Heat Pump Dryer Airflow Pulsing for Faster Low-Energy Drying
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Solution Overview
Problem
Tumble dryers with Peltier heat pumps experience long drying times and high energy consumption due to low connected load and inefficient pump performance, which cannot be effectively shortened without compromising energy efficiency.
Innovation Solution
A method where the process air flow to the heat pump is generated in a clocked manner during the drying process, initially switching off the air flow until a temperature threshold is reached, then pulsing it to maintain optimal temperatures and efficiency, particularly for Peltier heat pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the connected load of the heat pump is increased to shorten drying time, then the drying time is reduced, but the energy efficiency deteriorates
Solution Approach 1:
The patent implements periodic action by alternately switching the process air flow between active and inactive states during the heating phase. The control unit activates the process air flow only during specific time intervals when the heat pump temperature exceeds a threshold value, rather than maintaining continuous flow. This periodic activation allows the heat pump to reach higher temperatures more efficiently during active periods while reducing overall energy consumption during inactive periods, thereby resolving the contradiction between drying time and energy efficiency.
2Productivity
If the connected load of the heat pump is increased to improve pump performance, then the pump performance is improved, but the energy consumption increases
Solution Approach 1:
The patent applies dynamics by making the process air flow dynamic rather than static. The control unit continuously monitors the heat pump temperature and dynamically adjusts the process air flow activation accordingly. When the temperature exceeds the threshold, the flow is activated to enhance cooling and maintain pump performance; when the temperature is within acceptable ranges, the flow is deactivated to reduce energy consumption. This dynamic adjustment resolves the contradiction between maintaining high pump performance and minimizing energy consumption.
3Productivity
If the heating phase is extended to reach higher temperatures, then the pump performance is improved, but the drying time increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring the heat pump temperature and using this information to control the process air flow activation. The control unit compares the current temperature with a threshold value and adjusts the process air flow accordingly. This feedback mechanism allows the system to reach higher temperatures more quickly by activating the process air flow only when necessary, thereby improving pump performance without extending the heating phase duration, thus resolving the contradiction between pump performance and heating phase duration.
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 significantly shortens drying time and reduces energy consumption by improving pump performance and efficiency, ensuring quick heating and optimal energy management throughout the process.
Implementation Method 1
The heat pump can be a so-called Peltier heat pump, i.e. a heat pump that works with semiconductor components (so-called Peltier elements) that use the thermoelectric effect to produce a heat flow or a temperature difference
Implementation Method 2
a process air flow is generated in a clocked manner during a first process phase of the drying process
Data Source
AI summary
The invention relates to a method for operating a household appliance for laundry care, according to which a heat pump of the household appliance is activated and electrically supplied with energy in order to dry the laundry, and a process air stream flowing towards the heat pump is generated during a drying process. The process air stream is generated in a clocked manner during a first process phase of the drying process.