Accessory Subcooling Coil Using Condenser Airflow
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Solution Overview
Problem
Existing refrigerated air conditioning systems using vapor-compression refrigeration cycles face inefficiencies in heat transfer, particularly in subcooling the refrigerant, which can be costly and complex to implement effectively, limiting the increase in refrigeration capacity and energy efficiency.
Innovation Solution
A simplified accessory sub-cooling unit with a serpentine heat exchange tube and parallel planar heat transfer fins is mounted to the condenser unit, utilizing existing air flow to subcool the refrigerant before it reaches the expansion valve, enhancing heat transfer without additional energy consumption or complex installations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional vapor-compression refrigeration systems are used without subcooling, then the system structure remains simple and cost-effective, but the refrigeration capacity and energy efficiency are limited
Solution Approach 1:
The subcooling heat exchange coil is nested within the condenser housing, utilizing the existing condenser structure and airflow path. The coil is positioned to receive ambient air flow from the condenser fan, allowing subcooling to occur without requiring separate airflow generation or additional external housing.
Solution Approach 2:
The condenser fan serves dual functions: cooling the condenser coil and providing airflow for the subcooling coil. The existing condenser structure is extended to accommodate the additional subcooling function, making the system multi-functional without proportionally increasing complexity.
2Use of energy by moving object
If subcooling is implemented to increase refrigeration capacity by 1% for every 2°F, then energy efficiency improves, but system complexity and installation difficulty increase
Solution Approach 1:
The subcooling coil is merged with the condenser assembly, sharing the same housing, airflow source, and mounting structure. This integration allows the subcooling function to be added while minimizing additional installation steps and maintaining ease of manufacture.
Solution Approach 2:
The subcooling coil utilizes the ambient air flow already generated by the condenser fan, eliminating the need for additional fans or separate airflow generation systems. The system serves its own subcooling cooling needs using resources already available in the condenser unit.
3Reliability
If a serpentine heat exchange tube with parallel planar fins is used for subcooling, then heat transfer efficiency increases, but manufacturing complexity and cost increase
Solution Approach 1:
The serpentine configuration of the heat exchange tube provides curved pathways that increase surface area and improve heat transfer efficiency. The parallel planar fins extend from the serpentine tube, creating an extended surface heat exchanger that maximizes thermal exchange with the passing ambient air.
Solution Approach 2:
The heat exchange coil is designed as a relatively simple, inexpensive component that can be easily manufactured and installed. The use of standard fin-and-tube heat exchanger technology keeps manufacturing costs low while providing reliable heat transfer performance.
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 efficiently subcools the refrigerant, increasing refrigeration capacity by 1% for every 2° F, while being inexpensive, easy to install, and non-intrusive to the existing system, thus improving overall energy efficiency without significant additional costs or maintenance.
Implementation Method 1
a serpentine heat exchange tube having one end fluidly connected downstream of the condensing coil prior to the expansion valve
Implementation Method 2
a plurality of parallel planar heat transfer fins to assist the heat transfer from the heat exchange tube to the ambient air
Implementation Method 3
a plurality of parallel planar heat transfer fins to assist the heat transfer from the heat exchange tube to the ambient air
Data Source
AI summary
A system and method for improving the efficiency of a refrigerated air conditioning system utilizing a vapor-compression refrigeration cycle. The improved system includes an accessory sub-cooling unit which is fluidly connected between the condensing coil and the expansion valve in a closed loop refrigeration system utilizing a vapor-compression refrigeration cycle. The accessory sub-cooling unit comprises a serpentine heat exchange tube having one end fluidly connected downstream of the condensing coil prior to the expansion valve. The accessory sub-cooling unit further comprises a plurality of parallel planar heat transfer fins to assist the heat transfer from the heat exchange tube to the ambient air. In accordance with the method of the present invention, the accessory sub-cooling unit is mounted to a side of the condenser unit in order to utilize the existing air flow generated by the exhaust fan of the condenser unit.