Hydronic

Hydronic: A ventilation system using heated or cooled water pumped through a building.
Hydrophilic: Having a strong affinity for water.
Hydrophobic: Having a strong aversion for water.

or HRS Hazardous Waste Heat Capture Technology Heat Compression Hexanone Hopenhagen Household Hazards Hybrid Car Hydroelectric Power Hydrofluorocarbons or HFCs Hydrogen Fuel Cells Hydrology Hydronic ...

See also: Hydrology, Compounds, Recycling, Hazardous waste, Hazardous chemical