Direct evaporative air handler
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Direct evaporative air handlers face challenges in controlling temperature and humidity in data centers under varying ambient conditions, particularly in cold weather where humidification can lead to freezing of evaporative media and in warm conditions where cooling and humidity levels are difficult to manage.
Innovation Solution
The air handler design includes an outdoor air port, a return air port, and an outdoor air bypass port, with dampers to control airflow through a direct evaporative cooler, allowing for mixing of recirculated and outdoor air to achieve precise temperature and humidity control, and includes multiple operation modes to address different ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If outdoor air is cooled using direct evaporative cooling, then the supply air temperature decreases, but the supply air becomes too cool or too humid
Solution Approach 1:
The evaporative cooler is divided into multiple cooling stages with separate wetting control. The first cooling stage and second cooling stage can be independently controlled, allowing the system to provide cooling in discrete stages and achieve more precise temperature control by selectively activating only the necessary stages.
Solution Approach 2:
Different portions of the evaporative media are wetted independently based on local cooling requirements. The control system selectively wets specific stages or portions of the media according to the outdoor conditions and desired supply air parameters, rather than uniformly wetting the entire media surface.
2Quantity of substance
If the evaporative media is wetted to humidify outdoor air, then the supply air humidity increases, but the media may freeze in cold weather
Solution Approach 1:
The system dynamically adjusts the wetting state of the evaporative media based on ambient conditions. During cold weather operation, the control system prevents wetting of media that would be exposed to freezing temperatures, while still providing humidification through controlled evaporation in non-freezing zones or through alternative humidification methods.
Solution Approach 2:
The bypass port serves as an intermediary pathway that allows outdoor air to enter the air handler without passing through the evaporative cooler. This enables the system to introduce outdoor air for pressure balance or partial humidification without exposing the media to freezing conditions.
3Temperature
If the damper stops wetting the media to prevent over-cooling, then the media remains wet for a significant period, but continues to cool and humidify the outdoor air
Solution Approach 1:
The evaporative cooler is divided into multiple independently controllable cooling stages. When cooling reduction is needed, the control system can selectively shut off wetting to specific stages rather than the entire media, allowing faster response time and more precise control without the delay associated with complete media drying.
4Adaptability or versatility
If multiple dampers and ports are added to control airflow paths, then the ability to mix outdoor and recirculated air improves, but the device complexity increases
Solution Approach 1:
The outdoor air bypass port serves multiple functions: it allows outdoor air to bypass the evaporative cooler during cold weather, provides a pathway for economizer operation, and enables flexible mixing ratios of outdoor and recirculated air. This multi-functionality reduces the need for additional specialized components.
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 design provides improved control over supply air temperature and humidity, optimizes energy efficiency, minimizes air stratification, and eliminates the risk of freezing during cold operations, while maintaining appropriate humidity levels across different ambient conditions.
Implementation Method 1
Direct evaporative air handlers are used to cool data centers by providing a relatively cooler supply air stream
Implementation Method 2
the supply fan mixes air that has been drawn through the outdoor air bypass port with recirculated air that has been drawn through the return air port and passed through the evaporative cooler
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A direct evaporative air handler for providing supply air to humidify and cool an enclosed space such as a data center. The air handler includes an evaporative cooler and a return air port that is positioned upstream of the evaporative cooler to allow recirculated air from the enclosed space to pass through the evaporative cooler. The air handler includes an additional return air port that is positioned downstream of the evaporative cooler to allow recirculated air from the enclosed space to bypass the evaporative cooler. The air handler includes an outdoor air port that is positioned upstream of the evaporative cooler to allow outdoor air to pass through the evaporative cooler and further includes an outdoor air bypass port that allows outdoor air to enter the air handler without passing through the evaporative cooler. The temperature and humidity of the supply air can be controlled under various ambient conditions by controlling the amount of air that enters the air handler through each port.