Ice Bank
Refrigerating systems that form a bank of ice around the evaporator to provide reserve cooling capacity.
Ice melting Effect
Amount of heat absorbed by melting ice at 32F (0°C) is 144 Btu per pound of ice or 288,000 Btu per ton.
Identification Plate
Provides information such as manufacturer, part number, and specification. Frequently mounted on the outside housing of motors and compressors.
Idler
Pulley used on some belt drives to provide belt tension and to eliminate belt vibration.
Ignition System
Method of lighting a furnace
Ignition Transformer
Transformer designed to provide a high-voltage current. Used in many heating systems.
Immersion Freezing
Freezing of articles by dipping them in to liquid refrigerant.
Impedance
Opposition in an electrical circuit to the flow of an alternating current that is similar to the electrical resistance to a direct current.
Impeller
Rotating part of a pump.
Incandescent
Glowing due to heat.
Incomplete Combustion
Combustion with insufficient oxygen.
Indoor Air Quality(IAQ)
The status of indoor air as measured by numerous factors: temperature, humidity, air flow, pollutants, occupants etc.
Induced Magnetism
Ability of a magnetic filed to produce magnetism in a metal.
Inductance
Inducing voltage in a coil due to the change in the rate of flow of current in the coil.
Induction Motor
An ac motor that operates on the principle of a rotating magnetic field. The rotor has no electrical connection, but received electrical energy by transformer action from field windings.
Inductive Reactance
Electromagnetic induction in a circuit creates a counter or reverse emf as the original current changes. It opposes the flow of alternating current.
Infiltration
Passage of outside air into building through doors, cracks, windows and other opening.
Infrared
Invisible rays just beyond red in the visible spectrum.
Inhibitor
Substance that prevents a chemical reaction.
Inspection
To examine and compare with established guidelines
Instrument
Used broadly to denote a device that has measuring, recording, indicating, or controlling abilities.
Insulation, Electric
Substance that has almost no free electrons.
Insulation, Thermal
Material that is a poor conductor of heat: used to retard flow of heat through wall.
Integrated Circuit
A circuit that incorporates multiple transistors and other semiconductors to a single circuit, sometimes called a "chip."
Integrated Circuit Board
Electronic circuit made from transistors, resistors, etc., all placed into a package referred to as a "chip," since all circuits are on one base of semiconductor material.
Interlocked
Controlled by a switch that does not allow a component to operate when a hazardous condition exists.
Intermittent Absorption System
Refrigeration system using a kerosene burner and ammonia, normally used in situations where gas and electricity is not available.
Intermittent Cycle
Cycle which repeats itself a varying time intervals.
Interstate Commerce Commission (ICC)
Government body that controls the design and construction of pressure containers.
Intrinsic Semiconductor
Material that is neither conductor nor insulator, such as silicon and germanium, often used in temperature sensing devices.
Ion
Group of atoms or a atom which is electrically charge.
IR Drop
Electrical term indicating the loss in a circuit expressed in amperes times resistance (IxR) or voltage drop.
Isothermal
Changes of volume or pressure under conditions of constant temperature.