Jovan Pantelic

Air pollution makes an impact on cardio-pulmonary health. Since people spend over 90% of their time indoors, exposures to the indoor environment make the most significant impact on health. Among indoor sources, cooking emits the most particles that disperse through the residential indoor environment and expose occupants. We use fully controlled sim...

Cities today encounter significant challenges pertaining to urbanization and population growth, resource availability, and climate change. Concurrently, unparalleled datasets are generated through Internet of Things (IoT) sensing implemented at urban, building, and personal scales that serve as a potential tool for understanding and overcoming thes...

Research is needed to explore the limitations and potential for improvement of machine learning for building energy prediction. With this aim, the ASHRAE Great Energy Predictor III (GEPIII) Kaggle competition was launched in 2019. This effort was the largest building energy meter machine learning competition of its kind, with 4,370 participants who...

It is widely accepted that most people spend the majority of their lives indoors. Most individuals do not realize that while indoors, roughly half of heat exchange affecting their thermal comfort is in the form of thermal infrared radiation. We show that while researchers have been aware of its thermal comfort significance over the past century, sy...

A data-driven simulation technique is proposed for the calculation of the 3-dimensional radiant temperature distribution across a room with the aid of a ray tracing method. The proposed simulation accounts for interreflections of radiant heat fluxes from surfaces reflective in the longwave range within the indoor environment. The simulation provide...

Tracer gas experiments were conducted in a 158 m3 room with overhead supply diffusers to study dispersion of contaminants from simulated speaking in physically distanced meeting and classroom configurations. The room was contained within a 237 m3 cell with open plenum return to the HVAC system. Heated manikins at desks and a researcher operating th...

A simulation technique is proposed as a tool to assess the efficacy of Ultraviolet Germicidal Irradiation (UVGI) devices as measures for controlling virus spread in occupied rooms’ retrofits. UVGI devices disinfect the air and surfaces in their range through intense UV-C radiation that causes DNA or RNA damage to microorganisms. This disinfection m...

Natural ventilation (NV) represents the most energy-efficient way to operate buildings and, in an attempt to reduce the built environment's global carbon footprint, represents a resource, the usage of which has to be maximized. This study demonstrated how a combination of an IoT environmental sensing network implemented locally outdoors and indoors...

Assessment of integrated personal exposure (PE) to airborne particulate matter (PM) across diverse microenvironments (MEs) over 24 h under different exposure scenarios is necessary to identify appropriate strategies to improve urban air quality and mitigate the health effects of PM. We carried out a collaborative study in a densely populated city-s...

The use of Ultraviolet Germicidal Irradiation (UVGI) devices in the upper zones of occupied buildings has gained increased attention as one of the most effective mitigation technologies for the transmission of COVID‐19. To ensure safe and effective use of upper‐room UVGI, it is necessary to devise a simulation technique that enables engineers, desi...

Radiant cooling-assisted natural ventilation is an innovative technical approach that combines new radiant cooling technology with natural ventilation to increase fresh air delivery into buildings year-round with minimal energy cost and improves air quality. Currently, the standard paradigm for HVAC (heating, ventilation and air conditioning) is ba...

This research proposes the use of membrane-assisted radiant panels to improve the thermal comfort of naturally ventilated spaces in hot and humid climates. These radiant panels are capable of conditioning naturally ventilated spaces, which is impractical with conventional mechanical cooling systems. For conventional systems, a permeable envelope wi...

This research proposes the use of membrane-assisted radiant panels to improve the thermal comfort of naturally ventilated spaces in hot and humid climates. These radiant panels are capable of conditioning naturally ventilated spaces, which is impractical with conventional mechanical cooling systems. For conventional systems, a permeable envelope wi...

The use of smiley-face polling stations has had a rapid growth as a means of automatically and efficiently collecting user satisfaction verdicts in airports, restrooms, museums, and retail. Their advantages are that they are low cost, efficient for both respondents and analysts, in addition to having higher response rates than other survey types. T...

Human activity is known to leave significant effects on indoor airflow patterns. These patterns are carefully designed for many facilities such as cleanrooms, pharmaceutical settings, and healthcare environments, where human‐induced wakes contribute to the transport of contaminants. Therefore, the knowledge about these wakes as it relates to indoor...

Significance In this paper, we present results from a radiant cooling pavilion, demonstrating a method of cooling people without cooling the air. Instead, surfaces are chilled, and thermal radiation is used to keep people cool. A thermally transparent membrane is used to prevent unwanted air cooling and condensation, a required precursor to deployi...

Background It has long been known that nasal inoculation with influenza A virus produces asymptomatic to febrile infections. Uncertainty persists about whether these infections are sufficiently similar to natural infections for studying human‐to‐human transmission. Methods We compared influenza A viral aerosol shedding from volunteers nasally inoc...

Uncertainty about the importance of influenza transmission by airborne droplet nuclei generates controversy for infection control. Human challenge-transmission studies have been supported as the most promising approach to fill this knowledge gap. Healthy, seronegative volunteer ‘Donors’ (n = 52) were randomly selected for intranasal challenge with...

Uncertainty about the relative importance of modes of influenza transmission, particularly airborne droplet nuclei (aerosols), fuels controversy concerning recommendations for healthcare worker protection during pandemics. In-depth review by an expert panel, a proof-of-concept study, and an international workshop concluded that human challenge-tran...

Singapore is a tropical country with a high density of daycare facilities whose indoor environments may be adversely affected by outdoor fine particle (PM2.5) air pollution. To reduce this problem requires effective, evidence‐based exposure‐reduction strategies. Little information is available on the penetration of outdoor PM2.5 into daycare enviro...

In this paper, we present results from a world-first radiant cooling pavilion, demonstrating a method of cooling people without cooling the air. Instead, surfaces are chilled and thermal radiation is used to keep people cool. A thermally-transparent membrane is used to prevent unwanted air cooling and condensation, a required precursor to deploying...

In this paper, we present results from a world-first radiant cooling pavilion, demonstrating a method of cooling people without cooling the air. Instead, surfaces are chilled and thermal radiation is used to keep people cool. A thermally-transparent membrane is used to prevent unwanted air cooling and condensation, a required precursor to deploying...

For thermal comfort research, globe thermometers have become the de facto tool for mean radiant temperature, tr, measurement. They provide a quick means to survey the radiant environment in a space with nearly a century of trials to reassure researchers. However, as more complexity is introduced to built environments, we must reassess the accuracy...

[This corrects the article DOI: 10.1371/journal.pone.0223136.].

Air conditioning demand is projected to increase rapidly over the next 50 years, particularly in already hot and humid climates. Radiant cooling can be an energy efficient strategy to mitigate comfort energy demand with high air temperatures, thereby reducing both sensible and latent loads in spaces. We have built an outdoor radiant cooling pavilio...

Singapore is a tropical country that can be affected by outdoor fine particle air pollution. Little information is available on the penetration of outdoor fine particles into daycare environments. Our study attempted to address the following objectives: to measure indoor infiltration factor ( F inf of PM 2.5 from outdoor fine particles and to deter...

Inhalation exposure to pure and metabolic elevated carbon dioxide (CO2) concentration has been associated with impaired work performance, lower perceived air quality, and increased health symptoms. In this study, the concentration of metabolic CO2 was continuously measured in the inhalation zone of 41 subjects performing simulated office work. The...

Wildfires and associated emissions of particulate matter pose significant environmental and health concerns. In this study we propose tools to evaluate building resilience to extreme episodes of outdoor particulate matter using a combination of indoor and outdoor IoT measurements, coupled with survey-based information of occupants’ perception and b...

For thermal comfort research, globe thermometers have become the de facto tool for mean radiant temperature, tr, measure- ment. They provide a quick means to survey the radiant environment in a space with nearly a century of trials to reassure researchers. However, as more complexity is introduced to built environments, particularly with radiant he...

Radiant cooling and heating systems provide an opportunity to achieve significant energy savings, peak demand reduction, load shifting, and thermal comfort improvements compared to conventional all-air systems. As a result, application of these systems has increased in recent years, particularly in zero-net-energy (ZNE) and other advanced low-energ...

In this study, we enhance the understanding and design of a radiant cooling technology for outdoor comfort in tropical climates, originally proposed by R.N. Morse in 1963, in this journal. We investigate a type of radiant cooling methodology whereby the cold temperature source is physically separated from the outdoor environment by an insulated enc...

The current standard procedure for design sizing of cooling systems is not well suited for design of buildings with radiant cooling. There are several reasons that the standard design procedure for radiant cooling systems (ASHRAE Systems & Equipment 2016 Chapter 6: Radiant Heating and Cooling) is flawed, including that the current standard definiti...

Background: Operating rooms (ORs) are usually over-pressurized in order to prevent the penetration of contaminated air and the consequent risk of surgical site infection. However, a door-opening can result in the rapid disappearance of pressure and contaminants can then easily penetrate into the surgical zone. Therefore, a broad knowledge and unde...

The satisfaction of occupants with an indoor environment supplied by a conventional central VAV air-conditioning system was compared to a novel system represented by decentralized ventilation units and a network of passive chilled beams. In parallel with occupant survey measurement of indoor air quality (IAQ) parameters was conducted with the devel...

Significance Lack of human data on influenza virus aerosol shedding fuels debate over the importance of airborne transmission. We provide overwhelming evidence that humans generate infectious aerosols and quantitative data to improve mathematical models of transmission and public health interventions. We show that sneezing is rare and not important...

Little is known about the amount and infectiousness of influenza virus shed into exhaled breath. This contributes to uncertainty about the importance of airborne influenza transmission. We screened 355 symptomatic volunteers with acute respiratory illness and report 142 cases with confirmed influenza infection who provided 218 paired nasopharyngeal...

In order to deal with corrosion, crossover and desiccant utilization issues encountered in commercially available liquid desiccant systems, we develop and characterize the performance of a hydrophilic nonporous membrane-based liquid desiccant absorber. The liquid desiccant is an alkoxylated siloxane mixture, a modified silicone oil for enhanced moi...

By using small, decentralized liquid desiccant dehumidification combined with radiant panels or other low exergy chiller technologies large amounts of energy can be saved. This study builds off previous work characterizing a novel liquid desiccant system using a vapor permeable Pebax® membrane in conjunction with an alkoxylated siloxane liquid desi...

The Thermoheliodome is an experimental pavilion that explores cooling without air conditioning. The two research aims were to explore the use of indirect evaporative cooling and the geometric reflection of radiant cooling. For evaporative cooling we utilize a cooling tower outside of the pavilion to indirectly supply water chilled near the wet-bulb...

As the world adapts to dual trends of climate change and urbanization, tall office buildings in hot and humid climate zones near the equator are among the prime candidates for a significant change in design approach. Though many individualized improvements to operating systems, envelopes and material selections have been introduced in recent years,...

The Thermoheliodome, a digitally fabricated radiant cooling pavilion, addresses the energy challenge of buildings through a novel form and concept. We control the effective radiant temperature of a large area by expanding the surface area through reflection, which minimizes convective losses. Our novel geometric analysis for capture and concentrati...

In large commercial buildings facing high cooling loads, conventional heating, ventilation, and air-conditioning (HVAC) systems are typically based on the use of one, or few, large-capacity air handling units (AHUs) to supply conditioned air throughout a centrally-managed air distribution network. The alternative concept of ‘decentralized’ HVAC typ...

In this paper, we present what was learned in the research & design process of a decentralized ventilation system with chilled ceilings for a commercial office in Singapore. We make two key observations from the knowledge gathered. First, we observe, in quantitative terms, that present-day radiant cooling panel products may not provide sufficient s...

Unlabelled: The inhalation intake fraction was used as an indicator to compare effects of desktop personalized ventilation and mixing ventilation on personal exposure to directly released simulated cough droplets. A cough machine was used to simulate cough release from the front, back, and side of a thermal manikin at distances between 1 and 4 m....

Unlabelled: The effects of the human convective boundary layer (CBL), room airflow patterns, and their velocities on personal exposure are examined. Two pollutants are studied which simulate particles released from the feet and generated at distances of 2 and 3 m by a human cough. A thermal manikin whose body shape, size, and surface temperatures...

Two independent studies by two separate research teams (from Hong Kong and Singapore) failed to detect any influenza RNA landing on, or inhaled by, a life-like, human manikin target, after exposure to naturally influenza-infected volunteers. For the Hong Kong experiments, 9 influenza-infected volunteers were recruited to breathe, talk/count and cou...

This study aims to characterize human convective boundary layer (CBL) in a quiescent indoor environment. The study has two objectives: first, to characterize the velocity field around the thermal manikin under two ambient temperatures and body postures; and secondly, the influence of clothing insulation/design, chair design, table positioning and s...

In the offices of the future, human occupants will become a major heat source since the airflow generated by heat sources such as lighting and equipment will be less important due to increased use of low-powered devices. In that regard, the volume flux of the human convective boundary layer is comparable to the total ventilation flow, thus having a...

In indoor environments where airborne infectious disease transmission is of concern, air change rate is conventionally used as the sole indicator of air delivery system performance. This indicator, based on the total volume dilution reasoning, suggests that increase of the supply flow rate will reduce risk of airborne infectious disease transmissio...