In commercial buildings, space heating, cooling, and ventilation account for 34 percent of energy used on site and 31 percent of primary energy use, according to the U.S. Department of Energy. The Green Proving Ground program selected multiple innovative HVAC technologies to investigate their usefulness, effectiveness, and applicability across the GSA portfolio.
Preliminary Technology Assessments
Chilled beams, which take advantage of water’s more efficient thermal transfer rate, promise energy savings of up to 30 percent, as well as reductions in space (no ductwork) and O&M costs (there are fewer moving parts).
GSHP systems rely on the earth’s relatively constant subsurface temperatures to effect heat transfer to and from buildings. They save energy (25 to 50 percent, compared to conventional systems), space, and reduce O&M costs significantly.
By extracting heat from waste gases, condensing boilers can achieve up to 98 percent thermal efficiency. Integrated on-demand project design yields additional energy savings.
Magnetic bearing compressors are essentially frictionless, and their speed is controlled by a variable frequency drive. Eliminating the friction in these compressors greatly increases their efficiency at part-load conditions, reducing space-cooling energy by an average of 40 percent.
Using refrigerant as the heating and cooling medium, VRF systems connect a single outdoor condensing unit to multiple, individually controlled indoor evaporators. Energy savings of up to 55 percent are predicted over comparable unitary equipment.
By treating the chilled water plant as an optimized complete system, variable-speed chiller plant control technology saves energy, water, and even provides the possibility of an overall plant-size reduction.