Air Conditioning Refrigerant Control for Priority Heat Exchangers
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Solution Overview
Problem
Conventional air-conditioning apparatuses fail to increase the heat exchange performance of high-priority heat exchangers by merely adjusting the pressure reducing devices, leading to insufficient heating performance when all indirect indoor heat exchangers are used for heating operations, and the flow rate of the heat medium is insufficient for heating loads in mixed water-cooling and water-heating modes.
Innovation Solution
The air-conditioning apparatus includes a compressor, four-way valves, intermediate heat exchangers for heat exchange with a heat medium, and direct heat exchangers for indoor air, with a controller that adjusts the compressor operation capacity and expansion device opening degrees to prioritize the heat exchange performance of specific heat exchangers, increasing the compressor capacity and reducing the refrigerant flow rate in non-priority heat exchangers to enhance the heat exchange performance of priority heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor capacity is increased to improve the heat exchange performance of priority heat exchangers, then the heating performance is improved, but the refrigerant flow rate in non-priority heat exchangers becomes insufficient
Solution Approach 1:
The patent applies local quality by differentiating the refrigerant flow requirements for different heat exchangers. Priority heat exchangers receive increased refrigerant flow through higher compressor capacity, while non-priority heat exchangers have their flow regulated down through expansion device control. This localized differentiation allows the system to optimize heat exchange performance where needed without wasting refrigerant on secondary locations.
Solution Approach 2:
The patent implements dynamics by making the compressor capacity variable rather than fixed. The controller dynamically adjusts the compressor operation capacity based on the priority status of different heat exchangers and the current heating load requirements. This dynamic adjustment enables the system to flexibly allocate refrigerant flow to meet changing performance requirements.
2Productivity
If the refrigerant flow rate in non-priority heat exchangers is reduced to improve priority heat exchanger performance, then the heat exchange performance is improved, but the overall system heating performance becomes insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the compressor operation capacity parameter. When priority heat exchangers require enhanced performance, the controller increases the compressor capacity parameter, which increases the overall refrigerant circulation. This parameter change ensures that even though non-priority heat exchangers receive reduced flow allocation, the total system heating capacity is maintained through the higher overall compressor output.
3Productivity
If the expansion device opening degree is adjusted to control refrigerant flow rate, then the heat exchange performance is improved, but the heat medium flow rate becomes insufficient for heating loads
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the expansion device opening degrees based on the priority status of heat exchangers before the heating demand occurs. When a heat exchanger is designated as priority, the system proactively configures the expansion devices to ensure adequate refrigerant flow will be available when heating is needed, preventing heat medium flow insufficiency before it occurs.
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 increases the heat exchange performance of priority heat exchangers while preventing excessive performance in secondary heat exchangers, ensuring sufficient heating and cooling performance even under large heating or cooling loads, and optimizing the heat medium flow rate for efficient heating and cooling.
Implementation Method 1
an outdoor unit including a compressor, a four-way valve, and an outdoor heat exchanger, and a plurality of indoor units each including an expansion valve and an indoor heat exchanger
Implementation Method 2
adjusting a flow rate of the refrigerant in the entire refrigeration cycle circuit by adjusting an operation capacity of the compressor using a condensing temperature of the indoor heat exchangers as a target value
Implementation Method 3
an evaporating pressure and a degree of superheat are adjusted within ranges determined in a predetermined extent
Implementation Method 4
an outdoor unit including a compressor
Implementation Method 5
each of the indoor units adjusts a flow rate of the refrigerant in the indoor heat exchanger by adjusting an opening degree of the expansion valve
Data Source
Figure 1~2
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AI summary
An air-conditioning apparatus includes a compressor 11, an indoor heat exchanger 13 configured to function as a condenser or an evaporator, indoor heat exchanges 31 a and 31 b each configured to function as a condenser or an evaporator, a plurality of expansion valves 32a and 32b each provided for a corresponding one of the indoor heat exchangers 31 a and 31 b and each configured to adjust a flow rate of a refrigerant that flows through the corresponding indoor heat exchanger 31 a or 31 b, and a controller (202, 203) configured to control an operation capacity of the compressor 11 and opening degrees of a plurality of expansion devices. When increasing heat exchange performance of the indoor heat exchanger 31 b, the controller increases the operation capacity of the compressor 11 and controls the opening degree of the expansion valve 32a corresponding to the indoor heat exchanger 31 a to decrease the flow rate of the refrigerant that flows through the indoor heat exchanger 31 a.