Burak Gunay

• Ph.D.
• Professor (Associate) at Carleton University

Fault-impact analysis (FIA) in heating, ventilation, and air conditioning (HVAC) systems involves forecasting system loads in the absence of equipment malfunction and inappropriate sequences of operations with the intention of setting a target for optimal operating energy use and encouraging and augmenting fault correction. Fault correction is an o...

ASHRAE RP-1747 is a CO2-based demand-controlled ventilation (DCV) approach which uses trim and respond logic to dynamically adjust variable air volume (VAV) terminal units’ minimum airflow setpoints based on zones’ ventilation requirements. While simulation results and laboratory testing have estimated the impact on heating, ventilation, and air co...

High-performance sequences of operation for variable air volume (VAV) air handling units (AHUs) respond to requests from zones, leaving these sequences vulnerable to faults that occur at the zone level. While prior research has shown that ASHRAE Guideline 36 reduces energy consumption, its ability to withstand zone-level faults is understudied. Thi...

The supply air temperature (SAT) of an air handling unit in multi-zone variable air volume systems could impact the energy use significantly. Formerly, buildings used a constant SAT which resulted in high energy consumption due to the increased load on perimeter heaters. Lately, ASHRAE guideline 36 introduced the trim and respond logic (Taylor, 201...

Many commercial buildings depend on fixed thermostat setpoints, which increases energy consumption and may compromise occupants' comfort. In recent years, many occupant-centric control (OCC) methods have been introduced that can learn occupants' thermal preferences and adjust thermostat setpoints accordingly. This study uses reinforcement learning...

This study delves into the relationship between income, housing qualities, and indoor environmental quality (IEQ) perceptions in Canada. An online survey of about 1,100 Canadian residents from diverse socioeconomic groups capturing a representative sample of Canadian society was conducted. Using various statistical analyses, and reclassification me...

ASHRAE RP-1747 is a CO2-based demand-controlled ventilation (DCV) approach which uses trim and respond logic to dynamically adjust variable air volume (VAV) terminal units' minimum airflow setpoints based on zones' ventilation requirements. While simulation results and laboratory testing have estimated the impact on heating, ventilation, and air co...

Peak electricity demand, particularly to facilitate cooling in buildings, imposes a strain on aging electricity grid infrastructure, and leaves the grid particularly susceptible to brownouts and blackouts. In response, incentives have been implemented to reduce or shift electricity use during anticipated peak-demand periods, including time-of-use p...

Building standards groups, including ASHRAE, are focusing on the decarbonization of buildings beyond traditional energy efficiency measures, given the building sector's significant contribution of global GHG emissions. A key concern is the accurate estimation of GHG emissions during building operations. Many rely on annual averaged emission factors...

Building standards groups, including ASHRAE, are focusing on the decarbonization of buildings beyond traditional energy efficiency measures, given the building sector's significant contribution of global GHG emissions. A key concern is the accurate estimation of GHG emissions during building operations. Many rely on annual averaged emission factors...

The complex operation of HVAC systems in large commercial buildings warrants regular implementation of advanced analytical approaches to operations and maintenance, and subsequent corrective measures to improve and maintain optimal energy performance. Despite the established capabilities of data-driven fault detection and diagnostics (FDD) to ident...

Direct load control (DLC) is a prominent solution for demand-side energy management, where utility providers adjust consumers' temperature setpoints through smart thermostats. However, occupant overrides can have a detrimental impact on the overall efficacy of DLC. This study focuses on understanding override mechanisms and occupant responses durin...

Direct load control (DLC) is considered a viable solution to promote demand-side energy management, in which the utility provider adjusts consumers’ temperature setpoints via smart thermostats. Users commonly have the option to interrupt DLC and override them by adjusting their thermostat setpoints. However, the occurrence of overrides can have a d...

Fault detection and diagnostics (FDD) tools provide valuable information regarding system faults and deviation from expected operation. Most existing FDD tools apply rule-based fault detection algorithms that generate an alarm when a rule is met; however, these tools cannot evaluate the overall performance of a system. Inverse-model-based FDD algor...

Occupant-centric controls (OCC) and operations have emerged as a key concept in shifting the focus from conventional building- (or better system-) centric operations to a more occupant-centric approach. Despite the potential of OCC to meet occupants’ demands and bridge buildings’ energy performance gap, its implementation in real-world settings has...

This paper outlines a methodology for disaggregating building-level occupancy data into zone-level occupant counts using opportunistic data from Wi-Fi access points, motion detectors, and CO2 sensors via sensor fusion for a floor of an academic office building. The efficacy of different combinations of data for this purpose is explored and the occu...

Submetering significantly enhances building performance monitoring capabilities by providing a higher resolution to resource use and revealing energy consumption across the building and systems that would otherwise remain hidden. Previous studies indicated that building automation system (BAS) trend data represents an untapped opportunity to disagg...

Building codes offer a promising opportunity to help ensure high-performance buildings through efficient building design and construction practices. Given that human behaviour is increasingly recognized as essential in building energy use, the validity of occupant-related assumptions in the building code and the energy performance modelling tools u...

Carbon dioxide (CO2) sensor grid configuration has implications on indoor air quality (IAQ) when used for demand-controlled ventilation (DCV). The non-homogeneity of occupancy across a floorplate can result in high localized concentrations of CO2 which may go unaddressed if unmonitored. This study identifies zone locations, occupancy-types, and occ...

CO2-based demand-controlled ventilation (DCV) requires placement of CO2 sensors in air handling units (AHUs) as well as in individual zones. In complex multi-zone systems or across building portfolios, the installation and maintenance costs of these sensors are non-negligible. This study explores how CO2 sensor grids can be configured in a sparser...

Occupant-centric controls (OCC) is an indoor climate control approach whereby occupant feedback is used in the sequence of operation of building energy systems. While OCC has been used in a wide range of building applications, an OCC category that has received considerable research interest is learning occupants’ thermal preferences through their t...

The 9th annual ACM BuildSys Conference was hosted on November 9--10, 2022 in Boston, Massachusetts. Through a double-blind review process, the technical program committee (TPC) recommended 34 for acceptance from a total of 105 submissions.

Despite the development of numerous fault detection and diagnostic (FDD) technologies for buildings, many errors remain undiscovered or are not discovered promptly, which reduces energy efficiency and occupants’ satisfaction. Crowdsourcing applications that continuously collect building occupants’ feedback as additional sensors can improve the accu...

Occupant-Centric Control and Operation (OCC) represents a transformative approach to building management, integrating sensing of indoor environmental quality, occupant presence, and occupant-building interactions. These data are then utilized to optimize both operational efficiency and occupant comfort. This paper summarizes the findings from the I...

Characterization of an existing building’s energy-related features is critical to inform maintenance and retrofit decisions. However, existing field-scale characterization methods tend to be labour intensive, invasive, and require high fidelity longitudinal data gathered through tightly regulated experiments. This highlights the need for a low cost...

Faults in variable air volume (VAV) air handling unit (AHU) system control hardware and software detrimentally affect indoor environmental quality and energy performance. Existing fault detection and diagnostics (FDD) platforms employ simplistic expert rules, offer limited visualization capabilities to their end-users, and do not utilize state-of-t...

This paper introduces a novel visualization tool that uses visual analytics to present energy data estimated by equipment-level virtual meters and allows end-users to interact with the visualization to gain insights that can be used to improve building energy performance. The features of the visualization tool are demonstrated through a case study...

To better inform retrofit decision-making and benchmark performance of the existing building stock, a scalable and computationally efficient method needs to be developed to estimate energy-related features. The conventional field-scale and inverse model-based characterization approaches are limited in their scalability due to high engineering costs...

Modelling green roof physics has mainly consisted of developing complex numerical models of fine spatial discretization to simulate physical processes that occur between the many surfaces and materials that define the green roof system. However, a recent review of these models points out that (1) increasing model complexity may not necessarily tran...

Initial and maintenance costs often prevent dense submeter installations that enable room-level thermal energy monitoring. Previous studies suggested that building automation system (BAS) trend data represents an untapped potential to disaggregate existing meter data for heating and cooling into device- and system-level end-uses. These techniques d...

Fault impact analysis is an important phase of fault detection and diagnosis (FDD), enabling prioritization of the faults detected and allocation of resources to procure services and materials. However, many existing fault impact analysis workflows rely on building performance simulation (BPS) models with high engineering cost, limiting their use i...

Best-practice sequences of operation in multiple-zone variable air volume (VAV) air handling unit (AHU) systems rely on zone-level sensors and actuators. For instance, a supply air temperature (SAT) setpoint reset sequence in a single duct VAV system is often programmed by looking at the number of cooling requests received from zones. Comparably, a...

Modelling green roof physics has mainly involved developing complex numerical models to simulate physical processes that occur between the many surfaces and materials that define a green roof system. However, a recent review of these models declares that (1) increasing model complexity may not necessarily translate into better predictability of key...

This paper outlines a methodology for disaggregating building-level occupancy data into zone-level occupant counts using opportunistic data from Wi-Fi access points, motion detectors, and CO2 sensors via sensor fusion for a floor of an academic office building. The efficacy of different combinations of data for this purpose is explored and the occu...

Carbon dioxide (CO2) sensor grid configuration has implications on indoor air quality (IAQ) when used for demand-controlled ventilation (DCV). The non-homogeneity of occupancy across a floorplate can result in high localized concentrations of CO2 which may go unaddressed if unmonitored. This study identifies zone locations, occupancy-types, and occ...

Submetering significantly enhances building performance monitoring capabilities by providing a higher resolution to resource use and revealing energy consumption across the building and systems that would otherwise remain hidden. Previous studies indicated that building automation system (BAS) trend data represents an untapped opportunity to disagg...

Uninformed building operations and mechanical faults and anomalies often lead to poor building energy performance. Though analytical software tools incorporating several data-driven methods that identify energy deficiencies and energy-saving opportunities have been proposed as an accessible method for building operators to improve energy performanc...

Maintaining CO2 sensors for demand-controlled ventilation (DCV) requires frequent and costly recalibration. Therefore, identifying the minimum CO2 sensing infrastructure needed to enable DCV can lower costs while improving indoor air quality (IAQ). This study simulates the floor of a building under ten stochastic occupancy scenarios to help inform...

Numerous fault detection and diagnosis (FDD) methods for buildings have been developed but many faults are still undetectable. There are also several crowdsourcing applications developed to collect building occupants' input. However, there is no solid framework enabling building operators to make the most of the collected data and directly integrat...

A holistic fault detection and diagnostics (FDD) method should explicitly consider the dependencies between faults at the system- and zone-level to isolate the root cause. A system-level fault can trigger false alarms at the zone-level, while concealing the presence of a zone-level fault. However, most FDD methods have focused on a single component...

Data-driven operation and maintenance analytics for improving building energy performance are prevalent in the literature and produce various visualizations and key performance indicators that identify hard and soft heating, ventilation, and air conditioning faults, occupancy patterns, and energy use deficiencies. However, an underlying assumption...

Energy data estimated by virtual meters provide operational staff with an opportunity to improve building energy performance. Interactive visualization of virtual metered energy serves as a tool that can be used to identify energy consumption patterns and gain insights that can support operational decisions. This paper introduces a novel interactiv...

While the emphasis of fault detection and diagnostic (FDD) research has been on hard faults (e.g., stuck/leaking/broken valve or damper), soft faults or, in general, human errors account for a significant portion of faults occurring in variable air volume (VAV) air handling unit (AHU) systems. Human errors encompass a wide range of errors occurring...

Partial occupancy of commercial offices has become the norm in the wake of the COVID-19 pandemic. Given this, occupant-centric control (OCC), which adapt building systems based on occupants’ presence or preferences, offer an alternative to traditional control that assumes full occupancy. However, poor sequences of operation can degrade the benefits...

This paper classifies common sequencing logic faults in multiple zone variable air volume (VAV) air handling unit (AHU) systems by conducting a critical review of the literature. Six broad categories of sequencing logic faults are identified affecting the state of operation, mode of operation, and supply air temperature and duct static pressure set...

Facility management (FM) teams routinely deal with numerous tasks, tools, and data sources to ensure the buildings they manage function properly. This diversity and the organizational complexity of these teams increase operational expenses related to interoperability. To address this, a methodology integrating BIM with maintenance management system...

Data-driven building operation and maintenance research such as metadata inference, fault detection and diagnosis, occupant-centric controls (OCCs), and non-invasive load monitoring have emerged (NILM) as independent domains of study. However, there are strong dependencies between these domains; for example, quality of metadata affects the usabilit...

Mixed-mode ventilation is a design feature to improve building energy efficiency and indoor air quality. However, in practice, it does not always achieve better performance, largely due to inappropriate window operations. The research effort is also limited when exploring approaches to regulate manually operable windows. The present study found tha...

Implementation of sequences of operation for heating, ventilation, and air conditioning (HVAC) systems into a building automation system (BAS) is a critical process for building performance. Mistakes are commonly made while interpreting the sequences of operation from the mechanical design, converting them into BAS programs, and making ad-hoc chang...

Although understanding end uses in large commercial and institutional buildings is of great utility for achieving energy efficiency, most new and existing buildings still lack adequate submetering except for large end uses. End use disaggregation methods offer an alternative to fulfill weaknesses in a metering network, especially in large commercia...

Peak load management strategies are useful to commercial building operators for saving on energy costs and also to electricity grid operators for helping to balance power supply and demand. Peak load demand reduction can be achieved through demand-side management that facilitates the planning and implementation of demand response strategies and mai...

Faults in air-based heating, ventilation, and air conditioning (HVAC) systems lead to energy waste and discomfort. While the emphasis of fault detection and diagnostic (FDD) research has been on hard faults in actuators, sensors, and equipment, faults arising from human errors account for a significant portion of faults occurring in HVAC systems. I...

Research suggests that—relative to conventional roofs—green roofs can significantly reduce rooftop heat exchange in moderate climates; however, limited research exists on the performance of green roofs in colder climates. This paper analyzes the comparative performance of two side-by-side roof assemblies: a conventional roof and a green roof locate...

Most commercial HVAC systems provide ventilation assuming near-full occupancy during working hours. As conditioning outdoor air requires significant energy, reducing the ventilation requirements based on actual occupancy can improve energy efficiency without significantly impacting occupant comfort. An occupancy-based predictive control program was...