Multi-Unit Air Conditioning Control for Thermo-ON Coordination
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Solution Overview
Problem
In air conditioning systems with multiple indoor units in the same indoor space, individual controls lead to situations where some units are thermo-ON while others are thermo-OFF, resulting in suboptimal overall system efficiency despite high individual unit efficiencies.
Innovation Solution
An air conditioning system with a control device that relaxes the thermo-ON condition of thermo-OFF units when both types are present, allowing more units to switch to thermo-ON, thereby increasing the heat exchange area and reducing pressure differential, while maintaining thermo-OFF conditions at different timings based on set temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual temperature control is performed on each indoor unit independently, then each indoor unit can maintain its set temperature, but the overall system efficiency deteriorates when some units are thermo-ON and others are thermo-OFF
Solution Approach 1:
The patent merges the control logic of multiple indoor units by introducing a centralized control device that coordinates thermo-ON/thermo-OFF decisions across all units. When at least one unit is thermo-ON, the control device prevents other units from switching to thermo-OFF, effectively combining their operations to maintain high system efficiency while still respecting individual temperature requirements.
Solution Approach 2:
The system dynamically adjusts the thermo-ON condition based on the operational state of other indoor units. The control device continuously monitors which units are thermo-ON and modifies the thermo-ON determination for each unit accordingly, creating a dynamic control strategy that adapts to changing system conditions to optimize overall efficiency.
2Productivity
If the number of thermo-ON indoor units is increased to improve heat exchange balance, then the differential pressure between evaporation and condensation pressure reduces, but the system complexity increases
Solution Approach 1:
The patent changes the thermo-ON condition parameter dynamically based on system state. Instead of using a fixed temperature differential threshold for determining thermo-ON status, the control device adjusts this parameter in real-time based on how many units are currently thermo-ON, thereby optimizing heat exchange balance without requiring complex hardware modifications.
3Productivity
If thermo-ON condition is relaxed for thermo-OFF units, then more units can switch to thermo-ON to increase heat exchange area, but individual unit temperature control precision may deteriorate
Solution Approach 1:
The patent applies local quality by allowing different thermo-ON condition thresholds for different indoor units based on their specific operational context. The control device evaluates each unit's temperature control precision requirements individually and adjusts the relaxation of thermo-ON conditions locally, ensuring that units with stricter precision requirements maintain tighter control while others can operate with relaxed conditions to maximize heat exchange area.
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 approach enhances overall system efficiency by increasing the number of thermo-ON units, balancing heat exchange, and reducing pressure differential, while ensuring that air-conditioning capabilities meet the requirements of all units and preventing temperature imbalances.
Implementation Method 1
an outdoor unit including a heat-source-side heat exchanger for conducting heat exchange with refrigerant circulating through the usage-side heat exchangers
Data Source
AI summary
An air conditioning system includes a plurality of indoor units installed in the same indoor space, an outdoor unit and a control device. The indoor units include respective usage-side heat exchangers capable of setting set temperatures individually. The outdoor unit includes a heat-source-side heat exchanger. The control device performs temperature control using a thermo-ON condition set in advance in accordance with the set temperatures, and relaxes the thermo-ON condition of thermo-OFF indoor units when the indoor units include both those that are thermo-ON and those that are thermo-OFF and a predetermined condition is satisfied. The predetermined condition is that at least one of the plurality of indoor units continues to be thermo-ON for a first elapsed time or longer, and at least one of the plurality of indoor units continues to be thermo-OFF for a second elapsed time or longer.