Development and Application of Schema Based Occupant-Centric Building Performance Metrics

Cory Mosiman,Herbert Els,Gregor Henze

doi:10.3390/en14123513

Abstract

Occupant behavior can significantly influence the operation and performance of buildings. Many occupant-centric key performance indicators (KPIs) rely on having accurate counts of the number of occupants in a building, which is very different to how occupancy information is currently collected in the majority of buildings today. To address this gap, the authors develop a standardized methodology for the calculation of percent space utilization for buildings, which is formulated with respect to two prevalent operational data schemas: the Brick Schema and Project Haystack. The methodology is scalable across different levels of spatial granularity and irrespective of sensor placement. Moreover, the methods are intended to make use of typical occupancy sensors that capture presence level occupancy and not counts of people. Since occupant-hours is a preferable metric to use in KPI calculations, a method to convert between percent space utilization and occupant-hours using the design occupancy for a space is also developed. The methodology is demonstrated on a small commercial office space in Boulder, Colorado using data collected between June 2018 and February 2019. A multiple linear regression is performed that shows strong evidence for a relationship between building energy consumption and percent space utilization.

Highlights

Climate change mitigation efforts require increasing the share of renewable energy sources, while simultaneously decreasing total energy use across all sectors
A key contribution of this study is to enable buildings with code prescribed occupancy detection systems to calculate occupant-centric key performance indicators (KPIs)
The space utilization for System A and System C are calculated using the methodology described in Section 2.3, where the space utilization is determined on an hourly basis

Summary

Introduction

Climate change mitigation efforts require increasing the share of renewable energy sources, while simultaneously decreasing total energy use across all sectors One of these sectors is the buildings sector, which consumes roughly one third of primary energy globally [1]. Buildings underpin many aspects of society by providing shelter and security, places for people to travel from and to, places to work, and places that we call home. They have always been designed and developed to support some aspect of our lives, yet formal analysis of how people use and interact with buildings has been lacking. Recent research on UK buildings has found that occupancy behavior can account for 10–80% of the discrepancies between designed and operational energy performance in buildings [3]

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