Heat-Medium Air-Conditioning Layout to Isolate Indoor Refrigerant
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Solution Overview
Problem
Existing air-conditioning apparatuses for buildings face issues with refrigerant leakage into indoor spaces, high energy consumption due to long circulation paths, poor construction ease, high costs, noise, and inefficient energy use, particularly when multiple indoor units are connected.
Innovation Solution
The air-conditioning apparatus includes a compressor, heat source side heat exchanger, expansion device, and use side heat exchanger, with refrigerant and heat medium circuits designed to minimize pipe length, reduce pipe count, and incorporate a relay unit to facilitate efficient heat exchange between refrigerant and heat medium, using larger heat medium pipes to reduce conveyance power and enhance safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant is circulated to indoor unit, then cooling/heating function is achieved, but refrigerant leakage into indoor space occurs
Solution Approach 1:
The patent introduces a heat medium (water or antifreeze solution) as an intermediary substance that carries thermal energy between the outdoor heat source unit and indoor units. This heat medium circulates through dedicated pipes that do not connect directly to the refrigerant circuit, creating a physical barrier that prevents refrigerant from entering indoor spaces while still achieving the desired heating or cooling effect.
2Adaptability or versatility
If heat medium circulation path is made long to reach indoor units, then heating/cooling coverage is improved, but conveyance power consumption increases
Solution Approach 1:
The patent divides the system into segments by placing heat medium circulation pumps at each indoor unit rather than using a single centralized pump for the entire system. This segmentation allows each pump to handle only the local heat medium circulation requirements, significantly reducing the total conveyance power needed compared to pumping heat medium through long distances to reach multiple distant indoor units.
3Adaptability or versatility
If four pipes are arranged to connect outdoor unit to indoor unit for simultaneous cooling and heating, then versatility is improved, but construction ease deteriorates
Solution Approach 1:
The patent makes the heat medium circulation system universal by enabling each indoor unit to independently select between cooling and heating modes through a mode selection switch. The same heat medium pipes and circulation infrastructure are used for both cooling and heating operations, eliminating the need for separate pipe systems for each function and significantly simplifying construction while maintaining full versatility.
4Use of energy by moving object
If secondary refrigerant heat exchanger is disposed near each indoor unit, then heat exchange efficiency is improved, but refrigerant leakage risk increases
Solution Approach 1:
The patent places the heat medium-to-refrigerant heat exchangers in the outdoor unit rather than near indoor units, using the heat medium as an intermediary to transfer thermal energy over distance. The heat medium absorbs or releases heat from the refrigerant in the outdoor unit, then circulates to indoor units where it exchanges heat with room air through indoor heat exchangers. This arrangement maintains efficient heat exchange while completely isolating the refrigerant from indoor spaces.
5Productivity
If multiple indoor units are connected to outdoor unit, then system capacity is improved, but energy efficiency deteriorates due to refrigerant path mixing
Solution Approach 1:
The patent segments the thermal energy transfer paths by providing dedicated heat medium circulation circuits for each indoor unit, each with its own pump and control. This allows each indoor unit to independently control its heat medium flow rate and temperature, enabling precise matching of energy supply and demand for each zone. Multiple indoor units can operate simultaneously with different cooling or heating loads without the energy efficiency penalties associated with refrigerant path mixing in shared circuits.
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, improves safety by minimizing refrigerant exposure, simplifies construction, and enhances energy efficiency by optimizing pipe layout and heat exchange processes.
Implementation Method 1
heat being exchanged between the heat-source-side refrigerant and the heat medium in the heat exchanger related to heat medium
Data Source
AI summary
An air-conditioning apparatus achieves improvement of safety and further achieves saving of energy without allowing a refrigerant to circulate in or near an indoor unit. The air-conditioning apparatus is configured such that heat medium pipes have a larger inner cross-sectional area per unit capacity than that of refrigerant pipes.