Below are definitions of some of the common terminology and abbreviations used on this website.
ACEEE - American Council for an Energy-Efficient Economy.
ARRA - American Recovery and Reinvestment Act of 2009.
CHP - Combined heat and power; CHP systems are also known as cogeneration, trigeneration, clean heat and power, and combined cooling, heating, and power.
DG - Distributed generation; generating power on-site or near site. CHP typically is considered a DG system with recovery of thermal energy that otherwise would be wasted.
DOE - U.S. Department of Energy.
EE - Energy efficiency.
EEA - Energy and Environmental Analysis, Inc.
EERE - Energy Efficiency and Renewable Energy (U.S. DOE).
EPA - U.S. Environmental Protection Agency.
ESCO - Energy service company.
ESPC - Energy savings performance contract.
HVAC- Heating, ventilating, and air conditioning.
IAQ - Indoor air quality.
ICF - ICF International.
ITP - Industrial Technologies Program (U.S. DOE).
RE - Renewable energy.
SE-CEAC - US DOE Southeast Clean Energy Application Center.
USCHPA - U.S. Clean Heat and Power Association.
W/kW/MW/GW – Watt/kilowatt/megawatt/gigawatt is a unit for measuring power. A kilowatt is one thousand Watts. A megawatt is one million Watts. A gigawatt is one billion Watts.
WHR - Waste heat recovery.
Absorption Chiller - Water chiller based on absorption of refrigerant vapor into a liquid solution, pumping of the solution to elevated pressure, and the release (desorption) of refrigerant vapor through addition of heat; absorption chillers require less energy because the pumping process involves a liquid; direct-fired chillers employ natural gas burners, indirect-fired chillers use steam or hot water from a separate process (such as the hot exhaust gases from electric generation); single-, double-, and triple-effect chillers employ multiple stages of desorption and internal use of waste heat to boost efficiency.
Demand Charge - Charges for the use of electricity based on the maximum power requirement, electrical demand, during a specified period of time, typically a month ($/kW.
Desiccant - A solid or liquid material with an affinity for absorbing water molecules.
Engine-Generator - Electrical generator using a reciprocating, Stirling , or rotary engine.
Enthalpy Wheel - Heat exchanger rotating through building supply and exhaust air flows to transfer energy from one air stream to the other.
Evaporative Cooling - Lowering the temperature of air through the evaporation from a water or wetted membrane; direct evaporative cooling adds water to the supply air while indirect evaporative cooling adds water to the exhaust air and incorporates a heat pipe or thermal wheel for indirect cooling of the supply air.
Fuel Cell - Device for producing electricity from hydrogen using an electrochemical process rather than conventional combustion process to turn a traditional electric generator.
Heat Wheel - Heat exchanger rotating through building supply and exhaust air flows to transfer heat from one air stream to another.
Latent Cooling Load - Amount of cooling required to reduce humidity of air in conditioned space to specified level for comfort.
Line Losses - Electric energy lost as heat in power transmission lines.
Microturbine - Turbine-engine driven electrical generator with output power under 300 kW.
Power Reliability - Percent or fraction of the time (hours) power is available in a year (8760 hours).
Real Time Pricing - Charges for electrical demand and consumption based on instantaneous cost of production and distribution as opposed to fixed rates or fixed time-of-day rates.
Sensible Cooling Load - Amount of cooling required to reduce the temperature of air in the conditioned space to a specified level for comfort.
Thermal Energy - Total amount of heat contained in a substance or required to achieve a task.
Thermal Wheel - Heat exchanger rotating between two air flows to transfer heat from one to the other.
Ton Or Refrigeration Ton - Quantity of cooling available from melting 2000 pounds of ice; 12,000 Btu/h or 3.1413 kW.
Vapor Compression Air Conditioning - Cooling system based on compression of a gaseous refrigerant to a high pressure, and heat transfer with changes of state (i.e. Liquid and vapor) to produce useful heating or cooling.
Waste Heat - Portion of the energy input to a mechanical process which is rejected to the environment.