ASHRAE’s Winter Conference welcomed more than 3,000 HVACR industry professionals to Atlanta, Feb. 4-8. The five-day conference featured more than 100 technical sessions, updates from society leaders, tours, social events, and much more.

Securing Our Future

Farooq Mehboob, Fellow Life Member, ASHRAE, is ASHRAE’s president for the 2022-2023 term. Mehboob previously served on the ASHRAE board of directors as president-elect, treasurer, vice president, region-at-large director, and regional chair.

Mehboob’s theme for the 2022-2023 ASHRAE society year is “Securing Our Future.”

“We are living in times of great change; the events of today are absolutely unprecedented,” said Mehboob during a press conference at the 2023 AHR Expo. “When it seemed like everything else was falling apart, the relationships I’ve forged helped secure my future. Securing the future of ASHRAE and our industry depends upon harnessing the strength of our global relationships. We have 66 associate ASHRAE societies around the world. As an alliance, we rely upon the strength of the industry, its great manufacturers, and all of our associate societies. It’s our responsibility to harvest all the information that’s available and then take leadership all around the world.

“A meaningful and powerful future will not come to us,” he continued. “We must collectively seek it, create it, and secure it. And that’s what we’ll do, because that’s who we are. It’s in ASHRAE’s DNA. We need to be diverse, equitable, and inclusive to see, understand, and take advantage of what is changing. The two key prerequisites for ASHRAE’s diversity are transparency and participation.”

For his time and commitment to ASHRAE and the HVACR industry, Mehboob received the society’s Distinguished Service Award and Regional Award of Merit. As director and regional chair, he worked hard to improve internal and external communications and became a true advocate for ASHRAE’s globalization efforts. In 2016, Mehboob was a part of ASHRAE’s first international board meeting in Bangkok. In addition to his time served on the board of directors, he served as chair of the Appointments Roadmap Committee, chair of the Publishing and Education Council, coordinating officer of the Conferences and Exposition Committee, coordinating officer of the Historical Committee, coordinating officer of the Training and Education Committee and coordinating officer of the Development Committee, among other participation.

ASHRAE 2022-2023 president Farooq Mehboob
FIGURE 1. ASHRAE 2022-2023 president Farooq Mehboob meets with members during a presidential meet-and-greet session. Images courtesy of ASHRAE

“It’s imperative that we continue to hunger for, and seek information about, our market, changing world, and technological advances,” Mehboob continued. “Breaking down silos and embracing change will infuse a new dynamism in our society at all levels, bringing to our members new knowledge, technology, and tools in a timely fashion, helping them to successfully navigate the rapidly changing world. Leveraging relationships, knowledge, and change is the formula to securing our future.”

Building Decarbonization

Jurisdictions globally are confronting climate change and recognizing that building decarbonization is a significant component of their efforts. The worldwide building sector accounts for about 40% of energy-related carbon emissions, and the global building stock is predicted to double by 2060.

Buildings remain a key sector that lack sufficient climate change mitigation policies. As the standards authority for energy usage in buildings, ASHRAE recognizes its long-standing initiatives in energy efficiency should include greenhouse gas emission reductions based on a holistic analysis, including healthy, safe, and comfortable environments; energy efficiency; environmental impacts; sustainability; operational security; and economics.

The ASHRAE Task Force For Building Decarbonization (TFBD) webpage includes technical resources, information, videos, and publications to expedite the adoption of climate change mitigation policies and reaffirms the society’s goals stated in the ASHRAE Vision 2020 report, approved by ASHRAE’s board of directors, as well as the ASHRAE Position Document on Building Decarbonization, to achieve net-zero GHG emissions in operation for all new buildings by 2030.

Conference attendees meet and mingle
FIGURE 2. Conference attendees meet and mingle at the Young Engineers in ASHRAE meeting.

“Over the years, ASHRAE has demonstrated its leadership in reducing GHG emissions by addressing energy efficiency and sustainability, as articulated in some of our most notable technical guidance, such as Standards 90.1 and 189.1,” said Kent Peterson, chair, ASHRAE TFBD. “The TFBD is working to provide vital technical guidance in new guidebooks and the redesigned webpage. ASHRAE is helping accelerate the transition from commitment to action in reducing global built environment GHG emissions.”

Eliminating greenhouse gas (GHG) emissions from the built environment is essential to address climate change, states the ASHRAE TFBD.

By 2030, the global built environment must halve its 2015 GHG emissions:

  1. All new buildings must be net-zero GHG emissions in operation;
  2. Widespread energy-efficiency retrofits of existing assets must be well underway; and
  3. Embodied carbon of new construction must be reduced by at least 40%.

By 2050, at the latest, all new and existing assets must be net-zero GHG emissions across the whole life cycle.

The newly released Building Performance Standards (BPS): A Technical Resource Guide was created to provide a technical basis for policymakers, building owners, practitioners, and other stakeholders interested in developing and implementing a BPS policy. The first in a series of seven guidebooks by ASHRAE on building decarbonization, this guide focuses on reducing building operating energy use and the resulting emissions in existing commercial and multifamily buildings, as established by several U.S. cities and states. Jointly developed by ASHRAE, the U.S. Department of Energy (DOE), and its national laboratories, the BPS guide is meant to provide the information needed to make informed policy design decisions that drive deeper existing building decarbonization and provide equitable outcomes for all involved.

“There is a growing demand for ASHRAE’s technical guidance,” said Jeff Littleton, executive vice president of ASHRAE. “The ASHRAE Task Force for Building Decarbonization has been working tirelessly on a wide spectrum of decarb resources. We launched ASHRAE’s new decarbonization online resource hub that will feature a wide spectrum of decarb tools and guidance. You can now download the new, free publication, Building Performance Standards: A Technical Resource Guide, produced in partnership with the Department of Energy and Pacific Northwest National Labs. We are building upon our 129-year legacy in today's perfect storm of demand to make buildings better.”

Green Guide

At the 2023 Winter Conference, one session, “Building on Twenty Years of Guidance Toward Decarbonization: The ASHRAE GreenGuide,” focused on the latest release of ASHRAE’s GreenGuide and showcased the document’s history.

Almost 23 years ago, as awareness of the built environment’s impact on the natural environment and human occupants started to blossom, the interest in, and need for, sustainable engineering concepts emerged. At that point in time, the ASHRAE GreenGuide, a landmark publication in the sustainable building arena, was created.

ASHRAE’s 2022-2023 board of directors
FIGURE 3. ASHRAE’s 2022-2023 board of directors.

The sixth edition of ASHRAE’s GreenGuide was released in December 2022. The publication has been revised and streamlined to become a reference resource for practicing building industry professionals. Each stage of the building process, from planning to operation, is detailed with an emphasis on collaboration between practitioners.

“This is ASHRAE’s decarbonization guide for buildings,” said Janice Means, P.E., LEED AP, FESD, FASHRAE, professor emerita, Lawrence Technological University. “The guide is intended for experienced professionals, covering a lot of decarbonization topics, resilience, pandemic response, Legionnaires’ disease, evolving technologies, and much more.”

Updates to the sixth edition include:

  • An in-depth discussion of emerging industry trends, including building decarbonization and zero-energy emissions;
  • New material on designing and operating buildings and their systems in response to current and expected climate change and accompanying extreme weather events; the need to increase resilience in the built environment; and identifying the interrelationship of sustainability, efficiency, and smart technologies with building resilience; and
  • Updated GreenTips and Digging Deeper sidebars, which provide detailed, practical examples.

Means further summarized the updates during the presentation.

“In Chapter 3, we offer a few project strategies that focus on digital tools, digital twins, drones, augmented reality, etc.,” she said. “Chapter 5 from the previous version is now Chapter 4, covering architectural design and planning. We took a lot of material out of this one because much of it was very fundamental. Also, recommendations have been added examining how the climate is changing.

“Chapter 8 features a new section called benefits of enhanced indoor environmental quality and a new table detailing indoor environmental contaminants,” continued Means. “This chapter was written prior to the pandemic, so, unfortunately, we don't have many IAQ recommendations that resulted from the pandemic. Chapter 9 includes new sections on energy use conversion and distribution as well as energy savings for elevators, escalators, and commercial kitchens. Finally, Chapter 10 has a new section covering renewable energy sources and grid integration.”

Hydrogen-Blended Gas Operation

Power-to-Gas (P2G) is gaining interest in the energy industry to support broad decarbonization goals by storing excess renewable electricity as hydrogen in the existing gas grid, which is then consumed in blends with natural gas by existing combustion systems. Hydrogen offers a significant means of seasonal energy storage at energy densities not matched by electric batteries and could create additional value for renewable electricity projects, which may otherwise curtail generation during periods of excess capacity.

While multiple pilots are already underway in Europe and North America, these studies are in their infancy. More work is still needed to develop the underlying technologies and to demonstrate safety, reliability, and economic benefits of the approach. Multiple studies have identified that end-use appliances (residential, commercial, and industrial combustion systems) are likely to pose the lowest limits of hydrogen compatibility when no changes are made to the burners and controls. Limits of compatibility of 15%-30% of hydrogen by volume have been cited. The wide range of blending limits is in large part due to the variety of gas combustion systems used throughout the world. In North American residential and commercial applications, the vast majority of natural gas burners are low-cost partial premix burners, found in appliances, such as gas furnaces, boilers, and water heaters, as well as non-HVAC equipment, such as cooking ranges and gas dryers. Partial-premix burners are characterized by low-pressure injection of fuel into the burner, which entrains 50%-70% of the total air required for combustion, with the balance made up as secondary air at the flame.

These types of burners have been extensively used since the 19th century for their stability, efficiency, and high turn-down. For this reason, the design approaches used in the product development of partially-premixed gas-fired appliances have not substantially changed since the mid-20th century when a broad transition from the use of town gas (up to 50% hydrogen) to natural gas occurred. While the fundamental design of the partial-premix burners has not changed, more recent design requirements around efficiency and low emissions have forced some burner designs toward novel configurations not previously used with hydrogen-blended gas.

In a presentation titled “Burner Design Considerations for Hydrogen-Blended Gas Operation,” Aleksandr Fridlyand, Ph.D., senior engineer at GTI Energy, summarized the results of a theoretical and numerical investigation into the fundamentals of gas burner designs, identifying important characteristics that permit a wider compatibility with hydrogen-blended gas and potential limitations of this technology with respect to hydrogen blending.

“There’s no silver bullet when it comes to decarbonization, reducing greenhouse gas emissions, etc.,” said Fridlyand. “Hydrogen goes hand-in-hand with beneficial electrification, as it offers high energy storage capacity and is able to utilize the existing gas grid.”

According to Fridlyand, hydrogen operates at a lower volumetric energy density with higher flame temperatures and speeds. But its impact on a burner’s performance is a complicated matter.

“There are two types of major burner classes,” he said. “In the natural gas world, there's premix burners, which are used with most power systems. For this study, we focused on partially premix burners and atmospheric burners as well, which are still ubiquitous in North America. You can find them in the majority of furnaces, rooftop units, storage units, water heaters, cooking fireplaces, outdoor equipment, hot water units, steam boilers, process heaters, etc.

“This study focused on the theoretical aspects of burner performance when hydrogen is introduced,” Fridlyand said. “So, the main concern is that hydrogen’s going to burn hotter. Thus, there will be more Nox, and there is going to be flashback.”

One of the first concerns when introducing a hydrogren blend is derating.

“Because hydrogen has a lower volumetric energy density, for every unit of hydrogen that is blended with natural gas, you're going to have to burn more of it to get the same amount of heat out,” he said. "The theoretical prediction of how much derate should occur is fairly consisten “With 30% hydrogen by volume, you should have roughly a 7% derate. In this experiment, this was not necessarily the case, and it's been a little bit tricky to try and explain that. For instance, for a pancake-style burner in a water heater, which is a very conventional device, we were seeing 10% derate at 30% hydrogen as opposed to 7%.”

Another element worth examining is the discharge coefficient.

“Gas-type orifice capacity charts define a fixed gas orifice discharge coefficient that holds for natural gas under certain conditions,” Fridlyand said. “However, hydrogen has sufficiently different physical properties, like viscosity, the volume flow of gas through the orifice changes, etc. The discharge population is actually a function of the Reynolds number. Once we started blending in hydrogen, a lot of the parameters started changing. This experiment was informative, but there's still some unexplained differences that need a little bit further investigation.”

Finally, the paper studied aeration.

“These burners operate on the principle of injecting 50%-70% of the air required for complete combustion, which is called primary air,” he said. “That changes as we change the physical properties of the gas. With hydrogen, if we keep the orifice size and manifold pressure the same, the amount of air being injected actually decreases on the pure volumetric basis. However, because hydrogen requires a lot less air for combustion, the overall dilution of the fuel mixture increases. So, we see an increase in primary aeration. This is counterintuitive as to what we've been seeing with burner tests. Because the derate drops off as well, we actually saw a drop in the flue gas temperatures, again, without making any compensations. There was an increase in the flame speed. A flame speed increasing up to 30%, 40%, or 50% with hydrogen is actually very modest. You're going from maybe 20-30 centimeters per second to maybe 50. It's only when you get the very high concentrations of hydrogen that you see a much higher increase with flame speeds.