Multi-Room Air Conditioning Control for Stable Priority Heating
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Solution Overview
Problem
Conventional multi-room air-conditioning systems face challenges in increasing the heating performance of indoor units beyond their designed capacity without compromising the performance of other units, particularly when adjusting refrigerant flow rates and condensing temperatures, leading to difficulties in controlling refrigerant flow and achieving optimal heating performance.
Innovation Solution
The system includes a compressor, multiple use side heat exchangers, expansion devices, and a controller that adjusts the heat exchange capacity and refrigerant flow rates to prioritize the performance of a specific indoor unit during simultaneous cooling and heating operations, allowing for increased heating performance by decreasing the heat exchange capacity of the outdoor heat exchanger and reducing refrigerant flow in other units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the refrigerant flow rate is increased to improve heating performance of an indoor unit, then the heating capacity increases, but the condensing temperature control becomes difficult and system stability deteriorates
Solution Approach 1:
The patent changes the condensing temperature target value as a parameter to enable higher refrigerant flow rates. By allowing the condensing temperature target to be higher than the standard value, the system can increase heating capacity while maintaining stable operation through coordinated control of the expansion valve and outdoor fan speed.
Solution Approach 2:
The patent implements dynamic control where the condensing temperature target value is adjusted based on system conditions. The controller dynamically modifies the target condensing temperature and coordinates it with expansion valve opening and outdoor fan speed to maintain system stability while achieving enhanced heating performance.
2Power
If the condensing temperature is increased to improve heating performance, then the heating capacity increases, but the energy efficiency decreases
Solution Approach 1:
The patent uses dynamic control to adjust the condensing temperature target value only when enhanced heating performance is required. The controller monitors system conditions and temporarily increases the condensing temperature target, coordinating it with expansion valve and fan control to minimize energy efficiency loss while achieving the desired heating capacity increase.
Solution Approach 2:
The patent applies local quality by selectively increasing heating capacity for a specific indoor unit that requires enhanced performance, rather than uniformly increasing capacity across all units. This targeted approach minimizes overall energy consumption while meeting specific heating demands.
3Power
If the expansion valve opening is increased to improve refrigerant flow, then the heating performance increases, but the degree of subcooling control becomes difficult
Solution Approach 1:
The patent implements dynamic control where the expansion valve opening is adjusted in coordination with changes in the condensing temperature target value. When the condensing temperature target is increased, the expansion valve opening is simultaneously adjusted to maintain appropriate subcooling levels, ensuring both enhanced heating performance and precise subcooling control.
Solution Approach 2:
The patent uses feedback control to monitor the degree of subcooling and adjust the expansion valve opening accordingly. The controller continuously measures subcooling conditions and modifies the expansion valve position to maintain optimal values, even when operating with elevated condensing temperature targets for enhanced heating capacity.
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 effectively enhances the heating performance of the prioritized indoor unit while preventing excessive performance in other units, ensuring balanced operation and improved heating capacity beyond the designed limits.
Implementation Method 1
a compressor (11) which compresses a refrigerant
Implementation Method 2
a plurality of use side heat exchangers (31) which function as condensers or evaporators
Implementation Method 3
a saturation temperature at which the refrigerant condenses or evaporates
Implementation Method 4
a saturation temperature at which the refrigerant condenses or evaporates
Data Source
AI summary
An air-conditioning apparatus according to the present invention includes at least indoor heat exchangers. In response to a request to increase heat exchange performance from the indoor heat exchanger, the air-conditioning apparatus decreases a heat exchange capacity of an outdoor heat exchanger and controls an opening degree of an expansion valve corresponding to the indoor heat exchanger to decrease a flow rate of a refrigerant that flows through the indoor heat exchanger.