Steve discusses ASHRAE Publication's philosophy behind its mobile and web app strategy and talks about its successes and issues so far. In addition, Steve discusses future mobile and web app plans and also solicit feedback from forum attendees.

Energy recovery ventilation (ERV) is an emerging and growing application for polymeric membranes used in energy efficient building ventilation systems. In these enthalpy exchange devices, heat and moisture are transported through a membrane which separates fresh supply air streams and building exhaust air streams.  Membranes for these devices must have high water vapor permeance and good selectivity of water vapour over indoor air contaminants. They must be robust to withstand temperature and humidity cycling, condensation, and freezing. This presentation will discuss the current state of membranes for sensible and latent transfer as well as ongoing membrane research, development and testing.

Liquid desiccant energy recovery systems exchange temperature and humidity between the building exhaust air and the outside makeup air via an energy transfer solution. Liquid desiccant energy recovery systems have many features that building owners will find attractive. In addition to energy savings, the system features include a flexible design, winter humidification, no microbiological cross contamination, and improved IAQ via the biocidal desiccant solution.

In this presentation, valuable information about demand control ventilation (DCV) in laboratory animal facilities will be shown as stated below. 1) Practical approach and method of DCV by indoor air quality (IAQ) sensing, 2) Actual trend graphs of IAQ sensing and ventilation rates which are synchronized with animal biorhythm (circadian rhythm) and 3) Successful results of saving HVAC energy by reducing total ventilation.

 In a major Japanese laboratory animal facility, a multiplexed IAQ sensing system which continually measures certain types of IAQ values at multiple locations was installed, and VAV control which varies ventilation rates based on those IAQ measurements was implemented. Because it was a first trial of automated DCV in Japan, target areas were confined to two (one rodents’ and one primates’) animal holding rooms, and a step-by-step approach was taken as follows. 1) In order to find out the correlation between ventilation rates and IAQ values, ventilation rates was changed manually (6, 9, 12, 15 ACH for every 2 weeks) with continuing multiplexed IAQ sensing. 2) Based on the results of the foregoing analysis, automated DCV in accordance with concentration differences between supply and room (or room exhaust) air was implemented. The DCV was tried under the conditions of three series of set points (“low”, “middle” and “high”). In the case of “low” set points, ACH varied synchronized with animal biorhythm (circadian rhythm) and total ventilation was saved by 20.6-27.5%. On the other hand, in the case of “high” set points, ACH almost did NOT increase except during the in-room activity (e.g., cage changing or room cleaning) and total ventilation was saved by 47.5-48.7%

The safe and effective operation of a science facility deep underground poses a number of ventilation and cooling challenges. Ventilation air must be delivered from the surface to the occupied space and conditioned to meet the space requirements. Exhaust air and heat generated by the facility and its supporting infrastructure must be removed from the underground spaces and rejected back to the surface. The mechanical design must overcome these challenges while limiting its footprint given the high cost of underground excavation.

This paper will present the details of the mechanical ventilation and cooling design for a science facility located 4,850 ft underground in a former gold mine. The site will be comprised of 3 large caverns and a network of tunnels to be excavated over 6 phases. The installation of airside and waterside equipment will take place as the excavation proceeds posing operational challenges in meeting the space requirements. Mine ventilation air will be cooled and supplied to the experiment caverns through water cooled air handling units picking up heat from the spaces. Exhaust fans remove air from the space meeting the air change requirement and deliver the air to an underground spray chamber. The spray chamber is an excavated space where condenser water from the chiller is sprayed into the exhaust airstream. The exhaust airstream picks up heat from the sprayed water and returns to the surface through a vertical borehole while cooled condenser water returns to the chillers.

The paper also presents the constructability considerations which are a result of the phased excavation and operation of the facility. The mechanical design is flexible to limit the incremental changes between phases while maximizing the use of the excavated space and minimizing the client’s costs.

Energy efficiency in the industrial processes  has great potential to reduce the energy demand, as well as green house gases emission, which is the most concerned topic in the gobal warming debate. In fact, the improvement of energy efficiency and an intelligent linkage of the energy consumer, distribution, storage, and energy supply are the keys to lower the energy consumption in the industry. In this paper, the research is focused on the study of these combinations in the industry via a plastic factory case study at different climate conditions. The plastic processing industry uses mainly electric power for their machines and facilities. Especially, plastic products for the food and pharmaceutical sector requires significant demands on air temperature and humidity control. This leads to high energy requirements on the power supply system. In order to obtain flexibitlity in using machines from many different energy sources such as CHP processes, the burning of gas, or electrical grid, the electrical heating method is changed to thermal oil heating in many production machines. The reconstruction of many molding machines, building techonolgy, and the thermal grids in the plastic factory enhances the use of heat generated by a CHP unit. In addition, by changing the refrigeration supply from a compression to an absorption chiller, the use of the heat is increased even further. From a case study presented, the primary energy demand is lowered by up to 57 percent. The study shows the energy savings potential for a manufacturing company located in three different locations: in Germany, Canada and the USA.

Publication of Standard 30, Method of Testing for Liquid Chilling Packages, is pending a second public review period. Significant changes have been made to this method of test (MOT) for chillers that was last published in 1995.  A summary overview will guide users through the testing requirements.

ASHRAE Standard 184 is the Method of Test for Field Performance of Liquid-Chilling Systems.  It has been under development and is now in the final stages and public review before being published later this year. This Standard differs from Standard 30 in that it applies to chillers in their actual field installation and operation rather than the "bench" testing done under Standard 30.  This speaker will present an overview of this Standard that will be valuable to system Owners, Engineers, and Designers.

Most ASHRAE members may not be aware of ten basic measurement standards beginning with Standard 41.1, Standard for Temperature Measurement, and including 41.2 through 41.11 standards for measuring pressure, airflow, air velocity, humidity, gas flow, liquid flow, refrigerant flow, and power. This presenter describes the utility of each of these standards for application to product testing and for incorporating into other ASHRAE testing standards.  Revised versions of all of these standards have been published since 2013 and are current and useful.

Recent standards have defined a lower minimum air velocity in kitchen exhaust air ducts. While the aim remains in place to maintain an acceptable in duct air velocity and expel exhaust air-borne particles or fluids towards filters/exhaust outlet. Steel ducts are usually specified to a standard steel gauge thickness, capable of handling the extreme load conditions of high temperatures, possible corrosive conditions, and negative pressure levels within exhaust duct. This paper simulates a typical kitchen exhaust air duct performing under extreme temperature conditions and the low air duct velocities. Lower exhaust air velocities should correspond to lower in duct negative pressure values and therefore, possibly a reduction in steel duct wall thickness.
A CFD/thermals tress analysis was carried out under the most extreme load conditions specified under recently issued standards. This analysis has demonstrated that a lower steel duct thickness is more than sufficient than what is specified in recent standards, and therefore, a lower steel thickness gauge can be used. Provided a comprehensive simulation is carried out demonstrating that the reduced exhaust duct sheet thickness is well within the steel duct mechanical material properties as explained in this paper.

The primary purpose of this study is to develop engineering methods to assess the impact of increased make-up air velocity in atria. The current restriction defined by NFPA 92 states that make-up air must not exceed 1.02 m/s (200 fpm) during the operation of a mechanical smoke exhaust system. This limitation not only limits creative and aesthetic atria designs but may also represent a significant cost. The present study analyzes the effect of make-up air injected by a variety of vent sizes at elevations at or below the limiting elevation of the flame through numerical simulations. This study focuses on identifying worst-case scenarios for the interaction of make-up air with an axisymmetric plume, by modeling multiple configurations, observing the results, and adapting further simulations to elicit the most extreme cases. A mass flow rate diagnostic is used to assess the increase in entrainment, i.e. smoke production. This mass flow diagnostic is developed to provide a comparative analysis, assessing the increase in the rate of smoke production with a specified make-up air velocity with that produced with no mechanical make-up air. The proportional increase in entrainment is defined as an alpha factor. The most significant smoke production increase and smoke layer stabilization descent is associated with the 1 MW fire, when lesser increases observed for the 2.5 MW and 5 MW fires. As the make-up air is introduced further from the edge of the flame, the apparent effect of the airflow velocity is reduced.

The National Research Council of Canada (NRC) conducted full-scale fire experiments to investigate whether pressure compensating systems are needed to maintain tenable conditions within pressurized stairwells. Ten tests were conducted in the NRC 10-storey test facility with the stairwell in the facility pressurized. The tests were conducted with the stairwell door on the fire floor closed and selected stairwell doors on the other floors open. Two fire scenarios with a shielded sprinklered fire and non-sprinklered fire were tested with varying number and location of open stairwell doors. Tenability analyses were conducted with experimental test results to investigate the performance of pressurized stairwell with and without pressure compensating systems. Without compensating for pressure losses, the pressure difference across the stairwell door on the fire floor decreased considerably with open stairwell doors. However, a non-compensated stairwell remained tenable for 30 minutes as long as the door on the fire floor was closed both for the shielded sprinklered fire and the non-sprinklered fire scenarios. It is concluded that if the base pressurization system meets the requirement of the design pressure difference with a proper arrangement of air injection points, the stairwell remained tenable as long as the door on the fire floor is closed for both sprinklered and non-sprinkled fire scenarios used in the tests.

Exposure to airborne influenza from patient’s cough and exhaled air causes potential flu virus transmission to the persons located nearby. Flu virus can be transmitted through air by patient’s cough creating aerosols containing flu virus. Hospital acquired influenza is a major airborne disease that occurs to health care workers (HCW).

The present study examines the air flow patterns and influenza-infected cough aerosol transport behavior in a ceiling-ventilated mock AIIR and its effectiveness in mitigating HCW’s exposure to airborne infection. The Computational Fluid Dynamic analysis of the air flow patterns and the flu virus dispersal behavior in a Mock AIIR is conducted using the room geometries and layout (room dimensions, bathroom dimensions and details, placement of vents and furniture), ventilation parameters (flow rates at the inlet and outlet vents, diffuser design, thermal sources, etc.), and pressurization corresponding to that of a traditional ceiling mounted ventilation arrangement observed in existing hospitals. The measured data showed that ventilation rates for the AIIR is about 12 ACH (Air changes per hour). However, the numerical results revealed incomplete air mixing, and that not all of the room air was changed 12 times per hour. Two life-sized breathing human models were used to simulate a source patient and a receiving HCW. A patient-cough cycle is introduced into the simulation, and the AI dispersal is tracked in time using a multi-phase flow simulation approach.

This research was sponsored by ASHRAE Technical Committee (TC) 4.3. The purpose of this Research Project is to provide a simple, yet accurate procedure for calculating the minimum distance required between the outlet of an exhaust system and the outdoor air intake to a ventilation system to avoid re-entrainment of exhaust gases. The new procedure addresses the technical deficiencies in the simplified equations and tables that are currently in Standard 62.1-2013 Ventilation for Acceptable Indoor Air Quality and model building codes. This new procedure makes use of the knowledge provided in Chapter 45 of the 2015 ASHRAE Handbook—Applications, and was tested against various physical modeling and full-scale studies. The study demonstrates that the new method is more accurate than the existing Standard 62.1 equation which under-predicts and over-predicts observed dilution more frequently than the new method. In addition, the new method accounts for the following additional important variables: stack height, wind speed and hidden versus visible intakes. The new method also has theoretically justified procedures for addressing heated exhaust, louvered exhaust, capped heated exhaust and horizontal exhaust that is pointed away from the intake.

Historic buildings have traditionally been granted exemptions in energy codes in both the US and EU.  This talk reviews existing guidance on energy efficiency and retrofits in historic buildings, in order to provide context for ASHRAE’s recent work. The defining features of historic buildings and special considerations for their retrofit are introduced, along with the basic tenets of historic preservation.  The nature of code exemptions is explored in some ASHRAE’s standards (e.g. 90.1, 100) and from the EU. The contents, approach, and key recommendations in a number of existing guidance documents (CIBSE, AiCARR) are reviewed, highlighting similar trends and major differences.

This presentation gives an overview of the contents in the new ASHRAE GPC 34 Guideline which provides direction on addressing the unique issues associated with making historic buildings more energy efficient. Work on the guideline was initiated in late fall of 2012 by a relatively small, but internationally- and discipline-diverse ASHRAE committee. Seminar attendees will be educated on the structure and general recommendations in the guideline.  This document is intended to advise design teams. The developers went to great lengths to respect and preserve historic architecture and associated artifacts while striving to optimize the buildings’ energy efficiency and occupant comfort.

Energy efficiency is critical for the continued utility and function of a historic building, but energy efficiency measures (EEMs) should not diminish the building’s durability or its character-defining features. Historic buildings vary greatly in envelope construction, condition, spatial configuration, climatic context, use and occupancy.  These variations preclude broad prescriptive EEMs since some EEMs may have unintended negative impacts on a specific building.  ASHRAE Guideline 34 addresses this concern by identifying EEMs with high benefit and low risk and EEMs which may have negative impacts and require study.  Attendees will learn how to apply ASHRAE Guideline 34 to this important issue.

Understanding the long term requirements of the campus facilities is a key element in developing an Integrated Sustainability and Energy Master Plan. This involved evaluating Carleton’s long-term needs and then the APPA Energy and Sustainability Assessment Tool,(ESAT) to assess our current energy infrastructure, prioritize the opportunities, and develop a comprehensive plan of upgrades for individual buildings as well as the Campus Infrastructure to: save energy and operational costs, fund renewal and indoor environment upgrades through energy savings, improve facilities for our students, faculty and staff and demonstrate environmental leadership to our key stakeholders and the community.

The process of energy metering a campus served by central plants always begins with a simple plan, to determine the energy consumption of each building. In practice, however, this strategy can take several years and millions of dollars to execute, with no guarantee that the data is accurate. Successful campus energy metering projects require an in-depth analysis of not just each utility serving a building but also the campus control system, utility distribution layout, and campus network infrastructure. 8760 Engineering has used a simple process to help our clients design, install, maintain and ultimately use accurate meter data.

Large, multi-building portfolios can contain buildings of many different ages and use types. However, they all require monitoring and continuous or retro-commissioning to maintain their optimum energy efficiency. The reality of value engineering and expedited timelines to occupancy often renders even new commercial buildings less energy efficient than intended. This can leave the owner with a need to perform formal energy audits and retro-commissioning within the early life of the building. Cushman & Wakefield has implemented a phased and multi-pronged process to optimizing and maintaining energy performance of the client's home office campuses in St. Louis, MO and Tempe, AZ.

This paper addresses the challenge of improving the performance of Heat Pumps (HPs) in cold climate condition by applying refrigerant mixtures. The potential benefits of implementing R32/CO2 zeotropic refrigerant mixtures in three different residential air-source HPs for cold climates is studied. The cases studied are: conventional residential HP, HP with variable mixture control system and HP with variable compressor speed. The seasonal performance of a heating system with these air-source HPs, supplemented with an auxiliary electric heater is studied in the cold climate city of Montreal. To this aim, a detailed screening HP model previously developed is modified and used. The obtained results highlight the potential HP performance improvement of applying refrigerant mixtures.

Instances of counterfeit refrigerants causing violent and unexpected explosions, resulting in multiple fatalities, have been reported in mobile refrigeration units around the world. In addition, counterfeit refrigerants have caused system reliability issues in numerous air-conditioning applications. It was initially believed the inclusion of methyl chloride (R40) in the refrigerant composition caused these explosions and reliability issues. ASHRAE research project RP-1665 was commissioned to examine reactivity of R40 with R134a refrigeration system materials. R40 reactivity, in concentration ranges of 0.01 to 10 percent, was studied in the presence of R134a, polyolester lubricant (POE), aluminum 1100 metal, aluminum 380 metal, in the presence of iron metal, copper metal, sodium aluminum silicate zeolite and alumina catalysts. R40 was shown to have varying levels of reactivity, generally mild, but showing the potential for catastrophic reactivity. This paper contains a summary of the work from ASHRAE Research project 1665 and will provide insights into the impact of R40 contamination, by providing the chemistry of the reactions, preventative safeguards, threshold levels, and assessment procedures. RP-1665 was conducted by McCampbell Analytical Inc., located in Pittsburg, California.

The presence of unsaturated fluorocarbon contaminants in the refrigerants used in HVAC&R systems may result in reaction products that could potentially cause problems in system performance or reliability. Since 2007, the 40 ppm limit for unsaturated halogenated contaminants in new and reclaimed refrigerants set by AHRI 700 has proven to be more restrictive to reclaimers, recyclers and HVAC&R system providers than previously thought. In addition, compounds such as hydro-fluoro-olefins (HFO) have been tested as low global warming potential (GWP) alternative refrigerants and shown to have acceptable stability in some applications. So, it may not be appropriate to classify all unsaturated compounds as unstable and blanket them under the same restrictive limit.
This research project aimed at determining the effects of halogenated unsaturated contaminants present in refrigerants on the stability of refrigerant/lubricant systems and recommending a concentration limit specific to the unsaturated contaminant below which the refrigerant/lubricant system is thermally stable. The following refrigerant/lubricant mixtures with their corresponding contaminants were selected for stability study in sealed tube tests: (1) R-134a/POE with with 1,1-dichloroethylene, 1,2-dichloroethylene, R-1131 and HFO-1234yf; (2) R-1234yf/POE with HFO-1225ye(Z), HCFC-1233xf and HFC-1243zf; (3) R-123/Mineral Oil with R-1122, R-1123 and R-1131.
 Based on criteria such as visual changes, Total Acid Numbers (TAN), organic anion and dissolved metal concentrations after aging, it was concluded that the R-134a/POE system was as stable as the control (without contaminant) when the concentration of its contaminants was less than 1000 ppm. The R-1234yf/POE system was stable when its contaminants were less than 5000 ppm, while the R-123/Mineral Oil system was stable when its contaminants were less than three weight-%. These maximum concentration limits were however based on sealed tube stability tests and would need to be balanced against other safety concerns, such as toxicity, flammability, handling and recycling practices.

The increasing use of parametric ensembles with building energy models to study sensitivity and accommodate uncertainty has the potential to greatly inform energy studies, but can be mitigated by low statistical confidence from poor experimental design. In this talk, we present the tradeoffs between common statistical approaches to design of experiments and how they can be used in cloud or supercomputing resources.

Building Energy Models are complex and have a lot of inputs, and a minority of the inputs them have a significant effect on a result.  Sensitivity screening tools are designed to be computationally cheap (requiring a relatively small number of simulations) as they rank the model inputs in order of their influence on a particular output.  The goal is to identify which model inputs require the modelers attention, and which can be ignored.  Speakers in this session discuss and demonstrate the use of the Morris Method, a commonly used sensitivity screening algorithm.

Energy modelers are starting to try to quantify the uncertainty in their energy models. The methods for estimating uncertainty when inputs are independent are fairly well known. However, in the case of buildings, many inputs are not independent.  In particular, occupant related loads such as plug loads, lighting loads, and occupant heat loads are known to be well correlated. Uncertainties of correlated variables can be propagated if joint probability distributions are used and the joint distributions are properly sampled.  In this paper, the selection and sampling of joint distributions for uncertainty with correlated inputs is discussed.

The International Code Council (ICC) and International Association of Plumbing and Mechanical Officials (IAPMO) both promulgate mechanical codes that have required residential load calculations for years.  Manual J is the only ANSI-recognized consensus standard for residential load calcs, and is referenced specifically by both code organizations.  This portion of the presentation will review the specific code requirements in the International Residential Code (IRC) and the Uniform Mechanical Code (UMC), and then go on to explain the CLTD method for residential load calculations contained in Manual J.

Most residential cooling load calculations rely on CLTD methods that use single-point calculations for at most a few design days.  CLTD procedures make implicit assumptions about the time profiles of heat gains and the moderation of cooling loads by building thermal mass.  The heat balance method has the advantage of first-principles 24 hour calculations – gains are combined following their actual profiles.  It handles subtle interactions that occur in low energy houses and evaluates the effect of temperature swing that is typical of residential systems.  The presentation describes the heat balance method and shows comparisons to CLTD results.

Stephen discusses how HVAC technicians are using mobile devices to perform residential HVAC load calculations. So much processing power is now packed into mobile devices that complex software such as this that once could only run on desktop computers can easily run on these mobile devices. HVAC technicians have quickly embraced these devices to perform all manner of field-based work. Some of the benefits include: Saving time by entering all information onsite and emailing required reports to code officials and clients and calculating more accurate HVAC cooling and heating loads so that equipment is sized correctly.

This presentation covers the PMP Energy Protocols, including Basic, Intermediate and Advanced methods for characterizing building energy performance. For the Basic protocols the required information includes: building characteristics and annual whole-building energy use of all fuels to calculate indices. At the Intermediate level, monthly or weekly data are used to calculate regression models of the building’s energy use versus the influencing variables. At the Advanced level the protocols utilize daily, hourly or sub-hourly data to refine the regression models and/or apply diagnostic measures using regression models or calibrated simulation. Examples of all three levels are provided.

This presentation reviews the ASHRAE Performance Measurement Protocols for water and how these protocol and calculations can be used to properly calculate water use reductions with typical examples of savings.

This presentation covers the PMP Indoor Environmental Quality (IEQ) protocols which includes thermal comfort, indoor air quality, lighting, and acoustics and provides a demonstration of how to apply the ASHRAE PMP IEQ protocols in a holistic way in order to evaluate a building’s overall IEQ performance. A case study is presented, including a comprehensive IEQ monitoring cart which was developed to collect continuous IEQ data based on ASHRAE PMP.

Building Indoor Environmental Quality (IEQ) measurements are often complex, time consuming, expensive, and not easily conducted in a manner that covers all commercial building types, therefore evaluating IEQ is not standard practice. This presentation will cover the basic, intermediate, and advanced levels of thermal comfort measurement techniques prescribed in ASHRAE's Performance Measurement Protocols (PMP), which provides users with clear measurement methods and reference standards for evaluation. In addition to a review of the PMP measurement and evaluation procedures, a detailed case study will be presented, including an open-source software tool that helps users collect, analyze, and present measured IEQ data.

Optimizing the combustion performance and reduction of emissions of Methane gas by varying excess air has been and continues to be an area of interest for researchers, manufacturers and operators. With the aim of developing more energy efficient systems meeting stricter environmental emission controls. The aim of this paper is to provide a comprehensive graphical presentation for easier optimization of the combustion process in relation to; energy, temperature, and pollutants. Easy to use equations were developed with guidance on how to accurately optimize combustion.

Methodology; numerical software tools were used in analyzing injected; Methane gas and – variable excess air ratios. Emissions such as; Carbon Dioxide, Carbon Monoxide, and Nitrogen Oxides, were also recorded, and analyzed for optimum energy output versus lower emissions. .

Results; were tabulated and graphs generated. Equations were derived using industry established software tools. The accuracy of the developed equations was assessed on statistical basis. Discussions on advantages and disadvantaged on excess air are included.

Enhancement of heat and mass transfer in sorption fluids coulde improve the overall performance of an absorption chiller. Active mechanisums were proposed as a potential effective means to achieve this goal. A testing facility is needed to evaluate the impact on the performance of chiller after adding an active mechanisums. The challenges we face include the fulfillment of mechanism motion to driving extra heat and mass transfer in an absorber, the measurement of related variables and the stablility & repeatability of findings. The issues come from the fact that an absorption chiller is a close-loop system with large heat exchangers, has a low inside pressure and can sustain only small pressure drop along the refrierant loop. Measures are needed to exclude the impact from the vibration to the untargeted components in the system. In this paper, we introduce the details of the lab construction methodology, including the vibator, the auxiliary water loop system, and the measuring instruments. Then, we present several examples to show the operation and testing procedure and stability. At last, the experiment plan matrix and analysis methodology are presented which will be applied in the next phase experiment. This paper provides useful information of active mechanism experiment setup and test methodology for the researchers in the same area who may conduct related work.

An HVAC systems assessment and HVAC retrofit was required and completed on a science building just 10 years old.  A unique approach to assessing the needed system upgrades was undertaken. The project approach included an ASHRAE Level III audit plus gathering additional field test data to score the operating efficiency of the HVAC systems.  This data was then used to diagnose the systems and create a scope of work for the project.

Upon completion of the audit and retrofit work, testing was completed to measure, document, quantify and verify the energy and water savings produced by the system upgrades.

The multi-nozzle chamber method for air mass flow measurement has been in use in the HVAC&R industry for decades.  The primary flow element is the elliptical nozzle defined by American Society of Mechanical Engineers (ASME) standards.  The ASME nozzle is a passive, ridged construction element that does not require periodic calibration.

As the HVAC&R industry is subject to greater performance efficiency requirements, measurement accuracy for airflow becomes a critical issue.  The accuracy of many instruments for the measurement of temperature, pressure, humidity, and power has improved over the past couple decades.  New test standards now require the evaluation of the uncertainty of measurements and derived values.  These developments have raised questions about what can be realistically expected for the accuracy of the multi-nozzle chamber air flow meter (AFM), especially due to the lack of open literature test data with multi-nozzle configurations.

To determine the accuracy (or uncertainty) to be expected from typical multi-nozzle chambers, a four-nozzle AFM was constructed in strict accordance with current standards and tested at an independent, multi-industry, gas flow test laboratory.  The test laboratory used their primary National Institute of Standards and Technology (NIST) traceable critical flow Venturi test method with an average uncertainty of +0.3% of the flow.  Six nozzle flow configurations consisting of each of the four nozzles separately, a particular combination of three nozzles and all four nozzles simultaneously, were each subjected to three nozzle throat velocities for a total of 18 different tests.  The velocities included the lowest and highest defined by industry standards and one intermediate velocity.

The test laboratory utilized their NIST traceable, independent mass flow measurement in series with the test AFM and included a measurement of three required parameters: nozzle differential pressure, inlet temperature, and barometric pressure.  Dry air was used to eliminate errors associated with the calculation of moist air properties.  Confirming air mass flow rates were calculated using the nozzle diameters, nozzle flow coefficients, and the measured parameters.  The results of all 18 flow rate tests were compared and shown to be within +0.2 to +0.4%.  This project demonstrates that a typical multi-nozzle AFM, when constructed in accordance with industry standards, can be used for air flow measurements that are accurate to better than +0.4% of reading over the entire flow range.

This study develops a method to estimate the energy performance of blowers that are driven by electronically commutated motors (ECM) in residential gas furnaces based on the measurement of blower rotational speeds. As the first step, the airflow and power of six different ECM blowers from four manufacturers were measured over a range of external static pressures (ESPs) from 0.1 to 1.2 in. w.g. (25 to 300 Pa) in a well-instrumented laboratory environment with a calibrated nozzle airflow chamber. Then, the ECM blower energy performance was determined from the airflow and power measurements and characterized in terms of efficacy, which is the ratio of blower power to airflow rate. In addition, the relationship between parameters of blower rotational speed and efficacy was investigated, leading to the linear correlation development for each tested blower by taking the blower rotational speed as the independent variable and the efficacy as the dependent variable.

Results from the linear correlation development show that ECM blower efficacies can be accurately predicted by using blower rotational speeds as evidenced by the high R² values ranging from 0.961 to 0.981. For the six tested ECM blowers, the linear factor for the developed correlations varies from -2.881 to -2.657, and the offset factor is in a range of 3.287 to 3.551. Furthermore, a comparison between the predicted and measured efficacies shows an accuracy of ±15% for the developed correlations.

Results generated from this study provide a method to predict the energy performance in terms of efficacies for ECM blowers based on the knowledge of rotational speed. In addition, the experimental data and correlations produced in this study can be used to model the ECM blower efficacy behaviors at different operating speeds.

Methods like the Log-Tchebycheff and Equal Area are commonly used to define the average air velocity across a traverse section. The testing, adjusting and balancing (TAB) of HVAC systems has been adopting those methods to ensure that the installed system is meeting its design capacity. The flow measurements are compromised when space constraints limit the optimal air handling system design; consequently, inadequate straight ductwork with close upstream and downstream fitting disturbances cause common measurement issues. For example, according to ASHRAE 111-1988 field airflow measurements over CAV systems made by experienced technicians commonly have an error as much as 30% when recommended vane anemometers are used while reading irregular flows. Through in-situ airflow measurements in ten air-handling-units, this paper summarizes the statistical studies of measurement uncertainties to explain why the large errors occur in field measurements even though the standard procedures are strictly followed. As a result, a more accurate and robust in-situ airflow local measurement method is introduced in this paper. The proposed method uses hot-wire as the air velocity measurement device due to its proven accuracy at speeds lower than 800 fpm (1 m/s). In order to overcome additional turbulence in the ductwork that is caused by limited duct space, a holding device was also developed for facilitating the time weighted of local airflow measurements.

Health care facilities are the only spaces where an ASHRAE-authored standard uses air changes exclusively. This presentation looks at the origins of health care ACRs, their intents, and changes over time. It discusses the outcomes addressed by those ACRs, and how those same outcomes could be addressed using alternate methodologies.  It also looks at some of the leading health care air quality management strategies used abroad, and how those could be adopted domestically.

People working in laboratories rely on proper operation of laboratory hoods and ventilation systems to prevent over exposure to hazardous airborne contaminants generated during scientific procedures.  Lab safety can depend on the quantity and distribution of airflow.  The OSHA Laboratory Standard 29 CFR 1910.1450 and other relevant standards recommend between 4 air changes per hour (ACH) and 12 ACH of one pass air.  There is little guidance on correlating risk with ACH and assessing the effectiveness of contaminant dilution and removal.  This paper explores specification of ACH for labs and the impact on lab safety and energy efficiency.

Cleanrooms typically rely upon air change rates to help maintain a given cleanliness class. Air change rates can vary between 2 ACH to well over 500 ACH. There is much anecdotal data supporting a correlation between cleanroom cleanliness and the air change rates with little empirical data. Many cleanroom owners are compelled by regulating authorities to maintain high air change rates. This presentation reviews the current regulatory guidance for cleanroom air change rates as well as present data on cleanrooms that have been able to reduce their air change rates and still maintain their required cleanliness.

Air Change Rates are often specified assuming well mixed conditions in the spaces to achieve overall dilution of contaminants. Actual distribution of contaminants in the space are seldom uniform and depends on several factors including the locations of air supply and returns, strengths and location of contaminant sources, and strength and locations of heat sources. The flow path of contaminants in the space play important role in determining the concentration levels and overall effectiveness of contaminant removal. This presentation demonstrates how airflow paths affect the effectiveness of contaminant removal in patient rooms, cleanrooms, and laboratories.

This paper presents the results of research project RP-1561, “Procedures to Adjust Observed Climatic Data for Regional or Mesoscale Variations”. This project included a WRF modeling campaign designed to cover ten significant climate regions across North America. Model results were compared against mesoscale monitoring data in order to assess the model’s performance for a single year’s hourly weather. Subsequently, a long-term climate model evaluation was performed by running WRF over 4 regions in North America for 8 years. Overall, the model performed well against observed temperature and humidity, reasonably well against observed wind, and relatively poorly against observed solar and precipitation. Guided by this evaluation, a complete mesoscale numerical modeling procedure was developed for coastal, mountain valleys, mountain plateaus, and major city centers, to provide site-specific climate data, i.e., a freely-available software solution for developing localized climate data.

As air-conditioning demand increased significantly during the last decade, efficient energy use has become more important due to large electric power demands and limited reserves of fossil fuel. Electrical energy use fluctuates significantly during a 24-hour day due to variable demand from industrial, commercial and residential activities. In hot and cold climates, the dominant part of the load fluctuation is due to cooling and heating demands, respectively. If electric loads could be shifted from peak hours to off-peak hours, not only would building operation costs decrease, the need to run peaker plants, which typically use more fossil fuels than non-peaker plants, would also decrease. Thus, shifting electricity consumption from peak to off-peak hours promotes economic and environmental savings. This paper utilizes simulation and experimental work to examine a total of twelve precooling strategies in three residential buildings in the Phoenix, Arizona climate. The selected buildings are considered to represent majority of residential buildings in the area. Results of this project show that precooling can save up to 46% of peak energy demand in a home constructed with concrete or cementitious block and up to 35% in wood frame homes. Homeowners can save up to US $244/year in block construction and up to US $119/year in wood frame homes.

Environmental concerns and limited energy supply today make energy storage to be very important especially in solar energy utilization. The latent heat storage method has the advantage of storing a large amount of energy in a relatively small volume. Achieving thermal energy storage with latent heat application using Phase Change materials (PCMs) involves the heat of fusion at the solid-liquid phase transition. The problem with today’s PCMs is that their very low thermal conductivity values severely limit their energy storage capability. This also makes the melting and solidification times to be too long for meeting the desired results. Investigations to solve this problem include improved design configurations and addition of nanoparticles to the PCM to enhance the thermal conductivity. This study is on the effects of nanoparticle dispersion in melting of a phase change material (PCM) in a triplex-tube heat exchanger heated under constant surface temperature conditions. The governing equations for the configuration and process were discretized via finite volume method and solved numerically. The model developed, which was validated shows good agreement when compared to a previous related experimental study. The computations were performed for nanoparticle volume fractions ranging from 1% to 3%. The results which are shown in the form of isotherms and contours of the solid – liquid interface over different periods of charging time are presented and discussed. The results show an enhancement in the melting rate with doping nanoparticles of different volumetric concentrations. The results also show melting time saving of 17% as a result of adding nanoparticles to the PCM. This is for nanoparticle volume fraction of 1%. Higher volume fractions were found to not result in significant melting time savings for the process in the triplex-tube heat exchanger.

This paper details experimental measurements and mathematical modeling of air flow through a perforated duct with an open area of 22% and capped at the end. Measurements were conducted on ducts with uniform diameters of 12 in., 10 in., and 8 in. (0.20 m, 0.25 m and 0.30 m). All ducts were 20 ft (6.10 m) long and inlet flow rates ranged from approximately 350 to 700 cfm (165 to 330 L/s). Flow rates were measured along the length of the duct using the pitot traverse method. The static pressure was also measured. The flow through the duct was modeled assuming one-dimensional flow and a differential equation was derived using the mass, momentum and energy equations. The resulting differential equation was solved numerically and the results were compared to the experimental measurements. Good agreement was achieved when comparing the experimental and model flow rates for all test runs with a maximum difference of 14.0% and an average difference of 2.0%. Results for the static pressure showed the same trends between the experiments and the model. The pressure was largest at the capped end of the duct where the experimental measurements exceeded the model results by a maximum of 21.8%.

Low evaporator airflow is one of the common faults for rooftop units, which can be caused by dirty filter, evaporator fouling, or loose belt. Low airflow could result in frozen evaporator coil, reduced cooling capacity and indoor comfort issues. Accordingly, more fan power is consumed as longer operating time is required. With the widespread use of variable frequency drives (VFDs) on rooftop units, low evaporator airflow can be potentially detected by monitoring the fan power variation. In the paper, the principle of fan-power based detection is introduced first. Then, the detection algorithm is proposed including development of baseline and comparison of operational data with baseline. At last, the field test was conducted to verify the proposed method. The test results indicated that fan power based method can effectively detect low evaporator airflow for rooftop units.

A traditional mass and energy balance component approach was used to characterize the performance of fixed airflow series fan powered terminal units for applications in building simulation programs. The approach included developing relevant energy and mass balance equations for the components in a fan powered terminal unit – heating coil, fan/motor combination, and mixer. Fan motors that included permanent split capacitor motors controlled by silicon controlled rectifiers or electronically commutated motors were included in the model development. The paper demonstrates how to incorporate the fan/motor combination performance models for both permanent split capacitor and electronically commutated motors into the mass and energy balance approach. The fan models were developed from performance data that were provided by multiple fan powered terminal unit manufacturers. The fan/motor performance data included a fan airflow range from 250 to 3500 ft³/min (0.118 to 1.65 m³/s) and a motor size range from one-third to one hp (248.6 to 745.7 W).

A mass and energy balance approach was used to characterize the performance of parallel fan powered terminal units for applications in building simulation programs. The approach included developing relevant mass and energy balance equations for each component in a parallel fan powered terminal unit – heating coil, fan/motor combination, and mixer. Only fixed airflow applications were included. Two locations of the heating coil were considered. One location, designated as the traditional configuration, was at the discharge of the unit. The second location, designated as the alternative configuration, was at the secondary air inlet. Fixed airflow parallel FPTUs use fan motors that include either permanent split capacitor motors controlled by silicon controlled rectifiers or electronically commutated motors. The paper demonstrated how to incorporate fan/motor combination performance models for both permanent split capacitor and electronically commutated motors into the mass and energy balance approach. These fan models were developed from performance data provided by multiple fan powered terminal unit manufacturers The fan/motor performance data included FPTU a fan airflow range from 250 to 3500 ft³/min (0.118 to 1.65 m³/s) and a motor size range from one-third to one hp (249 to 746 W). Leakage was included in the models. Sample runs were used to illustrate the effect of leakage in both cooling and heating operations.

Standard 100-2015 includes significant revisions to the 2006 version with the objective of becoming impactful and relevant as a code intended standard. The 2015 version provides greater guidance and a more comprehensive approach to the retrofit of existing buildings for increased energy efficiency.  It sets specific Energy Targets based on performance compared to the 25^th or 40^th percentile of CBECS or RECS data by building type, climate zone, and building occupancy.  It also includes an energy audit path for buildings without energy targets.  This presentation summarizes the objectives and options for compliance with the updated requirements.

EUI energy targets in Standard 100-2015 were derived from the 2003 CBECS and 2005 RECS databases, supplemented by energy modeling as necessary, for 53 building types in 16 U.S. climate zones.  An analysis of CBECS data to investigate the impact of operating schedule by building type enabled development of “shift multipliers” that could be used to adjust building energy use intensities in commercial buildings.  This presentation provides details on the development of the standard's energy target tables and shift multipliers, along with options for updating the tables based on the new CBECS database scheduled for publication in 2016.

This presentation highlights a success story for BIM where a strong MEP Contractor took the lead on the model development effort and used the tool to advance a quality product and make for a happy customer.  Key in this effort was the contractor integrating construction sequences to MEP layouts and design, thus truly integrating the building model into the construction process. Come and learn some tricks.

BIM holds much promise as a powerful tool to improve and enhance the design and construction process.  But experience tells us that any tool can be a weapon if you hold it right.  This portion of the program looks at some of the features and facets of BIM, how they differ from what we ‘used to do’ and how you can get a hedge against some of those less than ideal outcomes that we all worry about but don’t want to talk about.

The measurement and test methods used to diagnose and score the efficiency of these HVAC systems before and after this project was completed will be discussed. Many ten year old systems in the building were operating at less than 50% of rated capacity. Insight into emerging technologies used to identify and surgically repair the specific causes of these deficiencies will be presented.

An analysis of the impact of the completed scope of work on the energy, comfort and increased reliability of the buildings will be offered in this segment of the seminar. The bearing of the improvements on peak load will also be discussed. The process of using commissioning data to benchmark and maintain the improved level system performance will also be spotlighted.

Data center CFD is often criticized for being too slow. In practice the speed rarely causes an issue since construction and hardware changes are normally planned in advance. However the common approach is to simplify the physics or excessively simplify the geometry resulting inaccurate or, perhaps worse still, uncertainty in whether the results are representative. This discusses two options for increasing productivity while retaining the full physics: Unstructured grid to reduce solution time while retaining the ability to model details where they are important and localized simulations to analyze the impact of small operational changes without a full simulation

Stanchions (also referred to as jacks, posts, or pedestals) support the raised floor system common to most data centers.  These small-scale objects are often omitted from CFD models of data centers because they are thought to have negligible impact on airflow or because of the increased computational effort required to model them explicitly.   This presentation discusses how and why stanchions should be included in data center simulations.   A compact modeling approach is proposed which is based on a combination of experimental data and a new analytical model.  The model is validated by detailed CFD simulation and actual data center measurements.

In the early design of new data centers or modification of existing ones, the need for an optimal solution of many design parameters such as inlet air flow rate, inlet temperature, and server heat load is of paramount importance. The traditional way using computational fluid dynamics (CFD) to create alternative designs options can be problematic because of their intensive running time. This presentation introduces the Response Surface Methodology (RSM), which is based on CFD data but allows the study of many design parameters in data centers more feasible and economical in terms of modeling time while preserving reasonable accuracy.

Martin discusses how BIM authoring tools perform the following: Coordinating duct design, sizing calculations, pressure drop calculations, design validation – visualize areas of high velocity / pressure drop and pressure loss reporting. Martin uses an example from the ASHRAE Handbook of Fundamentals that will show near apples-to-apples comparison of the results from the BIM software vs. the results from hand calcs.

Joe discusses software used for schematic modeling of HVAC systems and why it is so important for initial conceptual design. Such tools are important for automatically modeling simple and complex air, hydronic and steam systems in new or existing buildings. They are also used to calculate ASHRAE 62.1 loads. Through use of interop schemas like gbXML, HVAC schematic tools can import HVAC load information and export HVAC system information to and from BIM authoring and analysis software tools.

Stephen gives an overview of various interoperability schemes like the open-source Green Building XML that allow building information modeling (BIM) authoring tools to transfer information to HVAC analysis tools. As BIM becomes more accepted, it is vital that information be shared between various HVAC design tools. For example, HVAC engineers are able to extract the mechanical and building property information to perform duct and pipe design, and HVAC load calculations. As software becomes more available in the "cloud", interoperability schemas become much more important since information needs to be transferred in a structured format from mobile and desktop devices.