Control method and apparatus for compression system, and air energy heat pump water heater
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Solution Overview
Problem
The air energy heat pump water heater faces challenges in adjusting intermediate pressure and optimizing operation efficiency, particularly in scenarios where the temperature difference between the compressor's exhaust and the water tank's maximum temperature is not effectively managed.
Innovation Solution
A control method for a compression system that adjusts the first electronic expansion valve's target step number based on temperature differences, decreasing the target step number when the temperature difference is less than a preset value to prevent excessive refrigerant flow and ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the first electronic expansion valve operates with a fixed target step number, then the control is simple, but the heating efficiency cannot be optimized under varying temperature conditions
Solution Approach 1:
The patent implements dynamic adjustment of the first electronic expansion valve's target step number based on real-time temperature difference detection. The controller continuously monitors the temperature difference between compressor exhaust and water tank maximum temperature, and dynamically adjusts the valve's step number accordingly, transforming the static control into a dynamic adaptive control system that optimizes heating efficiency under varying conditions.
Solution Approach 2:
The patent establishes a feedback control mechanism where the controller detects the temperature difference between compressor exhaust and water tank maximum temperature, compares it with preset values, and uses this feedback information to adjust the first electronic expansion valve's target step number. This closed-loop feedback system enables continuous optimization of heating efficiency while maintaining simple overall control architecture.
2Productivity
If the first electronic expansion valve opens larger to increase refrigerant flow, then the heating efficiency improves, but liquid carryover in the compressor occurs
Solution Approach 1:
The patent uses temperature difference feedback to prevent liquid carryover. When the temperature difference between compressor exhaust and water tank maximum temperature is small, indicating high risk of liquid carryover, the controller automatically decreases the first electronic expansion valve's target step number, thereby reducing refrigerant flow and preventing liquid from entering the compressor while maintaining heating efficiency.
Solution Approach 2:
The patent changes the operating parameters of the first electronic expansion valve dynamically based on temperature conditions. By adjusting the target step number parameter according to the detected temperature difference, the system optimizes refrigerant flow rate to prevent liquid carryover during high-efficiency heating operation, thus protecting compressor reliability.
3Reliability
If the first electronic expansion valve opens smaller to prevent liquid carryover, then the compressor reliability improves, but the heating efficiency decreases
Solution Approach 1:
The patent implements dynamic adjustment of the first electronic expansion valve's opening degree based on real-time temperature difference detection. Instead of using a fixed small opening that would limit heating efficiency, the system dynamically adjusts the target step number: when temperature difference is large (low liquid carryover risk), the valve opens larger for high heating efficiency; when temperature difference is small (high liquid carryover risk), the valve opens smaller to prevent liquid carryover. This dynamic approach resolves the contradiction between reliability and efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method improves the reliability and heating efficiency of the compression system by balancing the refrigerant flow, preventing liquid carryover in the compressor, and optimizing heating performance across varying temperature conditions.
Implementation Method 1
determining a temperature difference between a current exhaust temperature of the compressor and a current maximum water temperature of a water tank... decreasing the first target step number by a first correction step number in a case where the temperature difference is less than a first preset value
Data Source
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AI summary
The present disclosure relates to the technical field of water heaters, and provides a control method and apparatus for a compression system, and an air energy heat pump water heater. The compression system comprises a compressor provided between an outdoor first heat exchanger and a second heat exchanger of a water tank, a first electronic expansion valve provided between the second heat exchanger and a flash evaporator, and a second electronic expansion valve provided between the flash evaporator and the first heat exchanger. The method comprises: executing a first control step at least once, executing the first control step every time comprising: determining a first target step number of the first electronic expansion valve; after the first electronic expansion valve is controlled to operate for a first time period according to the first target step number, determining a temperature difference between the current exhaust temperature of the compressor and the current highest water temperature of the water tank; when the temperature difference is less than a first preset value, decreasing the first target step number by a first correction step number, the first preset value being greater than 0 degree Celsius, and the first correction step number being greater than 0 step; and controlling the first electronic expansion valve to operate according to the decreased first target step number.