Closed variable-frequency heat pump drying device with heat regenerator and control method thereof
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Solution Overview
Problem
Existing heat pump drying devices face challenges in efficiently regulating heating load and controlling process parameters, leading to high energy consumption and suboptimal drying rates and product quality due to their fixed-frequency operation, and the integration of heat regeneration technology has not adequately addressed these issues.
Innovation Solution
A closed variable-frequency heat pump drying device with a heat regenerator and a control method that automatically adjusts the compressor and fan frequencies, as well as the ratio of straight-through to regenerated air volume, based on real-time temperature and humidity sensors to maintain set process parameters, optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable-frequency heat pump technology is used to regulate heating load, then adaptability to drying process requirements is improved, but energy consumption increases when air volume is not properly controlled
Solution Approach 1:
The control system continuously monitors drying process parameters (temperature, humidity) and adjusts compressor and fan frequencies in real-time based on actual process conditions. This feedback mechanism ensures the system operates at optimal energy consumption levels while maintaining required heating load regulation capacity throughout the drying process.
Solution Approach 2:
The system dynamically adjusts both compressor frequency and fan frequency independently based on real-time process conditions. This dynamic control allows the air volume to be precisely matched to drying requirements, preventing energy waste from excessive air circulation while maintaining adaptability to varying heating load demands.
2Productivity
If air volume is increased to improve drying rate, then drying efficiency is improved, but fan power consumption and heat pump system energy consumption increase
Solution Approach 1:
The fan frequency is dynamically adjusted based on real-time monitoring of drying process parameters. The control system determines the optimal air volume required for current drying conditions and adjusts fan speed accordingly, achieving high drying rates only when necessary while minimizing fan power consumption during lower-demand phases.
Solution Approach 2:
The system changes the operating parameters of the fan (speed/frequency) in response to drying process requirements. By varying fan speed rather than operating at constant high speed, the system achieves high drying rates when needed while reducing energy consumption during periods when lower air volumes suffice.
3Use of energy by moving object
If air volume is decreased to reduce energy consumption, then energy saving is achieved, but drying rate and material homogeneity deteriorate
Solution Approach 1:
The control system uses feedback from temperature and humidity sensors to determine when increased air volume is necessary for maintaining acceptable drying rates. This ensures energy consumption is minimized only during periods when drying requirements are low, while automatically increasing air volume when drying rate or material homogeneity begins to deteriorate.
4Device complexity
If fixed-frequency heat pump technology is used, then device complexity is reduced, but adaptability to drying process requirements and energy efficiency deteriorate
Solution Approach 1:
The system employs dynamic frequency adjustment of both compressor and fan based on real-time process conditions. This dynamic control capability provides high adaptability to varying drying requirements while the integrated control algorithm manages the complexity, achieving better overall efficiency than simpler fixed-frequency systems.
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
This solution enables efficient energy conservation by dynamically regulating air volume and humidity, reducing energy consumption while ensuring the drying process meets the required parameters, thereby improving drying efficiency and product quality.
Implementation Method 1
a heat regenerator, a three-way valve... An outlet of the heat regenerator faces one side of the condenser, and another outlet of the heat regenerator faces one side of the evaporator. An inlet of the heat regenerator faces the other side of the evaporator
Implementation Method 2
an evaporator... An inlet of the heat regenerator faces the other side of the evaporator... Condensed water of the evaporator is directly discharged outside through a pipeline
Data Source
AI summary
A closed variable-frequency heat pump drying device with a heat regenerator includes a variable-frequency compressor, a condenser, a throttling valve, an evaporator, a heat regenerator, a three-way valve, a variable-frequency fan, an air inlet temperature sensor, an air inlet humidity sensor, a drying bin, an air outlet temperature sensor, an air outlet humidity sensor and a controller. The controller regulates frequency of the variable-frequency compressor by comparing magnitudes of actual and set air inlet temperatures; a ratio of a straight-through air volume to a regenerated air volume of the three-way valve by comparing magnitudes of actual and set air inlet humidity; and frequency of the variable-frequency fan by comparing magnitudes of actual and set air humidity difference and magnitudes of actual and set air temperature difference of medium air entering and exiting the drying bin.