With sustainability rising to heightened importance, we need a revolution to improve building energy efficiency by orders of magnitude to address global climate challenges. HVAC systems are the largest energy consumers in most buildings, and reducing inherent energy losses are a valuable, but underutilized, strategy.
Advanced axial fan technology
Dr. Bert Willke, PhD, is a retired Massachusetts Institute of Technology (MIT) professor of acoustical physics who has patented an advanced air-handler that cut fan power needs in half. Precision-designed axial fan equipment minimizes turbulence and noise to create negative system effects while maximizing efficiency, reducing equipment footprints and minimizing fan heat for added chiller and water energy savings. Additional capital cost savings result from reducing electrical infrastructure, emergency generators, sound attenuators, roof ductwork and mechanical equipment footprints for more space to fulfill architectural requirements.
BEST (Buildings Engineered with Smart Technology), has been formed to drive the industry to expect extreme efficiencies by re-using energy commonly lost in traditional HVAC equipment. Using advanced physics of fluid flow and acoustics to optimize fan and air-handler designs, required fan energy is cut in half, while the acoustics are reduced by 20 to 30 dBs. These energy savings show up as a reduction of internal air-handler unit (AHU) total pressure losses of about two to three inches, which can save approximately 1 W/cfm, so every building can have a new and robust energy-efficiency upgrade measure. For net-zero energy buildings, BEST fans reduce capital costs because the AHU cost/Watt saved equals the installed cost of photovoltaics. Alternatively, BEST fans can be used to turn these buildings into positive-energy buildings at no extra costs. It turns out half the energy we put into traditional fans turns into noise nobody wants to pay for, and they take up too much space that should be re-purposed for architectural applications.
LAV and smart air valve
In addition to the field-proven axial fan technologies, Dr. Willke has applied his advanced low-flow fluid control wisdom to create the next-generation VAV box known as the Smart Air Valve. This new device brings even more efficiency and cost effectiveness to improve overall building efficiency. With an accurate integral airflow sensor, a .02-in pressure drop at full flow, and a 250:1 turndown ratio, the Smart Air Valve opens a new HVAC system design strategy known as the low air volume (LAV) systems. LAV systems are the next natural step after CAV and VAV systems, as we demand more efficiency and increased facility value for the following reasons:
- The Smart Air Valve will save approximately 1 in of total system pressure, because most traditional VAV boxes consume 0.75 in or more for proper control and often are balanced at even higher values.
- Controlling airflows down to code-minimum ventilation levels will reduce overall fan power requirements exponentially and enable better usage of occupancy signals.
- The Smart Air Valve’s accurate integral airflow monitor will deliver capital and operating cost savings because no downstream duct pressure or flow sensors are needed, future facility modifications need software changes only, and design practices will be simplified with one size fits all modularity.
- The air-handler output will be controlled by the furthest LAV box, which will run at full open position and make AHU discharge pressure resets obsolete.
- Most LAV systems won’t need any reheat by avoiding over-ventilation, greatly reducing energy usage, capital costs, system complexities and above ceiling congestion.
Factory-fabricated mechanical systems
The optimized performance of today’s buildings is often limited by the knowledge of the installers, engineers, commissioning agents and system operators. For this reason, large-scale factory fabrication of entire mechanical central plant systems, along with factory commissioning, is necessary to ensure optimized system performance and equipment synergies, reduced capital costs, increased installation quality and minimized construction, commissioning and system turnover durations.
Applying acoustical physics to HVAC system components combined with nimble responsive and adaptive building controls is revolutionizing building designs with the largest impacts for data centers, critical facilities, tall buildings and showcase projects. A new paradigm of efficiency in the built environment is now available to address global climate challenges economically and pave the way for affordable generative buildings.
Gary Shamshoian, PE, LEED AP, BEAP, is the Smart Technology Director for BEST Technologies (Buildings Engineered with Smart Technology). BEST is creating innovative and energy-efficient HVAC systems based on low pressure drop technologies, and leading in the development of LAV systems.