Dual-Circuit Air Conditioning for Low-Leakage Cooling and Heating
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Solution Overview
Problem
Existing air-conditioning apparatuses face challenges with high refrigerant leakage risks, environmental impact, and increased energy consumption due to the use of high-pressure refrigerants like R410A, as well as safety concerns in server rooms where water-based heat mediums are not suitable.
Innovation Solution
An air-conditioning system with separate refrigerant and heat medium circuits, utilizing a compressor, heat exchangers, and relay units to efficiently transfer cooling or heating energy between an outdoor unit, refrigerant indoor units, and heat medium indoor units, allowing for direct or indirect cooling/heating operations, and incorporating check and on-off valves for refrigerant passage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-pressure refrigerant (R410A) is used for cooling operation, then cooling performance is improved, but refrigerant leakage risk increases and environmental harm worsens
Solution Approach 1:
The system divides the air-conditioning function into two separate circuits: a refrigerant circuit for cooling (using R410A between outdoor unit and refrigerant indoor unit) and a heat medium circuit for heating (using water between outdoor unit and heat medium indoor unit). This segmentation allows each circuit to use the most appropriate medium for its function, enabling high-performance cooling while eliminating refrigerant leakage risks in heating applications
Solution Approach 2:
The system changes the operating parameters by using different heat transfer media for different functions: high-pressure R410A refrigerant for cooling operations where superior heat transfer performance is needed, and water-based heat medium for heating operations where environmental safety is prioritized. This parameter change resolves the contradiction by matching medium properties to functional requirements
2Device complexity
If water is used as heat medium for both cooling and heating operations, then installation complexity is reduced, but energy consumption for water conveyance increases significantly
Solution Approach 1:
The system segments the heat transfer medium by function: refrigerant for cooling circulation and water for heating circulation. This allows each medium to be conveyed only when and where needed, rather than continuously circulating water for both functions, thereby reducing unnecessary energy consumption while maintaining installation flexibility
3Adaptability or versatility
If water-based heat medium system is used in server rooms or power rooms, then heating/cooling capability is improved, but safety risk increases due to water leakage potential
Solution Approach 1:
The system applies different heat medium types to different locations based on local requirements: refrigerant indoor units are installed in server rooms and power rooms where water leakage would cause damage, while heat medium indoor units are installed in ordinary spaces. This local differentiation maintains heating/cooling capability across all areas while eliminating safety risks in critical environments
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 configuration enhances safety, reliability, and installation flexibility by separating direct and indirect cooling/heating operations, reducing refrigerant usage, and minimizing energy consumption, while ensuring safe operation in environments where water-based systems are not feasible.
Implementation Method 1
transferring heating energy or cooling energy, which is generated in the heat source unit and stored in a heat source side refrigerant, to a heat medium different from the heat source side refrigerant via the heat exchangers related to heat medium
Implementation Method 2
at least one outdoor unit equipped with at least a compressor and a heat source side heat exchanger
Data Source
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AI summary
An air-conditioning apparatus that that is capable of saving energy is provided. An air-conditioning apparatus B includes a refrigerant indoor unit 70 that air-conditions a conditioned space by using a heat source side refrigerant supplied from an outdoor unit 1, and a heat medium indoor unit 2 that air-conditions a conditioned space by using a heat medium different from the heat source side refrigerant. The air-conditioning apparatus B includes a first heat medium relay unit that is supplied with the heat source side refrigerant from the outdoor unit 1, a third heat medium relay unit 90 interposed between the first heat medium relay unit and the refrigerant indoor unit 70, and a third heat medium relay unit 110 interposed between the first heat medium relay unit and the heat medium indoor unit 2.