A dual cold source fresh air treatment system and control method

Abstract

The application discloses a double-cold-source fresh air treatment system and a control method. The system comprises a heat pump air conditioner system, a pulsating heat pipe heat recovery system and a heat pump-heat pipe heat exchanger connecting structure. The heat pump air conditioner system comprises a compressor, an indoor heat exchanger, a throttling device, an outdoor heat exchanger and a four-way reversing valve. The pulsating heat pipe heat recovery system comprises a fresh air duct, an exhaust air duct and a heat pipe flat tube. The heat pipe flat tube is divided into three sections. The first bypass valve of the heat pump-heat pipe connecting structure is located between the throttling device and the indoor heat exchanger, and the second bypass valve is located between the indoor heat exchanger and the compressor. The two ends of the branch flat tube are respectively communicated with two heat pipe copper pipe adapters. A part of the branch flat tube and a part of the heat pipe fresh air side flat tube are arranged in a heat exchange container to perform heat exchange. The air source heat pump air conditioner unit is coupled with the heat pipe fresh air heat recovery unit, the branch of the heat pump is used to assist the fresh air system under a large heat load, and the comfort and energy saving effect are improved.

Description

Technical Field

[0001] This invention relates to a dual-cold-source fresh air treatment system and its control method. Background Technology

[0002] Currently, building energy consumption accounts for approximately 27.5% of my country's total end-use energy consumption. With the further development of urbanization in my country, the total number of buildings will continue to increase, and both the total energy consumption of buildings and their proportion of total social energy consumption will continue to rise. Simultaneously, the focus of building consumption will shift from "hardware" (decoration and durable consumer goods) to "software" (functionality and environmental quality) consumption. Therefore, the energy consumption required to ensure indoor air quality (air conditioning, ventilation, heating, and hot water supply) will rise rapidly. Air conditioning accounts for a major proportion of building energy consumption, approximately two-thirds. Air conditioning is an indispensable means of indoor environmental regulation in modern buildings, providing a comfortable and efficient environment for people's production and life, while consuming a large amount of electricity. To reduce air conditioning energy consumption while meeting people's requirements for thermal and humidity environments, pollutant concentrations, and CO2 concentrations, more and more buildings are adopting heat recovery fresh air units.

[0003] Fresh air heat recovery units typically use sensible heat or total heat recovery devices as their core. They employ forced convection of fresh and exhaust air via a fan to recover energy from the exhaust air. Total heat recovery devices usually utilize polymer membranes or paper core structures, achieving moisture recovery when a water vapor partial pressure difference exists between the two ends. This results in high heat recovery efficiency, but moisture recovery is delayed, and after a period of operation, the humid environment can easily breed bacteria, contaminating the fresh air. Intermediate refrigerant heat recovery units use an intermediate refrigerant circulating between two heat recovery units, preventing cross-contamination and not being limited by distance. However, due to the thermal resistance of the intermediate medium, their thermal efficiency is lower. Rotary heat recovery units convert energy by having exhaust and fresh air flow in opposite directions during the rotation of a wheel. This method is highly efficient and has a self-cleaning function, but the unit occupies a large area, has transmission equipment, consumes power, and cannot avoid cross-contamination.

[0004] Heat pipe heat recovery machines utilize the phase change of the working fluid for heat transfer. Heat pipes are highly efficient heat transfer elements, with thermal conductivity hundreds of times higher than that of metals. They also feature good temperature uniformity, adjustable heat flux density, and reversible heat transfer direction. Heat pipe heat exchangers are easy to install, have a long service life, and simple air inlet and outlet separation, making them ideal energy-saving products for air conditioning, ventilation, waste heat recovery, and solar energy absorption.

[0005] Simple heat pipe heat recovery systems cannot effectively heat or cool the fresh air to near the indoor temperature when there is a large temperature difference between indoors and outdoors or when a large amount of fresh air is required. If the fresh air system is turned on in this case, it will put a huge load on the indoor temperature and humidity environment and affect comfort.

[0006] Heat pipe heat recovery systems are generally large in size. They use gravity heat pipes, which require the condenser section to be higher than the evaporator section. They are highly susceptible to installation angle and vibration. When used as heat recovery units, the installation direction needs to be reversed in winter and summer, making them relatively complex to use. Summary of the Invention

[0007] In view of this, the present invention provides a dual-cold-source fresh air handling system that couples an air source heat pump air conditioner unit with a heat pipe fresh air heat recovery unit, using dual cold (heat) sources: the waste heat of the exhaust air and the auxiliary heat of the heat pump system. Under a large heat load, the heat pump branch is used to assist the fresh air system, thereby improving comfort and energy saving effect.

[0008] To address the aforementioned problems, according to one aspect of this application, an embodiment of the present invention provides a dual-cold-source fresh air handling system, comprising: a heat pump air conditioning system, a pulsed heat pipe heat recovery system, and a heat pump-heat pipe heat exchanger connection structure;

[0009] The heat pump air conditioning system includes: a compressor, an indoor heat exchanger, a throttling device, an outdoor heat exchanger, and a four-way reversing valve. The components are connected in sequence by pipes, and the refrigerant circulates internally.

[0010] The pulsed heat pipe heat recovery system includes: a fresh air duct, an exhaust air duct, and a heat pipe flat tube; the heat pipe flat tube passes through the fresh air duct and the exhaust air duct, the fresh air duct includes a fresh air inlet, a fresh air outlet, and a fresh air fan; the exhaust air duct includes an exhaust air inlet, an exhaust air outlet, and an exhaust fan; the heat pipe flat tube is divided into three sections: a heat pipe fresh air side flat tube, a heat pipe insulation section flat tube, and a heat pipe exhaust side flat tube, with the heat pipe insulation section flat tube located between the fresh air duct and the exhaust air duct;

[0011] The heat pump-heat pipe connection structure includes a first bypass valve, a second bypass valve, a branch flat tube, a heat exchange container, and a flat tube copper tube adapter.

[0012] The first bypass valve is located between the throttling device and the indoor heat exchanger, and the second bypass valve is located between the indoor heat exchanger and the compressor. The first bypass valve is connected to a flat copper tube adapter, and the second bypass valve is connected to another flat copper tube adapter. Both ends of the branch flat tube are connected to the two flat copper tube adapters respectively. A portion of the branch flat tube and a portion of the heat pipe fresh air side flat tube are placed in the heat exchange container for heat exchange.

[0013] In some embodiments, the branch flat tube is bent into a U-shaped structure, and the heat pipe fresh air side flat tube is also bent into a U-shaped structure in the heat exchange container. A branch flat tube U-shaped structure is inserted between the U-shaped structures of two adjacent heat pipe fresh air side flat tubes, and the U-shaped structure of the heat pipe fresh air side flat tube is in contact and fixed with the adjacent branch flat tube U-shaped structure.

[0014] In some embodiments, a filter device is provided in the fresh air duct, which is located between the fresh air inlet and the heat pipe fresh air side flat pipe, and is used to remove foreign dust from the air.

[0015] In some embodiments, fins are provided on the outer side of the heat pipe exhaust side flat pipe and the outer side of the portion of the heat pipe fresh air side flat pipe that does not extend into the heat exchange container, and the ratio of the coverage width of the fins on the heat pipe fresh air side flat pipe to the total width of the heat pipe fresh air side flat pipe is 0.6-0.8.

[0016] In some embodiments, the heat exchange container is located inside the fresh air duct, and a guide plate is provided inside the fresh air duct. The guide plate has guide holes, and the guide holes corresponding to the heat exchange container are provided with louver structures to guide the airflow to the fin portion on the outside of the heat pipe fresh air side flat tube.

[0017] In some embodiments, the heat pipe insulation section flat tube is wrapped with polyurethane insulation material.

[0018] In some embodiments, the heat exchange container contains a liquid, such as ethanol, to enhance heat exchange and its uniformity.

[0019] In some embodiments, the flat tube copper tube adapter includes a liquid distribution chamber, which is provided with a copper tube connection port and a branch flat tube connection port. The copper tube connection port is connected to a first bypass valve and a second bypass valve through pipes, and the branch flat tube connection port is connected to a branch flat tube.

[0020] In some embodiments, there are multiple branch flat tubes, one end of each branch flat tube is connected to a branch flat tube connection port on the liquid distribution chamber of two flat tube copper tube adapters, and the middle of each branch flat tube is bent to form a U-shaped structure.

[0021] In some embodiments, the number of branch flat tubes is one, and the two ends of the branch flat tube are respectively connected to a branch flat tube connection port on the liquid distribution chamber of two flat tube copper tube adapters. The middle part of the branch flat tube is bent to form multiple U-shaped structures.

[0022] According to another aspect of this application, embodiments of the present invention also provide a control method based on the above-described dual-cold-source fresh air handling system, which includes the following steps:

[0023] S101: Heat pump system starts, obtain indoor temperature T in Outdoor temperature T out To determine summer and winter operating conditions and indoor-outdoor temperature differences. To obtain carbon dioxide concentration. The indoor air quality is determined by the heat pump running time t1, and then proceeds to step S102.

[0024] S102: Comparison of carbon dioxide concentrations and setting carbon dioxide concentration Size and heat pump running time t1 and set running time t 01 The size, if Or t1>t 01 If the air quality is good, it means the air in the room is not fresh and the fresh air system needs to be activated. Proceed to step S103; otherwise, there is no need to introduce fresh air and return to step S101.

[0025] S103: The fresh air heat recovery system starts, turning on the fresh air fan and exhaust fan, and setting both to speed N. xin and N pai If both are equal to the set speed N0, proceed to step S104.

[0026] S104: Obtain the fresh air outlet temperature T in the fresh air duct. xin,out The exhaust inlet temperature T in the exhaust duct pai,in Proceed to step S105.

[0027] S105: Compare the fresh air outlet temperature T xin,out and exhaust inlet temperature T pai,in The absolute value of the difference and the magnitude of the set temperature difference ΔT1, if |T xin,out -T pai,in If |>ΔT1, it means that the energy recovered from the exhaust air is insufficient to bring the fresh air close to the room temperature, affecting comfort, and proceed to step S106; otherwise, the fresh air heat recovery system meets the requirements under this condition, and proceed to step S301.

[0028] S106: Reduce the speed of the fresh air fan by a set value ΔN, so that the fresh air volume decreases while the exhaust volume remains unchanged, so that the fresh air approaches the indoor temperature and ensures comfort, then proceed to S107.

[0029] S107: Compare the fresh air fan speed N xin With the set minimum speed value N min The size of N, if xin <N min The pressure cannot be reduced further, otherwise the pressure difference between the inside and outside of the room will be too large and affect comfort. Proceed to S201; otherwise, return to S105.

[0030] S201: Heat pump auxiliary system starts, bypass valve opens, opening degree K is the set initial value K1, and the refrigerant bypass branch inlet temperature T is obtained. pass,in Bypass branch outlet temperature T pass,out Proceed to step S202.

[0031] S202: Compare the inlet temperature T of the bypass branch. pass,in Temperature T at the outlet of the bypass branch pass,out The absolute value of the difference and the magnitude of the set temperature difference ΔT2, if |T pass,in-T pass,out If |>ΔT2, it indicates that the bypass flow is small, proceed to step S203; otherwise, proceed to step S204.

[0032] S203: Increase the bypass valve opening by a large amount of ΔK, then return to step S202.

[0033] S204: Compare the inlet temperature T of the bypass branch. pass,in Temperature T at the outlet of the bypass branch pass,out The absolute value of the difference and the magnitude of the set temperature difference ΔT3, if |T pass,in -T pass,out If |<ΔT2, it indicates that the bypass flow is large, proceed to step S205; otherwise, the bypass valve has been adjusted to a suitable opening, proceed to S301.

[0034] S205: Increase the bypass valve opening by a large amount of ΔK, then return to step S204.

[0035] S301: Maintain this fan speed and this bypass valve opening for a period of time, then proceed to step S302.

[0036] S302: Obtain the fan operating time t2 and carbon dioxide concentration. Proceed to step S303.

[0037] S303: Comparison of carbon dioxide concentrations and setting carbon dioxide concentration Size and fan running time t2 and set running time t 02 The size, if or t2>t 02 If the air quality meets the freshness standard, proceed to step S304; otherwise, return to step S301.

[0038] S304: Shut down the fan and bypass valve to end operation.

[0039] In the above control methods: setting the carbon dioxide concentration and The standard for judging whether room air is fresh is selected according to GB / T18883-2022 "Indoor Air Quality Standard". The human body is very sensitive to increases in atmospheric carbon dioxide; every 0.5% increase in carbon dioxide content will cause noticeable reactions. When no one is in the room, the carbon dioxide concentration is generally around 500 to 700 PPM. When the concentration reaches 1000 PPM, people will feel stuffy, have difficulty concentrating, and experience palpitations. When the concentration reaches 1500-2000 PPM, people will experience shortness of breath, headaches, and dizziness. Above 2000 PPM, cognitive abilities will significantly decline. Set to 1000 PPM. Set to 700 PPM.

[0040] Set heat pump running time t 01 And fan running time t 02 It is a standard to help determine whether the air in a room is fresh. 01 The fan running time is set to 1-2 hours, t. 02 Set the time to 20-30 minutes.

[0041] The fan setpoint speed N0 is the initial fan speed, determined by the air-side pressure drop, fan performance curve, and the air volume required by the occupants. The fan speed variation ΔN is an indicator for adjusting air volume to adapt to the heat load; the setpoint can be 20-50 r / min. The minimum setpoint speed N... min This is to prevent excessive differences in the volume of fresh air and exhaust air from causing excessive pressure difference between the inside and outside of the room, which would affect human comfort. The setting is based on the fan speed N0 and the air volume required by the people in the room.

[0042] Compared with the prior art, the dual-cold-source fresh air handling system of the present invention has at least the following beneficial effects:

[0043] (1) The present invention couples the air source heat pump air conditioner unit with the heat pipe fresh air heat recovery unit, and uses the heat pump branch to assist the fresh air system under a large heat load, thereby reducing the fresh air load and improving energy saving effect and human comfort.

[0044] (2) The heat pipe adopts a convenient heat recovery form: a new type of pulsating heat pipe made of microchannel flat tubes. It transfers heat by using the surface tension of the working fluid to form a gas-liquid plug. It is pump-free and capillary core-free, horizontally installed, and automatically switches the evaporation and condensation process according to the season. It does not require changing the installation angle, is easy to use, and reduces costs.

[0045] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a general diagram of the dual-cold-source fresh air handling system of the present invention;

[0048] Figure 2This is a three-dimensional structural diagram of the pulsating heat pipe section;

[0049] Figure 3 This is a structural diagram of one embodiment of a heat pump-heat pipe connection structure;

[0050] Figure 4 This is a structural diagram of another embodiment of the heat pump-heat pipe connection structure;

[0051] Figure 5 These are the front and top views of the air deflector;

[0052] Figure 6 This is a flowchart of the control method for a dual-cold-source fresh air handling system.

[0053] The attached figures are labeled as follows:

[0054] 1-Heat pump air conditioning system, 101-Compressor, 102-Indoor heat exchanger, 103-Throttling device, 104-Outdoor heat exchanger, 105-Four-way reversing valve.

[0055] 2-Pulsating heat pipe heat recovery system; 201-Filter device; 202-Baffle plate; 203-Fresh air fan; 204-Exhaust air fan; 205-Fresh air duct; 206-Exhaust air duct; 207-Heat pipe fresh air side flat tube; 208-Heat pipe insulation section flat tube; 209-Heat pipe exhaust side flat tube; 210-Fins; 211-Fresh air inlet; 212-Fresh air outlet; 213-Exhaust air inlet; 214-Exhaust air outlet.

[0056] 3-Heat pump-heat pipe heat exchanger connection structure, 301-Bypass valve, 302-Bypass valve, 303-Branch flat tube, 304-Heat exchange container, 305-Flat tube copper tube adapter.

[0057] 4. Testing and control devices. Detailed Implementation

[0058] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0059] In the description of this invention, it should be clearly stated that the terms "first," "second," etc., in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence; the terms "vertical," "lateral," "longitudinal," "front," "rear," "left," "right," "up," "down," "horizontal," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, and are merely for the convenience of describing this invention, and do not mean that the device or element referred to must have a specific orientation or position, and therefore should not be construed as a limitation of this invention.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] Example 1

[0062] This embodiment provides a dual-cold-source fresh air handling system. (See [link]) Figure 1 It includes: a heat pump air conditioning system 1, a pulsed heat pipe heat recovery system 2, a heat pump-heat pipe heat exchanger connection structure 3, and a testing and control device 4.

[0063] Specifically, see Figure 1 The heat pump air conditioning system 1 includes: a compressor 101, an indoor heat exchanger 102, a throttling device 103, an outdoor heat exchanger 104, and a four-way reversing valve 105. The components are connected in sequence through pipes, and the refrigerant circulates internally.

[0064] See Figure 1 and Figure 2 The pulsed heat pipe heat recovery system 2 includes: a fresh air duct 205, an exhaust air duct 206, and a heat pipe flat tube; the heat pipe flat tube passes through the fresh air duct 205 and the exhaust air duct 206. The fresh air duct 205 includes a fresh air inlet 211, a fresh air outlet 212, and a fresh air fan 203; the exhaust air duct 206 includes an exhaust air inlet 213, an exhaust air outlet 214, and an exhaust fan 204; the heat pipe flat tube is divided into three sections: a heat pipe fresh air side flat tube 207, a heat pipe insulation section flat tube 208, and a heat pipe exhaust side flat tube 209. The heat pipe insulation section flat tube 208 is located between the fresh air duct 205 and the exhaust air duct 206.

[0065] In some preferred embodiments, the fresh air duct 205 is further provided with a filter device 201 and a guide plate 202. The filter device 201 is located between the fresh air inlet 211 and the heat pipe fresh air side flat pipe 207, and is used to remove foreign dust in the air.

[0066] Outdoor fresh air enters the fresh air duct 205 through the fresh air inlet 211, and then passes through the filter 201 to remove foreign particles and dust, the guide plate 202, and the heat pipe fresh air side flat tube 207 for heat exchange. After being pressurized by the fresh air fan 203, it is delivered into the room through the fresh air outlet 212. Indoor exhaust air enters the exhaust duct 206 through the exhaust air inlet 213, recovers energy through the heat pipe exhaust side flat tube 209, and is then pressurized by the exhaust fan 204 before being discharged outdoors through the exhaust outlet 214. The heat pipe insulated section flat tube 208 is located between the two ducts and is wrapped with polyurethane insulation material.

[0067] Specifically, see Figure 1 The heat pump-heat pipe connection structure 3 includes a first bypass valve 301, a second bypass valve 302, a branch flat pipe 303, a heat exchange container 304, and a flat pipe copper pipe adapter 305. The first bypass valve 301 is located between the throttling device 103 and the indoor heat exchanger 102, and the second bypass valve 302 is located between the indoor heat exchanger 102 and the compressor 101. The first bypass valve 301 is connected to one flat pipe copper pipe adapter 305, and the second bypass valve 302 is connected to another flat pipe copper pipe adapter 305. Both ends of the branch flat pipe 303 are connected to the two flat pipe copper pipe adapters 305 respectively. A portion of the branch flat pipe 303 and a portion of the heat pipe fresh air side flat pipe 207 are placed in the heat exchange container 304 for heat exchange.

[0068] In some embodiments, see Figure 1 Fins 210 are provided on the outer side of the heat pipe exhaust side flat tube 209 and the outer side of the portion of the heat pipe fresh air side flat tube 207 that does not extend into the heat exchange container 304. The heat pipe fresh air side flat tube 207 can be divided into a heat pump auxiliary section and a finned heat exchange section. The width of the heat pipe fresh air side flat tube 207 should be the sum of the width covered by the fins 210 and the width of the heat exchange container 304 within the air duct.

[0069] In a preferred embodiment of the present invention, the ratio of the coverage width of the fins 210 on the heat pipe fresh air side flat tube 207 to the total width of the heat pipe fresh air side flat tube 207 is between 0.6 and 0.8. In areas with small indoor-outdoor temperature differences, the higher value of the range can be selected; in areas with large indoor-outdoor temperature differences, the lower value of the range can be selected, and more heat pump assistance can be used.

[0070] In a preferred embodiment of the present invention, the heat pipe fresh air side flat tube 207, the insulation section flat tube 208, and the exhaust side flat tube 209 are formed by bending a flat aluminum tube with microchannels inside, and are filled with working fluid. Preferably, the working fluid filling amount FR and the microchannel flat tube size should meet the following requirements:

[0071] FR=0.4~0.7*[(2*W1+(N-2)*W2)*H]*L

[0072] FR is the amount of working fluid filled, N is the number of microchannels in the flat tube, W1 and W2 are the widths of the microchannels on both sides and the middle of the flat tube, respectively, H is the height of the microchannels in the flat tube, and L is the total length of the flat tube.

[0073] Preferably, the physical properties of the working fluid and the dimensions of the microchannel flat tube should meet the following requirements:

[0074]

[0075] g is the acceleration due to gravity, which is 9.81 m / s². 2 π is the mathematical constant pi, which is 3.1415926…; σ is the surface tension coefficient of the working fluid, in N / m; ρ l and ρ v These are the liquid phase density and gas phase density of the working fluid, respectively, in kg / m³. 3 .

[0076] Specifically, see Figure 3 and Figure 4 The branch flat tube 303 is bent into a U-shaped structure, and the heat pipe fresh air side flat tube 207 is also bent into a U-shaped structure in the heat exchange container 304. A branch flat tube 303 U-shaped structure is inserted between the U-shaped structures of two adjacent heat pipe fresh air side flat tubes 207. The U-shaped structure of the heat pipe fresh air side flat tube (207) is fixed in contact with the U-shaped structure of the adjacent branch flat tube (303), for example, by welding.

[0077] In some embodiments of the present invention, the heat exchange container 304 is located within the fresh air duct 205, see [link / reference]. Figure 2 and Figure 5 The guide vane 202 consists of a louvered section with an opening angle on the left and a horizontal flow hole section on the right. The width of the louvered section is equal to the width of the heat exchange container 304 within the air duct. This directs the airflow to the right-side finned heat exchange section. The right-side horizontal flow hole ensures even and uniform airflow, enhancing heat exchange.

[0078] In this embodiment, during summer, the indoor heat exchanger 102 functions as an evaporator, with a portion of the refrigerant flowing sequentially through the first bypass valve 301, the flat copper tube adapter 305, and the branch flat tube 303, before returning through the second bypass valve 302. During winter, the indoor heat exchanger 102 functions as a condenser, with a portion of the refrigerant flowing sequentially through the second bypass valve 302, the flat copper tube adapter 305, and the branch flat tube 303, before returning through the first bypass valve 301. The branch flat tube 303 is welded to a portion of the flat tube on the heat pipe's fresh air side 207 and placed in the heat exchange container 304. During the transition between winter and summer, as the heat pump system reverses its operation, the heat pipe, as a passive heat exchange element, automatically reverses the operation of its evaporation and condensation sections without requiring a change in installation location.

[0079] In some embodiments of the present invention, the heat exchange container 304 contains a liquid, such as ethanol, to enhance heat exchange and its uniformity. The bending radius of the U-shaped structure of the branch flat tube 303 is equal to the spacing between the rows of the heat pipe fresh air side flat tubes 207.

[0080] In some embodiments of the present invention, see Figure 1 The flat tube copper tube adapter 305 includes a liquid distribution chamber, which is provided with a copper tube connection port and a branch flat tube connection port. The copper tube connection port is connected to the first bypass valve 301 and the second bypass valve 302 through pipes respectively, and the branch flat tube connection port is connected to the branch flat tube.

[0081] As a preferred embodiment of the present invention, see [link to previous document]. Figure 3 The number of branch flat tubes is multiple, and the multiple branch flat tubes are connected in parallel. One end of each branch flat tube is connected to a branch flat tube connection port on the liquid distribution chamber of two flat tube copper tube adapters 305. The middle of each branch flat tube is bent to form a U-shaped structure. A branch flat tube 303 U-shaped structure is inserted between the U-shaped structures of two adjacent heat pipe fresh air side flat tubes 207.

[0082] As a preferred embodiment of the present invention, see [link to previous document]. Figure 4 The number of branch flat tubes is one. The two ends of the branch flat tube are respectively connected to a branch flat tube connection port on the liquid distribution chamber of the two flat tube copper tube adapters 305. The middle part of the branch flat tube is bent to form multiple U-shaped structures. This structure is in series mode. A branch flat tube 303 U-shaped structure is inserted between the U-shaped structures of two adjacent heat pipe fresh air side flat tubes 207.

[0083] According to another aspect of this application, see Figure 6 The embodiments of the present invention also provide a control method based on the above-mentioned dual-cold-source fresh air handling system, which includes the following steps:

[0084] S101: Heat pump system starts, obtain indoor temperature T in Outdoor temperature T outTo determine summer and winter operating conditions and indoor-outdoor temperature differences. To obtain carbon dioxide concentration. The indoor air quality is determined by the heat pump running time t1, and then proceeds to step S102.

[0085] S102: Comparison of carbon dioxide concentrations and setting carbon dioxide concentration Size and heat pump running time t1 and set running time t 01 The size, if Or t1>t 01 If the air quality is good, it means the air in the room is not fresh and the fresh air system needs to be activated. Proceed to step S103; otherwise, there is no need to introduce fresh air and return to step S101.

[0086] S103: The fresh air heat recovery system starts, turning on the fresh air fan and exhaust fan, and setting both to speed N. xin and N pai If both are equal to the set speed N0, proceed to step S104.

[0087] S104: Obtain the fresh air outlet temperature T in the fresh air duct. xin,out The exhaust inlet temperature T in the exhaust duct pai,in Proceed to step S105.

[0088] S105: Compare the fresh air outlet temperature T xin,out and exhaust inlet temperature T pai,in The absolute value of the difference and the magnitude of the set temperature difference ΔT1, if |T xin,out -T pai,in If |>ΔT1, it means that the energy recovered from the exhaust air is insufficient to bring the fresh air close to the room temperature, affecting comfort, and proceed to step S106; otherwise, the fresh air heat recovery system meets the requirements under this condition, and proceed to step S301.

[0089] S106: Reduce the speed of the fresh air fan by a set value ΔN, so that the fresh air volume decreases while the exhaust volume remains unchanged, so that the fresh air approaches the indoor temperature and ensures comfort, then proceed to S107.

[0090] S107: Compare the fresh air fan speed N xin With the set minimum speed value N min The size of N, if xin <N min The pressure cannot be reduced further, otherwise the pressure difference between the inside and outside of the room will be too large and affect comfort. Proceed to S201; otherwise, return to S105.

[0091] S201: Heat pump auxiliary system starts, bypass valve opens, opening degree K is the set initial value K1, and the refrigerant bypass branch inlet temperature T is obtained. pass,in Bypass branch outlet temperature Tpass,out Proceed to step S202.

[0092] S202: Compare the inlet temperature T of the bypass branch. pass,in Temperature T at the outlet of the bypass branch pass,out The absolute value of the difference and the magnitude of the set temperature difference ΔT2, if |T pass,in -T pass,out If |>ΔT2, it indicates that the bypass flow is small, proceed to step S203; otherwise, proceed to step S204.

[0093] S203: Increase the bypass valve opening by a large amount of ΔK, then return to step S202.

[0094] S204: Compare the inlet temperature T of the bypass branch. pass,in Temperature T at the outlet of the bypass branch pass,out The absolute value of the difference and the magnitude of the set temperature difference ΔT3, if |T pass,in -T pass,out If |<ΔT2, it indicates that the bypass flow is large, proceed to step S205; otherwise, the bypass valve has been adjusted to a suitable opening, proceed to S301.

[0095] S205: Increase the bypass valve opening by a large amount of ΔK, then return to step S204.

[0096] S301: Maintain this fan speed and this bypass valve opening for a period of time, then proceed to step S302.

[0097] S302: Obtain the fan operating time t2 and carbon dioxide concentration. Proceed to step S303.

[0098] S303: Comparison of carbon dioxide concentrations and setting carbon dioxide concentration Size and fan running time t2 and set running time t 02 The size, if or t2>t 02 If the air quality meets the freshness standard, proceed to step S304; otherwise, return to step S301.

[0099] S304: Shut down the fan and bypass valve to end operation.

[0100] In the aforementioned control method: a carbon dioxide concentration is set. and The standard for judging whether room air is fresh is selected according to GB / T18883-2022 "Indoor Air Quality Standard". The human body is very sensitive to increases in atmospheric carbon dioxide; every 0.5% increase in carbon dioxide content will cause noticeable reactions. When no one is in the room, the carbon dioxide concentration is generally around 500 to 700 PPM. When the concentration reaches 1000 PPM, people will feel stuffy, have difficulty concentrating, and experience palpitations. When the concentration reaches 1500-2000 PPM, people will experience shortness of breath, headaches, and dizziness. Above 2000 PPM, cognitive abilities will significantly decline. Set to 1000 PPM. Set to 700 PPM.

[0101] Set heat pump running time t 01 And fan running time t 02 It is a standard to help determine whether the air in a room is fresh. 01 The fan running time is set to 1-2 hours, t. 02 Set the time to 20-30 minutes.

[0102] The fan setpoint speed N0 is the initial fan speed, determined by the air-side pressure drop, fan performance curve, and the air volume required by the occupants. The fan speed variation ΔN is an indicator for adjusting air volume to adapt to the heat load; the setpoint can be 20-50 r / min. The minimum setpoint speed N... min This is to prevent excessive differences in the volume of fresh air and exhaust air from causing excessive pressure difference between the inside and outside of the room, which would affect human comfort. The setting is based on the fan speed N0 and the air volume required by the people in the room.

[0103] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous technical features can be freely combined and superimposed.

[0104] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A dual-cold-source fresh air handling system, characterized in that: It includes a heat pump air conditioning system (1), a pulsed heat pipe heat recovery system (2), and a heat pump-heat pipe heat exchanger connection structure (3). The heat pump air conditioning system (1) includes: a compressor (101), an indoor heat exchanger (102), a throttling device (103), an outdoor heat exchanger (104), and a four-way reversing valve (105). The components are connected in sequence through pipes, and the refrigerant circulates internally. The pulsed heat pipe heat recovery system (2) includes: a fresh air duct (205), an exhaust air duct (206), and a heat pipe flat tube; the heat pipe flat tube passes through the fresh air duct (205) and the exhaust air duct (206). The fresh air duct (205) includes a fresh air inlet (211), a fresh air outlet (212), and a fresh air fan (203); the exhaust air duct (206) includes an exhaust air inlet (213), an exhaust air outlet (214), and an exhaust fan (204); the heat pipe flat tube is divided into three sections: a heat pipe fresh air side flat tube (207), a heat pipe insulation section flat tube (208), and a heat pipe exhaust side flat tube (209). The heat pipe insulation section flat tube (208) is located between the fresh air duct (205) and the exhaust air duct (206). The heat pump-heat pipe connection structure (3) includes a first bypass valve (301), a second bypass valve (302), a branch flat pipe (303), a heat exchange container (304), and a flat pipe copper pipe adapter (305). The first bypass valve (301) is located between the throttling device (103) and the indoor heat exchanger (102), and the second bypass valve (302) is located between the indoor heat exchanger (102) and the compressor (101); the first bypass valve (301) is connected to a flat tube copper tube adapter (305), and the second bypass valve (302) is connected to another flat tube copper tube adapter (305); the two ends of the branch flat tube (303) are respectively connected to the two flat tube copper tube adapters (305); a part of the branch flat tube (303) and a part of the heat pipe fresh air side flat tube (207) are placed in the heat exchange container (304) for heat exchange; The branch flat tube (303) is bent into a U-shaped structure, and the heat pipe fresh air side flat tube (207) is also bent into a U-shaped structure in the heat exchange container (304). A branch flat tube (303) U-shaped structure is inserted between the U-shaped structures of two adjacent heat pipe fresh air side flat tubes (207), and the U-shaped structure of the heat pipe fresh air side flat tube (207) is in contact and fixed with the U-shaped structure of the adjacent branch flat tube (303).

2. The dual-cold-source fresh air handling system according to claim 1, characterized in that: Fins (210) are provided on the outer side of the heat pipe exhaust side flat tube (209) and the outer side of the portion of the heat pipe fresh air side flat tube (207) that does not extend into the heat exchange container (304). The ratio of the coverage width of the fins (210) on the heat pipe fresh air side flat tube (207) to the total width of the heat pipe fresh air side flat tube (207) is 0.6-0.

8.

3. The dual-cold-source fresh air handling system according to claim 2, characterized in that: The heat exchange container (304) is located inside the fresh air duct (205). The fresh air duct (205) is provided with a guide plate (202). The guide plate (202) has a guide hole. The guide hole corresponding to the heat exchange container (304) is provided with a louver structure to guide the airflow to the fin (210) part on the outside of the heat pipe fresh air side flat pipe (207).

4. The dual-cold-source fresh air handling system according to claim 3, characterized in that: The flat tube copper tube adapter (305) includes a liquid distribution chamber, which is provided with a copper tube connection port and a branch flat tube (303) connection port. The copper tube connection port is connected to the first bypass valve (301) and the second bypass valve (302) respectively through pipes, and the branch flat tube (303) connection port is connected to the branch flat tube (303).

5. The dual-cold-source fresh air handling system according to claim 4, characterized in that: The number of branch flat tubes (303) is multiple. One end of each branch flat tube (303) is connected to a branch flat tube (303) connection port on the liquid distribution chamber of two flat tube copper tube adapters (305). The middle part of each branch flat tube (303) is bent to form a U-shaped structure.

6. The dual-cold-source fresh air handling system according to claim 5, characterized in that: The number of the branch flat tube (303) is one. The two ends of the branch flat tube (303) are respectively connected to a branch flat tube (303) connection port on the liquid distribution chamber of the two flat tube copper tube adapters (305). The middle part of the branch flat tube (303) is bent to form multiple U-shaped structures.

7. The dual-cold-source fresh air handling system according to any one of claims 1-6, characterized in that: The fresh air duct (205) is equipped with a filter device (201), which is located between the fresh air inlet (211) and the heat pipe fresh air side flat pipe (207).

8. The dual-cold-source fresh air handling system according to claim 7, characterized in that: The heat pipe insulation section flat tube (208) is wrapped with polyurethane insulation material; the heat exchange container (304) is filled with liquid to enhance heat exchange and its uniformity.

9. A method of using the dual-cold-source fresh air handling system according to any one of claims 1-8, characterized in that, Includes the following steps: S101: Heat pump system starts, obtain indoor temperature T in Outdoor temperature T out To determine the summer and winter operating conditions and the indoor and outdoor temperature difference, obtain the carbon dioxide concentration φ and the heat pump running time t1 to determine the indoor air quality, and proceed to step S102. S102: Compare carbon dioxide concentration φ with the set carbon dioxide concentration φ 01 Size and heat pump running time t1 and set running time t 01 The size, if φ>φ 01 Or t1>t 01 If the air quality is good, it means the air in the room is not fresh and the fresh air system needs to be activated. Proceed to step S103; otherwise, there is no need to introduce fresh air and return to step S101. S103: The fresh air heat recovery system starts, turning on the fresh air fan and exhaust fan, and setting both to speed N. xin and N pai If both are equal to the set speed N0, proceed to step S104; S104: Obtain the fresh air outlet temperature T in the fresh air duct. xin,out The exhaust inlet temperature T in the exhaust duct pai,in Proceed to step S105; S105: Compare the fresh air outlet temperature T xin,out and exhaust inlet temperature T pai,in The absolute value of the difference and the magnitude of the set temperature difference ΔT1, if |T xin,out -T pai,in If |>ΔT1, it means that the energy recovered from the exhaust air is insufficient to bring the fresh air close to the room temperature, affecting comfort, and proceed to step S106; otherwise, the fresh air heat recovery system meets the requirements under this condition, and proceed to step S301. S106: Reduce the speed of the fresh air fan by a set value ΔN, so that the fresh air volume decreases while the exhaust volume remains unchanged, so that the fresh air approaches the indoor temperature and ensures comfort, then proceed to S107. S107: Compare the fresh air fan speed N xin With the set minimum speed value N min The size of N, if xin <N min The pressure cannot be reduced further, otherwise the pressure difference between the inside and outside of the room will be too large and affect comfort. Proceed to S201; otherwise, return to S105. S201: Heat pump auxiliary system starts, bypass valve opens, opening degree K is the set initial value K1, and the refrigerant bypass branch inlet temperature T is obtained. pass,in Bypass branch outlet temperature T pass,out Proceed to step S202; S202: Compare the inlet temperature T of the bypass branch. pass,in Temperature T at the outlet of the bypass branch pass,out The absolute value of the difference and the magnitude of the set temperature difference ΔT2, if |T pass,in -T pass,out If |>ΔT2, it indicates that the bypass flow is small, proceed to step S203; otherwise, proceed to step S204. S203: Increase the bypass valve opening by a large amount of ΔK, then return to step S202; S204: Compare the inlet temperature T of the bypass branch. pass,in Temperature T at the outlet of the bypass branch pass,out The absolute value of the difference and the magnitude of the set temperature difference ΔT3, if |T pass,in -T pass,out If |<ΔT2, it indicates that the bypass flow is large, proceed to step S205; otherwise, the bypass valve has been adjusted to the appropriate opening, proceed to S301. S205: Increase the bypass valve opening by a large amount of ΔK, then return to step S204; S301: Maintain this fan speed and this bypass valve opening for a period of time, then proceed to step S302; S302: Obtain the fan running time t2 and carbon dioxide concentration φ, then proceed to step S303; S303: Compare the carbon dioxide concentration φ with the set carbon dioxide concentration φ0, and the fan running time t2 with the set running time t. 02 The size, if φ < φ 02 or t2>t 02 If the air quality meets the freshness standard, proceed to step S304; otherwise, return to step S301. S304: Shut down the fan and bypass valve to end operation.

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