Environmental Engineering Reference
In-Depth Information
Carbon monoxide (CO):
A colorless, odorless gas produced by incomplete combus-
tion. Carbon monoxide is poisonous if inhaled.
Carbon output rate:
The amount of carbon by weight per kilowatt-hour of electric-
ity produced.
Carbon sequestration:
Process through which carbon dioxide is removed from the
atmosphere—for example, in forests through the process of photosynthesis.
During this process, carbon dioxide is taken up through plants' leaves and
incorporated into the plants' wood biomass.
Carbon sinks:
Carbon reservoirs and conditions that take in and store more carbon
(carbon sequestration) than they release. Carbon sinks can serve to partially
offset greenhouse gas emissions. Forests and oceans are common carbon
sinks.
Carnot cycle:
An ideal heat engine (conceived by Sadi Carnot) in which the sequence
of operations forming the working cycle consists of isothermal expansion,
adiabatic expansion, isothermal compression, and adiabatic compression
back to its initial state.
Cascading heat:
A process that uses a stream of geothermal hot water or steam to
perform successive tasks requiring lower and lower temperatures.
Casing:
Pipe placed in a wellbore as a structural interface between the wellbore and
the surrounding formation. It typically extends from the top of the well and
is cemented in place to maintain the diameter of the wellbore and provide
stability.
Cast silicon:
Crystalline silicon obtained by pouring pure molten silicon into a ver-
tical mold and adjusting the temperature gradient along the mold volume
during cooling to obtain slow, vertically advancing crystallization of the
silicon. The polycrystalline ingot thus formed is composed of large, rela-
tively parallel, interlocking crystals. The cast ingots are sawed into wafers
for further fabrication into photovoltaic cells. Cast-silicon wafers and rib-
bon-silicon sheets fabricated into cells are usually referred to as
polycrys-
talline photovoltaic cells
.
Cathode:
The electrode at which reduction (a gain of electrons) occurs. For fuel cells
and other galvanic cells, the cathode is the positive terminal; for electrolytic
cells (where electrolysis occurs), the cathode is the negative terminal.
Cation:
A positively charged ion.
Cells:
Refers to the unencapsulated semiconductor compounds of a module that con-
vert solar energy to electricity.
Cells to OEM (non-PV):
Cells shipped to non-photovoltaic original equipment
manufacturers such as boat manufacturers, car manufacturers, etc.
Cellulose:
The main carbohydrate in living plants. Cellulose forms the skeletal
structure of the plant cell wall.
Cellulosic ethanol:
Ethanol produced from cellulosic and hemicellulosic biomass.
Chained dollars:
A measure used to express real prices. Real prices are those that
have been adjusted to remove the effect of changes in the purchasing power
of the dollar; they usually reflect buying power relative to a reference year.
Prior to 1996, real prices were expressed in constant dollars, a measure based
on the weights of goods and services in a single year, usually a recent year. In
