Mr. Nall is a professional engineer, a registered architect, an ASHRAE and an AIA Fellow, a LEED Fellow, an ASHRAE Certified Building Energy Modeling Professional, a certified High Performance Building Design Professional and a Certified Passive House Consultant. He is a member of the ASHRAE-AIA Liaison Committee, the Advanced Energy Design Guide Steering Committee, ASHRAE SPC240P, Evaluating Greenhouse Gas (GHG) and Carbon Emissions in Building Design, Construction and Operation and is a member of the 2024 International Energy Conservation Code Commercial Consensus Committee. He was a member of the 2021-2022 ASHRAE Task Force for Building Decarbonization, the ASHRAE Vision 2030 Presidential Ad-Hoc Committee, was Chair of ASHRAE Standards Project Committee 227P, the Passive Building Design Standard, and was a member of the Commercial Buildings Working Group of the New York City Local Law 97 (Building Carbon Emissions Limitation) Advisory Group. He has been involved in building energy efficiency and HVAC engineering for 45 years. He has been a faculty member at the Schools of Architecture at the University of Pennsylvania, Princeton University, Cornell University and Columbia University. He is the author of numerous papers in professional and technical journals. He has also presented at numerous USGBC, AIA and ASHRAE national conferences and conventions, and at international events in Spain, Italy, Brazil, Argentina, UAE, India, and Indonesia. His areas of expertise include underfloor air distribution, thermally active floors, thermal storage, central plant design, energy recovery and building electrification. Projects for which he has had a substantive engineering design contribution include 270 Park Avenue (the J.P. Morgan Chase Headquarters), the BlackRock Headquarters at 55 Hudson Yards, 200 West Street (Goldman Sachs Headquarters), the New York Times Headquarters, the Hearst Tower all in NYC, the William J. Clinton Presidential Center, the University of Virginia Albert and Shirley Small Special Collections Library, the Delaware State Archives, the Alcoa Headquarters in Pittsburgh, the Banco Macro Headquarters in Buenos Aires and the U.S. Embassies in Sofia, Bulgaria, Cape Town. South Africa, and Kathmandu, Nepal.
Building Services Systems for Building Decarbonization
As the building community becomes more aware of the causes and the remedial strategies for climate change, the drive for energy efficiency in buildings is being replaced by a drive for decarbonization. In many areas of the world, the electrical grid is rapidly decarbonizing, so that fully electric buildings are seen as a primary strategy for decarbonization. The primary challenges for decarbonization are building space heating and domestic water heating. This presentation discusses strategies for electrifying these building services in ways that maximize energy efficiency and reduce first cost while maintaining comfort and functionality. The presentation also discusses how these systems can be configured to shift loads from periods of high grid carbon intensity to periods of low grid carbon intensity. Some of these strategies include:
•Separating building sensible cooling from building dehumidification and separately sourcing cooling for these functions
•Providing space temperature control with low temperature hot water and high temperature chilled water
•Maximizing heat recovery throughout building systems to minimize exterior heat sourcing for space and water heating.
•Minimize the lift of heat pump systems providing space and domestic water heating.
•Energy storage to facilitate load shifting for grid integration.
Learning goals for the presentation. After the presentation, the attended should be able to:
1.How to use energy and load modeling to get the information necessary for the design early in the design process
2.Configure systems to achieve maximum heating and cooling efficiency by minimizing temperature difference necessary to achieve desired conditioning (heating, cooling dehumidification)
3.Maximize beneficial heat recovery.
4.Incorporate demand response options for grid integration into building systems to coordinate with grid carbon intensity.
Hydronic System Design for Condensing Boilers
Condensing boilers are capable of higher efficiency operation than standard boilers, but they require specific characteristics of the hydronic distribution system to achieve this efficiency. Experience has shown that most installed condensing boilers never reach their efficiency potential because they are rarely operating in condensing mode. The standard designs for hydronic distribution systems for use with conventional boilers are often inappropriate for use with condensing boilers. Specifically, hydronic systems design should be oriented toward minimizing the return temperature of hot water to the boiler, avoiding recirculation of supply water into the return stream and providing a means for maintaining the boiler minimum firing rate above a level that would raise excess outdoor air to inefficient levels. This presentation will discuss the characteristics of condensing boilers and will suggest some system design strategies to maintain efficient operation by accommodating their operational requirements.
Learning Goals
1.Recognize the operating characteristics that affect condensing boiler efficiency
2.Know how to design space heating delivery systems to maximize the effectiveness of condensing boilers
3.Select condensing boilers based upon the operating characteristics of a particular application
4.Understand how to avoid excessive cycling and mixing of return and supply water during part load operation
The Advanced Energy Design Guide for Zero Energy Office Buildings
This session will introduce designers to the latest volume of the Advanced Energy Design Guide series, developed jointly by the AIA, ASHRAE, IES, and USGBC with support from the U.S. Department of Energy. Following the success of the earlier 30% Savings and 50% Savings series, this volume of the Zero Energy series addresses small to medium office buildings. Attendees will be introduced to an easy-to-follow step-by-step methodology to achieve this lofty energy efficiency goal. The latest volume of the Advanced Energy Design Guides extends the successful approach of the previous guides to Zero Energy Small to Medium Office Buildings. The new guide focuses on the architects and engineers designing the building, adding in an owner/operator perspective on Zero Energy. Guidance is based on strategies and pathways which have been pre-computed using energy models giving designers a starting point for design. The new guide follows the \"a way, but not the only way\" approach of previous guides, presenting a comprehensive, integrated, systematic approach to achieving the aggressive energy efficiency targets necessary for Zero Energy. This program will teach the architect how to use the Zero Energy Office Buildings Advanced Energy Design guide to access valuable information on:
•The integrated design process
•Zero Energy programming and design
•Coordination and commissioning
•Design strategies by climate and system
•Electric grid integration
•How-to tips and detailed caveats
Learning Goals
1.Understand the entire scope of a zero energy office project, including the owner’s perspective.
2.Recognize which energy conservation measures are effective in which climates to achieve the zero energy goal.
3.Use the AEDG to help communicate to clients the challenge of operating a Zero Energy building according to the design intent, insuring that the aggressive energy goal is met.
4.Improve their management of the design process to achieve the Zero Energy goal.
The Advanced Energy Design Guide for Zero Energy K12 Schools
This volume of the Advanced Energy Design Guides, extends the successful approach of the previous guides to Zero Energy Building K-12 School Design. The new guide focuses on the previously targeted audience: architects and engineers designing the building, but adds an owner/operator perspective on Zero Energy. Rather than focusing on renewable energy systems, the guide spotlights the design, operational, usage, and behavior approaches necessary to achieve zero energy. The new guide follows the \"a way, but not the only way\" approach of previous guides, presenting a comprehensive, integrated, systematic approach to achieving the aggressive energy efficiency targets necessary for Zero Energy. This program will teach the architect how to use the Zero Energy K-12 School Advanced Energy Design guide to access valuable information on:
•The integrated design process;
•Zero Energy programming and design
•Benchmarking, coordination, and commissioning;
•Design strategies by climate and program element
•How-to tips and detailed caveats
Learning goals for the presentation. After the presentation, the attended should be able to:
1.Understand the entire scope of a zero energy K12 School project, including the owner’s perspective.
2.Recognize which energy efficiency measures are appropriate for a Zero Energy K12 school in a specific climate.
3.Use the AEDG to help communicate to clients the challenge of using a Zero Energy building according to the design intent, insuring that the aggressive energy goal is met
4.Improve their management of the design process to achieve the Zero Energy goal.
Close Approach and High Delta-T: Powerful Strategies for Energy Efficiency
This presentation describes how minimizing the approach of various heat transfer processes with an HVAC system and maximizing the temperature differential across the entire distribution system can significantly enhance the efficiency of those systems. Almost all HVAC conditioning systems incorporate the transfer of heat from one fluid to another several times over the course of delivering conditioning to the space. In the overall system design, maximizing the temperature differential across the entire system minimizes the amount of air or water that must be moved to provide a certain capacity. Within the supply chain of the distribution system, however, minimizing the approach temperature of each step of heat transfer helps maximize the overall temperature differential of the system. This presentation presents strategies for achieving both minimal approach temperature and maximum system temperature differential in the quest for higher levels of energy efficiency.
Learning Goals
1.Review the strategies that are utilized to lower approach temperatures in heat transfer devices
2.Understand how minimizing approach temperature in the distribution system enables more efficient production of cooling and heating
3.Recognize how cooling coil selection can minimize both pumping energy and maximize chiller efficiency.
4.Select heat exchangers to maximize temperature differential in the overall hydronic distribution system.
Chiller Plant Low Delta-T Syndrome: What It Is and How to Avoid It
Low-delta-T syndrome is an operating condition for chiller plants that effectively reduced the capacity of the chiller plant below the rated capacity of the chillers and that reduced plant energy efficiency. It can be caused by several different circumstances, some of which can be remedied fairly easily and others that are deeply ingrained in the design of the system. It is the result of a control failure that fails to reduce chilled water flow proportionally with cooling load reduction, producing one of the following conditions.
1.At an operating condition, return temperature to the chiller is lower than at design
2.At an operating condition, supply temperature at the load is higher than at design
This lecture will present the primary causes of low-delta-T syndrome and the strategies to avoid or mitigate its effects. While some of these measures may be applied to existing plants, the best way to avoid the problem is in the design of the entire heat transfer system from the loads to the chillers.
Learning Goals
1.Recognize low-delta-T syndrome.
2.Understand the impact of low-delta-T syndrome on chiller plant operation
3.Understand what characteristics of a chiller plant system can result in this condition
4.Retrofit existing chiller plants to minimize this condition.
5.Design a new chiller plant that will avoid this condition entirely.
Thermally Active Structures for Green Buildings
Thermally active structure is an evolving strategy that has become a popular system in green buildings. Originally implemented for heating only, as radiant heating floors, this strategy has, over the past 20 years been implemented also as a cooling strategy. The addition of cooling capability adds a number of design constraints and potential operational problems to the successful implementation of the system. This presentation explores the many design, construction and operational issues of thermally active heating and cooling structures. Issues addressed include:
•Most effective applications of the technology
•Design tools
•Case studies of successful implementations•Design issues
•Construction issues
•Constraints and limitations
•How-to tips
The Advanced Energy Design Guide for Zero Energy Multi-Family Residential Buildings
The latest volume of the Advanced Energy Design Guides extends the successful approach of the previous guides to Zero Energy Building Multi-family Residential building Design. The new guide focuses on the previously targeted audience: architects and engineers designing the building but adds an owner/resident perspective on Zero Energy. Rather than focusing on renewable energy systems, the guide spotlights the design, operational, usage, and behavior approaches necessary to achieve zero energy. The new guide follows the \"a way, but not the only way\" approach of previous guides, presenting a comprehensive, integrated, systematic approach to achieving the aggressive energy efficiency targets necessary for Zero Energy. This program will teach the architect how to use the Zero Energy Multi-family Residential Building Advanced Energy Design guide to access valuable information on:
•The integrated design process
•Zero Energy programming and design
•Benchmarking, coordination, and commissioning;
•Design strategies by climate and program element
•How-to tips and detailed caveats
Learning goals for the presentation. After the presentation, the attended should be able to:1.Understand the entire scope of a zero energy Multi-family Residential project, not only from the perspective of the design and construction team but also from that of the owner and the resident.
2.Recognize which energy efficiency measures are appropriate for a Zero Energy Multi-family Residential Building in a specific climate.
Use the AEDG to help communicate to clients the challenge of using a Zero Energy building according to the design intent, insuring that the aggressive energy goal is met
3.Improve their management of the design process to achieve the Zero Energy goal.
Energy Policy from an Engineering Perspective
The “energy problem” is not a single problem but is an interconnected web of problems that have significant impact on the global environment and on the global economy. It actually can be evaluated as a set of disconnects between societal needs and the current energy infrastructure for meeting those needs. Currently proposed solutions to the perceived energy problems of today’s global community too often focus on specific technologies and address only a small portion of the overall problem. The tendency to “silo-ize” these issues tends to produce revolutionary solutions to minor problems and to foster neglect of larger issues. The approach described in this presentation attempts to deconstruct the “energy problem” into component parts to facilitate evaluation of proposed solutions and technologies in the larger context.