Common terms used in Boilers and Heaters

         heat pipe:   A compact heat exchanger consisting of a pressure vessel and a bundle of heat pipes. The heat pipes extract heat from a hot fluid and transport it into a pressure vessel where steam is generated.

header box:   The internally insulated structural compartment, separated from the flue gas stream, which is used to enclose a number of headers or manifolds. Access is afforded by means of hinged doors or removable panels.

header or return bend:   The common term for a 180-degree cast or wrought fitting that connects two or more tubes.

hot face layer:   The refractory layer exposed to the highest temperatures in a multilayer or multicomponent lining.

Heat Recovery Steam Generator (HRSG)

A system in which steam is generated and may be superheated or water heated by the transfer of heat from gaseous products of combustion or other hot process fluids.

Eutectic phase / point, Hpyoeutectic Alloy, Hypereutectic Alloy

Eutectic: An Eutectic phase diagram is obtained when the melting points of the two components of phase diagram are neither very close nor much different.

Hpyoeutectic Alloy - Alloys to the left of eutectic point
Hypereutectic Alloy - Alloys to the right of eutectic point

Hybrid electric vehicle (HEV)

Features a parallel drivetrain architechture, with a battery-driven electric motor and an internal combustion engine coupled into the same transmission. Usually features energy recovery technology to recharge the battery during operation

Heat rate

A ratio of incoming fuel energy (in BTU) to outgoing electrical energy (in kWh). Heat rates are a convenient way to assess the efficiency of a power plant. These rates will be larger than one (normally around the magnitude of 10,000) and indicate increases in effiency as the number goes down.

Heat Recovery Steam Generator (HRSG)

A specialized heat exchanger often used in power generation. These devices will produce steam for a specific process or to drive a steam turbine.

Heat Capacity (Cp) of the substance.

The ratio of the heat (Q) added to or removed from a substance to the change in temperature (∆T) produced is called the heat capacity (Cp) of the substance.

Humidity

Humidity is the amount of moisture (water vapor) in the air.

HRSG (Heat Recovery Steam Generators)

• HRSG is also a boiler which uses the heat rejected from other process or turbines to produce steam. Some HRSGs also have auxiliary firing facility.

HRSG (Heat Recovery Steam Generators)

• HRSG uses the heat rejected from other process or turbines to produce steam.

Hypermarket

A hypermarket is a multi-brand, multi-department store under one roof meant to offer cost-effective shopping for household requirements.

Hot Money

Money that moves across country/borders in response to interest rate differences and that, which moves away when the interest rate differential disappears.

Hierarchy

The line of authority in an organization that runs in order of rank from top management to the lowest level of the enterprise.

Hedge

Any action taken by a buyer / seller to protect his interest by spreading / lowering risk due to a change in price.