Indirect Evaporative Cooling Bypass for Chiller Energy Savings
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Solution Overview
Problem
Conventional cooling systems for buildings rely heavily on energy-intensive mechanical chillers and require significant water usage, with indirect evaporative cooling systems facing challenges in efficiency and contamination issues, especially in varying weather conditions.
Innovation Solution
An indirect evaporative cooling system with a supplemental chiller that can be bypassed, utilizing a closed coil evaporative cooler and a central computer to optimize operation based on weather conditions, allowing for efficient free cooling and reducing water usage by integrating a hydraulic bridge and three-way valve system to direct water flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical chillers are used for building cooling, then reliable cooling is achieved, but energy consumption is high
Solution Approach 1:
The system dynamically switches between evaporative cooling mode and mechanical chiller mode based on real-time weather conditions and cooling requirements. The evaporative cooler operates during favorable conditions to reduce energy consumption, while the mechanical chiller provides backup during unfavorable conditions, achieving both energy efficiency and reliable cooling
Solution Approach 2:
The system merges evaporative cooling and mechanical chiller into a hybrid system that operates as an integrated unit. The evaporative cooler and mechanical chiller work together, with the evaporative cooler handling base cooling loads during suitable conditions and the mechanical chiller providing supplemental cooling when needed, achieving energy efficiency without sacrificing reliability
2Use of energy by moving object
If indirect evaporative cooling is used, then energy consumption is reduced, but water usage increases
Solution Approach 1:
The system incorporates sensors and control mechanisms that continuously monitor weather conditions, cooling loads, and water usage. Based on this feedback, the system optimizes evaporative cooler operation, reducing water consumption during periods when mechanical cooling is more efficient or when water is scarce, while maintaining energy efficiency during periods when evaporative cooling is optimal
3Productivity
If evaporative cooler operates continuously, then cooling efficiency is maintained, but contamination of condenser circuit occurs
Solution Approach 1:
The system extracts and isolates the evaporative cooling function from the mechanical chiller system, allowing the evaporative cooler to operate independently during favorable conditions. This separation prevents contamination of the condenser circuit while maintaining cooling efficiency, as the evaporative cooler handles outdoor air cooling separately from the indoor refrigerant cycle
4Reliability
If mechanical chiller is used during unfavorable weather, then cooling demand is met, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the operating mode based on real-time weather conditions and cooling requirements. During unfavorable weather conditions, the system transitions to mechanical chiller operation to meet cooling demands reliably, while during favorable conditions, it switches to evaporative cooling to minimize energy consumption, achieving both demand satisfaction and energy efficiency through adaptive operation
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 achieves reduced energy consumption and water usage by leveraging evaporative cooling when conditions permit, ensuring efficient cooling without contaminating the condenser circuit and allowing safe operation during cold weather or water outages, while maintaining efficiency comparable to or exceeding that of air-cooled chillers.
Implementation Method 1
an outdoor heat exchanger in the form of an evaporative cooler with a water spray system that can be actuated to spray water onto the outdoor heat exchanger to cool the water flowing through the heat exchanger
Implementation Method 2
In the evaporator, the liquid refrigerant evaporates due to the absorption of heat from the water
Implementation Method 3
The compressor compresses the refrigerant significantly to increase its pressure, thereby increasing the temperature of the refrigerant
Implementation Method 4
The refrigerant is cooled sufficiently to cause condensation of the refrigerant to a liquid phase
Data Source
AI summary
An efficient indirect building cooling system that bypasses a conventional chiller mechanism by connecting the indoor and outdoor intermediate fluid systems when conditions permit. This system includes indoor and outdoor fluid cooling circuits, each of which interfaces with the conventional chiller mechanism. The two fluid cooling circuits are connected together when weather conditions make doing so more efficient.