Occupancy-Based Compressor Control to Prevent HVAC Start-Stop Cycling
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Solution Overview
Problem
Conventional air-conditioning systems experience decreased efficiency and increased power consumption due to start-stop operation of the compressor when operating at minimum rotation speed or lower in unoccupied rooms.
Innovation Solution
An air-conditioning apparatus that includes a controller to detect unoccupied rooms, adjust target indoor temperatures to reduce air conditioning load, and reset temperature correction amounts to maintain continuous compressor operation, preventing start-stop cycles and optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the rotation speed of the compressor is decreased to reduce air conditioning load in unoccupied rooms, then power consumption is reduced, but the compressor operates at minimum rotation speed or lower causing start-stop operation which decreases operation efficiency
Solution Approach 1:
The system dynamically adjusts the target indoor temperature parameter based on room occupancy status. When a room is detected as unoccupied, the controller modifies the target temperature to reduce the air conditioning load, thereby decreasing compressor operation capacity and power consumption while maintaining continuous operation above minimum speed
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors room occupancy status and adjusts the target indoor temperature accordingly. This closed-loop control ensures that the compressor operates at optimal capacity levels based on actual cooling/heating demands, preventing both excessive power consumption and inefficient start-stop cycles
2Loss of energy
If the compressor operation capacity is decreased to match reduced air conditioning load in unoccupied rooms, then energy efficiency is improved, but repeated operating and stopping occurs which increases power consumption
Solution Approach 1:
The system ensures continuous compressor operation by adjusting the target indoor temperature rather than allowing the compressor to stop. This maintains the refrigeration cycle in continuous operation, avoiding the energy losses associated with start-stop cycles while still reducing overall power consumption through optimized operating capacity
Solution Approach 2:
The compressor operation capacity is dynamically adjusted based on real-time occupancy detection and cooling/load requirements. The system transitions from static fixed-capacity operation to dynamic variable-capacity operation, optimizing energy efficiency while maintaining continuous operation to prevent start-stop inefficiencies
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
The system prevents efficiency loss and reduces power consumption by ensuring continuous compressor operation and optimizing air conditioning capacity based on occupancy, thereby enhancing operational efficiency and saving energy.
Implementation Method 1
a heat source unit 20 including a compressor 21
Implementation Method 2
an indoor unit 30...configured to perform cooling or heating of the plurality of rooms
Data Source
AI summary
A controller of an air-conditioning apparatus includes an operation control unit that controls operation of a compressor of a heat source unit based on target indoor temperatures of rooms, an unoccupied room detecting unit that detects an unoccupied room where no person is present among the rooms, and a correction amount setting unit that sets a temperature correction amount for correcting the target indoor temperature in a room controller of the unoccupied room detected by the unoccupied room detecting unit to reduce an air conditioning load for the unoccupied room. After the target indoor temperature is corrected by using the temperature correction amount in the room controller, when the operation capacity of the compressor controlled by the operation control unit is smaller than or equal to a preset operation capacity, the correction amount setting unit resets the temperature correction amount to be decreased by an adjustment amount.