Mark Handzel is Xylem’s vice president, product regulatory affairs, and director, HVAC commercial buildings. Xylem’s Bell & Gossett line is a leading name in HVAC systems and components with an emphasis on increased efficiency. As users seek higher performance across a variety of conditions, Mr. Handzel shared some of his thoughts on the advantages taking a total systems approach has in achieving that goal.
MPT: How would you best describe the benefit of taking a systems approach for HVAC—for designers, for manufacturers, and for end users?
Mark Handzel: The simplest way to explain the benefits of taking a systems approach is to look at the bottom line. With any HVAC system today where a Bell & Gossett product is going to be installed, everyone is going to be most concerned about the overall efficiency—the  owner, the engineer, everyone! Now, when assembling a system, one could just pick products clearly based on their individual efficiency values, but that fails to take into account the total systems approach of looking at the system—examining the different variables that people put into their different system designs to ensure that we’re not wasting energy.
However, by ensuring that the pumps are selected by strong operations through solid efficiency portions of the performance curve—what we call “Efficiency Islands”—to stay in the best efficiency area for those pumps, to ensure that you have valves that have low pressure drops, to ensure that they are installed properly and wide open after the system has been balanced—all of these metrics contribute to a system’s overall efficiency. If users take this view of how the whole system works, then they are better able to assess system efficiency.
MPT: What are the key goals for incorporating a total systems approach into HVAC operations?

Mark Handzel: When engineers design a system, they design the HVAC system for the “worst” day of the year—either the coldest day or the hottest day. But that necessarily means that there are a lot of days in between, where it is critical to look at the system and its overall efficiency performance so that users can take advantage of those non-design days and save energy.
Of course, HVAC system design is not an exact science. Obviously, engineers and trade associations like ASHRAE try to take as many internal and external variables out of the equation, but still some variables end up contributing to what one could call “over-design” factors. By considering the total system efficiency, we are developing a way to take those considerations and reduce those consumers of energy.
MPT: How can total systems design improve the bottom line? What are some of the performance benefits?
Mark Handzel: Clearly, taking a systems approach amounts to costs savings over the entire life of the building, which can prove sizable since ensuring the environmental comfort of the occupants of a building is traditionally such a big cost of operating any type of facility. Performance-wise, how successful a system is comes down to asking, “are the occupants of the building comfortable in this environment?” If it’s a cold day, do they have to run a space heater? If it’s a warm day, is everyone sweating? Are they uncomfortable?
MPT: How are you spreading the importance of taking a systems approach to your peers?
Mark Handzel: Bell & Gossett has been conducting educational programs directed at consulting engineers for over sixty years, most famously at our Little Red Schoolhouse training center. Most of these design techniques and approaches that I’m mentioning are the things engineers come to learn at these classes—what efficiency-minded engineers should be doing as opposed to what they may currently be doing.
Also, the Little Red Schoolhouse is available online, where if professionals can’t take three days away from their commitments in the field, they still have an opportunity to learn and employ some of these important principles. ◆
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