Integrated make-up air system in 100% air recirculation system
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Solution Overview
Problem
Existing 100% air recirculation systems in data centers face challenges in efficiently maintaining humidity levels and require external make-up air units that increase energy consumption and system footprint.
Innovation Solution
An integral make-up air system is integrated within the air conditioning system housing, featuring a make-up air unit and a humidifier that condition and mix with process air downstream of the air-to-air heat exchanger, reducing the need for external components and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external make-up air unit is used to provide fresh outdoor air, then ventilation requirements are met, but the system footprint and energy consumption increase
Solution Approach 1:
The make-up air unit is integrated within the housing of the 100% air recirculation system, merging two previously separate systems into one unified structure. This eliminates the need for a separate external make-up air unit, thereby reducing the overall system footprint while maintaining the ability to provide required fresh outdoor air to meet ventilation requirements
Solution Approach 2:
The integrated make-up air unit serves multiple functions: it provides fresh outdoor air for ventilation, conditions the air (heating/cooling), and integrates with the existing recirculation system. This multi-functionality allows a single integrated unit to replace what would traditionally require separate external components, reducing overall system footprint
2Reliability
If an external make-up air unit is used to condition outdoor air, then ventilation requirements are met, but energy consumption increases
Solution Approach 1:
The make-up air unit is integrated within the housing of the 100% air recirculation system, merging two previously separate systems into one unified structure. This eliminates the need for a separate external make-up air unit, thereby reducing the overall system footprint while maintaining the ability to provide required fresh outdoor air to meet ventilation requirements
Solution Approach 2:
The integrated make-up air unit acts as an intermediary that introduces fresh outdoor air into the existing recirculation system at a strategic point. By positioning the make-up air inlet downstream of the air-to-air heat exchanger, the system can more efficiently condition the mixed air, reducing the energy required compared to separately conditioning make-up air externally
3Use of energy by moving object
If process air is continuously recirculated in a 100% air recirculation system, then energy efficiency is improved, but humidity level maintenance becomes challenging
Solution Approach 1:
The humidifier is positioned to add humidity to the process air before it enters the air-to-air heat exchanger. This preliminary humidification action ensures that the air is properly conditioned with respect to humidity levels before the cooling/exchange process, preventing over-drying that would occur if humidification were attempted after recirculation
Solution Approach 2:
The integrated make-up air unit acts as an intermediary that introduces fresh outdoor air into the existing recirculation system at a strategic point. By positioning the make-up air inlet downstream of the air-to-air heat exchanger, the system can more efficiently condition the mixed air, reducing the energy required compared to separately conditioning make-up air externally
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 maintains optimal humidity and temperature levels in the process air with reduced energy consumption and system footprint, compared to traditional external make-up air systems.
Implementation Method 1
an air-to-air heat exchanger (AAHX) arranged inside the housing. The scavenger air can indirectly and sensibly cool the warm process air
Implementation Method 2
The DX coil can be selectively used depending on the outdoor air conditions. If the outdoor air is cool, the DX coil may not be needed
Data Source
AI summary
Systems and methods for controlling conditions in an enclosed space can include an integral make-up air system that can be arranged in the interior of the housing for an air conditioning system that uses scavenger air in an air-to-air heat exchanger (AAHX) to condition process air from an enclosed space. The make-up air system can take replenishment air from outside the air conditioning system and deliver it into the process air stream. The make-up air system can include at least one heating or cooling device to condition the replenishment air before the replenishment air mixes with the process air. In an example, the make-up air system can include a DX coil to selectively cool and dehumidify the replenishment air. The make-up air system can include a humidifier arranged in the flow path of process air between the process air inlet and the AAHX to selectively add humidity to the process air.