Air Conditioner Fan Deceleration Control for Heating Mode Stability
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Solution Overview
Problem
Air conditioning apparatuses experience excessive refrigerant pressure increases when switching between heating modes, leading to compressor shutdowns due to sudden fan speed decreases, which can occur when switching from hot air mode to normal heating mode or vice versa.
Innovation Solution
The air conditioning apparatus includes a control unit that adjusts the rotational speed of the indoor fan at a slower rate when switching between heating modes, using a second rate if the refrigerant pressure is above a threshold, and a temperature sensor to determine when to apply this slower rate, eliminating the need for a pressure sensor and allowing precise control of fan speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotational speed of the fan is suddenly decreased when switching from hot air mode to normal heating mode, then the heating efficiency is improved, but the refrigerant pressure increases excessively causing compressor shutdown
Solution Approach 1:
The patent applies dynamics by making the fan rotational speed adjustable and controllable at different rates. The control unit dynamically adjusts the fan speed based on the current operating mode and refrigerant pressure conditions, switching between first rate (faster decrease) and second rate (slower decrease) to optimize both heating efficiency and prevent compressor shutdown.
Solution Approach 2:
The patent changes the parameter of fan rotational speed adjustment rate based on operating conditions. By changing the rate parameter from first rate to second rate depending on refrigerant pressure thresholds, the system resolves the contradiction between improving heating efficiency and maintaining compressor reliability.
2Measurement precision
If a pressure sensor is used to control fan speed based on refrigerant pressure, then the control precision is improved, but the device complexity increases
Solution Approach 1:
The patent uses temperature as an intermediary parameter to indirectly measure refrigerant pressure conditions. Instead of directly measuring pressure with a pressure sensor, the system measures the temperature of the heat exchanger (which correlates with pressure) and uses this temperature information to control fan speed, thereby avoiding the need for a pressure sensor.
Solution Approach 2:
The patent substitutes a pressure sensor (mechanical/electrical measurement device) with a temperature sensor and control algorithm. This replacement reduces device complexity while maintaining adequate control precision through the relationship between temperature and pressure in the refrigerant system.
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 suppresses excessive refrigerant temperature increases in the indoor heat exchanger, allows for controlled fan speed adjustments based on refrigerant pressure, and simplifies control processes without requiring a pressure sensor, ensuring stable operation.
Implementation Method 1
The indoor heat exchanger generates conditioned air by exchanging heat between refrigerant and room air
Implementation Method 2
The temperature sensor detects the temperature of the condenser
Data Source
AI summary
An air conditioning apparatus is equipped with an indoor fan, an indoor heat exchanger, and a control unit. The indoor heat exchanger generates conditioned air by exchanging heat between refrigerant and room air. The control unit sets operating modes. The control unit controls the rotational speed of the indoor fan. More specifically, in a case where the operating mode has been switched from one to the other of a normal heating mode and a hot air mode in which the conditioned air higher in temperature than in the normal heating mode is generated, the control unit lowers the rotational speed at a second rate that is slower than a first rate which is a rate of decrease in the rotational speed in a case where the operating mode is set to the normal heating mode.