Freezer Air Return Port Sizing for Frost-Free Heat Exchange Efficiency
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Solution Overview
Problem
Existing freezers, particularly air-cooled models, face issues with frost accumulation on communicating pipes affecting heat exchange efficiency and temperature uniformity, leading to reduced refrigeration effectiveness and increased energy consumption.
Innovation Solution
The design includes a freezer with a liner defining air supply and return channels, featuring an air return cover plate that divides the interior space into storage and evaporator cavities, with strategically positioned air return inlets and evaporators, and incorporates evaporator groups with communicating pipes in foaming layers and heat conducting fins to minimize frost formation and optimize airflow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If air-cooled freezer design is used, then frost-free operation is achieved, but heat exchange efficiency deteriorates due to frost accumulation on communicating pipes
Solution Approach 1:
The communicating pipes are segmented into multiple sections, with insulation layers applied selectively to different portions. The pipe sections near the evaporator are provided with thicker insulation, while other sections have thinner or no insulation, optimizing both frost prevention and heat exchange efficiency.
Solution Approach 2:
The communicating pipes utilize composite material construction with multi-layer insulation structures. The insulation layers are made of materials with different thermal properties, combining materials that resist frost formation with materials that maintain heat exchange efficiency, creating a composite pipe structure that addresses both contradictory requirements.
2Temperature
If air return inlet area is increased, then temperature uniformity is improved, but device complexity increases due to additional air return cover plate components
Solution Approach 1:
The air return cover plate is designed to perform multiple functions simultaneously: it serves as a structural support component, an air flow distribution element, and a temperature regulation device. By integrating these functions into a single component, the design increases temperature uniformity without proportionally increasing device complexity.
Solution Approach 2:
The air return inlet is designed with a three-dimensional configuration that utilizes vertical space within the freezer cavity. By arranging air return openings at different heights and positions in three dimensions, the design achieves improved temperature uniformity throughout the storage space without requiring excessive horizontal area or additional complex components.
3Productivity
If evaporator volume is increased, then refrigeration effectiveness is improved, but energy consumption increases
Solution Approach 1:
The evaporator design utilizes parameter optimization by adjusting the heat exchange coefficient, surface area distribution, and airflow velocity parameters. By changing these parameters rather than simply increasing evaporator volume, the system achieves improved refrigeration effectiveness while maintaining energy efficiency through optimized heat transfer conditions.
Solution Approach 2:
The design replaces mechanical expansion methods with thermodynamic optimization. Instead of using larger mechanical evaporator structures, the system achieves improved refrigeration effectiveness through optimized refrigerant flow dynamics, heat exchange surface configuration, and airflow patterns that enhance natural heat transfer processes.
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 enhances heat exchange efficiency, improves temperature uniformity, and reduces energy consumption by preventing frost buildup and optimizing airflow circulation, thereby meeting actual refrigeration requirements.
Implementation Method 1
The evaporator is located in the evaporator cavity... airflow in the storage cavity is capable of flowing into the evaporator cavity through the air return inlet
Implementation Method 2
at least part of the communicating pipe is disposed in the foaming layer, avoiding the whole communicating pipe from frost affecting the heat exchange
Implementation Method 3
incorporates evaporator groups with communicating pipes in foaming layers and heat conducting fins to minimize frost formation
Implementation Method 4
airflow in the storage cavity is capable of flowing into the evaporator cavity through the air return inlet... optimizing airflow circulation
Data Source
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AI summary
The present application relates to the technical field of refrigeration apparatuses, and discloses a freezer. The freezer comprises a liner, an air return cover plate and an evaporator. An inner space is defined by the liner, and an air supply channel having an air supply port is defined by the liner. The air return cover plate is located in the inner space and divides the inner space into a storage cavity and an evaporator cavity, an outlet of the evaporator cavity is communicated with an inlet of the air supply channel, the air return cover plate is provided with an air return port, and airflow in the storage cavity can flow into the evaporator cavity through the air return port. The evaporator is located in the evaporator cavity. The relationship between the total volume V of the evaporator and the total area S of the air return port is yS=V, wherein y is greater than or equal to 50. Refrigeration requirements for the freezer can be met by setting the relationship between the total volume V of the evaporator and the total area S of the air return port to satisfy yS=V, wherein y is greater than or equal to 50. In this way, the air return port of the freezer can be configured more reasonably, such that the freezer can conduct effective refrigeration, and the actual refrigeration requirements are met.