Laundry Dryer Condensate Management for Sequential Heat Pump Flushing
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Solution Overview
Problem
Conventional laundry drying devices with heat pumps face performance issues due to condensate wetting the condenser, which is typically avoided by keeping condensate levels low, but this contradicts the need for sufficient condensate for effective flushing.
Innovation Solution
A device with a condensate management system that increases the condensate level in the condensate pan by draining from the tank before flushing, allowing for a controlled condensate reservoir and sequential flushing of the evaporator and condenser using a valve unit and control electronics to optimize condensate usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If condensate is regularly discharged from the floor pan to keep condensate level low, then condenser performance is maintained, but insufficient condensate is available for effective flushing of the heat pump components
Solution Approach 1:
The system performs preliminary action by accumulating condensate in the condensate tank during normal operation, then releasing it in advance before the flushing operation begins. The control unit opens the flushing valve only after sufficient condensate has been accumulated, ensuring both condenser performance during drying and adequate flushing capability.
Solution Approach 2:
The condensate tank serves as an intermediary storage component between the condensate pan and the flushing device. It temporarily holds condensate during normal operation and releases it when flushing is required, mediating between the conflicting requirements of maintaining low condensate levels for condenser performance and providing sufficient condensate for flushing.
2Quantity of substance
If condensate is accumulated in the condensate pan for flushing, then sufficient condensate is available for flushing, but condensate wets the condenser and impairs its performance
Solution Approach 1:
The system segments the condensate management into two distinct functional areas: a condensate pan for collecting condensate during operation and a condensate tank for storing it. The condenser is positioned to be served by the pan without direct contact with accumulated condensate, while the tank provides the reservoir needed for flushing without wetting the condenser.
Solution Approach 2:
The system performs preliminary action by accumulating condensate in the condensate tank during normal operation, then releasing it in advance before the flushing operation begins. The control unit opens the flushing valve only after sufficient condensate has been accumulated, ensuring both condenser performance during drying and adequate flushing capability.
3Quantity of substance
If the flushing valve is opened during condensate pump operation, then condensate is drained into the pan, but the pump cannot effectively pump condensate due to insufficient level
Solution Approach 1:
The control unit implements preliminary action by opening the flushing valve and allowing condensate to drain into the pan before activating the condensate pump. This ensures sufficient condensate level is present in the pan to enable effective pump operation and prevent air intake or inefficiency.
Solution Approach 2:
The control unit monitors the operational state and uses feedback control to sequence the flushing valve and pump activation. It opens the flushing valve first, observes the condensate level increase, and then activates the pump when conditions are favorable, ensuring optimal pump performance.
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 ensures effective flushing of the heat pump components while minimizing condensate-induced performance impairment, allowing for efficient drying with reduced energy consumption and cycle duration.
Implementation Method 1
heat is extracted from the exhaust air exiting the drying chamber by means of an evaporator of the heat pump and is fed back to the process air that has entered the process air system in a refrigerant circuit of the heat pump by means of a condenser of the heat pump
Implementation Method 2
at least one condensate pump for pumping a liquid contained in the condensate pan into the condensate tank
Implementation Method 3
at least one flushing device connected to the condensate tank for flushing an evaporator of the heat pump
Data Source
Figure 1
AI summary
Device (1) for drying laundry comprising a process air system (3), a heat pump (7), a condensate tray (13), a condensate container (14), a condensate pump (15), an evaporator rinsing device (17) and a rinsing valve (18). To provide a more effective means of cleaning a condenser (8) of the heat pump (7), the device (1) has at least one valve unit (19) connected between the condensate pump (15) and the condensate tank (14), at least one flushing unit (20) connected to the valve unit (19) for flushing a condenser (8) of the heat pump (7), and at least one control electronics unit (6) for controlling the condensate pump (15), the flushing valve (18), and the valve unit (19), wherein the valve unit (19) is configured such that in a first switching position it connects the condensate pump (15) to the condensate tank (14), and in a second switching position it connects the condensate pump (15) to the flushing unit (20).and wherein the control electronics (6) are configured to control the condensate pump (15), the flushing valve (18) and the valve unit (19) such that, before the valve unit (19) switches to the second switching position and the condensate pump (15) is activated, the flushing valve (18) is opened with the condensate pump (15) deactivated for a predetermined period, which ends before the valve unit (19) switches to the second switching position and the condensate pump (15) is activated.