Heat Pump Dryer Compressor Control for Circuit Board Cooling
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Solution Overview
Problem
Heat pump laundry dryers face issues with circuit board overheating due to high compressor speeds, leading to potential damage and inefficient energy use, as existing cooling methods like natural convection are insufficient for managing increased temperatures during varying drying loads.
Innovation Solution
A variable speed compressor system with a temperature sensor and control unit that adjusts the speed of the compressor and a cooling fan to maintain optimal circuit board temperatures, using forced convection cooling and strategic placement of components to prevent overheating and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor speed is increased to reduce drying time and energy consumption, then the productivity is improved, but the circuit board temperature increases excessively causing potential damage
Solution Approach 1:
A cooling fan is introduced as an intermediary device between the heat source (compressor/circuit board) and the surrounding environment. The cooling fan actively removes heat from the circuit board area, enabling the compressor to operate at high speeds without causing overheating damage to the control electronics.
Solution Approach 2:
The cooling fan speed is dynamically adjusted based on the compressor operating conditions. When the compressor runs at high speed, the cooling fan increases its rotation speed to provide sufficient cooling. This dynamic response allows the system to maintain both high productivity and safe operating temperatures.
2Device complexity
If a heat sink is used for natural convection cooling of the circuit board, then the device complexity is minimized, but the cooling effectiveness is insufficient under high compressor load
Solution Approach 1:
The cooling system transitions from passive natural convection to active forced convection by introducing a cooling fan. This dynamic enhancement of the cooling mechanism provides sufficient heat dissipation under high compressor load conditions while maintaining circuit board reliability, with the fan being activated only when needed based on operating conditions.
3Temperature
If the cooling fan speed is increased to cool the circuit board, then the temperature is reduced, but the energy consumption increases
Solution Approach 1:
The cooling fan operates with variable speed control rather than running continuously at maximum speed. The fan speed is dynamically adjusted to match the cooling demand, which varies with compressor load and ambient conditions. This ensures adequate cooling while minimizing unnecessary energy consumption during low-load operations.
Solution Approach 2:
The system uses temperature sensing and control logic to create a feedback mechanism that regulates cooling fan operation. When the circuit board temperature exceeds a threshold or the compressor operates at high speed, the cooling fan is activated or its speed is increased. When cooling demand is low, the fan speed is reduced or it stops, optimizing energy consumption based on actual thermal conditions.
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
The solution effectively prevents circuit board damage, increases compressor efficiency, and reduces energy consumption by dynamically adjusting compressor and fan speeds, ensuring reliable operation and improved energy management.
Implementation Method 1
The components on the circuit board are cooled by a heat sink and a cooling fan that cools the heat sink by forced convection
Implementation Method 2
a heat sink (10) that provides the components on the circuit board (9) to be cooled
Data Source
AI summary
The present invention relates to a heat pump laundry dryer (1) comprising a drum (2) wherein the laundry to be dried is placed, a processing air fan (3), an air circulation duct (4) wherein the air cycle is performed by means of the processing air fan (3), a variable speed compressor (5) that performs the refrigerant cycle and provides the suction and discharge of the refrigerant, the speed of which is adjusted in accordance with the drying load, an evaporator (6) that cools and condenses the processing air, a condenser (7) that provides the processing air to be heated, an expansion member (8) disposed on the cooling line, between the condenser (7) and the evaporator (6), a circuit board (9) that drives the compressor (5), and a heat sink (10) that provides the components on the circuit board (9) to be cooled.