Nearly 600 papers were reviewed regarding the effects of humidity on comfort, health, and indoor environmental quality (IEQ), of which 70 focused on low humidity (RH40%) and were thoroughly analyzed. Low humidity had little effect on thermal comfort, but increased skin dryness, eye irritation, and static electricity. Low humidity increased the survival of some pathogens, e.g. influenza. Low humidity showed non-uniform effects on volatile organic compound emissions and indoor air quality. Temperature, ventilation rates and time were noted as confounding variables. Most studies with adults utilized exposure times of maximum three hours; few studies used children, adolescents or elderly subjects.

Today, humidification is used primarily to protect materials and aid in manufacturing processes. However, data tells us that proper air hydration is also essential for our health. People resist short term dehydration by thirst-prompted (dry mouth) fluid intake. Conversely, chronic dehydration from water evaporation through skin and respiratory tissues in dry indoor air is unperceivable, yet has dire health consequences. Dry indoor air decreases our resistance to infections and allergies while providing a perfect environment to enhance microorganisms' infectivity and dissemination. This seminar presents new and existing data on the health benefits of proper air humidification.

ASHRAE research project “Limiting criteria for human exposure to low humidity” was conducted in 2001-2002 at the Technical University of Denmark. The impact of humidity on comfort and working performance was measured subjectively and objectively at 5%rh, 15%rh, 25%rh and 35%rh at 22°C (71.6°F) and at 18°C, 22°C and 26°C at 2.4 g/kg. The effect of low humidity was observed at both clean and polluted indoor environment. The results found that low humidity had negative impact on mucous quality and working performance that requires visual attention. Some interactions between low humidity and air pollution on dryness symptoms were observed.

ASHRAE Standard 199 was published in June 2016 to evaluate the performance of industrial pulse-cleaned dust collectors. The workshop covers development of this standard, and its progress to a new ISO standard. This method of test applies to bag, cartridge, or envelope industrial dust collectors that recondition the filter media by using pulses of compressed air to discharge the dust cake from the filter media. Attendees will learn how the test evaluates dust collector performance in terms of energy consumption and particulate emissions.

Research Project 1284 provided foundational research for evaluating dust collector performance. Speakers discuss that research and its conclusions, and how those conclusions were applied to ASHRAE Standard 199. The workshop also looks at some actual test data from tests using Standard 199 to explain results.

With the inception of heating, ventilation and air conditioning systems (HVAC) and ever more energy efficient building structures there is an increased focus on the quality of air within the built environment. The desiccant solutions, LiCl and CaCl₂, used with the LDD technology are extremely germicidal. Any microorganism contacting the solution is eradicated. The critical nature of the Healthcare environment is paramount in respect to IAQ. A focus on the application of LDD within Healthcare settings will be presented, specifically the impact upon pathogens associated with Healthcare acquired infections.

Two novel, high latent, compressor-based air conditioners were operated at military installations during the 2015 summer under the Department of Defense’s Environmental Security Technology Certification Program (ESTCP). Both air conditioners use a liquid desiccant to more than double the latent cooling provided by a conventional air conditioner. Although tested in configuration where they processed an 85/15 mix of return and outdoor air, the high latent capacity of the air conditioners make them ideal candidates for treating 100% ventilation air. The seminar presentation will focus on the field-monitored performance of the prototypes and the positive impact they had on indoor comfort.

In the spring of 2016, a 20 ton pilot air conditioner was installed in the extreme climate of Jubail, Saudi Arabia. Liquid desiccant heat exchangers enable systems to condition air to the desired temperature and humidity in a single step. This is made possible because the supply air exiting these exchangers has a dew-point near or even below the evaporator temperature. A system model, used to design the system, predicts a 33% reduction in energy use compared to other available systems. This presentation provides a brief overview of the system design and compare the demonstrated and predicted performance.

UV-C technology has been used as a disinfection method for decades in the healthcare industry. The UV-C wavelength of 253.7 nanometers has been proven to be effective at eliminating or neutralizing dangerous pathogens like C. difficile, Methicillin resistant Staphylococcus aureus and more. The current technologies focus on cleaning surfaces to reduce healthcare associated infections. Three studies were conducted at an acute care hospital, a children’s hospital and a long term acute care facility to determine if reducing the number of colony forming units of bacteria and/or fungus in the air would improve indoor air quality.

Volatile organic compounds (VOCs) are a major gaseous contaminant group affecting indoor air quality. Various technologies have been applied for the removal of VOCs. There are conventional systems based on adsorption process, i.e., activated carbon and/or potassium permanganate alumina pellets in trays or deep beds, particulate filters incorporating very thin beds of activated carbon or alumina pellets, and carbon cloth. The objective of this study is to investigate the effects of air flow rates on the performances of oxidation-based air cleaning technologies including UV with photocatalysts, plasma and ozone generators.

To prevent corrosion, tri-cresyl-phosphate (TCP) is added to aircraft engine oil. TCP occurs in a mixture of ten different isomers. The ortho isomers of TCP are known to be the most neurotoxic, however at present it is unknown in what concentration the ortho and the other isomers occur in cabin air, due to leakage in the air conditioning system, and in engine exhaust fumes. Various professions of airline staff may be exposed to concentrations of TCP. This research describes the assessment of the exposure through measurements inside the cockpit during flight, spot measurements on the ramp and personal measurements of ground mechanics.

ASHRAE Standard 161, Air Quality within Commercial Aircraft, includes a requirement for bleed air sensors to detect contamination from lubricating oil. One potential approach to meeting this requirement is through particle detection. A four-part experimental program was conducted to develop a detailed characterization of particles that result when bleed air is contaminated with lubricating oil. This research shows that development of sensors for detecting oil contamination in aircraft bleed air should focus on ultrafine particle detection and sensing of low contamination levels may require sensitivity to extreme ultrafine particles 10 nanometers and smaller.

The outside air used to pressurize and ventilate the cabin during flight is supplied by bleed air from the propulsion engine compressors on most airliners. The potential for this air to be contaminated by lubricating oil from leaking engine seals and other sources is believed to be rare. ASHRAE Standard 161, Air Quality within Commercial Aircraft, addresses this issue and includes a requirement for bleed air oil contamination sensing. This standard does not address the technology to be used for this sensing nor does it provide guidance about the physical characteristics of the contaminants as they appear in the bleed air.

In this work, a novel approach for the automated fault detection and diagnostics (AFDD) of building HVAC operation is introduced utilizing properties of the Koopman operator to extend the capabilities of rules-based FDD approaches. The Koopman operator is an infinite-dimensional, linear operator that captures nonlinear, finite dimensional dynamics. These mathematical aspects translate into algorithms which can effectively evaluate the magnitude and coincidence of data. Using properties of the operator, building management system (BMS) trend data can be decomposed into components which allow the capture of device-to-device interactions as well as device behavior at varying time-scales.

Natural ventilation is one of the most important green building features. Although the intention is often to reduce energy consumption, natural ventilation strategies may deteriorate indoor air quality (IAQ) when in close proximity to major roadways. This study employs a CFD-based air quality model to quantify the impact of traffic-related air pollution on the IAQ of a naturally ventilated building in a near-road environment. Our study found that the building envelope restricts dispersion and dilution of particulate matter (PM).

As cars are parked within an underground parking structure, CO and other exhaust fumes are emitted into the atmosphere. There is a need for an efficient ventilation system that can remove these toxins, circulate fresh air into the garage, and assist fire fighters in the case of a fire emergency. There are two options for this task: ducted or ductless ventilation. Ducted ventilation is heavily used in the US and other global markets. While this has been the standard for many years, innovations in the field of ventilation have shifted the conventional ventilation system towards ductless designs.

ASHRAE Standard 62.1-2013 provides two alternative procedures for selecting the minimum ventilation rate for commercial buildings: the prescriptive Ventilation Rate Procedure (VRP); and the rarely used performance-based Indoor Air Quality Procedure (IAQP). The IAQP allows lower ventilation rates than the VRP and, at a minimum, maintains the same indoor air quality, providing additional contaminant reduction strategies are applied. This paper provides examples, benefits and lessons learned from applying IAQP in various commercial buildings located in a variety of climates.

Flexible duct air distribution systems are used in a large percentage of residential and small commercial buildings in the United States. Very little empirical or predictive data is available to help provide the HVAC design engineers with reliable information. The aim of this research is to measure experimentally using the guidelines of ANSI/ASHRAE Standard 120-2008 the friction loss of the air flow inside a realistic layout out flexible duct used for residential/small commercial buildings.

One barrier to adoption of natural ventilation is the knowledge that application in inappropriate climates or during inappropriate hours could lead to conditions in buildings which may affect both comfort and IAQ. As such, designers must diligently determine whether a climate is appropriate for natural ventilation. A series of tests on the typical meteorological year weather data can be used for this purpose. For many US climates, even mild climates, under normal design conditions, natural ventilation alone may not assure occupant satisfaction. In most cases, spaces may be advised to use mixed-mode ventilation systems, which combine natural ventilation and mechanical ventilation.

Natural ventilation can provide fresh air for a building and is one strategy for reducing building energy demand while maintaining or improving indoor air quality. However, there exists uncertainties regarding implications of naturally ventilated commercial buildings with respect to indoor air quality. This presentation summarizes a review of the state of building codes and standards, case studies, and research literature regarding the application of natural ventilation to commercial buildings with specific attention to IAQ objectives, including: i) air pollutants of concern, ii) modeling approaches, iii) prescriptive approaches, and iv) new directions for improving IAQ in naturally ventilated buildings

Two often overlooked but crucial parts of the design process for buildings wanting to take advantage of wind-driven natural ventilation are 1) obtaining accurate facade pressures, and 2) using them in such a way as to accurately predict the amount of air which will enter a space. Through a review of extant sources and presentation of new research, this presentation looks at the various methods for obtaining and using facade pressures and discusses strengths and weaknesses of each.

Natural ventilation in buildings has been around for many years, Robert Boyle provided a description on how to design such a system in the 1800’s. Today's current trend of incorporating natural ventilation or a natural ventilation scheme into building design has led to a quest for a more detailed analysis of space conditions. This presentation presents some modern day applications of natural ventilation which also include space moisture conditions and analysis of air movement within a space.

This presentation compares the effect of two pollutant control strategies on both exposures to contaminants of concern (COCs) and energy use in a high-performance multinational technology company. The first control strategy was the conventional ventilation strategy following the ventilation rate procedure of ASHRAE Standard 62.1-2013. The second strategy consisted of applying the LEED Pilot Alternative Compliance Path 68: Indoor Air Quality Procedure while using air cleaning along with reduced ventilation. This presentation provides results from field measurements of energy and IAQ and documentation of meeting LEED IAQP objective and subjective requirements.

The USGBC LEED process is intended to transform the way our buildings are designed, constructed and operated. Recognizing the limitation of ASHRAE 62.1 VRP prescriptive requirements, USGBC developed an alternate compliance path that allows a robust design and verification process to balance good IAQ with optimization of HVAC system for energy conservation and reduced negative impact of energy production on the environment. This presentation describes implementation of the LEED ventilation process through air quality measurement and verification including occupant surveys. The presentation describes energy and HVAC system economic savings from optimization of ventilation rate versus prescriptive approach.

The largest independent co-educational college-preparatory day school in the United States is located in the Atlanta (GA) metropolitan area. Several buildings use geothermal wells for heating and cooling, however, the existing well field did not have sufficient capacity for the new humanities building and the cost of new wells was prohibitive. Consequently, the design team opted to use LEED Pilot Credit 68: Indoor Air Quality Procedure to reduce the overall load on the well field, provide for capital cost savings, and ongoing energy savings. This presentation describes how the IAQ Procedure was successfully applied towards achieving LEED Gold certification.

This presentation discusses how to conduct optimal design of an indoor environment based on specific design objectives by controlling the thermo-fluid boundary conditions, such as air supply location, size, and parameters. This study used a CFD-based adjoint method to identify the othermo-fluid boundary conditions. Through defining the air distribution in a certain area (design domain) as a design objective in an indoor space, the adjoint method can identify the air supply location, size, and parameters. The adjoint method can only achieve local design optimal but the computing costs did not depend on the number of design variables.

This talk presents a method that combines the genetic algorithm (GA) with computational fluid dynamics (CFD) technique, which can efficiently optimize the flow inlet conditions with various objective functions. A coupled simulation platform based on GenOpt (GA program) and Fluent (CFD program) was developed. Two new design methods were provided: the constraint method and the optimization method. A simple 2-D office and an aircraft cabin were evaluated, as demonstrations, which reveal both methods have superior performance in system design. The optimization method provides more accurate results while the constraint method needs less computation efforts.

Transporting patients to the hospitals in emergencies, the heliport is usually located on the roof of the hospital. This may cause the exhaust emitting from the helicopter to get into the air-intakes of the ventilation equipment on the roof, open entrances, and windows, leading to odor complaints and health related issues inside the hospital. Considering complexity of the problem and number of the design parameters, this study used CFD to investigate the helicopter exhaust fume entrainments into the hospital under different wind directions and speed, which helps find the optimum placement for air-intakes to reduce the particles and gas entrainment.

Protecting the health of aircraft painters in an industrial environment that contains hazardous metals and organics motivates design and operation of hangar ventilation systems for maximum effectiveness, with a secondary consideration of energy use in these large and tempered spaces. There lacks of consensus regarding optimal air velocities in vehicular painting facilities. This study evaluated cross-flow velocity vs. exposure at approximately 50, 75, and 100 fpm, during fixed- and rotary-wing aircraft painting, using CFD, tracer experiments, and personal exposure monitoring. Contaminant removal effectiveness (CRE) was greater for crossflow ventilation than for other airflow path designs.

It is well known that displacement ventilation can potentially decrease energy usage while improving indoor air quality. There is little to no guidance on how to apply displacement ventilation in an industrial setting for the purposes of controlling airborne particles. The presentation focuses on a large factory space where the control of manganese particles from the welding processes is of primary concern. CFD simulations with particle tracking are used to assess the effectiveness of the design and highlight the most important design parameters that affect breathing zone particle concentrations.