Mixed mode cooling system
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Solution Overview
Problem
Centrifugal compressors in chillers face efficiency limitations due to minimum and maximum compression ratio constraints, leading to inefficiencies at extreme temperatures, and existing systems either compromise performance or require additional components like glycol-free cooling coils, which worsen efficiency at high temperatures.
Innovation Solution
A mixed mode cooling system with multiple condensing modules that can switch between compressed and free-cooling modes, utilizing centrifugal or oil-free compressors, segregation valves, and pumped refrigerant economizers to optimize efficiency across varying ambient temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If glycol free cooling coils are added to handle cold temperatures, then the system can operate at low temperatures, but device complexity and cost increase
Solution Approach 1:
The heat exchangers serve dual purposes: they function as free-cooling coils during cold temperature operations and as supplemental cooling elements during warmer conditions. This multi-functionality eliminates the need for separate glycol-based free-cooling systems, reducing overall system complexity while maintaining adaptability across temperature ranges.
2Adaptability or versatility
If free-cooling coils are added to the system, then low temperature operation is enabled, but efficiency worsens at high temperatures due to additional coils
Solution Approach 1:
The system employs dynamic control to selectively engage or disengage free-cooling coils based on ambient temperature conditions. During high temperature operations, the free-cooling coils are deactivated or bypassed, preventing their negative impact on efficiency. During low temperature operations, they are activated to provide efficient free-cooling, thus maintaining high efficiency across different temperature ranges.
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 enhances efficiency by allowing seamless transitions between cooling modes, reducing reliance on glycol and minimizing aeraulic pressure drops, thereby increasing efficiency and reducing installation costs and space requirements.
Implementation Method 1
an evaporator configured to transfer heat to a two-phase cooling fluid
Implementation Method 2
two-phase cooling fluid
Implementation Method 3
a compressor downstream of the evaporator in a first fluid path of the two-phase cooling fluid
Implementation Method 4
a first condenser downstream of the compressor in the first fluid path
Implementation Method 5
a first expansion valve downstream of the first condenser in the first fluid path
Implementation Method 6
a first pump downstream of the second condenser in the second fluid path and upstream of the evaporator in the second fluid path
Data Source
AI summary
A cooling system can include an evaporator configured to transfer heat to a two-phase cooling fluid, a compressor downstream of the evaporator in a first fluid path of the two-phase cooling fluid, a first condenser downstream of the compressor in the first fluid path, a first expansion valve downstream of the first condenser in the first fluid path and upstream of the evaporator in the first fluid path, a second condenser downstream of the evaporator in a second fluid path of the two-phase cooling fluid, and a first pump downstream of the second condenser in the second fluid path and upstream of the evaporator in the second fluid path.