Three-Path Heat Exchanger for Dual-Mode Refrigerated Air Drying
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Solution Overview
Problem
Conventional refrigerated air dryers for compressed air systems are energy-intensive due to the need for cooling, which increases operational and maintenance costs, and there is a need for improved designs that offer better thermal performance and energy efficiency.
Innovation Solution
A refrigerated air dryer system with a three-path heat exchanger that includes an air path, a refrigerant path, and a fluid path, allowing for dual cooling modes by using a precooler/reheater and a thermal storage fluid system, where the refrigerant compressor, condenser, and expansion device work in conjunction with a glycol/water mix to modulate cooling capacity and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a refrigerated air dryer operates in conventional single cooling mode, then the cooling function is simple and device complexity is low, but energy efficiency is poor and thermal performance is insufficient
Solution Approach 1:
The cooling function is segmented into two distinct modes: a first cooling mode using only the refrigerant system, and a second cooling mode using both the refrigerant system and fluid system simultaneously. This segmentation allows the system to optimize energy efficiency by selecting the appropriate cooling mode based on thermal demand, thereby resolving the contradiction between energy efficiency and device complexity.
Solution Approach 2:
The system dynamically switches between different cooling modes depending on operational requirements. The controller activates or deactivates the pump to switch between single-refrigerant cooling and dual-system cooling, enabling the system to adapt to varying thermal loads and improve overall energy efficiency without requiring permanent complex infrastructure.
2Temperature
If the cooling capacity is increased to improve thermal performance, then moisture removal effectiveness is improved, but energy consumption increases
Solution Approach 1:
The system applies partial cooling action by selectively activating only the refrigerant system when moderate cooling is sufficient, and excessive cooling action by activating both refrigerant and fluid systems when maximum cooling capacity is required. This partial/excessive action strategy allows the system to match cooling output to actual demand, improving energy efficiency while maintaining the capability for high cooling capacity when needed.
Solution Approach 2:
The system changes operational parameters by switching between different cooling mode configurations. The controller adjusts system parameters (which cooling systems are active) based on thermal demand, allowing flexible modulation of cooling capacity to match load requirements and optimize energy consumption across different operating conditions.
3Use of energy by moving object
If a dual cooling mode system is implemented to improve energy efficiency, then energy consumption is reduced, but device complexity increases
Solution Approach 1:
The heat exchanger serves multiple functions: it acts as a refrigerant evaporator when only the refrigerant system is active, and serves as both a refrigerant evaporator and fluid heat exchanger when both systems are active. This multi-functionality allows a single component to handle different cooling modes, reducing the need for separate dedicated components and thereby limiting the increase in device complexity while enabling energy-efficient dual-mode operation.
Solution Approach 2:
The system uses its own existing components (the heat exchanger and refrigerant system) to provide cooling in both modes, rather than requiring entirely separate independent systems. The fluid system leverages the existing heat exchanger infrastructure, allowing the system to serve itself across different operational requirements without proportionally increasing complexity.
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 system achieves improved thermal performance and energy efficiency by allowing for flexible cooling capacity modulation, reducing energy costs, and maintaining reliable operation while effectively removing moisture from compressed air.
Implementation Method 1
The refrigerant path acts as an evaporator such that the refrigerant removes heat from the three path heat exchanger
Implementation Method 2
The refrigerant compressor compresses a refrigerant that passes through the condenser, through the expansion device, and through the refrigerant path in the three path heat exchanger
Implementation Method 3
A precooler/reheater is positioned downstream of the air compressor and receives the hot, wet compressed air and precools the air
Implementation Method 4
The precooled wet compressed air flows through the air path and is cooled below the dew point of the now cooled, wet compressed air
Implementation Method 5
separates liquid water that has condensed out of the compressed air
Implementation Method 6
a pump that pumps the fluid through the fluid path of the three path heat exchanger
Implementation Method 7
a thermally insulated tank that contains a supply of a thermal storage fluid
Data Source
AI summary
A refrigerated air dryer includes a three-path heat exchanger 18 having an air path 18a, a refrigerant path 18b, and a fluid path 18c. The three flow paths exchange heat within a single unit to provide a compact heat exchanger with improved thermal performance at a lower production cost.