Relay Heat Exchanger Layout for Leak-Safe Air Conditioning
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Solution Overview
Problem
Conventional air-conditioning apparatuses face issues with refrigerant leakage indoors and inefficient energy consumption due to longer water and anti-freezing liquid circulation paths, which can lead to increased energy consumption and difficulty in handling varying air-conditioning loads.
Innovation Solution
An air-conditioning apparatus design that separates the refrigerant and heat medium circulation paths, using a relay unit with an intermediate heat exchanger to reduce the length of the heat medium circulation path and prevent refrigerant leakage into indoor spaces, thereby enhancing safety and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If refrigerant is made to circulate into the indoor unit, then heat exchange efficiency is improved, but refrigerant leakage into indoor space occurs
Solution Approach 1:
The system is divided into two separate circulation paths: a refrigerant circulation path (outdoor unit only) and a heat medium circulation path (outdoor unit → relay unit → indoor unit). This segmentation prevents refrigerant from entering the indoor unit while maintaining heat exchange functionality through the heat medium in the relay unit.
Solution Approach 2:
A heat medium (water or anti-freezing liquid) acts as an intermediary between the refrigerant and the indoor air conditioning system. The refrigerant exchanges heat with the heat medium in the outdoor unit, and the heat medium then carries this thermal energy through the relay unit to the indoor unit, eliminating direct refrigerant contact with indoor spaces.
2Power
If heat medium circulation path is extended to connect outdoor unit and indoor unit directly, then heat exchange capacity is improved, but energy consumption for carrying heat increases
Solution Approach 1:
The relay unit is positioned in an intermediate spatial location between the outdoor unit and indoor unit, creating a multi-stage heat transfer path. This dimensional arrangement allows the heat medium to be heated/cooled in the outdoor unit, then transported a shorter distance to the relay unit, and finally distributed to indoor units, reducing overall transport energy requirements while maintaining heat exchange capacity.
3Productivity
If more refrigerant is made to circulate to handle increased air-conditioning load, then cooling or heating capacity is improved, but energy consumption for circulating refrigerant increases
Solution Approach 1:
The system changes the physical parameters of the heat transfer medium from refrigerant (in the outdoor unit) to heat medium (in the relay unit and indoor units). This parameter change allows for more efficient heat transfer at the indoor unit level, as the heat medium can be circulated at lower pressures and temperatures, reducing the energy required for circulation while maintaining or improving cooling/heating capacity.
4Productivity
If heat medium circulation circuit is designed to cope with high air-conditioning load, then load handling capacity is improved, but carrying power becomes excessively large
Solution Approach 1:
The heat medium circulation system is segmented into multiple stages with the relay unit as an intermediate heat exchange station. This allows the circulation pumps to operate at lower powers in each stage rather than requiring one high-power pump to transport heat medium over the entire distance from outdoor unit to all indoor units, thereby coping with high loads while keeping carrying power manageable.
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 ingress into indoor spaces, reduces energy consumption by minimizing the heat medium circulation path length, and effectively manages air-conditioning loads through controlled temperature and pressure adjustments, ensuring both safety and efficiency.
Implementation Method 1
a relay unit 3 which exchanges heat between the refrigerant and the heat medium
Implementation Method 2
a heat medium circulation circuit 5 which circulates the heat medium
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To obtain an air-conditioning apparatus that does not make a refrigerant circulate up to an indoor unit and further can achieve energy-saving. A refrigeration cycle is configured by connecting a compressor 10 that pressurizes a refrigerant, a four-way valve 11 that switches a circulation path of the refrigerant, a heat source side heat exchanger 12 that performs heat exchange, expansion valves 16a to 16d for pressure-adjusting the refrigerant, and a plurality of intermediate heat exchangers 15a and 15b that performs heat exchange between the refrigerant and the heat medium to heat and cool the heat medium, with piping. A heat medium circuit is configured by connecting intermediate heat exchangers 15a and 15b, pumps 21a and 21b that pressurize the heat medium, and a plurality of use side heat exchangers 26a to 26d that perform heat exchange between the heat medium and the air in the indoor space 7, with piping.