Clothes Dryer Cycle With Staged Airflow and Temperature Control
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Solution Overview
Problem
Current clothes dryers consume excessive energy due to constant airflow rate and drum inlet air temperature, leading to inefficient energy usage and potential overheating or underheating of clothes, despite the use of sensors and controls to manage moisture and temperature.
Innovation Solution
The method involves dividing the drying cycle into three stages: preheating, latent heat transfer, and sensible heat transfer, with varying airflow rates and inlet air temperatures, including a low airflow rate at a high temperature initially, increasing airflow at a lower temperature during the latent heat transfer stage, and further increasing airflow at the lowest temperature in the sensible heat transfer stage, while also utilizing external warm air sources and exhaust air recovery to optimize energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant airflow rate and drum inlet air temperature are maintained, then complete drying performance is achieved, but energy consumption increases
Solution Approach 1:
The patent applies dynamics by making the airflow rate and drum inlet air temperature variable rather than constant. The system dynamically adjusts these parameters in three distinct stages: preheating (lower airflow, higher temperature), latent heat transfer (moderate airflow, moderate temperature), and sensible heat transfer (higher airflow, lower temperature). This dynamic adjustment optimizes energy consumption while maintaining complete drying performance.
Solution Approach 2:
The patent implements parameter changes by systematically varying both airflow rate and temperature parameters throughout the drying cycle. Each stage has specific parameter ranges that are optimized for that particular phase of moisture removal. This approach allows the system to match energy input to the actual drying needs at each moment, reducing overall energy consumption while ensuring reliable drying results.
2Productivity
If high temperature is used for drying, then moisture removal efficiency improves, but risk of overheating and damaging clothes increases
Solution Approach 1:
The patent applies segmentation by dividing the drying process into three distinct stages, each with its own temperature and airflow characteristics. The preheating stage uses higher temperatures for initial moisture removal, while subsequent stages use progressively lower temperatures. This segmentation allows efficient moisture removal when needed while protecting clothes from overheating damage during later stages when less moisture remains.
Solution Approach 2:
The patent implements periodic action by cycling through different temperature and airflow regimes in sequential periods corresponding to the three drying stages. Each period is optimized for the specific moisture content level at that time, providing high temperature efficiency when appropriate while preventing damage through lower temperatures in later periods.
3Reliability
If drying time is extended to ensure complete drying, then drying performance improves, but energy consumption and potential overheating increase
Solution Approach 1:
The patent uses dynamics to adapt the drying process to the actual moisture content of the clothes throughout the cycle. By continuously adjusting airflow and temperature based on the drying stage, the system achieves complete drying in optimized time without unnecessary extension of the cycle. This prevents energy waste from prolonged operation while ensuring thorough drying through appropriate parameter selection at each stage.
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 approach reduces energy consumption by up to 16.61% while maintaining similar drying performance, avoiding overheating and ensuring efficient moisture removal without damaging clothes, through the strategic adjustment of airflow and temperature throughout the drying process.
Implementation Method 1
a heater, such as a combustion chamber
Implementation Method 2
a blower that moves the air into the dryer drum
Implementation Method 3
a drum that rotates for drying clothes
Implementation Method 4
an exhaust system that removes moisture from the drum
Data Source
AI summary
Energy efficiencies are achieved in a dryer or washer/dryer by selectively varying temperature ranges, time periods, heater power levels, and air flow rates. Efficiency improvements on the order of 16% were obtained over typical constant power, constant temperature, timed drying cycles by varying one or more of these parameters. Efficiencies can also be improved by drawing air from alternative warm sources such as an attic or warm external environment, or by heat recovery from dryer exhaust passages.