Heat-Medium Air Conditioning Layout for Leak-Safe Indoor Cooling
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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 heat medium 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 connected via refrigerant and heat medium pipes, with the compressor and heat source side heat exchanger in an outdoor unit, the expansion device and heat exchanger in a relay unit, and the use side heat exchanger in an indoor unit, featuring larger inner cross-sectional areas for heat medium pipes to reduce energy consumption and improve 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 piping systems, completely isolating the refrigerant circulation to the outdoor unit only. The heat exchangers at indoor units transfer heat between the heat medium and indoor air without requiring refrigerant presence, thereby eliminating refrigerant leakage risks while maintaining effective heating and cooling functions.
2Ease of operation
If heat medium circulation path is made long to reach indoor units, then heating/cooling function is achieved, but energy consumption increases
Solution Approach 1:
The patent employs variable speed pumps in the outdoor heat source unit that can dynamically adjust their operating speed based on system demands and circulation path characteristics. This dynamic control allows the system to optimize pump energy consumption by matching flow rates to actual heating/cooling loads, rather than operating at constant high speeds. The system adapts pump performance to minimize conveyance power requirements while ensuring adequate heat medium circulation throughout the building.
3Adaptability or versatility
If four pipes are arranged to connect outdoor unit to indoor units for simultaneous cooling and heating, then versatility is improved, but construction ease deteriorates
Solution Approach 1:
The patent implements a dual-pipe system where the same two pipes carrying heat medium serve both heating and cooling functions by reversing flow directions. The outdoor heat source unit contains heat exchangers that can operate in either heating or cooling mode, and the system controls refrigerant flow direction to enable the heat medium to be heated or cooled accordingly. This universal dual-purpose system eliminates the need for separate four-pipe infrastructure, achieving full heating and cooling versatility through a simplified two-pipe connection that is much easier to install and maintain.
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, enhances safety by minimizing refrigerant circulation near indoor units, improves construction ease, and optimizes energy efficiency by reducing the number of connecting pipes, thereby achieving long-term energy savings.
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
Figure 1~2
Figure 3
Figure 3A
AI summary
To provide an air-conditioning apparatus which achieves improvement of safety and further achieves saving of energy without allowing a refrigerant to circulate in or near an indoor unit. An air-conditioning apparatus 100 is configured such that pipes 5 have a larger inner cross-sectional area per unit capacity than that of refrigerant pipes 4.