Heat Exchanger Cleaning Fan Control for Overflow-Free Drying Airflow
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Solution Overview
Problem
In household appliances like laundry drying devices with heat pumps, the second heat exchanger often gets contaminated with fluff and hair, leading to reduced effectiveness, and existing cleaning methods can cause excess water to enter the air flow channel, potentially moistening laundry and affecting drying performance.
Innovation Solution
A system where a fan and cleaning device are used to direct cleaning liquid onto both heat exchangers, with the fan's operation controlled based on the collection container's filling level to prevent overflow and ensure effective cleaning without carrying water into the air flow channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan is operated at high speed to improve cleaning effectiveness of the second heat exchanger, then more cleaning liquid is directed onto the second heat exchanger, but cleaning liquid overflows from the collection container and enters the air flow channel
Solution Approach 1:
The control device monitors the filling level of the collection container and adjusts the fan's operating state accordingly. When the collection container approaches full capacity, the control device reduces or stops fan operation to prevent cleaning liquid from being carried into the air flow channel, thus eliminating the harmful effect while maintaining cleaning effectiveness during normal operation
Solution Approach 2:
The fan's operating state is dynamically adjusted based on real-time conditions (collection container filling level) rather than running at constant high speed. This allows the system to optimize cleaning performance when needed while preventing water contamination when the collection container is full
2Reliability
If the fan operates continuously to clean both heat exchangers, then cleaning coverage is improved, but energy consumption increases
Solution Approach 1:
Instead of continuous operation, the fan is operated periodically based on the collection container's filling level. The fan runs at high speed when cleaning is needed and the container has capacity, then operates at reduced speed or stops when the container is full, creating a periodic operation pattern that reduces overall energy consumption while maintaining cleaning coverage
Solution Approach 2:
The fan's operating parameters (speed, runtime) are changed based on the collection container's filling level. The control device adjusts these parameters dynamically to optimize the balance between cleaning coverage and energy consumption, running the fan only when necessary and at appropriate speeds
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 allows for efficient cleaning of both heat exchangers while preventing water from entering the air flow channel, maintaining even drying and appliance performance.
Implementation Method 1
a fan (7) for moving air in an air flow channel in a flow direction
Implementation Method 2
a cleaning device (5) for cleaning the first heat exchanger (4) with cleaning liquid (W) under a high impulse as a cleaning agent
Implementation Method 3
The first heat exchanger (4) cools the process air P, which condenses as a result
Implementation Method 4
the second heat exchanger (6), which heats up the process air P again
Data Source
Figure 1
Figure 2
AI summary
A household appliance 1 has a fan 7 for moving air in an air flow duct 3 in a flow direction, a first heat exchanger 4 and a second heat exchanger 6, which are arranged one behind the other in the air flow duct 3 with respect to the flow direction, a cleaning device 5 for cleaning the first heat exchanger 4 with cleaning liquid W, with at least part of the cleaning liquid W being able to be directed towards the second heat exchanger 6 when the cleaning device 5 and the fan 7 are in operation, and a collection container 11 for the cleaning liquid W dripping off the second heat exchanger 6, with the fan 7 being dependent can be operated from a filling level L of the collection container 11 . A method is used to operate a household appliance 1, with the fan 7 being operated as a function of a filling level L of the collection container 11. The invention can be applied particularly advantageously to laundry drying devices, in particular to circulating air laundry drying devices. The invention can be applied particularly advantageously to household appliances with a heat pump.