On quantifying building performance adaptability to variable occupancy

TLDR: A technology-independent approach is presented to define adaptability as a building performance attribute and introduce metrics to quantify it and show how the proposed metrics highlighted the additional benefits of these control strategies, especially under low-occupancy scenarios.

About: This article is published in Building and Environment.The article was published on 2019-05-15 and is currently open access. It has received 27 citations till now. The article focuses on the topics: Occupancy & Building automation.

Figures

Figure 7 Changes in occupant-normalized light energy use and lights utilization factor with different control strategies and occupancy scenarios

Table 2 Adaptability metrics calculated based on simulation results of a single-story office building in ASHRAE climate zone 6a

Table 1 Evaluation of the proposed metrics relative to the key characteristics of effective performance metrics adapted from O’Brien et al. [24]

Figure 5 Changes in fans utilization factor and occupant-normalized fan energy use with and without DCV under different occupancy scenarios

Frequently asked questions

Q1. What should be the focus of future research?

Future research should focus on standardizing building performance data collection and processing methods as well as the protocols for calculating adaptability metrics to ensure their reproducibility as benchmarks to evaluate building performance. 

Q2. What are the key developments that enable collecting occupancy data at higher temporal and spatial resolutions?

the proliferation of new technologies and occupant sensing infrastructure are key developments that enable collecting occupancy data at higher temporal and spatial resolutions [24]. 

Q3. What is the key requirement to quantify adaptability to variable occupancy?

To quantify adaptability to variable occupancy, it is imperative that access to data regarding occupancy patterns is a key requirement. 

Q4. What is the effect of temperature setbacks on building occupancy?

reducing temperature setback periods results in maintaining comfortable conditions for a longer period than occupancy, especially if parts of the building remain unoccupied for relatively long periods. 

Q5. What is the definition of the performance objective to be quantified using the proposed metrics?

The performance objective to be quantified using the proposed metrics is defined as “building operations’ adaptability to variable occupancy”. 

Q6. What are the important aspects of the proposed adaptability metrics?

These systems enable remote collection of granular energy use data [42], which can be used to calculate the proposed adaptability metrics. 

Q7. What is the purpose of the proposed adaptability metrics?

By providing reproducible and comparable metrics that fit the purpose of evaluating adaptability, building designers and operators can quickly evaluate the effect of different operational strategies on this aspect of building performance. 

Q8. What is the way to calculate the unoccupied energy use?

the minimum unoccupied energy use would be zero, but practical limitations due to safety and operational requirements mean that energy use is still needed even when the building is completely unoccupied. 

Q9. What is the time to calculate unoccupied ratios?

*Note that these metrics can be calculated at different temporal and spatial scalesA lower unoccupied ratio is more desirable for all end-uses since it indicates that less energy is used when the building or zone is unoccupied. 

Q10. What are the main reasons why adaptable control strategies can reduce energy use?

Other adaptable control strategies to control lighting, heating and cooling set-points were also found to achieve significant energy savings in previous studies [12]–[18].