Intermediate Heat Exchanger Layout for Leak-Safe Air Conditioning
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Solution Overview
Problem
Conventional air-conditioning apparatuses face issues with refrigerant leaks indoors, leading to safety concerns and high energy consumption due to the transfer of high-pressure refrigerants, and chillers require large conveying power for heat exchange.
Innovation Solution
An air-conditioning apparatus with an intermediate heat exchanger that separates the refrigerant and heat medium flow paths, using a heat medium circulation circuit with separate heat exchangers and flow path switching valves to control the heat medium flow, ensuring no high-pressure refrigerant is transferred indoors and reducing energy consumption by optimizing heat medium conveying power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-pressure refrigerant is transferred to indoor unit, then cooling or heating function is achieved, but refrigerant leak deteriorates indoor environment
Solution Approach 1:
The system divides the refrigeration cycle into two separate loops: a refrigerant loop containing the compressor and first heat exchanger, and a heat medium loop containing the second heat exchanger and pump. This segmentation prevents refrigerant from being present in indoor units, eliminating the harmful effect of potential refrigerant leaks while maintaining cooling or heating functionality through the heat medium loop.
Solution Approach 2:
A heat medium (such as water or antifreeze solution) is introduced as an intermediary substance that transfers thermal energy between the refrigerant and the indoor environment. The heat medium circulates through the second heat exchanger in indoor units, allowing heat transfer without requiring direct refrigerant presence, thus protecting the indoor environment from refrigerant contamination.
2Loss of energy
If heat exchange is performed outdoors between refrigerant and water, then cooling or heating energy is transferred, but conveying power of water is extremely large
Solution Approach 1:
The system changes the operating parameters of the heat medium circulation by using a two-loop configuration where the refrigerant loop handles high-pressure heat exchange outdoors and the heat medium loop operates at lower pressures. This parameter change allows the pump to convey water with significantly reduced power requirements while maintaining effective cooling or heating energy transfer to indoor units.
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
The solution prevents refrigerant leaks into indoor spaces and reduces energy consumption by minimizing the conveying power of the heat medium, enhancing safety and energy efficiency.
Implementation Method 1
at least one intermediate heat exchanger that exchanges heat between a refrigerant and a heat medium that is different from the refrigerant
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
In the air-conditioning apparatus, the heat source side heat exchanger 12, the intermediate heat exchangers 15a and 15b, and the use side heat exchangers 26a and 26b are separately formed respectively and adapted to be disposed at separate locations from each other. A flow path switching valves 22a to 22d and 23a to 23d are provided with each of inlet side and outlet side of heat medium side flow path of the use side heat exchangers 26a to 26d to switch the flow path so as to connect with each intermediate heat exchangers 15a and 15b. Pumps 21a to 21d that circulate the heat medium in a heat medium circulation circuit is installed either in a flow path between the use side heat exchangers 26a to 26d and the flow path switching valves 22a to 22d disposed at the inlet side of the use side heat exchanger, or in the flow path between the use side heat exchangers 26a to 26d and the flow path switching valves 23a to 23d disposed at the outlet side of the use side heat exchanger.