Rule-based load shedding algorithm for building energy management
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Solution Overview
Problem
Existing building automation systems face challenges in reducing power consumption without causing occupant discomfort, as disrupting HVACR or lighting loads can lead to discomfort and render zones unusable, lacking effective user control and occupant perceptibility.
Innovation Solution
A building power management system that includes intelligent circuit breakers and controllers to prioritize and shed loads based on occupancy and environmental conditions, dynamically ranking load shedding priorities to minimize discomfort and user impact, using sensors to detect occupancy and adjust HVACR and lighting set points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If building automation systems turn off controllable loads to reduce power consumption, then power consumption is reduced, but occupant comfort deteriorates
Solution Approach 1:
The system applies different load shedding strategies to different building zones based on their specific occupancy and environmental conditions. Each zone is evaluated independently, allowing the system to maintain comfort in occupied zones while reducing power in unoccupied zones, thus resolving the contradiction between power reduction and comfort maintenance.
Solution Approach 2:
The system performs preliminary testing of HVACR loads by temporarily suspending operation and measuring temperature change rates before actual load shedding decisions. This preliminary action allows the system to predict the impact of load shedding on occupant comfort and avoid shedding loads that would cause discomfort.
2Loss of energy
If lighting loads are turned off to reduce power consumption, then power consumption is reduced, but building zone usability deteriorates
Solution Approach 1:
The system evaluates each building zone's lighting needs independently based on ambient light conditions and occupancy status. Lighting loads are selectively adjusted or shut off only in zones where it does not impact usability, while maintaining lighting in zones that require it, thus resolving the contradiction between power reduction and usability maintenance.
3Loss of energy
If existing building automation systems implement load shedding, then power consumption is reduced, but occupant perceptibility increases
Solution Approach 1:
The system performs preliminary testing by temporarily suspending HVACR load operation and measuring the resulting temperature change rate. This preliminary action provides information about how sensitive each zone is to load shedding, allowing the system to select loads for shedding that will minimize temperature changes and thus minimize occupant perceptibility.
Solution Approach 2:
The system continuously monitors temperature changes in building zones and uses this feedback to adjust load shedding decisions. By measuring the actual temperature change rate during testing and during operation, the system can adaptively select which loads to shed to minimize occupant perception while achieving power reduction goals.
4Loss of energy
If building automation systems disrupt HVACR loads during demand response, then power consumption is reduced, but occupant comfort deteriorates
Solution Approach 1:
Before implementing load shedding during demand response events, the system performs preliminary testing by temporarily suspending HVACR load operation and measuring the temperature change rate. This allows the system to identify which HVACR loads can be shed without causing excessive temperature changes that would lead to occupant discomfort.
Solution Approach 2:
The system applies demand response strategies locally to individual building zones or HVACR loads based on their specific characteristics, occupancy status, and measured temperature change rates. This localized approach allows the system to reduce power consumption during demand response while maintaining comfort in zones where load shedding would cause discomfort.
Data Source
AI summary
Unique systems, methods, techniques and apparatuses of building power management are disclosed herein. One exemplary embodiment is a system comprising a load management controller and a power circuit interrupter. The load management controller is configured to repeatedly perform a first test wherein a time rate of change of temperature of building regions is determined, repeatedly perform a second test wherein a lighting controller is operated to rank a plurality of lighting loads according to ambient light of building regions associated with the plurality of lighting loads, assign the plurality of HVACR loads and lighting loads to a plurality of load shed groups, and reduce power consumption by the plurality of HVACR loads and the plurality of lighting loads in order of the ranked load shed groups effective to minimize occupant perceptibility of the power consumption reduction while implementing the operator specified priority criteria.