Adaptive Enhanced Jet Enthalpy Control Method and System for Heat Pumps under High Ambient Temperatures

Abstract

This invention discloses an adaptive enhanced jet enthalpy-boosting heat pump control method and system under high ambient temperature. The method adjusts the opening of the auxiliary enthalpy-boosting electronic expansion valve in real time by adjusting the numerical difference between the actual jet pressure value and the theoretical intermediate pressure value. This fundamentally solves the problem of backflow of supplementary gas and failure of enthalpy boosting caused by the jet pressure being lower than the intermediate pressure chamber pressure of the compressor under high temperature conditions. It can ensure that the supplementary gas is continuously and positively supplied, and stably exert the enthalpy boosting efficiency.

Description

Technical Field

[0001] This invention relates to the field of heat pump technology, and in particular to a heat pump control method and system for adaptive enhanced jet enthalpy enhancement under high ambient temperatures. Background Technology

[0002] Air source heat pumps are widely used in building heating and cooling, industrial hot water, and data center cooling due to their advantages such as energy saving, environmental protection, and wide applicability. However, with the increasing frequency of extreme heat events globally and the growing demand for special scenarios such as high-temperature hot water and heat dissipation in confined spaces, heat pump systems often need to operate in ambient temperatures exceeding 38°C. Under such high-temperature conditions, conventional vapor compression heat pump systems experience a significant increase in condensing pressure and compression ratio, leading to a rapid rise in compressor exhaust temperature. This results in a severe decrease in the unit's cooling and heating capacity and energy efficiency, and may even frequently trigger thermal protection shutdowns, making it difficult to guarantee stable output and operational reliability in high-temperature scenarios.

[0003] Jet enthalpy enhancement technology is a common technique for expanding the operating range of heat pumps and improving their performance under extreme conditions. It supplements the medium-pressure refrigerant to the medium-pressure chamber of the compressor through the economizer heat exchange branch, achieving a two-stage compression effect and reducing exhaust temperature and increasing circulation flow to a certain extent.

[0004] However, conventional jet enthalpy enhancement technology is a common technique for expanding the operating range of heat pumps and improving performance under extreme conditions. It supplements the medium-pressure refrigerant to the medium-pressure chamber of the compressor through the economizer heat exchange branch, which can achieve a two-stage compression effect and reduce the exhaust temperature and increase the circulation flow rate to a certain extent. However, existing conventional jet enthalpy enhancement schemes still have significant shortcomings under high ambient temperature conditions, failing to fully realize their enthalpy enhancement efficiency. Specifically: First, existing control logics mostly rely on auxiliary circuit superheat and exhaust temperature as the sole adjustment basis, without establishing a closed-loop control that compares jet pressure with the theoretical intermediate pressure of the system. Under high-temperature conditions, the injection state fluctuates greatly and has poor controllability. The actual jet pressure is prone to being lower than the compressor intermediate pressure, and in severe cases, refrigerant backflow may even occur, directly leading to enthalpy enhancement failure. Second, the heat exchange area design of conventional economizers is conservative, with insufficient intermediate pressure establishment capability and injection heat exchange margin, further limiting the upper limit of injection volume and injection ratio, exacerbating the problem of enthalpy enhancement effect attenuation under high-temperature conditions. Third, there is a lack of a quantitative feedback mechanism for the actual enthalpy enhancement effect. Adjustments are made solely based on preset parameters, making it impossible to dynamically optimize the injection volume according to the actual capacity output of the unit, thus making it difficult to achieve optimal performance and energy efficiency matching under high-temperature conditions.

[0005] In summary, existing jet enthalpy enhancement technology cannot meet the operational requirements of high ambient temperature conditions. There is an urgent need for a heat pump solution that can achieve stable and effective gas replenishment and adaptive optimization of enthalpy enhancement at high temperatures, so as to comprehensively improve the unit's operating capacity, energy efficiency and reliability under high temperature conditions. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes an adaptive enhanced jet enthalpy-enhancing heat pump control method and system under high ambient temperatures, primarily resolving the issues raised in the background technology.

[0007] To address the aforementioned technical problems, the first aspect of this invention proposes an adaptive enhanced jet enthalpy control method for heat pumps under high ambient temperatures, comprising the following steps:

[0008] Step 1: Obtain the current condensing pressure and evaporating pressure of the heat pump system, and calculate the theoretical intermediate pressure based on the condensing pressure and evaporating pressure.

[0009] Step 2: Obtain the current actual jet pressure value of the heat pump system;

[0010] Step 3: Compare the actual jet pressure value with the theoretical intermediate pressure value, and adjust the opening of the auxiliary enthalpy-increasing electronic expansion valve in real time to ensure that the actual jet pressure value is always greater than the theoretical intermediate pressure value.

[0011] In some implementations, the theoretical intermediate pressure value is calculated as follows: Pmid=

[0012] Where Pmid is the theoretical intermediate pressure value, Pc is the condensation pressure value, and Pe is the evaporation pressure value.

[0013] In some embodiments, when adjusting the opening of the auxiliary enthalpy-increasing electronic expansion valve in real time, the actual jet pressure value is controlled to be 0.3~1.0 bar higher than the theoretical intermediate pressure value.

[0014] In some implementations, a condition triggering step is included before performing step 1:

[0015] The system detects the current ambient temperature. When the ambient temperature is ≥38℃, the heat pump system enters the enhanced vapor injection enthalpy enhancement mode. When the ambient temperature is <35℃, the heat pump system exits the enhanced vapor injection enthalpy enhancement mode.

[0016] In some implementations, in addition to ensuring that the actual jet pressure is greater than the theoretical intermediate pressure, a capability feedback optimization step is also included:

[0017] Collect the inlet and outlet water temperatures of the condenser in the heat pump system, and calculate the inlet and outlet water temperature difference based on the inlet and outlet water temperatures.

[0018] Based on the changing trend of the inlet and outlet water temperature difference, the opening of the auxiliary enthalpy-increasing electronic expansion valve is dynamically fine-tuned with a fixed step size to find the optimal air replenishment amount.

[0019] In some embodiments, the step of finely adjusting the opening of the auxiliary enthalpy-increasing electronic expansion valve with a fixed step size based on the changing trend of the inlet and outlet water temperature difference includes the following steps:

[0020] If the temperature difference between the inlet and outlet water increases, the opening of the auxiliary enthalpy-increasing electronic expansion valve should be increased further.

[0021] If the inlet and outlet water temperature difference remains stable, the current opening of the auxiliary enthalpy-increasing electronic expansion valve shall be maintained.

[0022] If the temperature difference between the inlet and outlet water decreases, the opening of the auxiliary enthalpy-increasing electronic expansion valve should be reduced.

[0023] In some embodiments, the heat pump system employs an enhanced economizer, the heat exchange area of ​​which is 1.3 to 2.0 times that of a conventional economizer.

[0024] The second aspect of this invention proposes an adaptive enhanced vapor injection enthalpy-boosting heat pump system under high ambient temperature, comprising a vapor injection enthalpy-boosting compressor, a condenser, an economizer, a main circuit electronic expansion valve, an auxiliary circuit enthalpy-boosting electronic expansion valve, an evaporator, a four-way valve, a gas-liquid separator, a one-way valve, a liquid receiver, a high-pressure sensor, a low-pressure sensor, a vapor injection pressure sensor, and a controller.

[0025] The exhaust port of the jet enthalpy-increasing compressor is connected to the refrigerant inlet of the condenser via the four-way valve, and the refrigerant outlet of the condenser is connected to the main inlet of the economizer;

[0026] The main outlet of the economizer is divided into two paths. One path connects to the refrigerant inlet of the evaporator via the liquid receiver and the main electronic expansion valve. The refrigerant outlet of the evaporator connects to the main suction port of the vapor injection compressor via the four-way valve and the gas-liquid separator. The other path connects to the auxiliary inlet of the economizer via the auxiliary electronic expansion valve. The auxiliary outlet of the economizer connects to the medium-pressure injection port of the vapor injection compressor via the check valve.

[0027] The high-pressure sensor is located at the exhaust port of the vapor injection enthalpy-enhancing compressor and is used to detect the condensing pressure value; the low-pressure sensor is located at the main suction port of the vapor injection enthalpy-enhancing compressor and is used to detect the evaporating pressure value; the vapor injection pressure sensor is located at the auxiliary outlet of the economizer.

[0028] The controller is electrically connected to the high-pressure sensor, the low-pressure sensor, the jet pressure sensor, and the auxiliary enthalpy-increasing electronic expansion valve, respectively.

[0029] The controller is configured to perform the above-described adaptive enhanced jet enthalpy heat pump control method under high ambient temperatures.

[0030] In some embodiments, an inlet water temperature sensor and an outlet water temperature sensor are also included, which are respectively located at the inlet and outlet of the condenser.

[0031] The beneficial effects of this invention are as follows: by adjusting the opening of the auxiliary enthalpy-increasing electronic expansion valve in real time by adjusting the numerical difference between the actual jet pressure value and the theoretical intermediate pressure value, the problem of backflow of supplementary gas and failure of enthalpy increase caused by the jet pressure being lower than the intermediate pressure chamber pressure of the compressor under high temperature conditions is fundamentally solved, which can ensure that the supplementary gas is continuously and positively introduced and stably exert the enthalpy-increasing efficiency. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the adaptive enhanced jet enthalpy heat pump system under high ambient temperature disclosed in Embodiment 2 of the present invention;

[0033] Among them: 1-jet enthalpy-increasing compressor, 2-condenser, 3-economizer, 4-main circuit electronic expansion valve, 5-auxiliary circuit enthalpy-increasing electronic expansion valve, 6-evaporator, 7-four-way valve, 8-gas-liquid separator, 9-one-way valve, 10-liquid receiver, 11-high pressure sensor, 12-low pressure sensor, 13-jet pressure sensor, 14-inlet water temperature sensor, 15-outlet water temperature sensor. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the content of this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to this invention are shown in the accompanying drawings, not all of them.

[0035] Example 1

[0036] This embodiment proposes an adaptive enhanced jet enthalpy increase heat pump control method under high ambient temperatures, including the following steps:

[0037] Step 1: Obtain the current condensing pressure and evaporating pressure of the heat pump system, and calculate the theoretical intermediate pressure based on the condensing pressure and evaporating pressure.

[0038] Step 2: Obtain the current actual jet pressure value of the heat pump system;

[0039] Step 3: Compare the actual jet pressure value with the theoretical intermediate pressure value, and adjust the opening of the auxiliary enthalpy-increasing electronic expansion valve in real time to ensure that the actual jet pressure value is always greater than the theoretical intermediate pressure value. The specific opening adjustment logic is as follows: if the actual jet pressure value is less than or equal to the theoretical intermediate pressure value, open the auxiliary enthalpy-increasing electronic expansion valve more fully to increase the jet pressure; if the difference between the actual jet pressure value and the theoretical intermediate pressure value exceeds a preset upper limit, maintain or slightly close the auxiliary enthalpy-increasing electronic expansion valve to avoid energy efficiency loss.

[0040] In this solution, the opening of the auxiliary enthalpy-increasing electronic expansion valve is adjusted in real time by the numerical difference between the actual jet pressure value and the theoretical intermediate pressure value. This fundamentally solves the problem of backflow of supplementary gas and failure of enthalpy increase caused by the jet pressure being lower than the intermediate pressure chamber pressure of the compressor under high temperature conditions. It can ensure that the supplementary gas is continuously supplied in the positive direction and stably exert the enthalpy-increasing efficiency.

[0041] The theoretical intermediate pressure value is calculated as follows: Pmid=

[0042] Where Pmid is the theoretical intermediate pressure value, Pc is the condensation pressure value, and Pe is the evaporation pressure value.

[0043] More preferably, in step 3, when adjusting the opening of the auxiliary enthalpy-increasing electronic expansion valve in real time, the actual jet pressure value is controlled to be 0.3~1.0 bar higher than the theoretical intermediate pressure value. In this preferred scheme, the pressure difference range between the actual jet pressure value and the theoretical intermediate pressure value can avoid insufficient gas supply stability caused by too small a pressure difference, and also prevent the exhaust temperature from rising and the energy efficiency from falling due to too large a pressure difference, thus balancing reliability and operating efficiency.

[0044] More preferably, before executing step 1, a condition triggering step is also included: detecting the current ambient temperature; when the ambient temperature is ≥38℃, the heat pump system enters the enhanced vapor injection enthalpy enhancement mode; when the ambient temperature is <35℃, the heat pump system exits the enhanced vapor injection enthalpy enhancement mode. In this preferred scheme, an ambient temperature higher than 38℃ is used as the threshold for high-temperature environmental conditions. Furthermore, by setting a 3℃ hysteresis switching range, frequent start-stop cycles can be avoided when the ambient temperature fluctuates slightly near the threshold, thus improving system operational stability and valve lifespan.

[0045] In addition to ensuring that the actual jet pressure is greater than the theoretical intermediate pressure, a capability feedback optimization step is also included:

[0046] First, the inlet and outlet water temperatures of the heat pump system condenser are collected. The inlet and outlet water temperature difference is then calculated based on these temperatures. The formula for calculating the inlet and outlet water temperature difference is: ΔT = T 出水 -T 进水During the adjustment process, the opening of the auxiliary enthalpy-increasing electronic expansion valve is gradually fine-tuned with a preset fixed step size. After each adjustment step, the system runs stably for a preset time, and then the current inlet and outlet water temperature difference is collected and calculated.

[0047] Then, based on the changing trend of the temperature difference between the inlet and outlet water, the opening of the auxiliary enthalpy-increasing electronic expansion valve is dynamically fine-tuned with a fixed step size to find the optimal air supply.

[0048] The above-mentioned capability feedback optimization steps use the actual heat exchange capacity of the unit (inlet and outlet water temperature difference) as the feedback basis, breaking through the limitations of traditional methods that only adjust single parameters such as temperature and pressure. It can adaptively match the optimal gas supply under different high-temperature operating conditions, achieving dual optimization of capability and energy efficiency.

[0049] Specifically, the above-mentioned method of finely adjusting the opening of the auxiliary enthalpy-increasing electronic expansion valve with a fixed step size based on the changing trend of the inlet and outlet water temperature difference includes the following steps:

[0050] (1) If the temperature difference between the inlet and outlet water increases, the opening of the auxiliary enthalpy-increasing electronic expansion valve should be increased further;

[0051] (2) If the temperature difference between the inlet and outlet water remains stable, then maintain the current opening of the auxiliary enthalpy-increasing electronic expansion valve;

[0052] (3) If the temperature difference between the inlet and outlet water decreases, reduce the opening of the auxiliary enthalpy-increasing electronic expansion valve.

[0053] The aforementioned pressure closed-loop regulation and capacity feedback optimization steps are continuously executed in a loop to achieve stable, optimal, and enhanced operation of the jet enthalpy enhancement under high-temperature conditions.

[0054] In a more optimized solution, the aforementioned heat pump system employs an enhanced economizer, whose heat exchange area is 1.3 to 2.0 times that of a conventional economizer. This enhanced economizer's increased heat exchange area improves heat exchange redundancy under high-temperature, high-flow-rate injection conditions, ensuring the auxiliary refrigerant fully evaporates into dry saturated gas, avoiding the risk of compressor liquid slugging, and further increasing the upper limit of the injection ratio to enhance high-temperature enthalpy enhancement.

[0055] Example 2

[0056] This embodiment proposes an adaptive enhanced jet enthalpy heat pump system under high ambient temperatures, such as... Figure 1 As shown, it includes a jet enthalpy-increasing compressor 1, a condenser 2, an economizer 3, a main circuit electronic expansion valve 4, an auxiliary circuit enthalpy-increasing electronic expansion valve 5, an evaporator 6, a four-way valve 7, a gas-liquid separator 8, a one-way valve 9, a liquid receiver 10, a high-pressure sensor 11, a low-pressure sensor 12, a jet pressure sensor 13, and a controller.

[0057] The exhaust port of the vapor injection enthalpy-increasing compressor 1 is connected to the refrigerant inlet of the condenser 2 via a four-way valve 7, and the refrigerant outlet of the condenser 2 is connected to the main inlet of the economizer 3. The main outlet of the economizer 3 is divided into two paths: one path is connected to the refrigerant inlet of the evaporator 6 via the liquid receiver 10 and the main electronic expansion valve 4, and the refrigerant outlet of the evaporator 6 is connected to the main suction port of the vapor injection enthalpy-increasing compressor 1 via the four-way valve 7 and the gas-liquid separator 8; the other path is connected to the auxiliary inlet of the economizer 3 via the auxiliary enthalpy-increasing electronic expansion valve 5, and the auxiliary outlet of the economizer 3 is connected to the medium-pressure gas injection port of the vapor injection enthalpy-increasing compressor 1 via a one-way valve 9. The one-way valve 9 only allows refrigerant to flow unidirectionally from the economizer auxiliary path to the compressor gas injection port, which can further prevent refrigerant backflow under high-temperature conditions and ensure the safety of gas injection.

[0058] The high-pressure sensor 11 (for detecting condensing pressure Pc) is located at the exhaust port of the vapor injection enthalpy-increasing compressor 1; the low-pressure sensor 12 (for detecting evaporating pressure Pe) is located at the main suction port of the vapor injection enthalpy-increasing compressor 1; and the vapor injection pressure sensor 13 (for detecting actual vapor injection pressure Pinj) is located at the auxiliary outlet of the economizer 3.

[0059] The controller (not shown) is electrically connected to the high-pressure sensor 11, the low-pressure sensor 12, the jet pressure sensor 13, and the auxiliary enthalpy-enhancing electronic expansion valve 5, respectively; the controller is configured to perform the adaptive enhanced jet enthalpy-enhancing heat pump control method under high ambient temperature as described in Embodiment 1.

[0060] Optionally, the system also includes an inlet water temperature sensor 14 and an outlet water temperature sensor 15, which are respectively located at the inlet and outlet of the condenser 2, for real-time acquisition of inlet and outlet water temperature data on the condenser side and transmission to the controller, providing data support for capability feedback optimization.

[0061] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A heat pump control method for adaptive enhanced jet enthalpy enhancement under high ambient temperatures, characterized in that, Includes the following steps: Step 1: Obtain the current condensing pressure and evaporating pressure of the heat pump system, and calculate the theoretical intermediate pressure based on the condensing pressure and evaporating pressure. Step 2: Obtain the current actual jet pressure value of the heat pump system; Step 3: Compare the actual jet pressure value with the theoretical intermediate pressure value, and adjust the opening of the auxiliary enthalpy-increasing electronic expansion valve in real time to ensure that the actual jet pressure value is always greater than the theoretical intermediate pressure value.

2. The heat pump control method for adaptive enhanced jet enthalpy enhancement under high ambient temperature as described in claim 1, characterized in that, The method for calculating the theoretical intermediate pressure value is as follows: Pmid= ; Where Pmid is the theoretical intermediate pressure value, Pc is the condensation pressure value, and Pe is the evaporation pressure value.

3. The heat pump control method for adaptive enhanced jet enthalpy increase under high ambient temperature as described in claim 1, characterized in that, When adjusting the opening of the auxiliary enthalpy-increasing electronic expansion valve in real time, the actual jet pressure value is controlled to be 0.3~1.0 bar higher than the theoretical intermediate pressure value.

4. The heat pump control method for adaptive enhanced jet enthalpy increase under high ambient temperature as described in claim 1, characterized in that, Before executing step 1, there is also a condition triggering step: The system detects the current ambient temperature. When the ambient temperature is ≥38℃, the heat pump system enters the enhanced vapor injection enthalpy enhancement mode. When the ambient temperature is <35℃, the heat pump system exits the enhanced vapor injection enthalpy enhancement mode.

5. The heat pump control method for adaptive enhanced jet enthalpy increase under high ambient temperature as described in claim 1, characterized in that, In addition to ensuring that the actual jet pressure is greater than the theoretical intermediate pressure, a capability feedback optimization step is also included: Collect the inlet and outlet water temperatures of the condenser in the heat pump system, and calculate the inlet and outlet water temperature difference based on the inlet and outlet water temperatures. Based on the changing trend of the inlet and outlet water temperature difference, the opening of the auxiliary enthalpy-increasing electronic expansion valve is dynamically fine-tuned with a fixed step size to find the optimal air replenishment amount.

6. The heat pump control method for adaptive enhanced jet enthalpy increase under high ambient temperature as described in claim 5, characterized in that, The step of finely adjusting the opening of the auxiliary enthalpy-increasing electronic expansion valve with a fixed step size based on the changing trend of the inlet and outlet water temperature difference includes the following steps: If the temperature difference between the inlet and outlet water increases, the opening of the auxiliary enthalpy-increasing electronic expansion valve should be increased further. If the inlet and outlet water temperature difference remains stable, the current opening of the auxiliary enthalpy-increasing electronic expansion valve shall be maintained. If the temperature difference between the inlet and outlet water decreases, the opening of the auxiliary enthalpy-increasing electronic expansion valve should be reduced.

7. The heat pump control method for adaptive enhanced jet enthalpy increase under high ambient temperature as described in claim 1, characterized in that, The heat pump system uses an enhanced economizer, whose heat exchange area is 1.3 to 2.0 times that of a conventional economizer.

8. A heat pump system with adaptive enhanced jet enthalpy enhancement under high ambient temperatures, characterized in that, It includes a vapor injection enthalpy-increasing compressor, condenser, economizer, main circuit electronic expansion valve, auxiliary circuit enthalpy-increasing electronic expansion valve, evaporator, four-way valve, gas-liquid separator, check valve, liquid receiver, high pressure sensor, low pressure sensor, vapor injection pressure sensor, and controller. The exhaust port of the jet enthalpy-increasing compressor is connected to the refrigerant inlet of the condenser via the four-way valve, and the refrigerant outlet of the condenser is connected to the main inlet of the economizer; The main outlet of the economizer is divided into two paths. One path connects to the refrigerant inlet of the evaporator via the liquid receiver and the main electronic expansion valve. The refrigerant outlet of the evaporator connects to the main suction port of the vapor injection compressor via the four-way valve and the gas-liquid separator. The other path connects to the auxiliary inlet of the economizer via the auxiliary electronic expansion valve. The auxiliary outlet of the economizer connects to the medium-pressure injection port of the vapor injection compressor via the check valve. The high-pressure sensor is located at the exhaust port of the vapor injection enthalpy-enhancing compressor and is used to detect the condensing pressure value; the low-pressure sensor is located at the main suction port of the vapor injection enthalpy-enhancing compressor and is used to detect the evaporating pressure value; the vapor injection pressure sensor is located at the auxiliary outlet of the economizer. The controller is electrically connected to the high-pressure sensor, the low-pressure sensor, the jet pressure sensor, and the auxiliary enthalpy-increasing electronic expansion valve, respectively. The controller is configured to perform the heat pump control method for adaptive enhanced jet enthalpy enhancement under high ambient temperatures as described in any one of claims 1-7.

9. The heat pump system with adaptive enhanced jet enthalpy enhancement under high ambient temperature as described in claim 8, characterized in that, It also includes an inlet water temperature sensor and an outlet water temperature sensor, which are respectively located at the inlet and outlet of the condenser.

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