WO2021042654A1

WO2021042654A1 - Total heat recovery defrosting control method and control device, and air conditioning apparatus

Info

Publication number: WO2021042654A1
Application number: PCT/CN2020/070797
Authority: WO
Inventors: 冷宇; 孙辉; 赵雷; 李振洪
Original assignee: 青岛海尔空调电子有限公司; 海尔智家股份有限公司
Priority date: 2019-09-05
Filing date: 2020-01-08
Publication date: 2021-03-11
Also published as: CN112443934A; EP4027070A1; EP4027070A4; CN112443934B; EP4027070B1; EP4027070C0

Abstract

A total heat recovery defrosting control method and control system (10), and an air conditioning apparatus. The method comprises the following steps: operating in a heating mode or a hot water mode; determining whether the current operating status satisfies a defrosting operating condition; if the current operating status satisfies the defrosting operating condition, comparing a heating demand with a hot water demand; if the heating demand is higher than the hot water demand, executing a hot-water defrosting mode; and if the hot water demand is higher than the heating demand, executing a heating defrosting mode. The control system (10) is provided with a defrosting determination module (101), a comparison module (102), and an execution module (103). By means of comparing the heat demand of a total heat recovery set on the heating and water heating of an air conditioner, a heat exchanger demanding less heat is selected to perform defrosting, thus avoiding a great amount of heat being lost by the heat exchanger in an operating mode, reducing the influence thereof on the usage experience of a user, and ensuring a heating demand or hot water demand of the user.

Description

Total heat recovery defrosting control method, control system and air conditioning device

Technical field

The invention belongs to the technical field of air conditioning equipment, and in particular relates to a total heat recovery defrosting control method, a total heat recovery defrosting control system and an air conditioning device.

Background technique

The air conditioning device with full heat recovery function is an air conditioning unit that integrates refrigeration, heating, and domestic hot water. Generally speaking, this air conditioning device includes a compressor, an outdoor air-side fin heat exchanger that exchanges heat with the air, a water-side heat exchanger, a total heat recovery heat exchanger that recovers heat energy, a four-way valve, and an electronic expansion valve. , Accumulator and multiple solenoid valves, one-way valves and other execution components that are set in the refrigeration cycle system to adjust the flow and direction of the refrigerant to perform different functions. Because the refrigerant can flow in different directions and exchange heat with multiple media in the heat exchanger, an air conditioning device with full heat recovery function can have multiple functional modes, including heating mode, cooling mode, and hot water Mode and so on. The Chinese patent application (Authorization Announcement No. CN201212721Y) discloses the refrigeration cycle structure and working method of the air-conditioning total heat recovery mechanism.

In heating operation mode or hot water mode, especially when the ambient temperature is low, the air-side fin heat exchanger located outdoors may appear frosting. When frosting occurs, the heat exchange is caused by the increase of the frost layer. The thermal resistance of the device increases, so that the heat exchange is gradually reduced. When the frost layer increases to a certain thickness, the heat exchange rate drops rapidly. In order to avoid the impact of reduced heat exchange on the operation of the air-conditioning device, corresponding heating and defrosting modes and hot water defrosting modes are configured. In the heating and defrosting mode, the high-temperature and high-pressure refrigerant is discharged from the compressor and enters the outdoor air-side fin heat exchanger through the four-way valve. In the outdoor air-side fin heat exchanger, the high-temperature and high-pressure refrigerant exchanges heat and defrosts with the air, and at the same time it condenses into a medium-temperature and medium-pressure refrigerant liquid. The medium-temperature and medium-pressure refrigerant liquid passes through the accumulator and is economical. The equipment such as the air conditioner is supercooled, and the low-temperature and low-pressure refrigerant liquid flows into the indoor water-side heat exchanger through the throttling device to exchange heat with the air-conditioning water. In the hot water defrosting mode, the high temperature and high pressure refrigerant is discharged from the compressor, enters the outdoor air-side fin heat exchanger through the four-way valve, and releases heat to the surrounding environment in the outdoor air-side fin heat exchanger. It is condensed into a medium temperature and medium pressure refrigerant liquid. The medium temperature and medium pressure refrigerant is further subcooled through the accumulator, economizer and other equipment, and is reduced in pressure by the throttling mechanism to become a low temperature and low pressure refrigerant liquid. To the heat recovery heat exchanger. It is not difficult to see that in the heating defrost mode or the hot water defrost mode, the defrost is achieved by sacrificing the heat of the indoor water-side heat exchanger or heat recovery heat exchanger respectively, which will inevitably affect the user's use Comfort.

The above-mentioned information disclosed in the background art is only used to increase the understanding of the background art of the present application, and therefore, it may include the prior art that is not known to those of ordinary skill in the art.

Summary of the invention

Aiming at the problem that the outdoor heat exchanger of the air conditioning device with full heat recovery function is prone to frost during cooling or hot water production in winter, and the defrosting operation will consume the heat exchange of the system and reduce the user experience, the present invention designs and provides a A total heat recovery defrost control method.

In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solutions to achieve:

A total heat recovery defrosting control method, including the following steps: operating in heating mode or hot water mode; judging whether the current operating conditions meet the defrosting operating conditions; if the current operating conditions meet the defrosting operating conditions, then comparing Heating demand and hot water demand; if the heating demand is higher than the hot water demand, the hot water defrosting mode is executed; if the hot water demand is higher than the heating demand, the heating defrosting mode is executed.

Further, when performing the comparison heating and hot water requirements demand the steps of: sampling the current water temperature set heating temperature T _r and a heat recovery heat exchanger side, T _wi; calculating a first temperature difference T _{_d1:} T _d1 = T _r -T _wi ; Sampling the current hot water set temperature _Thr _{and the outlet water temperature Th} on the heat recovery heat exchanger side; calculate the second temperature difference T _d2 : T _d2 = _Thr -T _h ; if the first temperature difference T _{If d1 is} greater than the second temperature difference T _d2 , it is determined that the heating demand is higher than the hot water demand, and the hot water defrosting mode is executed; if the first temperature difference T _{d1 is} less than the second temperature difference T _d2 , it is determined In order that the hot water demand is higher than the heating demand, the heating and defrosting mode is executed.

As another alternative, perform the following steps when comparing heating demand and hot water demand: Obtain the change rate of the inlet water temperature ΔT _wi on the side of the heat recovery heat exchanger in the set sampling period; Obtain the heat recovery exchange rate in the set sampling period The rate of change of the outlet water temperature ΔT _{h on the} heater side; if ΔT _wi > ΔT _h , it is determined that the heating demand is higher than the hot water demand, and the hot water defrosting mode is executed; if ΔT _wi <ΔT _h , it is determined as The hot water demand is higher than the heating demand, and the heating and defrosting mode is executed.

As another alternative, the heating performed when the comparison needs and hot water demand the steps of: sampling the current water temperature set heating temperature T _r and a heat recovery heat exchanger side T _wi, calculating a first temperature difference T _d1 :T _d1 =T _r -T _wi ; Sampling the current hot water set water temperature _Thr and the heat recovery heat exchanger outlet water temperature _Thr , and calculate the second temperature difference T _d2 :T _d2 =T _hr -T _h ; If the first temperature difference T _{d1 is} greater than the second temperature difference T _d2 _{, the rate of change ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side in the set sampling period is obtained, and the outlet water temperature of the heat recovery heat exchanger in the set sampling period is obtained rate of change ΔT _h; if ΔT _wi> ΔT _h, it is determined that the heating demand than hot water needs, perform hot defrost mode, if ΔT _wi <ΔT _h, it is determined that the hot water demand high For heating demand, perform the heating defrosting mode; if the first temperature difference T _{d1 is} less than the second temperature difference T _d2 _{, the rate of change ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side in the set sampling period is obtained _{And obtain the rate of change ΔT h} of the outlet water temperature of the heat recovery heat exchanger within the set sampling period; if ΔT _wi > ΔT _h , it is determined that the heating demand is higher than the hot water demand, and the hot water defrost mode is executed, if ΔT _wi <ΔT _h , it is determined that the hot water demand is higher than the heating demand, and the heating defrosting mode is executed.

_{Furthermore, obtaining the rate of change ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side during the _{set sampling period includes the following steps: Obtain the inlet water temperature T wi1} on the heat recovery heat exchanger side at the end of the set sampling period, so The end time of the set sampling period is the current time when it is determined that the defrosting operating conditions are met; the inlet water temperature T _wi2 on the heat recovery heat exchanger side at the start time of the set sampling period is obtained, and the heat recovery heat transfer in the set sampling period is calculated The rate of change of the inlet water temperature on the side of the device ΔT _wi ,

_{Furthermore, obtaining the rate of change ΔT h} of the outlet water temperature of the heat recovery heat exchanger within a set sampling period _{includes the following steps: obtaining the outlet water temperature T h1} on the heat recovery heat exchanger side at the end of the set sampling period, and the setting The end time of the sampling period is the current time when it is determined that the defrosting operating conditions are met; the outlet water temperature T _h2 on the heat recovery heat exchanger side at the start time of the set sampling period is obtained, and the inlet water temperature on the heat recovery heat exchanger side during the set sampling period is calculated. The rate of change of water temperature ΔT _h ,

Preferably, the duration of the set sampling period is 30 minutes.

Further, the defrosting operating conditions include: the continuous operating time is greater than or equal to a set operating period and the coil temperature of the outdoor heat exchanger is less than or equal to the set defrosting temperature, wherein the set operating period is greater than the set sampling period.

Another aspect of the present invention provides a total heat recovery defrosting control system, including: a defrosting determination module, which is used to determine whether the current operating conditions meet the defrosting operating conditions in the heating mode or the hot water mode; Module, which is used to compare heating demand and hot water demand; and execution module, which is used to execute the hot water defrost mode when the heating demand is higher than the hot water demand, and when the hot water demand is higher than the heating demand, Perform heating and defrosting mode.

Another aspect of the present invention provides an air conditioning device, the air conditioning device is a total heat recovery unit, which adopts a total heat recovery defrosting control method, and the total heat recovery defrosting control method includes the following steps: operating in heating mode or In hot water mode; judge whether the current operating conditions meet the defrost operating conditions; if the current operating conditions meet the defrost operating conditions, compare the heating demand with the hot water demand; if the heating demand is higher than the hot water demand, execute Hot water defrost mode; if the hot water demand is higher than the heating demand, the heating defrost mode is executed.

Compared with the prior art, the advantages and positive effects of the present invention are: by comparing the total heat recovery unit's heat demand for air-conditioning heating and hot water production, selecting a heat exchanger with a small heat demand for defrosting, avoiding operating mode The heat exchanger loses a lot of heat, thereby reducing the impact on the user experience and ensuring the user’s heating demand or hot water demand.

After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become clearer.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. A person of ordinary skill in the art can obtain other drawings based on these drawings without creative work.

Fig. 1 is a flowchart of an embodiment of the total heat recovery defrost control method disclosed in the present invention;

Figure 2 is a flowchart of the first alternative method for comparing heating demand and hot water demand;

Figure 3 is a flowchart of the second alternative method of comparing heating demand and hot water demand;

Figure 4 is a flowchart of a third alternative method for comparing heating demand and hot water demand;

Fig. 5 is a schematic block diagram of the structure of an embodiment of the total hot defrost control system disclosed in the present invention.

detailed description

In order to make the objectives, technical solutions and advantages of the present invention clearer, the following will further describe the present invention in detail with reference to the accompanying drawings and embodiments.

The terms "first", "second", "third", etc. in the specification and claims of the present invention and the drawings are used to distinguish different objects, rather than to describe a specific sequence. In addition, the terms "including" and "having" and any variations of them represent non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes unlisted steps or units, or optionally also includes Other steps or units inherent in these processes, methods, products or equipment.

In the present invention, "embodiment" means that a specific feature, structure, or characteristic described in conjunction with the embodiment can be included in at least one embodiment of the present application. In the specification, the appearance of the phrase in various positions does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art can understand that the embodiments described herein can be combined with other embodiments.

First, the total heat recovery unit is introduced. The total heat recovery unit can work in cooling mode, heating mode or hot water mode. It is necessary to defrost the outdoor heat exchanger in heating mode or hot water mode.

In the hot water mode, the low-temperature and low-pressure refrigerant vapor is compressed by the compressor into high-temperature and high-pressure superheated steam, which drives the corresponding valve group in the refrigeration cycle pipeline to open, and the high-temperature and high-pressure superheated steam flows to the heat recovery heat exchanger, and heat recovery Medium heat exchange on the heat exchanger side. The medium on the heat recovery heat exchanger side is usually the water in the water tank, so that the water in the water tank is heated to the set water temperature. At the same time, the high-temperature and high-pressure superheated steam is condensed into a medium-temperature and high-pressure liquid in the heat recovery heat exchanger, which further guides the refrigerator to flow to the accumulator, then passes through the filter, and then flows through the electronic expansion valve to be converted into a low-temperature and low-pressure liquid. The liquid further flows into the outdoor finned tube heat exchanger through the corresponding refrigerant pipeline, and the outdoor fan is turned on to exchange heat with the outdoor air. The low-temperature and low-pressure liquid evaporates into low-temperature and low-pressure gas, which flows to the compressor through the four-way reversing valve, completing the entire refrigeration cycle of the hot water mode.

In the heating mode, the low-temperature and low-pressure refrigerant vapor is compressed by the compressor into high-temperature and high-pressure superheated steam, which drives the corresponding valve group to open. The high-temperature and high-pressure superheated steam flows to the indoor water-side heat exchanger through the four-way reversing valve. It exchanges heat with the air-conditioning water to heat the air-conditioning water to the heating set temperature. At the same time, the high temperature and high pressure superheated steam condenses into a medium temperature and high pressure liquid. The medium-temperature and high-pressure liquid then passes through the refrigerant pipeline, filter, and electronic expansion valve to become a low-temperature and low-pressure liquid. The low-temperature and low-pressure liquid further flows into the outdoor fin-tube heat exchanger through the corresponding refrigerant pipeline, and the outdoor fan is turned on and Outdoor air heat exchange. The low-temperature and low-pressure liquid evaporates into low-temperature and low-pressure gas, which flows to the compressor through the four-way reversing valve, completing the entire refrigeration cycle.

The following describes the total heat recovery defrosting control method with reference to the drawings. Specifically, as shown in FIG. 1, it includes the following steps.

In step S101, the total heat recovery unit operates in heating mode or hot water mode. When the total heat recovery unit works in winter, it can automatically work in heating mode or hot water mode in time sharing, or automatically work in heating mode or hot water mode according to the heat load or hot water demand of the air-conditioned room.

In step S102, it is judged whether the current operating condition meets the defrosting operating condition. When frost is formed, the increase of the frost layer causes the thermal resistance of the outdoor finned tube heat exchanger to increase, which makes the heat exchange gradually decrease. When the frost layer increases to a certain thickness, the heat exchange rate drops rapidly, corresponding to the evaporating pressure and evaporating temperature of the unit to begin to drop at an accelerated rate. Therefore, according to the characteristics of the temperature and pressure changes of the coil, the dual factors of temperature and time can be used to determine whether the defrosting operating conditions are met. For example, the defrosting operating condition can be set as: the continuous operating time is greater than or equal to the set operating period, and the coil temperature of the outdoor fin and tube heat exchanger is less than or equal to the set defrosting temperature. Optionally, the set operating period can be set to 45 minutes, and the set defrost temperature can be set from -8°C to -5°C. In addition to the temperature and time dual-factor judgment conditions, the defrosting operating conditions can also be set as the pressure and time dual-factor judgment conditions. The defrost operation conditions can also be set to other defrost determination conditions used in the prior art.

In step S103, if the current operating conditions meet the defrosting operating conditions, the heating demand and the hot water demand are compared. Heating demand refers to heating the medium, such as air-conditioning water, to the heating set temperature and maintaining the required heat. Hot water demand refers to heating the water in the water tank to the set hot water temperature and maintaining the required heat The heat.

In step S104-1, if the heating demand is higher than the hot water demand, the hot water defrosting mode is executed, that is, the control target of the heating mode is preferably met and the heat exchange of the heat recovery heat exchanger is used to achieve the defrosting effect. In the hot water defrosting mode, the four-way valve is used to change the direction, and the high-temperature and high-pressure refrigerant vapor discharged from the compressor enters the outdoor fin-and-tube heat exchanger. In an outdoor fin-and-tube heat exchanger, high-temperature and high-pressure refrigerant vapor releases heat to the surrounding environment to melt the frost layer. The high-temperature and high-pressure refrigerant vapor releases heat and condenses into a medium-temperature refrigerant liquid, which is further subcooled through refrigerant pipelines, accumulators, economizers, etc., and passes through throttling mechanisms, such as electronic expansion valves, to become low-temperature and low-pressure refrigerants Liquid, low-temperature and low-pressure refrigerant liquid enters the heat recovery heat exchanger, exchanges heat with the water in the water tank, separates gas and liquid, and enters the compressor again for compression, thereby completing a refrigeration cycle in the hot water defrost mode. In this process, the operation of the heating mode with priority guarantee is less affected, and the user experience can be ensured to the greatest extent.

In step S104-2, if the hot water demand is higher than the heating demand, the heating defrosting mode is executed, that is, the control target of the hot water mode is preferably met and the heat exchange of the indoor water-side heat exchanger is used to achieve the defrosting effect. In the heating and defrosting mode, the four-way valve is used to change the direction, and the high-temperature and high-pressure refrigerant vapor discharged from the compressor enters the outdoor fin-and-tube heat exchanger. In an outdoor fin-and-tube heat exchanger, high-temperature and high-pressure refrigerant vapor releases heat to the surrounding environment to melt the frost layer. The high-temperature and high-pressure refrigerant vapor releases heat and condenses into a medium-temperature refrigerant liquid, which is further subcooled through refrigerant pipelines, accumulators, economizers, etc., and passes through throttling mechanisms, such as electronic expansion valves, to become low-temperature and low-pressure refrigerants Liquid, low-temperature and low-pressure refrigerant liquid enters the indoor water-side heat exchanger, exchanges heat with air-conditioning water and other media, and then separates gas and liquid, and enters the compressor again for compression, thereby completing a refrigeration cycle in the heating and defrosting mode . In this process, the hot water mode operation with priority guarantee has little impact and can ensure the user's use experience to the greatest extent.

The above-mentioned total heat recovery defrost control method compares the heat demand of the total heat recovery unit for air-conditioning heating and hot water production, and selects a heat exchanger with a small heat demand for defrosting, avoiding a large amount of heat in the heat exchanger in operation mode Loss, thereby reducing the impact on the user experience and ensuring the user’s heating demand or hot water demand.

Combining the structural characteristics of the total heat recovery unit and referring to Figure 2, the heating demand and hot water demand can be compared in the following way.

Step S201, the sampled current set heating water temperature T _r and a heat recovery heat exchanger side T _wi. Wherein the current set heating temperature T _r can be set user-set temperature, the temperature may be corrected in accordance with the user-set temperature value is corrected by an algorithm stored, the unit may also be made before delivery The written control algorithm is automatically generated according to the environmental parameters. Specifically, the heating temperature T _r may represent the set, air-conditioned room in order to achieve the environmental parameters to achieve the desired air-conditioning target temperature of water in the heating mode. Since the inlet water temperature in the entire total heat recovery unit can be considered the same, and the inlet water temperature T _wi on the heat recovery heat exchanger side can be detected by the temperature sensor provided at the water tank inlet, the detection is relatively convenient. Therefore, the inlet water temperature T _wi on the side of the heat recovery heat exchanger represents the current actual temperature of the air-conditioning water.

Step S202: Calculate the first temperature difference T _d1 : T _d1 =T _r -T _wi . Through the first temperature difference, the difference between the real-time temperature and the target temperature in the heating mode can be obtained, that is, the thermal load that needs to be adjusted in the heating mode.

Step S203, sampling the current hot water set water temperature _Thr _{and the outlet water temperature Th} on the heat recovery heat exchanger side. Similarly, the current hot water set temperature _Thr can also be the set temperature set by the user, or it can be the corrected temperature corrected by the stored algorithm according to the temperature set by the user, or it can be set by the unit. The temperature generated by the control algorithm written before leaving the factory according to the environmental parameters. Specifically, the hot water set water temperature _Thr is the target water temperature at which the user needs to use hot water, and the outlet water temperature _Th on the heat recovery heat exchanger side is the available water temperature in the current state. _{The outlet water temperature Th} on the side of the heat recovery heat exchanger can be detected by a temperature sensor arranged at the water outlet of the water tank.

Step S204: Calculate the second temperature difference T _d2 : T _d2 =T _hr -T _h . Through the second temperature difference, the difference between the real-time water temperature and the target water temperature in the hot water mode can be obtained, that is, the heat load that needs to be adjusted in the hot water mode.

Step S205-1, if the first temperature difference T _{d1 is} greater than the second temperature difference T _d2 , that is, the heating load that needs to be adjusted in the heating mode is higher than the heating load that needs to be adjusted in the hot water mode, it is further determined as the heating demand If it is higher than the hot water demand, select the heat exchanger with less impact for defrost operation, that is, execute hot water defrost mode.

Step S205-2, if the first temperature difference T _{d1 is} smaller than the second temperature difference T _d2 , that is, the heat load that needs to be adjusted in the hot water mode is higher than the heat load that needs to be adjusted in the heating mode, it is further determined as the hot water demand If it is higher than the heating demand, the heat exchanger with low impact is also selected for defrosting operation, that is, the heating and defrosting mode is executed.

Referring to Figure 3, heating demand and hot water demand can also be compared in the following way.

_{Step S301: Obtain the change rate ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side in the set sampling period.

Specifically, the rate of change of the inlet water temperature of the water tank on the heat recovery heat exchanger side within the set sampling period represents the temperature change of the water inlet of the water tank on the heat recovery heat exchanger side during a normal operation period. In the actual operation process, the water circulation in the total heat recovery unit is fast, and the temperature change of the water tank inlet on the side of the heat recovery heat exchanger will also accelerate; the water circulation in the total heat recovery unit is slow, and the heat recovery heat exchanger The temperature change of the water inlet of the water tank on the side will also be slowed down accordingly. Therefore, the temperature change of the water tank inlet on the heat recovery heat exchanger side represents the state of the water circulation in the total heat recovery unit, which is further dynamically reflected in the heating demand during the normal operating time before the defrost operating conditions are met.

_{Obtaining the rate of change ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side within the set sampling period can be achieved through the following steps:

_{Obtain the inlet water temperature T wi1} of the heat recovery heat exchanger at the end time of the set sampling period, and set the end time of the sampling period as the current time when it is determined that the defrosting operation condition is satisfied.

The unit pre-stores the length of the set sampling period and the inlet water temperature of the heat recovery heat exchanger at each set sampling point, and further obtains the heat recovery heat transfer at the start time of the set sampling period according to the set sampling period time _{The inlet water temperature T wi2} on the side of the device,

_{Calculate the change rate ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side during the set sampling period,

_{Step S302: Obtain the change rate ΔT h} of the outlet water temperature on the heat recovery heat exchanger side within the set sampling period.

Specifically, the change rate of the outlet water temperature of the water tank on the heat recovery heat exchanger side within the set sampling period represents the temperature change of the water outlet of the water tank on the heat recovery heat exchanger side during a normal operation period. In the actual operation process, if the user uses more hot water, the temperature change at the outlet of the water tank on the heat recovery heat exchanger side will also accelerate; if the user uses less water, the temperature change at the outlet of the water tank on the heat recovery heat exchanger side It will also slow down. Therefore, the temperature change of the water tank inlet on the heat recovery heat exchanger side represents the amount of hot water used by the user, which is further dynamically reflected in the hot water demand during the normal operating period before the defrost operating conditions are met.

_{Obtaining the change rate ΔT h} of the outlet water temperature on the heat recovery heat exchanger side during the set sampling period can be achieved through the following steps:

_{Obtain the outlet water temperature T h1} of the heat recovery heat exchanger at the end time of the set sampling period, and set the end time of the sampling period as the current time when it is determined that the defrost operation condition is satisfied;

The unit pre-stores the duration of the set sampling period and the outlet water temperature on the heat recovery heat exchanger side of each sampling point, and further obtains the outlet water on the heat recovery heat exchanger side at the beginning of the set sampling period according to the duration of the set sampling period Temperature T _h2 ,

_{Calculate the change rate ΔT h} of the outlet water temperature on the heat recovery heat exchanger side during the set sampling period,

In step S303-1, if ΔT _wi > ΔT _h , it is determined that the heating demand is higher than the hot water demand, and the hot water defrosting mode is executed.

In step S303-2, if ΔT _wi <ΔT _h , it is determined that the hot water demand is higher than the heating demand, and the heating defrosting mode is executed.

In the above two embodiments, the method in Figure 2 provides a way to compare and determine the heating demand and the hot water demand based on static parameters, such as the current heating set temperature and the current hot water set temperature, as shown in Figure 3. It provides a way to compare and determine the heating demand and hot water demand through dynamic parameters, such as the rate of change of the inlet water temperature and the rate of change of the outlet water temperature. In order to improve the accuracy of the judgment, as shown in Figure 4, a method for judging heating demand and hot water demand is also provided, which combines static and dynamic parameters. Specifically, it includes the following steps:

Step S401, the sampled current set heating temperature T _r and the inlet side temperature of the heat recovery heat exchanger tank T _wi, and calculates a first temperature difference calculating a first temperature difference _{_{_{T d1: T d1 = T r}}} -T wi;

Step S402, sampling the current hot water set water temperature _Thr _{and the outlet water temperature Th} on the heat recovery heat exchanger side, and calculating the second temperature difference T _d2 : T _d2 = T _hr -T _h ;

Step S403-1, if the first temperature difference T _{d1 is} greater than the second temperature difference T _d2 _{, obtain the change rate ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side in the set sampling period and obtain the heat in the set sampling period _{The rate of change ΔT h} of the outlet water temperature on the side of the recovery heat exchanger.

In step S404-1, if ΔT _wi > ΔT _h , it is determined that the heating demand is higher than the hot water demand, and the hot water defrosting mode is executed.

In step S404-2, if ΔT _wi <ΔT _h , take the user's dynamic usage as the priority, determine that the hot water demand is higher than the heating demand, and execute the heating defrosting mode.

Step S403-2, if the first temperature difference T _{d1 is} smaller than the second temperature difference T _d2 _{, obtain the change rate ΔT wi} of the inlet water temperature on the heat recovery heat exchanger side in the set sampling period and obtain the heat in the set sampling period _{The rate of change ΔT h} of the outlet water temperature on the side of the recovery heat exchanger.

In step S404-3, if ΔT _wi > ΔT _h , take the user's dynamic usage as a priority, determine that the heating demand is higher than the hot water demand, and execute the hot water defrosting mode.

In step S404-4, if ΔT _wi <ΔT _h , it is determined that the hot water demand is higher than the heating demand, and the heating defrosting mode is executed.

In the above three judgment methods, it is preferable to set the duration of the sampling period to 30 minutes. If the time and temperature dual factor is used as the defrosting operating condition, or the time pressure dual factor is used as the defrosting operating condition, the set operating period is preferably set to be greater than the set sampling period to ensure that the rate of change of water temperature can be dynamically determined Complete sampling and an accurate use cycle make the judgment result more accurate.

After the defrost is completed, the coil temperature and pressure of the outdoor heat exchanger will rise. When it rises to a certain value, it is determined that the conditions for exiting the defrost mode are met, and the operation in the heating mode or hot water mode is resumed.

Referring to Figure 5, a total heat recovery defrosting control system is provided. As shown in Fig. 5, the total heat recovery defrost control system 10 includes the following components.

The defrost determination module 101 is used to determine whether the current operating conditions meet the defrost operating conditions in the heating mode or the hot water mode.

For example, the defrosting operating condition can be set as: the continuous operating time is greater than or equal to the set operating period, and the coil temperature of the outdoor fin and tube heat exchanger is less than or equal to the set defrosting temperature. Optionally, the set operating period can be set to 45 minutes, and the set defrost temperature can be set from -8°C to -5°C. In addition to the temperature and time dual-factor judgment conditions, the defrost operating conditions can also be set as the pressure and time dual-factor judgment conditions. The defrost operation conditions can also be set to other defrost determination conditions used in the prior art.

The comparison module 102 is used to compare the heating demand and the hot water demand after the defrost determination module determines that the defrost operation condition is satisfied. Among them, the heating demand refers to heating the medium, such as air-conditioning water, to the set heating temperature and maintaining the required heat, and the hot water demand refers to heating the water in the water tank to the set water temperature and maintaining the required heat The heat.

The execution module 103 is configured to execute the hot water defrosting mode when the heating demand is higher than the hot water demand, and execute the heating defrosting mode when the hot water demand is higher than the heating demand.

The invention also provides an air conditioning device. The air conditioning device is a total heat recovery unit. The total heat recovery unit adopts the total heat recovery defrost control method. For the specific steps of the total heat recovery defrost control method, please refer to the detailed description of any of the foregoing embodiments, and will not be repeated here. The air conditioning device adopting the total heat recovery defrosting control method can achieve the same technical effect.

An embodiment of the present application also provides a computer storage medium, wherein the computer storage medium is stored in a computer program for electronic data exchange, and the computer program causes the air conditioning device to perform part or all of the steps of any method described in the above method embodiment .

In the above-mentioned embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in an embodiment, reference may be made to related descriptions of other embodiments.

In the several embodiments provided in this application, it should be understood that the disclosed device may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the above-mentioned units or modules is only a logical function division. In actual implementation, there may be other division methods, for example, multiple units or components may be combined or It can be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical or other forms.

The units described above as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, they may be located in one physical space, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

In addition, the functional units in the various embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or software functional unit.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, for those of ordinary skill in the art, the technical solutions of the foregoing embodiments can still be described. The recorded technical solutions are modified, or some of the technical features are equivalently replaced; these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

The total heat recovery defrost control method is characterized in that it comprises the following steps:

Run in heating mode or hot water mode;

Judge whether the current operating conditions meet the defrost operating conditions;

If the current operating conditions meet the defrosting operating conditions, compare the heating demand with the hot water demand;

If the heating demand is higher than the hot water demand, the hot water defrosting mode is executed; if the hot water demand is higher than the heating demand, the heating defrosting mode is executed.
The total heat recovery defrost control method according to claim 1, wherein:

Perform the following steps when comparing heating demand and hot water demand:

Sampling the current water temperature set heating temperature T r and a heat recovery heat exchanger side, T wi;

Calculate the first temperature difference T d1 : T d1 =T r -T wi ;

Sampling the active set hot water temperature and the water temperature T hr heat recovery heat exchanger side T h;

Calculate the second temperature difference T d2 : T d2 =T hr -T h ;

If the first temperature difference T d1 is greater than the second temperature difference T d2 , it is determined that the heating demand is higher than the hot water demand, and the hot water defrosting mode is executed;

If the first temperature difference T d1 is smaller than the second temperature difference T d2 , it is determined that the hot water demand is higher than the heating demand, and the heating and defrosting mode is executed.
The total heat recovery defrost control method according to claim 1, wherein:

Perform the following steps when comparing heating demand and hot water demand:

Obtain the change rate ΔT wi of the inlet water temperature on the heat recovery heat exchanger side within the set sampling period;

Obtain the change rate ΔT h of the outlet water temperature on the heat recovery heat exchanger side within the set sampling period;

If ΔT wi > ΔT h , it is determined that the heating demand is higher than the hot water demand, and the hot water defrosting mode is executed;

If ΔT wi <ΔT h , it is determined that the hot water demand is higher than the heating demand, and the heating defrosting mode is executed.
The total heat recovery defrost control method according to claim 1, wherein:

Perform the following steps when comparing heating demand and hot water demand:

Sampling the current water temperature set heating temperature T r and a heat recovery heat exchanger side T wi, calculating a first temperature difference T d1: T d1 = T r -T wi;

Sampling the active set hot water temperature and the water temperature T hr heat recovery heat exchanger T h, and calculates the second temperature difference T d2: T d2 = T hr -T h;

If the first temperature difference T d1 is greater than the second temperature difference T d2 , the rate of change ΔT wi of the inlet water temperature on the side of the heat recovery heat exchanger in the set sampling period is obtained, and the heat recovery heat exchanger's rate of change in the set sampling period is obtained. The rate of change of the outlet water temperature ΔT h ; if ΔT wi >ΔT h , it is determined that the heating demand is higher than the hot water demand, and the hot water defrost mode is executed. If ΔT wi <ΔT h , it is determined to be the hot water The demand is higher than the heating demand, and the heating and defrosting mode is implemented;

If the first temperature difference T d1 is smaller than the second temperature difference T d2 , the rate of change ΔT wi of the inlet water temperature on the heat recovery heat exchanger side in the set sampling period is obtained, and the heat recovery heat exchanger's temperature in the set sampling period is obtained. The rate of change of the outlet water temperature ΔT h ; if ΔT wi >ΔT h , it is determined that the heating demand is higher than the hot water demand, and the hot water defrost mode is executed. If ΔT wi <ΔT h , it is determined to be the hot water The demand is higher than the heating demand, and the heating and defrosting mode is implemented.
The total heat recovery defrost control method according to claim 3 or 4, wherein:

Obtaining the change rate ΔT wi of the inlet water temperature on the heat recovery heat exchanger side within a set sampling period includes the following steps:

Acquiring the inlet water temperature T wi1 on the heat recovery heat exchanger side at the end time of the set sampling period, where the end time of the set sampling period is the current time when it is determined that the defrost operation condition is satisfied;

Obtain the inlet water temperature T wi2 on the heat recovery heat exchanger side at the beginning of the set sampling period,

Calculate the change rate ΔT wi of the inlet water temperature on the heat recovery heat exchanger side during the set sampling period,
The total heat recovery defrost control method according to claim 5, characterized in that:

Obtaining the change rate ΔT h of the outlet water temperature of the heat recovery heat exchanger within a set sampling period includes the following steps:

Acquiring the outlet water temperature T h1 on the heat recovery heat exchanger side at the end time of the set sampling period, where the end time of the set sampling period is the current time when it is determined that the defrost operation condition is satisfied;

Obtain the outlet water temperature T h2 on the heat recovery heat exchanger side at the beginning of the set sampling period,

Calculate the change rate ΔT h of the inlet water temperature on the heat recovery heat exchanger side during the set sampling period,
The total heat recovery defrost control method according to claim 6, characterized in that:

The duration of the set sampling period is 30 minutes.
The total heat recovery defrost control method according to claim 6, characterized in that:

The defrost operating conditions include:

The continuous operating time is greater than or equal to the set operating period and the coil temperature of the outdoor heat exchanger is less than or equal to the set defrosting temperature, wherein the set operating period is greater than the set sampling period.
The total heat recovery defrosting control system is characterized in that it includes:

The defrost determination module is used to determine whether the current operating conditions meet the defrost operating conditions in the heating mode or the hot water mode;

Comparison module, which is used to compare heating demand and hot water demand; and

The execution module is used to execute the hot water defrosting mode when the heating demand is higher than the hot water demand, and execute the heating defrosting mode when the hot water demand is higher than the heating demand.
An air conditioning device, which is a total heat recovery unit, characterized in that the total heat recovery defrost control method according to any one of claims 1 to 9 is adopted