Cooling Fan Control for Heat-Pump Dryer Compressor Restart
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Solution Overview
Problem
Heat-pump laundry treatment apparatuses face inefficiencies and challenges in maintaining optimal operation, particularly in restarting the compressor after suspension, due to temperature fluctuations and pressure imbalances within the heat-pump system.
Innovation Solution
A method involving a cooling fan that maintains or increases its operation rate during compressor suspension to cool heat-pump system components, especially the compressor, and continues this cooling after resuming compressor operation for a predetermined period to ensure efficient heat-pump performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the compressor operation is suspended to avoid overpressures in the heat-pump system, then the refrigerant overpressure is reduced, but the cooling of heat-pump system components becomes insufficient and restart probability decreases
Solution Approach 1:
The cooling fan is activated or its conveyance rate is increased before the compressor is suspended, and continues to operate at an elevated rate for a predetermined period after suspension. This preliminary and extended cooling action ensures that the heat-pump system components are adequately cooled during and after the suspension period, maintaining optimal conditions for compressor restart while still allowing pressure to equalize.
Solution Approach 2:
The cooling fan operation is maintained continuously through the compressor suspension period and extends for a predetermined time after suspension ends. This continuous cooling action ensures that the cooling function does not lapse during the critical transition period when the compressor is suspended and when it is about to restart, thereby maintaining system reliability without compromising pressure management.
2Loss of energy
If the cooling fan operation is stopped when the compressor is suspended, then energy consumption is reduced, but the heat-pump system components overheat and performance deteriorates
Solution Approach 1:
The cooling fan is activated or its conveyance rate is increased before the compressor suspension begins, ensuring that cooling is already in progress before the compression stops. This preliminary action prevents temperature spikes that would occur if cooling were stopped simultaneously with compression, while the extended operation after suspension ensures adequate cooling throughout the entire suspension period.
Solution Approach 2:
The cooling fan operates in a controlled periodic manner: it maintains or increases its conveyance rate during the predetermined period after compressor suspension, then reduces or stops operation after this period expires. This periodic control pattern balances energy consumption with cooling requirements, providing intensive cooling when needed (during and after suspension) and reducing energy use when the system is stable.
3Reliability
If the cooling fan conveyance rate is increased during compressor suspension, then the cooling effect is enhanced and restart probability improves, but energy consumption increases
Solution Approach 1:
The cooling fan's conveyance rate is increased before compressor suspension and maintained at the elevated rate for a predetermined period after suspension. This timing ensures that the enhanced cooling occurs precisely when the system needs it most (during and immediately after suspension when pressure equalization is occurring), maximizing restart probability while limiting the duration of high energy consumption to only when necessary.
Solution Approach 2:
The cooling fan's conveyance rate is dynamically adjusted based on the compressor operation state: it is increased during and after suspension to improve cooling effectiveness and restart probability, then reduced or stopped after the predetermined period expires. This dynamic adjustment optimizes the balance between cooling performance and energy consumption, applying high cooling power only during the critical suspension transition period.
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 enhances the probability of successful compressor restart, maintains efficient heat-pump performance, and reduces downtime by actively managing temperature and pressure within the system, thus improving overall operational efficiency.
Implementation Method 1
The cooling fan is adapted to convey cooling air over the at least one heat-pump system component
Implementation Method 2
a compressor which is adapted to circulate a refrigerant through the heat-pump system
Data Source
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AI summary
The invention relates to a method for operating a cooling fan (54) for cooling at least one heat-pump system component (14) in a heat-pump laundry treatment apparatus, in particular heat-pump system dryer or heat-pump system washer dryer, wherein a compressor (14) is adapted to circulate a refrigerant through the heat-pump system (4) during a laundry drying operation and wherein a cooling fan (54) is adapted to convey cooling air (C) over the at least one heat-pump system component (14). In case that the compressor operation is suspended, and if the cooling fan (54) is active at the time of suspending the compressor operation, the cooling fan (54) operation is maintained at the same conveyance rate (r_convey) or the conveyance rate (r_convey) of the cooling fan (54) is increased. In case that the compressor operation is suspended, and if the cooling fan (54) is not active at the time of suspending the compressor operation, the cooling fan (54) is activated for conveying cooling air (C) to the at least one heat-pump system component (14). Further the invention relates to a laundry treatment apparatus adapted to implement the method.