Hydronic means "of, belonging to, or being" a heating or cooling system that uses a circulating fluid (such as water or vapour) to transport heat through a closed system of pipes.
Pumps, primary equipment (boilers, chillers), pipelines, fittings, coils, and control valves are all part of a hydronic system. A pump curve graphically represents the relationship between the flow and pressure created by a pump.
Water is used as the principal fluid in a hydronic HVAC system to transmit energy throughout the structure. The component that transfers energy from one place to another in the HVAC system is water, which is akin to blood in your body. Pumps move water in the same way as the heart circulates blood.
The use of liquid water, gaseous water (steam), or a water solution (typically glycol with water) as a heat-transfer medium in heating and cooling systems is known as hydronics (hydro- meaning "water").
A hydronic system is a cooling and heating system that uses water as one of its primary components. It offers a number of benefits, such as high efficiency, easy installation, and low noise.