Heat Pump Dryer Control for Energy, Time, and Fabric Care
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Solution Overview
Problem
Hybrid heat pump dryers offer limited user choices for drying processes, such as final humidity content and cycle duration, which restricts operational ranges and user preferences, particularly in terms of energy consumption, cycle time, and fabric care.
Innovation Solution
A goal-oriented control method that optimizes the balance between heating and cooling power by controlling the compressor speed, process air blower speed, heating element power, and auxiliary fan speed using dual-loop control architecture and temperature sensors to create customizable drying cycles, including Energy Optimized, Time Optimized, and Fabric Care Optimized cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hybrid heat pump dryers use simple control systems with limited heating and cooling options, then energy efficiency is improved, but user choice and operational range are reduced
Solution Approach 1:
The patent implements dynamic control of the heating element and auxiliary cooling fan based on real-time temperature sensor feedback. The controller adjusts heating power and cooling activation dynamically during the drying cycle, enabling multiple drying modes (energy-saving, time-saving, fabric-care) while maintaining system efficiency. This dynamic adjustment resolves the contradiction by providing user choice without sacrificing energy efficiency.
Solution Approach 2:
The system changes operational parameters (heating power levels, cooling fan activation, compressor cycling) based on detected temperature conditions and user-selected drying modes. By varying these parameters dynamically, the system offers multiple drying strategies (low-energy, fast-dry, gentle-dry) while maintaining optimal energy efficiency through sensor-based control.
2Adaptability or versatility
If the dryer provides multiple drying modes with different heating and cooling strategies, then user choice is improved, but system complexity increases
Solution Approach 1:
The patent uses temperature sensors positioned in the drum and refrigerant circuit to provide continuous feedback to the controller. This feedback enables automatic adjustment of heating and cooling operations, allowing multiple drying modes to be implemented through software control logic rather than additional hardware components. The feedback mechanism manages complexity by using intelligent control algorithms instead of complex mechanical systems.
3Temperature
If the compressor runs continuously to maintain cooling capacity, then cooling performance is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic compressor operation with on/off cycling based on temperature sensor feedback from the refrigerant circuit and drum. The compressor operates intermittently rather than continuously, activating when cooling is needed and deactivating when temperature thresholds are met. This periodic action maintains adequate cooling capacity while significantly reducing energy consumption compared to continuous operation.
Solution Approach 2:
The system uses temperature sensors and control logic to automatically manage compressor operation without continuous user input. The controller monitors temperature conditions and self-regulates compressor cycling to maintain optimal cooling performance while minimizing energy use, enabling the system to serve itself through intelligent control.
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
Enables increased user choices by optimizing energy consumption, cycle duration, and fabric care, with specific examples showing reduced energy use, adjusted drying times, and improved fabric protection through tailored control of the dryer's components.
Implementation Method 1
a refrigerant circuit including a compressor, a condenser, an expansion device, an evaporator, such condenser and evaporator being in heat exchange relationship with the process air circuit
Implementation Method 2
the refrigerant that with its phase variation transfer heat to the air circuit
Implementation Method 3
an auxiliary condenser cooled by an air flow driven by a fan
Implementation Method 4
an evaporator 18 where the moisture contained in the process air can condense
Implementation Method 5
a condenser 14 and an heating element 16 that heat the air going inside the drum 10
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
A laundry drying machine with heat pump system comprises a process air circuit including a rotating drum (10), a blower (12) and a heater (16), a refrigerant circuit including a compressor (22), a condenser (14), an expansion device (23), an evaporator (18), such condenser and evaporator being in heat exchange relationship with the process air circuit, an auxiliary condenser (20) cooled by an air flow driven by a fan (26), and at least two temperature sensors (T1, T2) placed in the process air circuit and/or in the refrigerant circuit. A method for controlling such laundry drying machine comprises inputting a desired behavior of the laundry drying machine selected in the group consisting of optimized use of energy, overall drying time and fabric care, and controlling the components (12, 16, 22, 26) of the machine according to signals from said two temperature sensors (T1, T2) and according to said desired behavior.