Daniel H. Nall, P.E.
Vice President
Syska Hennessy Group
80 Random Road
Princeton, NJ 08540
United States
Region: I
Honorarium: None

Mr. Nall is a graduate of Princeton University and Cornell University, he is a Registered Architect, a Professional Engineer, an ASHRAE Life Fellow, a Fellow of the AIA, a LEED Fellow, a certified Building Energy Modeling Professional, a High Performance Building Design Professional and a Certified Passive House Consultant. ASHRAE activities include the ASHRAE Advanced Energy Design Guide Steering Committee, chair of SPC 227, the Passive Building Standard, the Building Energy Quotient Ad-Hoc and Oversight Committees, and TC 4.7. He helped author the 30% Advanced Energy Design Guides (AEDG’s)’s for Small Office Buildings, Small Retail Buildings, Roadside Lodging and Small Warehouses, and the 50% AEDG’s for Medium Office Buildings, Medium and Big Box Retail Buildings, and Grocery Stores and the Zero Energy Guides for K12 Schools, Small and Medium Office Buildings and Multi-Family Residential Buildings. He was one of the contributors to the “Engineer’s Notebook” monthly column in the ASHRAE Journal. He received the ASHRAE New York Chapter Distinguished Service Award in 2011 and the ASHRAE Distinguished Service Award in 2012. He has been a member of the Board of Directors of the USGBC NY Chapter, the vice-chairman of the USGBC Energy and Atmosphere Technical Advisory Group, a member of the AIA National Committee on the Environment and is a member of the ACEC New York Chapter Energy Code Committee.

Mr. Nall was named one of the “25 Newsmakers of 2007” by Engineering News Record magazine. He was named “Outstanding Practitioner, 2004”, by the US Chapter of the International Building Performance Simulation Association. Notable projects include the BASF U.S. Headquarters, the Newseum in Washington, DC, the Hearst Corporate Headquarters, the U.S. Embassies in Sofia, Bulgaria and Cape Town, South Africa, the Clinton Presidential Library, the New York Times Headquarters and the Alcoa Corporate Headquarters. He is the author of over 40 papers in technical and professional journals. He has been a Visiting Lecturer at the University of Pennsylvania, Cornell University and Princeton University Schools of Architecture and an Adjunct Associate Professor of Architecture at Columbia.

The Advanced Energy Design Guide

This presentation provides background on the conception, development and potential use of the ASHRAE Advanced Energy Design Guide Series.  So far, AEDG volumes have been developed to guide designers in the achievement of 30 percent energy savings for Small Office Buildings, Small Retail Buildings, K-12 Schools and Warehouses. Future volumes will address Roadside Lodging and other building types and will extend the potential savings to 50 percent.

Sustainable Infrastructure for Green Communities

Community planners have the opportunity for significant reduction of the environmental impact of human activity.   The current interest in green buildings often overlooks the far greater conservation potential of sustainable communities. Creating net zero energy and net zero water usage communities is much easier than creating single buildings with the same performance. Communities can be vital, complex ecologies that obtain maximum use of consumed resources while minimizing waste discharge.  These goals are best achieved by exploiting the synergies among the separate infrastructure systems while obtaining multiple benefits from each conservation strategy.  For example, greenways can provide not only pedestrian pathways but also management and cleansing of storm water run-off.  Co-location of neighborhood scaled power, thermal, and waste water treatment plants allows the by-products of each system to be used as resources for others.  Sewage treatment plant gas can offset some fuel usage for power generation and sewage treatment plant water effluent provides cooling tower make-up for the cooling plants. Pursuing these issues at the community level addresses issues at the most effective scale.  For example, sewage treatment is best handled at a neighborhood scale so that the treated effluent water can be recycled for local non-potable uses, such as irrigation, exterior housekeeping and flushing.  Renewable energy production, on the other hand, is best handled on a regional scale, so that sites can be selected for most effective harvesting of the resource. When these strategies are pursued in a single building, both conservation and economic effectiveness are often seriously diminished.

Innovative Systems for Energy and Water Conservation: Four Corporate Headquarters

This presentation discusses the fundamentals of energy and water conservation in buildings, focusing on building mechanical systems.  It then presents how these principles have been implemented in four corporate headquarters offices buildings around the world.  Different approaches to energy conservation are presented, ranging from architecturally integrated HVAC systems to innovative applications of packaged equipment.  Presented water conservation strategies range from water conserving fixtures through desalination of brackish groundwater.

Energy Efficient HVAC Strategies

This presentation examines several different innovative approaches to HVAC systems that demonstrate significant improvements compared with conventional systems. Two approaches to reducing lift for compression refrigeration comfort systems are presented. 

Two airside system approaches to minimizing reheat for dehumidification are also presented.  The systems are designed for high airflow, humidity controlled spaces that ordinarily rely on reheat to maintain conditions, but the presented configurations significantly reduce the need for reheat. 

Underfloor Air Distribution

Underfloor Air Distribution Systems (UFAD) are rapidly penetrated the office building arena across the United States because they provide a number of advantages, (and a few disadvantages) over conventional office building HVAC systems. This session will present new design approaches and new solutions that refine and improve the performance and flexibility of UFAD systems.  Some of the issues to be dealt with include maintenance of uniform supply temperatures in the underfloor plenum, evaluation and exploitation of thermal stratification in the occupied spaces, avoidance of leakage issues in the floor plenum, control of space humidity for humid climates, and maintenance of comfort conditions in all occupied spaces.

Natural Ventilation Design for Commercial Buildings using Computational Fluid Dynamics

This presentation focuses on the opportunities for new buildings to forgo central air-conditioning and use pas­sive ventilation strategies (commonly called ‘natural ventilation’). The presentation is technical in nature and works through a decision flow chart of various aspects of the building that impact the ability to passively cool the building. Attendees will learn how to decide early in a project if it is a good fit for passive cooling.  The presentation will also show how computational fluid dynamics can not only inform the decision as to whether or not natural ventilation will work in a specific building, but can also guide detailed design decisions on design for natural ventilation.

LEED v4 Energy and Atmosphere Credits

This presentation gives a synopsis of the LEED v4.0 Energy and atmosphere credits.  It begins with a general description of and history of LEED.  It then describes the pre-requisite requirements for this section.  Next is a detailed discussion of each of the E&A credits, looking at the how the points are awarded, at the flow chart of the process of accruing points. Then follows an in depth discussion of whole building simulation and a detailed discussion of ASHRAE 90.1, Appendix G. Next is a discussion of the characteristics and limitations of the Appendix G methodology and the energy conservation strategies that perform well for this method.  Then, some of the ancillary tools for whole building energy simulation are presented.

Making Buildings Resilient to Natural Disasters and Acts of Terror

This presentation focuses on how to prepare buildings for natural disasters and acts of terror.  It identifies the elements of a building risk assessment, stressing realistic threats and realistic desired outcomes.  It shows strategies for making building life safety systems more resistant to catastrophic events.  The presentation presents the approach and some of the recommendations of the New York City Building Resilience Task Force, a group of professionals convened by the Mayor of New York to develop recommendations for the city and for building owners in the aftermath of Tropical Storm Sandy.

Free and Passive Cooling

One of the basic precepts of climate responsive building design is to use available free environmental resources to maintain comfort inside the building.  For mechanical engineers, it means using airside or waterside economizer.  This presentation will demonstrate the comparative effectiveness of these measures, along with some enhancements to increase that effectiveness. It will also examine the impact of climate responsive envelope design on energy efficiency and will briefly examine the limits of passive cooling design in several climates.

Water Conservation and HVAC Design

This presentation will discuss options for water conservation and wastewater harvesting techniques.  Technology for water conservation will be discussed.  Utilization of on-site non-potable water resources will be discussed, and methods of capturing and treating these resources will be presented.  The requirements of water consumption end-uses that can benefit from non-potable resources will be presented, along with technical issues that limit the exploitation of these resources.  A case study showing a 2/3 reduction in potable water consumption through the utilization of both conservation measures and non-potable water harvesting will be presented.

The 2016 New York City Energy Conservation Code

This presentation gives a synopsis of the requirements of the 2014 New York City Energy Conservation Code.  This code is based upon IECC 2012 but includes a number of important amendments, including some amendments to ASHRAE Standard 90.1-2010 that is referenced in IECC.  The presentation included a introduction to the submission requirements and to the inspectio0n protocols required to insure that the constructed works are consistent with the submitted documentation.

Energy Policy from an Engineering Pesrspective

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.

The Building Envelope

This presentation will focus on the thermal and optical performance of the building envelope and will demonstrate techniques that can be used to analyze envelope performance. The physics of glass and window frame performance will be presented.  A whole building analysis will be presented to show the impact of different configurations of the building envelope on energy performance.  Daylighting analyses will demonstrate the impact of glazing fraction on interior daylight levels.  Finally, the impact of exterior wall construction on building energy consumption will be demonstrated.

HVAC for “Passive House” Buildings

Passive House, a new standard for building energy efficiency has recently been introduced to the United States from Europe, appearing both in the European “Passiv Haus” version and in an American version, PHIUS + 2015, funded by US DOE, tailored for the wide climatic variation of the United States.  Both standards are very specific with respect to envelope design, but, specifications for HVAC systems are very general.  The standards share three pillars, the first of which limits space conditioning conduction and infiltration heat transfer, heating and cooling, peak and/or annual, but does not affect HVAC system design.  The second pillar, limits total source energy consumption, which implicitly affects HVAC system efficiency at meeting the limited heat transfer requirements in the first pillar.  The third pillar, air-tightness, reduces both sensible and latent loads on the system, but has no detailed implications for the system design.  Balanced heat recovery ventilation is required, with criteria for heat recovery efficiency and transport (fan) energy.  In Europe, space conditioning airflow rate is limited to the ventilation airflow, but this requirement has proved less than optimal for some North American climates, and has been modified in PHIUS +2015.  This presentation will explore characteristics of HVAC systems that are consistent with the Passive House standards.  It will present both detailed specifications of systems functionality and control sequences, and will present product types that are currently available in the marketplace.  The intent is to provide guidance for designing HVAC systems that complement Passive House architecture.

Learning goals for the presentation.  After the presentation, the attendee should be able to:

  1. Understand the strategies for building performance embodied in the Passive House standards.
  2. Recognize how these principles can be incorporated into building design to improve indoor comfort and improve efficiency of environmental control.
  3. Recognize which HVAC systems are compatible with Passive house.
  4. Overcome some of the unique challenges that Passive House buildings pose for HVAC system designers.
The Advanced Energy Design Guide for Zero Energy K12 Schools

The latest 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:

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.
The Impact of Outdoor Air Ventilation

This presentation demonstrates the effect of ventilation on the energy consumption of buildings.  The presentation will first examine energy efficiency strategies using outdoor air beyond the minimum required for ventilation.  These strategies include, natural ventilation, airside economizer and evaporatively enhanced airside economizers.  The presentation will then illustrate heat balance calculations for mixed air and dedicated outdoor air systems, including energy recovery systems.  The presentation will then address strategies for reusing relief air (air that must be exhausted from the building to allow the introduction of required outdoor ventilation) from heavily populated areas to provide make-up air for heavily exhausted air.  Finally, the presentation will examine the energy impact of the LEED enhanced ventilation credit in several climates.  

Learning Goals – At the end of this presentation, the attendee will be able to:

  1. Recognize advantages of outdoor air as a free-cooling strategy for a project in a given climate
  2. Recognize applicable new systems and design strategies that can optimize the energy impact of outdoor air ventilation.
  3. Understand how recycling relief air can relieve outdoor make-up air requirements for highly exhausted spaces.
  4. Understand the energy efficiency implications of increasing outdoor air ventilation rates to enhance indoor environmental quality.
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:

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.
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: 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.
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.
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