Parallel Refrigerant Paths in Heat Exchangers for Frost Control
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Solution Overview
Problem
In refrigerating apparatuses, the heat-source-side heat exchanger's evaporative capacity is compromised due to increased pressure loss and frost formation in the auxiliary heat exchange part during evaporation mode, leading to inefficient heat absorption and reduced cooling capacity.
Innovation Solution
A refrigeration apparatus with a heat-source-side heat exchanger featuring a main and auxiliary heat exchange part connected in parallel, utilizing a superheat degree controller and flow ratio controller to manage refrigerant flow and temperature equality between the two parts, reducing frost formation and enhancing evaporation capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If refrigerant flows through the auxiliary heat exchange part and main heat exchange part in series during evaporation mode, then the evaporative capacity is improved, but the pressure loss increases and frost formation occurs
Solution Approach 1:
The heat exchange part is divided into a main heat exchange part and an auxiliary heat exchange part that can operate in parallel during evaporation mode. This segmentation allows refrigerant to be distributed across multiple paths, reducing pressure loss while maintaining evaporative capacity through coordinated operation of both parts.
Solution Approach 2:
The system dynamically switches between series and parallel configurations of the main and auxiliary heat exchange parts based on operational mode. During evaporation mode, the auxiliary part connects in parallel to the main part, creating a dynamic flow path that optimizes both pressure loss and evaporative capacity.
2Productivity
If refrigerant flows through the auxiliary heat exchange part during evaporation mode, then heat absorption capacity is improved, but frost formation occurs on the auxiliary heat exchange part
Solution Approach 1:
Different parts of the heat exchange system are assigned different functions and operating characteristics. The main heat exchange part handles the primary heat absorption, while the auxiliary part provides supplemental capacity with controlled refrigerant flow. This local differentiation allows the auxiliary part to contribute to heat absorption without excessive refrigerant flow that would cause frost formation.
Solution Approach 2:
The system incorporates control mechanisms that monitor refrigerant flow and temperature conditions in both the main and auxiliary heat exchange parts. This feedback enables dynamic adjustment of refrigerant distribution to prevent frost formation on the auxiliary part while maintaining optimal heat absorption capacity.
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 effectively reduces frost formation on the auxiliary heat exchange part and increases the evaporation amount in the main heat exchange part, thereby improving the evaporative capacity and heat exchange efficiency of the heat-source-side heat exchanger.
Implementation Method 1
the heat-source-side heat exchanger (40) includes an upper main heat exchange part (50) and a lower auxiliary heat exchange part (55) arranged in a vertical direction... in an evaporation mode, refrigerant is evaporated in the heat-source-side heat exchanger (40)
Implementation Method 2
a refrigerant circuit in which a compressor (31), a heat-source-side heat exchanger (40), an expansion valve (33), and a utilization-side heat exchanger (32) are connected together and which is configured to perform a refrigeration cycle
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In an air conditioner (10) which is a refrigerating apparatus, a superheat degree controller (71) is provided, which is configured to control, in an evaporation mode of an outdoor heat exchanger (40), the opening degree of an expansion valve (33) such that the superheat degree of refrigerant whose flows are joined together after passing through a main heat exchange part (50) and an auxiliary heat exchange part (55) reaches a predetermined superheat degree. Moreover, in the air conditioner (10), a flow volume adjustment valve (66) configured to adjust, in the evaporation mode of the outdoor heat exchanger (40), a flow ratio between refrigerant flowing through the main heat exchange part (50) and refrigerant flowing through the auxiliary heat exchange part (55) and a flow ratio controller (72) configured to control the flow volume adjustment valve (66) such that the temperature of refrigerant having passed through the main heat exchange part (50) and the temperature of refrigerant having passed through the auxiliary heat exchange part (55) are substantially equal to each other are provided.