Combined heat and power (CHP) systems can help facilities cut energy consumption, as well as avoid thousands of tons of carbon dioxide emissions. To honor some of the highest-performing CHP facilities, the EPA has selected three projects as the winners of the 2015 ENERGY STAR Combined Heat and Power award for use of highly efficient CHP systems.
The technology can achieve operating efficiencies between 69-75% – much higher than the efficiency of producing the two separately, which is typically less than 50%. Additionally, the systems can provide improved reliability during power outages for campuses such as hospitals and universities. The EPA’s winners include Bowdoin College in Brunswick, ME, Pepco Energy Service, and Thermal Energy Corporation.
Bowdoin College’s CHP system uses an oil- or natural gas-fired boiler and a 630 kW steam turbine that operates at almost 87% efficiency and uses 12% less fuel than conventional heat and power production. The system provides space heating and hot water to 1.5 million square feet across 56 campus facilities while avoiding 1,000 tons of carbon dioxide emissions annually.
The system employed by Pepco Energy Service uses a 5.2 MW gas turbine and a heat recovery steam generator to provide chilled water for air conditioning and steam for space heating for a district energy system serving seven casinos and Atlantic City’s Boardwalk Hall. The system has an operating efficiency of over 76% and uses 23% less fuel than grid-supplied energy and steam production.
Thermal Energy Corporation operates a CHP system on the campus of the Texas Medical Center, which uses a 47 MW gas turbine and a heat recovery steam generator capturing heat from the turbine’s exhaust. With buildings not relying on on-site electric chillers for air conditioning, the necessary emergency generator capacity can be reduced up to 50%. The system operates at 68% efficiency while using around 30% less fuel than using grid-supplied electricity and conventional steam production.