DC Fan Pressure Feedback Control for Air Source Heat Pumps
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Solution Overview
Problem
Current air source heat pump systems face inefficiencies due to the general method of adjusting DC fan speed based on inlet/outlet temperatures, leading to increased energy consumption and suboptimal operating states, as system pressure values cannot be fed back in real time, causing the DC fan motor to operate at high speeds even when heat exchange capacity is sufficient.
Innovation Solution
A control device and method that adjusts the DC fan speed by comparing actual pressure with preset target pressure values, determined in conjunction with ambient temperature, to maintain the fan speed within a reasonable interval, ensuring better energy efficiency and accurate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the DC fan speed is adjusted based on inlet/outlet temperature comparison, then the control method is simple to implement, but the energy consumption increases and the system cannot reach optimal operating state
Solution Approach 1:
The patent introduces real-time pressure feedback from the heat exchanger to the control device. The control device compares actual pressure with target pressure (determined by ambient temperature) and adjusts DC fan speed accordingly. This closed-loop feedback mechanism enables precise control that reduces energy consumption while maintaining optimal system performance.
Solution Approach 2:
The patent changes the control parameter from temperature-based to pressure-based control. By detecting pressure values in real-time and comparing them with target pressure values corresponding to different ambient temperatures, the system achieves more accurate fan speed adjustment and better energy efficiency.
2Ease of operation
If the DC fan speed is adjusted based on inlet/outlet temperature comparison, then the control logic is straightforward, but the speed adjustment accuracy is insufficient
Solution Approach 1:
The control device receives real-time pressure feedback from the heat exchanger and continuously adjusts the DC fan speed based on the difference between actual and target pressure. This feedback mechanism significantly improves speed adjustment accuracy compared to simple temperature-based control.
Solution Approach 2:
The patent implements dynamic speed adjustment by continuously monitoring pressure changes and modifying fan speed in real-time. The control device dynamically adapts fan speed to match system requirements, achieving precise control that responds to changing operating conditions.
3Reliability
If the DC fan operates at highest speed to ensure target temperature is reached, then the temperature control is reliable, but the heat exchange capacity is wasted and energy is consumed unnecessarily
Solution Approach 1:
The real-time pressure feedback mechanism allows the control device to accurately determine when the target temperature/pressure is reached and reduce fan speed accordingly. This prevents unnecessary high-speed operation while maintaining reliable temperature control through precise monitoring and adjustment.
Solution Approach 2:
The patent applies partial action by adjusting fan speed to the minimum necessary level to achieve the target temperature/pressure. Instead of always operating at highest speed, the fan runs at partially reduced speed once the target is reached, eliminating energy waste while maintaining control reliability.
Data Source
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AI summary
Provided in the present invention are a control device and method for a DC fan of an air source heat pump system/air conditioning system, the method comprising the steps of presetting a heat exchanger to be on an evaporating side and on a condensing side, respectively, and presetting a dataset of preset target pressure values at different ambient temperatures; judging whether the DC fan is on the evaporating side or on the condensing side; according to a judgment result of a judgment module (3), an ambient temperature of an environment in which the DC fan operates and the dataset of preset target pressure values, obtaining a preset target pressure value of the heat exchanger corresponding in position to the DC fan at the ambient temperature; detecting an actual pressure Pa of the heat exchanger; and adjusting the speed of the DC fan according to a comparison result between the actual pressure Pa and the preset target pressure value. The method of the present invention enables the speed of the DC fan in a reasonable interval, improving the energy efficiency of the system and the accuracy of speed adjustment of the DC fan.