor until the second difference is less than or equal to the second threshold, and when the frequency of the compressor is raised to a maximum value and the second difference is still greater than the second threshold, the auxiliary heating package is started until the second difference is less than or equal to the second threshold.

10. A control method of a heat pump heating system, characterized by, The control method is applied to the heat pump heating system as claimed in claim 8, wherein the compressor is a fixed frequency compressor, and the control method comprises the following steps: acquiring an actual temperature of the fluid in the heating section, and comparing the actual temperature with a target temperature; if the actual temperature is greater than the target temperature, and a first difference between the actual temperature and the target temperature is greater than a first threshold, then the second fluid bypass valve is adjusted until the first difference is less than or equal to the first threshold; if the actual temperature is less than the target temperature, and a second difference between the target temperature and the actual temperature is greater than a second threshold, then the auxiliary heating package is started until the second difference is less than or equal to the second threshold.

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