Heat Exchanger Connection Pipe Sizing for Liquid Pool Control
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Solution Overview
Problem
Existing air conditioners with heat exchangers face inefficiencies due to the formation of liquid pools in heat-transfer pipes, which reduces heat-exchange efficiency and requires either insufficient or excessive refrigerant amounts, while also considering the Global Warming Potential (GWP) of refrigerants.
Innovation Solution
The air conditioner employs a heat exchanger design with heat-transfer pipes arranged horizontally and spaced vertically, featuring inflow and outflow paths connected by pipes with a hydraulic diameter of 4 mm or greater, ensuring a circulation flow rate and path number ratio that inhibits liquid pool formation and optimizes refrigerant usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the heat exchanger uses conventional heat-transfer pipes with small hydraulic diameter, then the device complexity is reduced and manufacturing cost is lowered, but liquid pool formation occurs which reduces heat-exchange efficiency
Solution Approach 1:
The patent changes the hydraulic diameter parameter of the connection pipe from conventional small dimensions to 4mm or greater. This parameter change prevents liquid pool formation by altering the flow dynamics, thereby maintaining heat-exchange efficiency without increasing overall device complexity
Solution Approach 2:
The patent creates equipotential flow conditions in the connection pipe by ensuring adequate hydraulic diameter (≥4mm), which equalizes pressure distribution and prevents liquid accumulation. This allows the thermal medium to flow smoothly from inflow to outflow paths without forming liquid pools that would reduce heat-exchange efficiency
2Productivity
If the circulation flow rate Gr is increased to prevent liquid pool formation, then heat-exchange efficiency is improved, but the ratio Gr/N exceeds the optimal range which increases refrigerant usage and production costs
Solution Approach 1:
The patent establishes the optimal parameter range 0.003≤Gr/N≤0.035 for circulation flow rate per path. By controlling this parameter within the specified range and combining it with connection pipes of hydraulic diameter ≥4mm, the system achieves effective liquid pool prevention while minimizing refrigerant usage and associated production costs
Solution Approach 2:
The patent applies partial action by using connection pipes with hydraulic diameter of 4mm or greater (not excessively large) and controlling the circulation flow rate ratio within a specific range rather than maximizing it. This partial optimization prevents liquid pool formation effectively while avoiding excessive refrigerant usage and unnecessary cost increases
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 design effectively prevents liquid pool formation, allows for appropriate refrigerant sealing, and enhances heat-exchange efficiency while minimizing refrigerant usage and production costs.
Implementation Method 1
at least one connection pipe through which an outlet side of one of the at least one inflow path communicates with an inlet side of one of the at least one outflow path, the at least one connection pipe having a hydraulic diameter of 4 mm or greater
Implementation Method 2
a plurality of heat-transfer pipes arranged to extend in a horizontal direction and to be spaced apart at predetermined intervals in a vertical direction and configured to allow a thermal medium to flow therein
Implementation Method 3
The refrigerant transfers heat to/from (exchanges heat with) an air flow passing the corrugated fins while the refrigerant passes through the heat-transfer pipes
Data Source
AI summary
An air conditioner that includes a heat exchanger including: heat-transfer pipes extending in a horizontal direction and spaced apart at predetermined intervals in a vertical direction and configured to allow a thermal medium to flow therein. A part of the heat transfer pipes are used for at least one inflow path into which the thermal medium flows from the outside of the heat exchanger and the other part of the heat transfer pipes are used for at least one outflow path from which the thermal medium flows out to the outside. At least one connection pipe through which an outlet side of one of the at least one inflow path communicates with an inlet side of one of the at least one outflow path.