Indoor Airflow Control to Prevent Cold Drafts in Air Conditioners
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Solution Overview
Problem
Existing air conditioners, especially multi-unit systems, often result in excessively low temperatures of air blown into rooms due to imbalances in indoor and outdoor unit capacities, leading to discomfort from cold winds, as they rely primarily on compressor frequency control without adequate management of air blower speeds and valve operations.
Innovation Solution
The air conditioner incorporates a variable rotational speed range for the outdoor air blower, controlled by outdoor temperature sensors, and adjusts the indoor unit's operation through on/off control and compressor frequency management to maintain comfortable temperatures, reducing coolant circulation and preventing excessive cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compressor frequency is lowered to reduce cooling capacity, then energy consumption decreases, but the air blower continues to operate at high speed causing excessively low air temperature and cold-wind discomfort
Solution Approach 1:
The patent applies dynamics by making the air blower speed variable and dynamically adjusting it according to the compressor operational frequency and outdoor temperature conditions. The control device continuously monitors compressor frequency and adjusts the air blower rotational speed accordingly, transforming the static high-speed operation into a dynamic adaptive system that prevents excessive cooling while maintaining energy efficiency
Solution Approach 2:
The patent changes the operational parameters of the air blower based on compressor frequency and outdoor temperature. When outdoor temperature is 20°C or lower and compressor frequency is 30 Hz or lower, the air blower rotational speed is restricted to a lower range, preventing the parameter combination that causes excessive cooling while allowing full speed operation under different conditions
2Temperature
If the air blower rotational speed is reduced to prevent excessive cooling, then air temperature comfort improves, but cooling efficiency decreases
Solution Approach 1:
The system dynamically adjusts air blower speed based on real-time compressor frequency and outdoor temperature conditions, optimizing the balance between comfort and efficiency. Rather than using a fixed low speed, the control device continuously adapts the blower speed to match the actual cooling demand, maintaining high cooling efficiency when needed while preventing excessive cooling when the compressor operates at low frequency
3Device complexity
If the lower limit of air blower rotational speed is fixed, then control simplicity is maintained, but adaptability to varying outdoor temperatures and compressor frequencies is insufficient
Solution Approach 1:
The patent transforms the fixed lower limit into a dynamic variable that adapts to outdoor temperature and compressor frequency conditions. The control device implements a temperature-dependent control strategy where the lower rotational speed limit is adjusted based on outdoor temperature thresholds, enabling the system to adapt to varying environmental conditions while maintaining relatively simple control logic
Solution Approach 2:
The patent changes the operational parameters of the air blower based on outdoor temperature and compressor frequency. By establishing temperature-based thresholds (e.g., 20°C), the system dynamically adjusts the permissible rotational speed range, improving adaptability to different environmental conditions while keeping the control mechanism straightforward and manageable
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 solution effectively prevents excessively low air temperatures, enhancing comfort by balancing cooling capacity and reducing energy consumption through optimized blower speed and compressor frequency control, ensuring a comfortable air-conditioning experience.
Implementation Method 1
an outdoor unit including a compressor
Implementation Method 2
an outdoor heat exchanger and an indoor heat exchanger
Implementation Method 3
an outdoor expansion valve, and an indoor expansion valve
Implementation Method 4
an air blower for the outdoor unit, and an air blower for the indoor unit
Data Source
Figure 1
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Figure 3
AI summary
In a cooling operation of an air conditioner, the control for a comfortable room temperature is carried out to prevent a cold-wind feeling due to a drop in temperature of air blown out of an indoor unit (21). The lowering of the temperature of air blown out of an indoor unit (21) during the cooling operation of an air conditioner is prevented to realize a comfortable indoor air-conditioning by the control of the rotational speed of an air blower for the indoor unit based on a temperature of air blown into a room, an outdoor outside air temperature and a operational frequency of a compressor (1), the control of the opening of an indoor expansion valve (7) based on the temperature of air blown into the room and the on-off control of a solenoid valve (10) for a bypass circuit based on a temperature of air discharged from the compressor (1).