Heat flux or thermal flux, sometimes also referred to as heat flux density, heat-flow density or heat flow rate intensity is a flow of energy per unit of area per unit of time.

A heat exchanger is a system used to transfer heat between two or more fluids.

In thermodynamics and engineering, a heat engine is a system that converts heat or thermal energy to mechanical energy, which can then be used to do mechanical work.

Heat is energy in transfer to or from a thermodynamic system, by mechanisms other than thermodynamic work or transfer of matter.

In thermal physics and thermodynamics, the heat capacity ratio, also known as the adiabatic index, the ratio of specific heats, or Laplace's coefficient, is the ratio of the heat capacity at constant pressure (CP) to heat capacity at constant volume (CV).

Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other earth materials.

The health and environmental impact of the coal industry includes issues such as land use, waste management, water and air pollution, caused by the coal mining, processing and the use of its products.

Water that is held by a dam and routed to penstock pipes that feed water turbines at a lower elevation.

A manifold that joins parallel loops to a common header pipe.

A HCNG dispenser is a type of fuel dispenser at a filling station that is used to pump HCNG into vehicles.

Hazardous waste is waste that has substantial or potential threats to public health or the environment.

Hazardous energy in occupational safety and health is any source of energy (including electrical, mechanical, thermal, chemical, hydraulic, and pneumatic sources of energy) that "can be hazardous to workers", such as from discharge of stored energy.

Hazard substitution is a hazard control strategy in which a material or process is replaced with another that is less hazardous.

Engineering controls are strategies designed to protect workers from hazardous conditions by placing a barrier between the worker and the hazard or by removing a hazardous substance through air ventilation.

Hazard elimination is a hazard control strategy based on completely removing a material or process causing a hazard.

Administrative controls are training, procedure, policy, or shift designs that lessen the threat of a hazard to an individual.

A hazard is a potential source of harm.

Harmonic filters are necessary for the elimination of the harmonic waves and for the production of the reactive power at line commutated converter stations.

Hard chrome, also known as industrial chrome, chrome gona, or engineered chrome, is used to reduce friction, improve durability through abrasion tolerance and wear resistance in general, minimize galling or seizing of parts, expand chemical inertness to include a broader set of conditions (such as oxidation resistance), and bulking material for worn parts to restore their original dimensions.

Half-life is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive.