Airside Economizer Start Control for Dynamic HVAC Load Changes
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Solution Overview
Problem
Traditional HVAC systems using airside economizers rely on fixed temperature thresholds to transition between mechanical cooling and economizer modes, which are inefficient as they assume peak internal loads and do not account for dynamic changes in outside air temperatures, leading to suboptimal operation.
Innovation Solution
The implementation of a dynamic control logic that adjusts the high start limits for airside economizer mode based on real-time load information from ICTE and power supply, indoor temperature, and ventilation rate, allowing for intelligent decision-making as outside air temperatures drop, thereby optimizing the transition from mechanical cooling to economizer mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed temperature threshold is used to start economizer mode, then the control logic is simple, but the system cannot adapt to dynamic changes in load and outside air temperature, leading to suboptimal operation
Solution Approach 1:
The patent implements dynamic economizer start control by continuously monitoring real-time load information from ICTE and power supply, indoor temperature, and ventilation rate. The control logic dynamically adjusts the high start limit temperature threshold based on current operating conditions rather than using a fixed threshold, allowing the system to adapt to varying loads and outside air temperatures.
Solution Approach 2:
The system incorporates feedback mechanisms by continuously measuring indoor temperature, load conditions, and ventilation rate, then using this feedback to adjust the economizer start threshold. This closed-loop control enables the system to respond to changing conditions and optimize economizer operation based on actual system state.
2Productivity
If a fixed temperature threshold is used for economizer start, then the control system is simple to implement, but it assumes peak internal loads which leads to premature or delayed economizer activation
Solution Approach 1:
The control system dynamically calculates the high start limit temperature threshold based on real-time measurements of indoor temperature, ventilation rate, and load conditions. This dynamic adjustment allows the economizer to start at the optimal moment for each operating condition, maximizing productive economizer operation hours while avoiding premature or delayed activation.
Solution Approach 2:
The patent changes the temperature parameter threshold dynamically rather than using a fixed value. The high start limit temperature is adjusted as a variable parameter based on the relationship between indoor temperature, ventilation rate, and load, allowing the system to optimize economizer operation across different operating conditions.
3Loss of time
If the economizer operates at higher outside ambient temperatures, then additional cooling hours are captured, but the risk of insufficient cooling capacity increases
Solution Approach 1:
The system uses feedback from real-time monitoring of indoor temperature, load conditions, and ventilation rate to determine the optimal economizer start threshold. This feedback mechanism ensures that the economizer operates at higher outside temperatures only when the calculated conditions indicate sufficient cooling capacity, maintaining reliability while maximizing economizer hours.
Solution Approach 2:
The control logic performs preliminary calculations using the measured parameters (indoor temperature, ventilation rate, load) to determine the appropriate high start limit threshold before economizer activation. This preliminary assessment ensures that economizer operation begins only when conditions predict adequate cooling performance, preventing insufficient cooling capacity.
Data Source
AI summary
A device stores control settings for an air conditioning unit for a space that houses power-consuming equipment. The air conditioning unit includes an economizer configured to supply outside cooling air when the economizer is in an active state. The device receives an inside temperature value associated with the space, and receives a real-time or near-real-time operating load value for the power-consuming equipment. The device determines, based on the inside temperature value, the operating load value, and the control settings, an outside temperature threshold for starting the economizer. The device determines if an outside temperature reading associated with the space is below the outside temperature threshold, and activates the economizer when the outside air temperature reading is below the outside temperature threshold.