Jargon Buster - H

A type of metal alloy. It is a high performance alloy.
Heat capacity
The amount of heat necessary to raise the temperature of a given mass by one degree. To calculate, it is the mass multiplied by the specific heat.
Heat engine
This is a mechanical device which converts heat to work. Common examples being; steam turbines and steam engines.
Heat exchanger
A device that transfers heat from one medium to another. They come in many different types and design. These include; plate heat exchangers, shell and tube heat exchangers, and plate and shell type.
Heat up time
This is the time taken to raise the temperature of a process from start-up to its normal working temperature.
Humidity is the measure of the amount of water held in given quantity of gas. Humidification is the process of increasing this water amount (the water is a vapour) in a gas. A typical steam injection humidifier will spray low pressure steam into an air stream to increase the moisture content (to the level desired by humidity stat).
This is used to describe the repetitive movement of a control valve from one position to another in response to an unstable control signal.
Heating, ventilation and air conditioning.
Hot water system.