Concentric Refrigerant Heat Exchanger for Air Conditioner Supercooling
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Solution Overview
Problem
The efficiency of heat exchange between main and branch streams of refrigerant in air conditioners is limited due to the spiral structure of the tubes, leading to inadequate supercooling of the refrigerant, which affects the overall refrigeration cycle efficiency.
Innovation Solution
An additional heat exchanger, or super cooling device, is introduced with a first flow passage guiding the refrigerant from the condenser to the evaporator and a second flow passage for heat exchange with the first passage, utilizing the outer surface area of inner tubes for enhanced heat transfer, thereby improving refrigeration cycle efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If spiral tubes are used for heat exchange between main and branch streams of refrigerant, then the device structure is compact, but the heat exchange area is limited and heat exchanger efficiency is decreased
Solution Approach 1:
The patent applies the nesting principle by placing the inner tube (carrying branch stream refrigerant) inside the outer tube (carrying main stream refrigerant). This concentric tube configuration allows both streams to flow simultaneously through nested passages, maximizing heat exchange area within a compact cross-sectional footprint. The inner tube is positioned coaxially within the outer tube, creating efficient thermal coupling between the two refrigerant streams.
Solution Approach 2:
The patent transitions from a two-dimensional spiral planar arrangement to a three-dimensional concentric cylindrical arrangement. By utilizing the radial dimension with nested tubes, the design achieves significantly increased heat exchange surface area compared to spiral tubes of equivalent outer dimensions. The heat exchange occurs across the cylindrical outer surface of the inner tube and the inner surface of the outer tube, providing extensive contact area.
2Reliability
If spiral tubes are used for heat exchange, then the structure is simplified, but the refrigerant supercooling is insufficient
Solution Approach 1:
The nested concentric tube configuration provides extended heat exchange area that enables sufficient supercooling of the main stream refrigerant. The branch stream refrigerant flowing through the inner tube absorbs heat from the main stream refrigerant in the outer tube, achieving the required degree of supercooling that spiral tubes cannot provide due to their limited surface area.
Solution Approach 2:
The patent ensures continuous and efficient heat exchange along the entire length of the concentric tubes. The counter-flow arrangement (where main and branch streams flow in opposite directions) maintains a consistent temperature gradient throughout the heat exchanger length, enabling continuous effective heat transfer and complete supercooling of the refrigerant before it enters the evaporator.
3Productivity
If heat exchange area is increased to improve supercooling, then refrigeration cycle efficiency improves, but the device complexity increases
Solution Approach 1:
The nested concentric tube design achieves large heat exchange area within a compact form factor. By nesting the inner tube within the outer tube, the patent multiplies the effective heat exchange surface area without proportionally increasing the device's external dimensions or structural complexity. This provides high refrigeration cycle efficiency while maintaining a space-efficient and relatively simple construction.
Solution Approach 2:
The concentric tube heat exchanger serves multiple functions simultaneously: it provides the required heat exchange area for supercooling, maintains a compact design, and enables counter-flow heat exchange for maximum efficiency. The same structural configuration accomplishes all these objectives without requiring additional separate components, thereby improving productivity without excessive complexity increase.
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 additional heat exchanger increases the heat exchange area, leading to more effective supercooling of the refrigerant, enhancing the refrigeration cycle efficiency and increasing the heating capacity of the air conditioner.
Implementation Method 1
heat is exchanged through the spiral tubes that make contact with each other
Implementation Method 2
The main stream of the refrigerant can be super-cooled through heat exchange with the branch stream
Data Source
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AI summary
Provided is an air conditioner. The air conditioner includes a compressor (10), a condenser (20,30), a super cooling device (100), and an evaporator (30,20). The super cooling device includes: a first flow passage disposed in the super cooling device to guide the refrigerant coming from the condenser toward the evaporator; and a second flow passage located in the super cooling device for exchanging heat with the first flow passage and guiding the refrigerant toward the compressor. One of the first and second flow passage includes: a distribution part configured to divide a flow of the refrigerant; and an inner tube connected to the distribution part. A stream of the refrigerant flowing in the first flow passage exchanges heat with a stream of the refrigerant flowing in the second flow passage while using an outer surface area of the inner tube as a heat exchange area.