Hybrid Air-Conditioning Circuit Layout for Low-Leakage Cooling
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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, and the need for additional infrastructure and labor costs when using water as a heat medium for cooling and heating operations, especially in sensitive environments like server rooms.
Innovation Solution
An air-conditioning system with separate units for refrigerant and heat medium operations, utilizing a compressor, heat exchangers, and relay units to efficiently transfer cooling or heating energy between a refrigerant circuit and a heat medium circuit, allowing for direct or indirect cooling/heating in different spaces, with 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 is divided into two separate circuits: a refrigerant circuit for cooling operations and a heat medium circuit for heating operations. This segmentation allows the high-pressure refrigerant circuit to be isolated from areas where leakage would cause harm, while the heat medium circuit uses safer working fluids in heating applications.
Solution Approach 2:
A heat exchanger acts as an intermediary between the refrigerant circuit and the heat medium circuit. The refrigerant transfers thermal energy to the heat medium (water or antifreeze) without direct contact, allowing the refrigerant to remain contained in the closed circuit while the heat medium distributes thermal energy to indoor units.
2Power
If water is used as heat medium for heating operation, then heating energy transfer is improved, but power consumption for conveying water increases
Solution Approach 1:
The system dynamically selects between two heat transfer modes: direct expansion cooling using refrigerant and indirect heating using heat medium. This dynamic operation allows the system to use the more energy-efficient refrigerant circuit for cooling while using the heat medium circuit primarily for heating, optimizing overall energy consumption based on operational requirements.
3Adaptability or versatility
If both cooling and heating operations are performed using water as heat medium, then installation flexibility is improved, but number of pipings and infrastructure increases
Solution Approach 1:
The outdoor unit is designed with multi-functionality, housing both the refrigerant circuit components (compressor, condenser, expansion valve) and the heat medium circuit components (heat exchanger, pump). This universal design allows a single system to perform both cooling and heating operations, eliminating the need for separate systems and reducing overall piping infrastructure.
Solution Approach 2:
The refrigerant circuit and heat medium circuit are merged into a single integrated outdoor unit. The heat exchanger serves as a common component where thermal energy transfer occurs between the two circuits, allowing both cooling and heating functions to be combined in one system with shared infrastructure.
4Power
If water is used as heat medium in server rooms or power rooms, then cooling capacity is improved, but risk of water leakage causing malfunction increases
Solution Approach 1:
The system segments cooling and heating functions into separate circuits. In server rooms or power rooms, only the refrigerant circuit operates for cooling, while the heat medium circuit is used exclusively for heating in other areas. This segmentation eliminates the risk of water leakage in sensitive environments while maintaining adequate cooling capacity through the refrigerant circuit.
Solution Approach 2:
The heat exchanger acts as an intermediary that isolates the water-based heat medium from the refrigerant circuit. By transferring thermal energy through this intermediary rather than using water directly in the refrigerant circuit, the system maintains cooling capacity while eliminating the reliability risks associated with water leakage in sensitive equipment areas.
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 reducing refrigerant usage, minimizing energy consumption, and eliminating the need for extensive piping and infrastructure, while ensuring safe operation in environments where water cannot be used as a heat medium.
Implementation Method 1
transferring the cooling energy or the heating energy to a heat medium, such as water or antifreeze, at a heat exchanger disposed in the outdoor unit
Implementation Method 2
an outdoor unit equipped with at least a compressor and a heat source side heat exchanger
Data Source
AI summary
An air-conditioning apparatus that that is capable of saving energy is provided. An air-conditioning apparatus includes a refrigerant indoor unit that air-conditions a conditioned space by using a heat source side refrigerant supplied from an outdoor unit, and a heat medium indoor unit that air-conditions a conditioned space by using a heat medium different from the heat source side refrigerant. The air-conditioning apparatus includes a first heat medium relay unit that is supplied with the heat source side refrigerant from the outdoor unit, a third heat medium relay unit interposed between the first heat medium relay unit and the refrigerant indoor unit, and a third heat medium relay unit interposed between the first heat medium relay unit and the heat medium indoor unit.