Occupancy-Based Fan and Compressor Control in Air Conditioning
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Solution Overview
Problem
Conventional air-conditioning apparatuses face issues with high power consumption due to repeated thermo ON and OFF operations based on temperature and humidity comparisons, leading to unnecessary fan operation even when no one is present, resulting in excessive cooling and wasteful energy use.
Innovation Solution
An air-conditioning apparatus that stops the refrigeration cycle and indoor fan operation when no human presence is detected, using a radiation sensor to determine occupancy and adjusting the control temperature to extend the thermo OFF period, thereby reducing power consumption and ensuring comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the indoor fan operates continuously to increase cool feeling, then comfortableness is improved, but power consumption increases
Solution Approach 1:
The indoor fan operation is made dynamic by detecting human presence and adjusting fan operation accordingly. The fan operates at high speed when humans are present to provide comfort, and stops or reduces speed when no humans are present to save energy, resolving the contradiction between comfort and power consumption
Solution Approach 2:
The system uses automatic human presence detection to control fan operation without manual intervention. The air-conditioning apparatus itself monitors the environment and adjusts fan operation based on detected human presence, eliminating the need for continuous operation while maintaining comfort when needed
2Measurement precision
If the compressor operates frequently to maintain set temperature, then temperature control precision is improved, but power consumption increases
Solution Approach 1:
The control system dynamically adjusts the set temperature based on detected human presence. When humans are present, the system maintains precise temperature control at the set point. When no humans are present, the system raises the set temperature threshold, allowing the compressor to stop earlier and reducing power consumption while maintaining adequate temperature control
Solution Approach 2:
The system changes the temperature control parameter (set temperature threshold) based on human presence detection. By dynamically adjusting this parameter, the system achieves precise temperature control when needed and energy savings when the room is unoccupied
3Reliability
If the indoor fan operates based on humidity comparison to prevent excessive drying, then humidity control is improved, but power consumption increases due to unnecessary operation when no one is present
Solution Approach 1:
The system merges human presence detection with humidity-based fan control logic. The fan operation is determined by combining both humidity conditions and human presence detection, ensuring the fan only operates when both conditions warrant it - preventing excessive drying when humans are present while avoiding unnecessary operation when the room is empty
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 reduces power waste by stopping the indoor fan when no one is present and extends the thermo OFF period, providing a comfortable cooling environment while minimizing compressor and fan power consumption.
Implementation Method 1
a radiation sensor that detects presence of a human body in the room
Data Source
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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).