TERMS & DEFINITIONS

Absorption Chiller

An absorption chiller uses steam or hot water to generate chilled water. When combined with a CHP system it provides a means of utilizing the waste heat collected during non-heating seasons. By producing chilled water, the CHP system also reduces the amount of electricity required by electric cooling equipment.

Biogas

Biogas typically refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. Also known as digester methane or landfill gas.

Chiller

A chiller is a device that produces chilled water using electricity (mechanical) or thermal energy (absorption). This chilled water can serve facility cooling or process loads. By producing chilled water, the CHP system also serves to reduce the amount of electricity required by electric cooling equipment.

CHP

Combined Heat & Power or CHP is on-site electricity generation that utilizes the heat that would otherwise be wasted to provide useful thermal energy in the form of hot water or steam which can be used for space heating, domestic hot water and industrial processes. Process can also involve cooling and chilled water, but may be referred to as CCHP.

Combined Heat & Power (CHP)

Combined Heat & Power or CHP is on-site electricity generation that utilizes the heat that would otherwise be wasted to provide useful thermal energy in the form of hot water or steam which can be used for space heating, domestic hot water and industrial processes. Process can also involve cooling and chilled water, but may be referred to as CCHP.

Cogen

A shortened form of the word cogeneration.

Cogeneration

Cogeneration is on-site electricity generation that utilizes the heat that would otherwise be wasted to provide useful thermal energy in the form of hot water or steam which can be used for space heating, domestic hot water and industrial processes.

Combined Cooling Heat and Power (CCHP)

CCHP or Combined Cooling Heat & Power, like CHP, is on-site electricity generation that utilizes the heat that would otherwise be wasted to provide useful thermal energy in the form of hot water, chilled water or steam which can be used for space heating, cooling, domestic hot water and industrial processes. The extra “C” for “Cooling” is often used when specifying a CHP project that includes air conditioning functions.

CCHP

CCHP or Combined Cooling Heat & Power, like CHP, is on-site electricity generation that utilizes the heat that would otherwise be wasted to provide useful thermal energy in the form of hot water, chilled water or steam which can be used for space heating, cooling, domestic hot water and industrial processes. The extra “C” for “Cooling” is often used when specifying a CHP project that includes air conditioning functions.

Combustion Turbine (CT)

Conventional combustion turbine (CT) generators typically range in size from about 500 kW up to 25 MW for distributed generation applications, and up to approximately 250 MW for central power generation. They are fueled by natural gas, oil, or a combination of fuels (“dual fuel”). Modern single-cycle combustion turbine units typically have efficiencies in the range of 20 to 45% at full load. Efficiency is somewhat lower at less than full load.

Gas Turbine

A gas turbine is a combustion engine that can convert natural gas or other liquid fuels to mechanical energy. This energy then drives a generator that produces electrical energy. To generate electricity, the gas turbine heats a mixture of air and fuel at very high temperatures, causing the turbine blades to spin. The spinning turbine drives a generator that converts the energy into electricity.

Grid

A term used as a short hand reference to the utility power grid.

Internal Combustion Engine

A reciprocating, or internal combustion (IC), engine converts the energy contained in a fuel into mechanical power. This mechanical power is used to turn a shaft in the engine. A generator is attached to the IC engine to convert the rotational motion into power. They are available from small sizes (~5KW) to large generators (~10 MW). Reciprocating engines use commonly available fuels such as gasoline, natural gas, and diesel fuel.

Microgrid

A series of onsite and smaller generation assets assembled to serve a cluster or series of loads. These assets work in a coordinated manner with each other and the utility grid to provide the greatest reliability and economic value to the site.

Microturbine

Microturbines are distributed generation technology being used for stationary energy generation applications. They are a type of combustion turbine that produces both heat and electricity on a relatively small scale.

Net Metering

The ability for an onsite generation asset to produce more power than is required at that specific time. The excess power is used to reduce purchases at other times and the final billing is the net of imports and exports.

Distributed Generation (DG)

Increased demands on the nation’s electrical power systems and incidences of electricity shortages, power quality problems, rolling blackouts, and electricity price spikes have caused many utility customers to seek other sources of high-quality, reliable electricity. Distributed Generation are small-scale power generation sources located close to where electricity is used (e.g., a campus or business), provide an alternative to or an enhancement of the traditional electric power grid.

On-site Generation

Onsite Generation is the production of electricity at the point of use rather than is a large central station. This eliminates the requirements for transmission and distribution networks external to the facility.

Prime Mover

Generally an engine, turbine or microturbine, the prime mover is responsible for converting the fuel source into electricity.

Separate Heat Power (SHP)

A Separate Heat Power System, or SHP, is a traditional configuration where by a facility obtains its electricity from the electric grid, and separately produces heat from a boiler using its own fuel source.

SHP

A shortened form of the Separate Heat and Power

Trigen

A shortened version of the word trigeneration.

Trigeneration

Trigeneration is on-site electricity generation that utilizes the heat that would otherwise be wasted to provide useful thermal energy in the form of hot water, chilled water or steam which can be used for space heating, cooling, domestic hot water and industrial processes. Can also be referred to as CCHP or Combined Cooling Heat & Power.