Split Refrigerant and Heat-Medium Circuit Layout for Indoor Leak Safety
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Solution Overview
Problem
Existing air-conditioning apparatuses for buildings face challenges such as refrigerant leakage into indoor spaces, high energy consumption due to long heat medium circulation paths, complex installations, and inefficient heat exchange, leading to increased costs and safety concerns.
Innovation Solution
The air-conditioning apparatus incorporates a refrigerant circuit with a compressor, refrigerant flow switching devices, and heat exchangers connected by refrigerant pipes, along with a heat medium circuit featuring a pump, heat exchangers, and flow control devices connected by heat medium pipes, optimizing refrigerant passage lengths and flow rates to reduce energy consumption and enhance safety while simplifying installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If refrigerant is circulated from outdoor unit to indoor unit, then heating or cooling can be performed directly at indoor unit, but refrigerant may leak into indoor space causing safety hazards
Solution Approach 1:
The system is divided into two separate circulation paths: a refrigerant circuit confined to the outdoor unit and a heat medium circuit distributed to indoor units. This segmentation isolates the refrigerant to the outdoor unit, eliminating leakage risks in indoor spaces while maintaining heating/cooling functionality through the heat medium (water or antifreeze) that circulates to indoor units.
Solution Approach 2:
A heat medium (water or antifreeze) is introduced as an intermediary substance between the refrigerant and the indoor units. The refrigerant heats or cools the heat medium in the outdoor unit, and this heat-exchanged heat medium is then circulated to indoor units through heat exchangers, enabling indirect heat transfer without refrigerant presence in indoor spaces.
2Ease of operation
If heat medium circulation path is extended to reach indoor units, then heating or cooling can be provided to indoor units, but energy consumption for conveying heat medium increases
Solution Approach 1:
The system replaces mechanical compression and long-distance refrigerant circulation with a thermal field approach. The refrigerant completes its phase change and heat exchange entirely in the outdoor unit, and the heat medium is circulated at lower pressures and temperatures, reducing the energy required for conveyance compared to pressurized refrigerant distribution.
3Adaptability or versatility
If four water pipes are arranged between outdoor unit and indoor units for heat recovery chiller, then cooling and heating can be simultaneously supplied, but installation becomes complex
Solution Approach 1:
The heat medium circulation system serves multiple functions: it can be directed to different indoor units for cooling or heating based on demand, and the same heat medium circuit can simultaneously serve different zones with different thermal requirements. This multi-functional design reduces the need for separate pipe systems for cooling and heating.
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 reduces energy consumption, minimizes refrigerant leakage, simplifies installation, and improves heat exchange efficiency, resulting in a safer and more efficient air-conditioning system with reduced operational costs.
Implementation Method 1
the plurality of heat exchangers related to heat medium exchange heat between the heat source side refrigerant and the heat medium
Implementation Method 2
a compressor, a first refrigerant flow switching device, a heat source side heat exchanger
Implementation Method 3
a plurality of expansion devices, refrigerant passages of a plurality of heat exchangers related to heat medium
Implementation Method 4
a heat medium circuit in which a pump, a use side heat exchanger, heat medium side passages of the plurality of heat exchangers related to heat medium
Data Source
AI summary
In an air-conditioning apparatus, an expansion device, a second refrigerant flow switching device, and heat exchangers related to heat medium, connected between the expansion device and the second refrigerant flow switching device such that a heat source side refrigerant flows in parallel, are connected in a part of refrigerant passages, and an expansion device, a second refrigerant flow switching device, and heat exchangers related to heat medium, connected between the expansion device and the second refrigerant flow switching device such that the heat source side refrigerant flows in series, are connected in the rest of the refrigerant passages.