Variable Speed Blower Fan for Balanced Moisture Removal in Dryers
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Solution Overview
Problem
Current laundry appliances with constant speed blower fans and closed loop refrigerant systems suffer from inefficiencies due to imbalances between moisture removal and supply rates, leading to suboptimal drying performance.
Innovation Solution
A laundry treatment appliance with a variable speed blower fan that adjusts its rotational speed based on the condensation capacity and mass flow rate of moisture in the process air, ensuring a balanced ratio to optimize drying efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant speed blower fan is used, then the device complexity is reduced, but the drying efficiency deteriorates due to imbalance between moisture removal and supply rates
Solution Approach 1:
The blower fan is designed with variable speed capability, transitioning from a fixed constant speed operation to a dynamic system that can adjust its rotational speed. The controller receives inputs from temperature and humidity sensors, then dynamically adjusts the blower fan speed to match the actual drying conditions, resolving the contradiction between device simplicity and drying efficiency.
Solution Approach 2:
A feedback control system is implemented where temperature sensors and humidity sensors continuously monitor the drying chamber conditions. The controller processes this feedback information and adjusts the blower fan speed accordingly, creating a closed-loop system that optimizes drying efficiency while maintaining reasonable device complexity.
2Productivity
If the blower fan operates at maximum speed continuously, then the moisture supply rate increases, but the energy consumption increases and may exceed the condensation capacity
Solution Approach 1:
The blower fan operates dynamically at variable speeds rather than continuously at maximum speed. The controller adjusts the fan speed based on real-time humidity and temperature conditions, allowing the system to match moisture supply rate with condensation capacity, thereby reducing energy consumption while maintaining productivity when conditions permit.
Solution Approach 2:
The rotational speed parameter of the blower fan is changed dynamically based on operating conditions. By adjusting this key parameter, the system optimizes the balance between moisture supply rate and energy consumption, avoiding the wasteful continuous maximum speed operation while preventing the condensation capacity from being exceeded.
3Device complexity
If the closed loop system and air flow system are operated at constant speeds, then the device complexity is reduced, but the drying efficiency deteriorates due to imbalance between moisture removal and supply rates
Solution Approach 1:
The system transitions from constant speed operation of both the closed loop refrigerant system and the air flow system to a dynamic configuration where the blower fan speed can be adjusted independently. This allows the air flow system to be dynamically matched with the condensation capacity of the refrigerant system, improving drying efficiency without significantly increasing overall device complexity.
Solution Approach 2:
A feedback control mechanism monitors the balance between moisture supply rate (from the air flow system) and moisture removal rate (by the closed loop system). Based on this feedback, the controller adjusts the blower fan speed to achieve optimal balance, resolving the contradiction between system simplicity and drying efficiency.
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 drying efficiency by precisely regulating air flow and moisture removal, matching the blower fan's speed to the system's capacity, thereby improving the overall performance of the drying cycle.
Implementation Method 1
The process air is conditioned by a conditioning system, e.g., to remove moisture from the process air after the air has absorbed water from articles and also heats the air to increase the moisture capacity of the air
Implementation Method 2
the moisture content in the air from the dryer is reduced by condensation over the evaporator
Implementation Method 3
a blower fan operable to move process air along the process air flow path
Data Source
AI summary
A laundry treatment appliance includes a cabinet; a drum rotatably mounted within the cabinet; a sealed system; a duct system; a blower fan capable of operating at variable rotational speeds; and a controller configured to perform an operation. The operation includes directing the blower fan at a preliminary rotational speed; determining a condensation capacity of the sealed system with regards to the process air in the duct system; determining a mass flow rate of moisture in the process air while directing the blower fan at the preliminary rotational speed; determining a target rotational speed of the blower fan corresponding to a set ratio of the determined condensation capacity to the determined mass flow rate; and directing the blower fan at the determined target rotational speed.