Occupancy-Based Indoor Fan Control for Thermo-Off Air Cooling
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Solution Overview
Problem
Conventional air-conditioning apparatuses face issues with high power consumption and wasteful fan operation due to repeated thermo ON and OFF cycles based on temperature and humidity comparisons, even when no human is present, leading to excessive cooling and unnecessary energy use.
Innovation Solution
An air-conditioning apparatus with an outdoor and indoor unit, featuring a compressor, heat exchangers, an indoor fan, temperature and human-body presence detectors, and control means that stop the refrigeration cycle and indoor fan when the room is unoccupied, optimizing power usage by extending the thermo OFF period and ensuring comfortable cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the indoor fan is continuously operated to increase cool feeling during thermo OFF operation, then comfortableness is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the fan operation status changeable based on detected conditions. The control unit dynamically adjusts the fan operation between continuous operation, stopped operation, and reduced rotation speed operation according to temperature differences, humidity levels, and user presence detection, thereby optimizing the balance between comfortableness and power consumption
2Use of energy by moving object
If the compressor is stopped to reduce power consumption during thermo OFF operation, then power consumption is reduced, but the room temperature may rise above set temperature
Solution Approach 1:
The patent applies feedback by continuously monitoring temperature and humidity conditions and using this information to control fan operation. The control unit receives feedback from temperature sensors and humidity sensors, and adjusts fan operation accordingly - maintaining fan operation during thermo OFF when humidity is high to enhance cool feeling, and stopping or reducing fan operation when humidity is low to save power
3Ease of operation
If the indoor fan operates based on humidity comparison without user presence detection, then cooling is provided, but power is consumed wastefully when no user is present
Solution Approach 1:
The patent applies self-service by enabling the system to automatically detect user presence and adjust its operation accordingly. The user presence detection unit automatically determines whether a user is present, and the control unit automatically adjusts fan operation based on this detection, eliminating the need for manual intervention and preventing wasteful power consumption when no user is present
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 reduces power consumption by minimizing fan operation when no human is present and extends the thermo OFF period, providing a comfortable cooled environment while minimizing energy waste.
Implementation Method 1
an indoor heat exchanger that executes part of the refrigeration cycle
Implementation Method 2
an outdoor unit housing a compressor
Implementation Method 3
an expansion valve each of which executes part of a refrigeration cycle
Data Source
AI summary
While cooling operation is continued, a compressor is stopped when a detection temperature Tm reaches a control temperature Tc that is a lower temperature than a set temperature Ts only by a bias temperature ΔTb, and rotation of a turbofan is stopped if a human body is not present in a room R, or the rotation of the turbofan is continued and a value of the detection temperature Tm is corrected to a correction detection temperature Ta that is a lower temperature than the detection temperature Tm only by a predetermined temperature correction amount ΔTm. While the correction detection temperature Ta is a temperature that is equal to or lower than the set temperature Ts (the control temperature Tc for prevention of hunting) (Ta=Tm−ΔTm≦Tc), the rotation of the turbofan is continued as long as a person is present in the room R, and thermo ON is resumed if the correction detection temperature Ta exceeds the set temperature Ts (Ta>Ts).