CO2 Refrigeration Intercooler Layout to Prevent Icing
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Solution Overview
Problem
Refrigeration apparatuses using carbon dioxide as a refrigerant in a supercritical range face inefficiencies due to high heat radiation loss and icing-up phenomena, particularly when the intercooler is integrated with the heat source-side heat exchanger and disposed in a way that reduces heat transfer performance and increases the risk of equipment reliability issues.
Innovation Solution
The intercooler is strategically integrated with the heat source-side heat exchanger and disposed in the upper part of the heat exchanger, optimizing air flow to enhance heat transfer coefficients and prevent icing-up by minimizing water adherence, thus improving overall heat transfer performance and equipment reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the intercooler is integrated with the heat source-side heat exchanger and disposed in the lower part, then device complexity is reduced, but heat transfer performance deteriorates and icing-up occurs
Solution Approach 1:
The patent changes the spatial dimension of intercooler placement from the lower part to the upper part of the heat source-side heat exchanger. This dimensional change optimizes air flow patterns and heat transfer coefficients, preventing icing-up while maintaining integration benefits. The upper placement allows melted water to drain away from the intercooler, eliminating the icing problem that occurs in lower placements.
Solution Approach 2:
The patent applies different functional qualities to different parts of the integrated heat exchanger system. The intercooler section in the upper part is optimized for cooling intermediate-pressure refrigerant with adequate heat transfer, while the lower part of the heat source-side heat exchanger is optimized for high-efficiency heat exchange with air. This local differentiation allows each component to perform its function optimally without compromising overall system reliability.
2Ease of manufacture
If the intercooler is disposed in the lower part of the heat exchanger, then manufacturing is simplified, but water adherence increases causing icing-up
Solution Approach 1:
The patent inverts the conventional placement logic by positioning the intercooler in the upper part rather than the lower part of the heat exchanger. This inversion exploits gravity to drain condensed water away from the intercooler surface, preventing ice formation. The harmful effect of water accumulation is eliminated by reversing the expected placement hierarchy.
3Device complexity
If the intercooler is integrated with the heat source-side heat exchanger, then device complexity is reduced, but heat radiation loss increases
Solution Approach 1:
By relocating the intercooler to the upper dimension of the heat source-side heat exchanger, the patent reduces the temperature difference between the refrigerant in the intercooler and the surrounding air. This dimensional repositioning minimizes heat radiation loss from the high-temperature refrigerant discharge line while preserving the integration benefits of the combined heat exchanger structure.
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 reduces heat radiation loss, enhances heat transfer performance, and prevents icing-up, leading to improved operational efficiency and reliability of the refrigeration apparatus.
Implementation Method 1
the intercooler functions as a cooler of the refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element
Implementation Method 2
the outdoor heat exchanger has much heat radiation loss
Data Source
AI summary
An air-conditioning apparatus uses carbon dioxide as a refrigerant, and includes a two-stage-compression-type compression mechanism, a heat source-side heat exchanger, an expansion mechanism, a usage-side heat exchanger, and an intercooler. The intercooler uses air as a heat source. The intercooler is configured and arranged to cool refrigerant flowing through an intermediate refrigerant tube that draws refrigerant discharged from the first-stage compression element into the second-stage compression element. The intercooler is integrated with the heat source-side heat exchanger to form an integrated heat exchanger, with the intercooler disposed in an upper part of the integrated heat exchanger.