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
The Green Proving Ground program, in association with federal laboratories, is currently subjecting the following technologies to real-world measurement and verification in GSA buildings. Preliminary technology assessments are available below as PDFs. Findings from these investigations will be available by 2015.
Central Plant Optimization Strategy > This central plant control technology is designed to optimize energy use in chilled water systems. To reduce energy consumption, chillers, cooling towers, and associated pumps are operated as a single system. In combination with the necessary Variable Frequency Drive (VFD) equipment, this technology applies a control algorithm to maintain optimal differential system pressure, reducing pumping energy and equipment runtime.
High Efficiency HVAC > High efficiency heating, ventilating, and air conditioning (HVAC) units are a new class of rooftop unit (RTU) that can reduce building energy needs by half without reducing HVAC effectiveness. Blowing conditioned air through central shafts and ceiling spaces, the new technology incorporates variable speed controls on the refrigerant compressor, valves, and fans to efficiently heat or cool designated spaces as desired. The high efficiency HVAC RTUs capture and reuse heat, cold, and humidity from a building’s exhaust air and utilize waste heat from the compressors to reheat air that has been purposely over-cooled.
Modular Absorption Chiller > Modular micro-channel absorption chillers are powered by readily available alternative or waste heat sources (excess solar thermal, heat exhaust, or cheaper natural gas) instead of electricity, and can directly replace legacy heating, ventilation, and air conditioning (HVAC) chillers. These modular absorption chillers provide an extremely efficient method of converting heat into cold, and represent a potentially revolutionary new type of HVAC system. In addition to air conditioning, this technology can also be dual-purposed for space heating.
Socially Driven HVAC > The socially driven web-based thermostat is a heating, ventilation, and air conditioning (HVAC) control system that enables office building occupants to control their thermal environment through a mobile device or web page. The software collects and processes occupant preferences in a “social networking /gaming” environment; artificial intelligence technologies then calculate the most efficient way to satisfy those preferences using the building’s HVAC system.
Variable-Speed Chiller Plant Control > 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.
Wireless Pneumatic Thermostat > The Wireless Pneumatic Thermostat provides standard pneumatic thermostats with networked Direct Digital Control (DDC) functionality. Wireless Pneumatic Thermostats can operate as a stand-alone system or integrate with an existing Building Automation System.
Wood-Pellet Biomass Boiler > Biomass boilers use agricultural, forest, urban, and industrial residues and waste to generate heat. Advances in biomass boilers have delivered efficiencies of 90% or better, comparable to state-of-the art gas-fired condensing boilers. The biomass boiler technology being evaluated uses wood pellets, which are more standardized and denser than wood chips.