Hybrid Air Cooling Modes for Data Center Energy and Water Limits

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Solution Overview

Problem

Current cooling systems in data centers, such as direct-air and indirect-air technologies, face limitations including high energy and water consumption, and decreased indoor air quality, which restrict server capacity and increase operating costs.

Innovation Solution

A hybrid cooling system that integrates direct and indirect cooling technologies, utilizing an external cooling unit with an evaporative cooler and a Liquid-to-Air Membrane Energy Exchanger to operate in multiple modes based on ambient conditions, optimizing water and energy usage by selecting the most efficient cooling method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If direct-air cooling technology is used, then cooling effectiveness is improved, but energy consumption and water consumption increase

Engineering Contradiction:
Improvecooling effectivenessVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between direct-air cooling, indirect-air cooling, and hybrid modes based on real-time monitoring of outdoor air conditions, server heat load, and ambient temperature. This dynamic adaptation allows the system to optimize energy consumption while maintaining effective cooling by selecting the most efficient cooling mode for each operating condition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cooling system is designed to perform multiple functions through a single integrated platform that can operate in direct-air cooling mode, indirect-air cooling mode, and hybrid mode. The system universally handles different cooling requirements by adjusting the proportion of outdoor air intake versus recirculated air, thereby reducing energy consumption across various operating scenarios while maintaining cooling effectiveness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If direct-air cooling technology is used, then cooling effectiveness is improved, but water consumption increases

Engineering Contradiction:
Improvecooling effectivenessVSAvoidwater consumption
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts water consumption by switching between cooling modes. In indirect-air cooling mode, the system uses recirculated air with minimal or no water consumption for evaporative cooling. In hybrid mode, the system optimizes the mix of direct and indirect cooling to reduce overall water usage while maintaining cooling effectiveness. This dynamic adjustment significantly reduces water consumption compared to pure direct-air cooling.

Inventive Principle:
Principle #15Dynamics

3Temperature

If outdoor air is delivered directly to enclosed space, then cooling is achieved, but indoor air quality decreases

Engineering Contradiction:
ImprovecoolingVSAvoidindoor air quality
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The system applies different air quality treatments to different air streams. Outdoor air intended for direct cooling is filtered and conditioned to remove particulates and contaminants before being delivered to the enclosed space. Recirculated indoor air is also filtered and mixed with fresh outdoor air in controlled proportions. This localized quality enhancement ensures that cooling is achieved while maintaining or improving indoor air quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system introduces an intermediary air handling process between outdoor air intake and indoor delivery. This intermediary stage includes filtration, humidity control, and temperature modulation to ensure that outdoor air meets indoor air quality standards before mixing with recirculated air and being supplied to the enclosed space, thereby resolving the conflict between cooling effectiveness and air quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If servers operate at higher capacity, then processing power increases, but temperature increases beyond cooling capability

Engineering Contradiction:
Improveprocessing capacityVSAvoidserver temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The system dynamically responds to increasing server heat loads by adjusting the cooling mode and intensity. As servers operate at higher capacity and generate more heat, the system increases the proportion of direct outdoor air intake for maximum cooling capacity, or activates the hybrid mode with optimized air mixing ratios. This dynamic adaptation enables the cooling system to match the thermal output of high-capacity servers, allowing them to operate at full processing capacity without exceeding temperature limits.

Inventive Principle:
Principle #15Dynamics

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 hybrid system reduces Water Usage Effectiveness (WUE) and Power Usage Effectiveness (PUE), achieving up to 90% savings in cooling costs and 50% in operating costs, while increasing server processing density by up to 100%, thereby enhancing data center capacity and efficiency.

Implementation Method 1

The external cooling unit can include an evaporative cooler and one or more additional components that enable the external cooling unit to operate in a dry mode and a wet mode

Methodology Applied
Scientific EffectEvaporative cooling: Evaporative Cooler

Implementation Method 2

The external cooling unit can include an evaporative cooler and one or more additional components that enable the external cooling unit to operate in a dry mode and a wet mode. In an example, the evaporative cooler of the cooling unit can include a Liquid-to-Air Membrane Energy Exchanger (LAMEE) operating as an evaporative cooler

Methodology Applied
Scientific EffectHeat transfer through membrane: Heat Exchanger

Data Source

PatentEP3679306B1Hybrid direct and indirect air cooling system
Publication Date: 2023.08.02 NORTEK AIR SOLUTIONS CANADA INC
  • EP3679306B1 patent drawingFigure 1A
  • EP3679306B1 patent drawingFigure 1B
  • EP3679306B1 patent drawingFigure 1C

AI summary

A hybrid system and method for conditioning air for an enclosed space can include a direct cooling system in combination with an indirect cooling system. The hybrid system can use direct cooling when ambient temperature and humidity levels are such that 100% outdoor air can be delivered to the enclosed space. The hybrid system can use indirect cooling when 100% of the return air can be conditioned using an external cooling unit and then returned to the enclosed space as supply air. The external cooling unit can include an evaporative cooler and operate in a dry mode and a wet mode. The external cooling unit can produce a reduced temperature cooling fluid and provide liquid cooling to the air when the system is operating in the indirect mode, and in some cases, in the direct mode. The hybrid system can operate in a mixed mode in which the external cooling unit is off and a mix of return air and outdoor air can be delivered to the enclosed space.