Air-conditioning apparatus and method of using air-conditioning apparatus
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Solution Overview
Problem
Existing air-conditioning systems face challenges in improving refrigerant distribution performance across a wide operating range due to limitations in refrigerant flow rate and speed, leading to reduced energy efficiency and increased costs.
Innovation Solution
A header design with a flow space that allows gas-liquid two-phase refrigerant to flow upward and discharge into branch tubes, where the thickness of the liquid phase is optimized based on flow speed, quality, and manifold diameter, promoting annular or churn flow patterns to enhance distribution efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If structural elements such as partitions or ejection ports are added to the header to improve refrigerant distribution, then refrigerant distribution performance is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The invention extracts and eliminates unnecessary structural elements from the header, retaining only the essential components. By removing complex partitions and ejection ports, the header structure is simplified while maintaining effective refrigerant distribution through the optimized flow space configuration and branch tube arrangement.
Solution Approach 2:
Instead of adding structural elements to improve distribution, the invention inverts the approach by removing elements and relying on the fundamental flow dynamics. The simplified header uses the natural two-phase flow characteristics and optimized geometry to achieve better distribution without complex additions.
2Reliability
If structural elements are added to the header to improve refrigerant distribution, then refrigerant distribution performance is improved, but pressure loss in the header increases significantly, reducing energy efficiency
Solution Approach 1:
The invention removes unnecessary structural elements that cause pressure loss, keeping only the essential header components. This extraction of redundant parts eliminates sources of flow resistance and energy loss while preserving the core refrigerant distribution function.
Solution Approach 2:
The invention optimizes parameters such as flow space cross-sectional area, branch tube insertion depth, and tube arrangement to minimize pressure loss. By carefully adjusting these geometric parameters, the header achieves efficient refrigerant distribution with reduced flow resistance and energy consumption.
3Adaptability or versatility
If a larger amount of refrigerant is distributed to the lower part of the header to match higher airflow volume, then refrigerant distribution matches airflow distribution, but refrigerant distribution performance and heat exchanger performance deteriorate
Solution Approach 1:
The invention applies different characteristics to different parts of the header system. The flow space cross-sectional area, branch tube insertion depths, and tube arrangements are locally optimized for each position to achieve balanced refrigerant distribution that matches the local airflow characteristics without causing overall performance deterioration.
Solution Approach 2:
The invention changes geometric parameters such as flow space area and branch tube insertion depth at different locations along the header. These parameter variations enable the system to adapt refrigerant distribution to local airflow conditions while maintaining overall distribution performance and heat exchanger efficiency.
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 improves refrigerant distribution performance over a wide operating range, reduces costs, and enhances energy efficiency by ensuring effective distribution of refrigerant to branch tubes, regardless of varying operating conditions.
Implementation Method 1
gas-liquid two-phase refrigerant flows upward and is discharged into the plurality of branch tubes
Implementation Method 2
If the refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow
Implementation Method 3
If the refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow
Data Source
AI summary
A header includes a plurality of branch tubes and a header manifold. If refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow, tips of the branch tubes inserted into the header manifold pass through a liquid-phase portion having a thickness δ [m] and reach a gas-phase portion. The thickness δ [m] of the liquid-phase portion is defined as δ=G×(1−x)×D/(4ρL×ULS), where G is a flow speed [kg/(m2 s)] of the refrigerant, x is a quality of the refrigerant, D is an inside diameter [m] of the header manifold, ρL is a liquid density [kg/m3] of the refrigerant, ULS is a reference apparent liquid speed [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into a flow space of the header manifold. The reference apparent liquid speed ULS [m/s] is defined as G(1−x)/ρL.