Split Condenser Head Pressure Control for Low-Ambient Cooling Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Air-cooled CRAC DX systems face challenges in maintaining adequate head pressure during low ambient temperatures, leading to inefficiencies and increased costs due to the need for complex and costly solutions like flooded receivers.
Innovation Solution
A cooling system with a split condenser and head pressure control valve, where the liquid header is divided into sections with different volumes and a head pressure control valve regulates the flow between them to maintain optimal condensing pressure, reducing the need for large receivers and complex components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional condenser design is used, then the system structure is simple, but the head pressure cannot be maintained at low ambient temperatures
Solution Approach 1:
The condenser is divided into a first condenser section and a second condenser section with different heat transfer areas. The first section has a larger heat transfer area for low ambient temperature operation, while the second section has a smaller heat transfer area for high ambient temperature operation. This segmentation allows the system to maintain effective head pressure across a wide ambient temperature range by selectively activating appropriate sections.
Solution Approach 2:
The system dynamically switches between different condenser sections based on ambient temperature conditions. A controller activates the first condenser section when ambient temperature is below a threshold and activates the second section when ambient temperature exceeds the threshold. This dynamic adaptation enables the condenser to maintain optimal head pressure regardless of ambient temperature variations.
2Temperature
If a flooded receiver is used to maintain head pressure, then head pressure control is effective, but the system complexity and cost increase
Solution Approach 1:
The invention extracts the head pressure control function from the traditional flooded receiver approach and integrates it directly into the condenser structure itself. By incorporating multiple condenser sections with different heat transfer areas and using a controller to switch between them, the system achieves head pressure control without requiring a separate flooded receiver, thereby reducing system complexity while maintaining effectiveness.
3Temperature
If the condenser heat transfer area is increased for low temperature operation, then head pressure is maintained, but the system becomes less efficient at high temperatures
Solution Approach 1:
The condenser is segmented into two sections with different heat transfer areas optimized for different operating conditions. The first section has a larger heat transfer area suitable for low ambient temperatures, while the second section has a smaller heat transfer area optimized for high ambient temperatures. This segmentation ensures that the system operates at peak efficiency regardless of ambient temperature conditions.
Solution Approach 2:
The system dynamically selects which condenser section to activate based on ambient temperature. When ambient temperature is low, the first section with larger heat transfer area is activated to maintain head pressure. When ambient temperature is high, the second section with smaller heat transfer area is activated to optimize cooling efficiency. This dynamic switching resolves the contradiction between maintaining head pressure and preserving cooling efficiency across different temperature conditions.
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 effectively maintains head pressure at low ambient temperatures, reducing costs and system complexity while ensuring efficient operation, as demonstrated by the experimental setup and cost analysis.
Implementation Method 1
a condenser fluidly coupled to the thermal expansion valve and configured to condense gas phase refrigerant to liquid phase refrigerant
Implementation Method 2
a head pressure control valve fluidly coupled to the liquid header and positioned between the condenser and the thermal expansion valve, the head pressure control valve configured to respond to changes in a pressure of liquid refrigerant
Data Source
AI summary
A condenser (404) configured to condense gas phase refrigerant to liquid phase refrigerant. The condenser (404) includes a gas header (408) configured to receive gas phase refrigerant, a liquid header (410) disposed opposite the gas header, the liquid header (410) separated into at least two sections, each section of the at least two sections having a port, and parallel tubes (406) extending between the gas header (408) and the liquid header (410).