Advances are being made to air movement and ventilation systems, especially in high-efficiency variable air volume (VAV) systems. This article dives into new regulations and technology, and how sweeping changes are slated to change the entire cooling industry.
Conditioned air needs to be moved. That hasn’t changed since 1842, when Dr. John Gorrie initially discovered mechanical refrigeration in an effort to cool the rooms of his yellow fever patients. Forty years later, Dr. Schuyler Wheeler was credited with the invention of the electric fan. High-efficiency air movement and ventilation have come a long way since then, though, and current trends are pointing toward unprecedented technological advances in this sector.
Driven by increased consumer awareness and the demand for high IAQ, advances have been made to air movement and ventilation systems, especially in high-efficiency variable air volume (VAV) systems, according to the Air Movement and Control Association Intl. (AMCA). Referred to by AMCA as high-performance air systems (HPAS), the association said that in the past 10 years, it doesn’t think that any other type of ventilation system has seen more innovation or greater advances than VAV.
“Through application of best practices and the use of modern components — such as electronically commutated motors (ECMs) — a new generation of VAV system has emerged: one that includes fan-powered VAV terminal units with modulating fans that track cooling demand in a space and automatically reset based on changes,” said Michael Ivanovich, senior director, Global Affairs, AMCA. “For example, static-pressure and supply-air-temperature reset, along with significant improvements in economizer control and reliability, have slashed energy consumption.”
Ivanovich also pointed out that part-load efficiencies have increased 50 percent with the addition of variable-speed technology for fans and compressors in chiller and rooftop equipment.
“Fan arrays, direct-drive fans, and advanced motors have reduced air-handler maintenance and unit size and driven up efficiency, while pretreatment, series energy recovery, bypass, and heat recovery have cut the amount of primary energy used for reheat to nearly zero,” he said. “What’s more, dehumidification of outside air before it is introduced to the mixed airstream provides the energy advantage of separated treatment with the maintenance advantages of a central filtration and cooling system.”
Increased awareness of the fan system effect is expected in this market sector as well. AMCA defines this as a result of insufficient duct length before transitions at the inlet and/or outlet of a fan. It has negative effects on energy, acoustics, and service life.
“AMCA is working with the International Organization for Standardization, the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA), and stakeholders to turn recent research into new guidance, education, and tools to quantify inlet and outlet fan system effect at the design phase,” said Ivanovich.