Heat Medium Branching Control for Multi-Unit Air Conditioning
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Solution Overview
Problem
Conventional air-conditioning systems face issues with energy efficiency due to long circulation paths of heat media, high construction complexity, noise, and increased risk of refrigerant leakage, particularly in systems with multiple indoor units and complex piping configurations.
Innovation Solution
The air-conditioning apparatus incorporates a refrigerant circuit with a compressor, refrigerant flow switching device, heat source side heat exchanger, and expansion devices, along with a heat medium circuit featuring heat medium flow switching devices and a controller that adjusts the flow rate of both refrigerant and heat medium to optimize energy efficiency by equalizing flow rates in heat exchangers during cooling or heating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the heat medium circulation path is extended to reach multiple indoor units, then the coverage area is improved, but the conveyance power and energy consumption increase markedly
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary component that enables heat transfer between the refrigerant and heat medium without requiring direct connection between the outdoor unit and all indoor units. This mediator allows the heat medium to be circulated through a more efficient path, reducing conveyance power requirements while maintaining coverage area.
Solution Approach 2:
The system divides the heat transfer function into two separate circuits: a refrigerant circuit in the outdoor unit and a heat medium circuit that can be distributed to multiple indoor units. This segmentation allows independent optimization of each circuit, enabling the heat medium circulation path to be extended to cover more areas without proportionally increasing energy consumption.
2Adaptability or versatility
If four water pipings are arranged to connect outdoor unit to each indoor unit for free cooling/heating selection, then the adaptability is improved, but the construction complexity increases
Solution Approach 1:
The patent makes the heat medium circuit multi-functional by enabling it to serve both cooling and heating functions through the same piping infrastructure. The heat exchanger can operate in different modes depending on the refrigerant flow direction, allowing a single heat medium circuit to replace what would traditionally require separate cooling and heating pipelines.
Solution Approach 2:
The system merges the cooling and heating functions into a unified heat medium circuit that shares common piping between the outdoor unit and indoor units. By combining these functions in a single circuit with controllable flow direction, the patent reduces the number of separate pipelines needed while maintaining the ability to provide both cooling and heating services.
3Temperature
If the heat exchanger is disposed near each indoor unit, then the heat transfer efficiency is improved, but the refrigerant leakage risk to indoor space increases
Solution Approach 1:
The patent uses the heat exchanger as a physical barrier and intermediary that separates the refrigerant circuit (containing potentially harmful refrigerant) from the indoor living space. The heat medium circulates on the indoor side of this barrier, allowing efficient heat transfer to occur at the heat exchanger interface while the refrigerant remains confined to the outdoor unit side, thus maintaining heat transfer efficiency while eliminating refrigerant leakage risk to occupants.
4Adaptability or versatility
If the heat medium circulation path is lengthened, then the system can serve more indoor units, but the conveyance power becomes markedly large
Solution Approach 1:
The patent segments the system into an outdoor unit containing the refrigerant circuit and heat exchanger, and separate indoor units connected via heat medium piping. This segmentation allows the heat medium circulation path to be extended to multiple indoor units without requiring the outdoor unit to be directly connected to all of them, thereby increasing adaptability while managing conveyance power requirements through efficient heat exchanger placement.
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 energy efficiency, reduces energy consumption, simplifies construction, and minimizes the risk of refrigerant leakage by controlling the flow rates and pathways, thereby improving overall system performance.
Implementation Method 1
a compressor that compresses a refrigerant
Implementation Method 2
a heat source side heat exchanger for exchanging heat with the refrigerant
Implementation Method 3
a plurality of expansion devices each controlling a flow rate of the refrigerant flowing in each heat exchanger related to heat medium by pressure control
Implementation Method 4
heat medium flow switching devices disposed on an inflow side and an outflow side of the heat medium of the use side heat exchanger in the heat medium circuit, the heat medium flow switching devices merging or branching the heat medium by setting an opening area that is in communication with the heat exchangers related to heat medium at an arbitrary degree by controlling an opening degree
Implementation Method 5
a use side heat exchanger exchanging heat between the heat medium and air related to a conditioned space
Data Source
AI summary
An air-conditioning apparatus includes a refrigerant circuit having a plurality of expansion devices that controls a flow rate of the refrigerant flowing in each of a plurality of heat exchangers related to heat medium; a heat medium circuit having the heat exchangers related to heat medium and a use side heat exchanger that exchanges heat between the heat medium and air; heat medium flow switching devices disposed on an inflow side and an outflow side of the use side heat exchanger to mix or diverge the heat medium pertaining to the heat exchangers related to heat medium; and a controller that controls at least the heat medium flow switching device on the inflow side or the outflow side that controls the amount of heat exchange in each of the heat exchangers related to heat medium during cooling only operation mode or heating only operation mode.