ASHRAE Journal - May 2021 - 40

TECHNICAL FEATURE

ing practices, public perception of occupant sensing
and indoor air quality standards in the wake of the
COVID-19 pandemic may make zone-level occupant
count sensing a necessity and lead to the development
of new and more robust occupant sensing solutions for
the built environment.
* Today, office workers have very diverse work schedules with unique first arrival and last departure times
and many days spent away from their offices. This diversity challenges traditional schedule-based HVAC control
with constant ventilation rates typically tailored for full
occupancy. Two simple pieces of occupant information
can translate into significant HVAC energy savings: the
highest expected number of occupants and the latest
expected arrival time in a zone.
The former takes advantage of inter-occupant scheduling diversity at the building level to adjust minimum
outdoor air damper position setpoints. The latter takes
advantage of absent weekdays at the zone level by reinstating the temperature setback when an arrival has
yet to occur by a prescribed latest arrival time. These
OCC approaches are the low-hanging fruit for energy
efficiency. The preference learning-based control
approaches introduced in this article can help practitioners to better monitor and improve occupant comfort.
* More detailed information on occupant sensing and
OCCs can be found in the ASHRAE Handbook.7
* Reported energy, cost and comfort benefits of OCCs
are still highly variable.18 Field implementations of OCC
have largely been limited to small-scale demonstrations (some with fewer than 10 occupants over less than
a few weeks of testing) and have not followed a standard measurement and verification protocol.4 Future
work is required to synthesize the findings from field
implementations and document best practices for OCC
implementations.

Acknowledgments

This research is supported by funding provided by
Natural Resources Canada, National Research Council
Canada, CopperTree Analytics, Sensible Building
Science, Delta Controls and BentallGreenOak. We have
greatly benefitted from discussions with other IEA EBC
Annex 79 researchers.

References
1. O'Brien, W., A. Wagner, M. Schweiker, A. Mahdavi, et al. 2020.
40

ASHRAE JOURNAL

ashrae.org

M AY 2021

" Introducing IEA EBC Annex 79: key challenges and opportunities
in the field of occupant-centric building design and operation. "
Building and Environment 178(July):106738.
2. NRC Canada. 2017. " National Energy Code of Canada for
Buildings 2017. " National Research Council Canada.
3. ANSI/ASHRAE/IES Standard 90.1-2019, Energy Standard for
Buildings Except Low-Rise Residential Buildings.
4. Park, J.Y., M.M. Ouf, B. Gunay, Y. Peng, et al. 2019. " A critical
review of field implementations of occupant-centric building
controls. " Building and Environment 165:106351.
5. Jung, W., F. Jazizadeh. 2019. " Human-in-the-loop HVAC
operations: a quantitative review on occupancy, comfort, and
energy-efficiency dimensions. " Applied Energy 239:1471-1508.
6. Melfi, R., B. Rosenblum, B. Nordman, K. Christensen.
2011. " Measuring building occupancy using existing network
infrastructure. " International Green Computing Conference and
Workshops 1-8.
7. 2019 ASHRAE Handbook-HVAC Applications, Chap. 65.
8. Lam, K.P., M. Höynck, B. Dong, B. Andrews, et al. " Occupancy
detection through an extensive environmental sensor network in
an open-plan office building. " IBPSA Building Simulation 145:1452-59.
9. Dong, B., V. Prakash, F. Feng, Z. O'Neill. 2019. " A review of
smart building sensing system for better indoor environment
control. " Energy and Buildings 199:29-46.
10. Hobson, B.W., D. Lowcay, H.B. Gunay, A. Ashouri, et al. 2019.
" Opportunistic occupancy-count estimation using sensor fusion: a
case study. " Building and Environment 159(July):106154.
11. Ashouri, A., G.R. Newsham, Z. Shi, H.B. Gunay. 2019. " Dayahead prediction of building occupancy using Wifi signals. " IEEE
15th International Conference on Automation Science and Engineering
(CASE), 1237-42.
12. Jayathissa P, M. Quintana, M. Abdelrahman, C. Miller. 2020.
" Humans-as-a-sensor for buildings-intensive longitudinal indoor
comfort models. Buildings 10(10):174. https://doi.org/10.3390/
buildings10100174.
13. Gunay, B., Z. Shi, A. Ashouri, G. Newsham. 2019. " Development
of a clustering-based morning start time estimation algorithm for
space heating and cooling. " Proceedings of the 6th ACM International
Conference on Systems for Energy-Efficient Buildings, Cities, and
Transportation 297 - 305.
14. Hobson, B.W. 2020. " Development and implementation
of occupancy-based predictive controls for modulation of air
handling units' outdoor air dampers. " Master's Thesis, Carleton
University, Ottawa.
15. O'Neill, Z.D., Y. Li, H.C. Cheng, X. Zhou, et al. 2020. " Energy
savings and ventilation performance from CO2-based demand
controlled ventilation: simulation results from ASHRAE RP-1747
(ASHRAE RP-1747). " Science and Technology for the Built Environment
26(July):257-81.
16. Gunay, H.B., W. O'Brien, I. Beausoleil-Morrison, W. Shen, et al.
2017. " The effect of zone level occupancy characteristics on adaptive
controls. " 15th International Conference of the International Building
Performance Simulation Association.
17. Gunay, B. 2016. " Improving energy efficiency in office buildings
through adaptive control of the indoor climate. " Ph.D. Thesis,
Carleton University, Ottawa.
18. Pang, Z., Y. Chen, J. Zhang, Z. O'Neill, et al. 2020. " Nationwide
HVAC energy-saving potential quantification for office buildings
with occupant-centric controls in various climates. " Applied Energy
279:115727.

https://www.mdpi.com/2075-5309/10/10/174 https://www.mdpi.com/2075-5309/10/10/174 http://www.ashrae.org

ASHRAE Journal - May 2021

Table of Contents for the Digital Edition of ASHRAE Journal - May 2021