ABSORBER -- The absorber is that part of the solar
collector which receives the incident radiant energy
and transforms it into heat energy.
ABSORPTIVE COATING -- Covers the absorber
plate and improves its ability to absorb energy without
reflecting it away.
ACTIVE SOLAR SYSTEM -- A system that traps
the sun’s energy and utilizes a mechanical subsystem
to move that energy to its point of intended use for
water heating, space heating and possibly space
cooling.
AQUASTAT -- Thermostat which measures liquid
temperatures.
BATCH -- Black tank that serves as both collector
and storage tank. Can be enclosed, with one side
glazed.
BATTERY -- A chemical storage device for DC
electricity. Batteries in solar electric systems are
normally of the lead acid type, similar to car batteries
but made for deep cycling.
BOS -- In photovoltaic systems - balance of system
refers to all other unspecified devices and materials
needed to complete a solar electric system
BREADBOX -- Black tank enclosed in an insulated
box that is glazed on one side. Tank serves as both
collector and storage tank.
BRITISH THERMAL UNIT (BTU) -- The amount
of heat required to raise the temperature of one pound
(one pint) of water, one degree Fahrenheit.
CENTRIFUGAL PUMP --
A type of pump which
has blades that rotate and whirls the fluid around so
that it acquires sufficient momentum to discharge
from the pump body. The fluid is thrown outward by
centrifugal force.
CHARGE CONTROL --
Also called a charge
regulator, it keeps batteries in a solar electric system
from over charging.
CLOSED LOOP SYSTEM -- System of which no
part is vented to the atmosphere or fed with fresh
liquid. The system liquid is recalculated.
COIL-IN-TANK HEAT EXCHANGER -- A coil in
a water tank. Most commonly used on solar water
heating systems.
COLLECTOR LOOP -- The part of the solar system
that has solar collectors. The collector loop may be
piped and include other components.
COLLECTOR TILT -- The angle between the
horizontal plane and the solar collector plane.
COUNTERFLOW HEAT EXCHANGER -- A selfcontained
heat exchanger in which the two substances
flow in opposite directions.
DEEP CYCLE BATTERY --
See Battery
DEGREE DAY -- The difference between 65 degrees
F. and the mean temperature - the higher the heating
degree days at any location, the colder the winter.
DIFFERENTIAL CONTROLLER --
Control
which measures the difference between the collector
and the tank temperatures.
DIFFUSE RADIATION -- Solar radiation received
after its direction has been changed by reflection and
scattering in the atmosphere.
DIRECT BEAM RADIATION -- Solar radiation
which is not scattered by dust or water droplets. It is
capable of being focused and casts shadows.
DIRECT PUMP -- Solar domestic hot water system
that uses existing water pressure to fill the collectors.
DOUBLE GLAZED -- Covered by two panes of
glass or other transparent material.
DOUBLE WALL SEPARATION -- Heat
exchangers utilizing non-potable heat transfer fluids
separated from the potable water system by use of two
walls between the fluids.
DRAIN-DOWN SYSTEM -- A liquid solar
collection system in which the collector fluid drains
down when the collector system pump is not
operating.
DRAINBACK SYSTEM -- Liquid system that only
fills the collector when the temperature differential is
appropriate. The water that is circulated through the
collectors is stored in a reservoir.
EXPANSION TANK -- Takes up the overflow
created when the heat transfer fluid expands.
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FLAT PLATE COLLECTOR --
Converts the sun’s
radiation into heat on a flat surface within a simple
box. Does not use reflecting surfaces or lens
arrangements to concentrate the sun’s energy.
GLYCOL --
(Propylene Glycol) An antifreeze, heat
transfer fluid that is circulated through liquid type
collectors.
HEAD -- For pumping considerations, the vertical
rise to the highest point in the system. Does not
include the horizontal run to that point. Head losses
are important for determining flow rates and pump
sizes.
HEADERS -- Main passages through which the heat
transfer medium enters into or exits from the
collector. Also called manifolds.
HEAT EXCHANGER -- A device that is used to
transfer heat between fluids and gasses through an
intervening metal surface.
HEAT TRANSFER MEDIUM -- Air or liquid that
is heated and used to transmit energy to its point of
use.
INDIRECT SYSTEM -- A solar heating or cooling
system in which the solar heat is collected outside the
building and transferred inside using
ducts or piping, and usually, fans or pumps.
INVERTERS -- An electrical device that converts
DC electricity to AC electricity to use normal
household appliances. Modified sine wave inverters
are good for stand alone systems - pure sine wave
inverters are required for electricity as pure as the
electrical utility grid.
LIQUID COLLECTOR -- A collector that uses a
liquid as the heat transfer medium.
MEAN DAY TEMPERATURE -- Average of the
minimum and maximum daily temperatures used to
determine the number of degree days.
OPEN LOOP SYSTEM -- Some part of the
system is vented to the atmosphere, or the system
contains fresh or changeable water.
PASSIVE SOLAR HEATING -- Solar heating of
a building accomplished by architectural design
without the aid of mechanical equipment.
PHOTOVOLTAICS --
Solar
modules used to
convert solar energy into electricity also known as
solar electric panels.
POTABLE -- Drinkable water.
PUMP STAGING -- A method of placing two or
more pumps together to increase flow or overcome
head losses. Series-staged pumps are placed in the
same line and increase the head. Parallel-staged
pumps are placed in two separate lines, feeding a
common line and increase the flow rate.
RISERS -- Flow passages (pipes or channels) that
distribute heat transfer fluid across the absorber
panel in a collector.
SENSOR --
Sensing device that changes its
electrical resistance according to temperature. Used
in the control system to generate input data on
collector and storage tank temperatures.
SOLAR COLLECTORS -- A solar collector is a
device designed to absorb incident solar radiation
and to transfer the energy to a fluid passing through
it.
SOLAR RADIATION -- The sun’s energy that
comes to earth in the form of direct, diffuse and
reflected rays.
SOLAR STORAGE -- A water tank or rock bed
that absorbs collected solar energy and holds it until
needed.
THERMOSTAT -- Temperature sensing device
which is used to switch mechanical equipment on
and off.
THERMOSYPHON -- Passive solar systems that
rely on the natural convection of liquids to collect
energy. Designed with the tank above the collection
surface.
TRANSFER FLUID, HEAT -- The heat transfer
fluid is the medium, such as air, water or other
fluid, which passes through the solar collector and
carries the absorbed thermal energy away from the
collector.
UNGLAZED COLLECTOR -- A collector with
no transparent cover plate. |
