Staged Cooling System with Pump-Based Free Cooling for Data Centers
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Solution Overview
Problem
Current data center cooling systems are inefficient, consuming at least half of the power used in a typical data center, with existing technologies failing to optimize energy usage effectively, especially in maintaining optimal temperature and humidity levels.
Innovation Solution
A high-efficiency cooling system with staged cooling using tandem digital scroll compressors and a pumped refrigerant economizer mode, where the system switches to a liquid pump-driven operation when outdoor temperatures are low enough to bypass the compressor, reducing energy consumption by utilizing a series of cooling circuits with varying capacities and modes of operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional compressor-based cooling systems are used, then cooling capacity is maintained, but energy consumption is high (consuming at least half of the power used in a typical data center)
Solution Approach 1:
The system dynamically switches between compressor-based cooling mode and pump-based free cooling mode based on outdoor temperature conditions. When outdoor temperatures are low, the system transitions to pump mode to eliminate compressor energy consumption, while maintaining adequate cooling capacity through the free cooling effect.
Solution Approach 2:
The system changes the operating parameters by switching the phase and flow regime of the refrigerant. In pump mode, liquid refrigerant is pumped through the evaporator without compression, changing the pressure-temperature relationship and enabling free cooling when outdoor temperatures are favorable.
2Loss of energy
If compressor is always on to maintain cooling capacity, then temperature control is reliable, but energy efficiency is reduced
Solution Approach 1:
The system uses the naturally cold outdoor air as a free cooling source when temperatures are low, eliminating the need for active compression. The pump-based liquid circulation system leverages the temperature differential between outdoor air and data center equipment to provide cooling without energy-intensive compression.
3Use of energy by moving object
If pump-based free cooling mode is used, then energy consumption is reduced, but cooling capacity may be insufficient in high-temperature conditions
Solution Approach 1:
The system dynamically adjusts between pump mode and compressor mode based on cooling demand and outdoor temperature. When outdoor temperatures rise or cooling demand increases, the system transitions to compressor mode to ensure adequate cooling capacity, while using pump mode during favorable conditions to minimize energy consumption.
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 approach significantly reduces energy consumption by optimizing compressor usage and leveraging the efficiency of liquid pumps over compressors in low-temperature conditions, enhancing the system's overall energy efficiency and capacity to maintain desired temperature and humidity levels.
Implementation Method 1
a liquid pump that pumps the refrigerant in a liquid phase
Implementation Method 2
an evaporator disposed in the cabinet... air moving units that move air to be cooled through the evaporators
Implementation Method 3
Heat rejection device 124 that provides cooled liquid to CRACs 116. Heat rejection device 124 is a device that transfers heat from the return fluid from CRACs 116 to a cooler medium, such as outside ambient air.
Data Source
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AI summary
A cooling system has a cabinet and a plurality of separate cooling stages including an upstream cooling stage and a downstream cooling stage. At least the upstream cooling state is a variable capacity cooling stage. Each cooling stage has a cooling circuit. Evaporators of the cooling circuits are arranged in the cabinet so that air passes over them in serial fashion. A controller when a Call for Cooling first reaches a point where cooling is needed, operating the upstream cooling circuit to provide cooling and not the downstream cooling circuit. When the Call for Cooling has increased to a second point, the controller additionally operates the downstream cooling circuit to provide cooling. The cooling capacity at which the upstream cooling circuit is being operated is less than its full capacity when the Call for Cooling reaches the second point.