hydronics

Hydronics is the technology of using circulated liquid to transfer heat or cold in buildings and industrial processes. In a hydronic system, water or another working fluid is heated or cooled at a central source and circulated through a network of pipes to emitters such as radiators, baseboard convectors, or radiant floors. The system can be closed, with the same fluid continuously circulating, or open, drawing heat from a source that is exposed to the environment.

A typical hydronic installation includes a heat source (such as a boiler, heat pump, or solar thermal system), a distribution system (pumps, pipes, valves, and manifolds), and heat emitters (radiators, panel radiators, or radiant floor and ceiling systems). Controls such as thermostats, zone valves, and variable-speed pumps regulate temperature and flow. In some industrial settings, heat exchangers and storage tanks are used to manage energy transfer and supply.

Common configurations include hot water heating for residential and commercial buildings, radiant floor heating, and hydronic cooling using chilled water circulated through air handlers or radiant slabs. Most modern systems are closed-loop, though open-loop configurations exist in certain climates or applications.

Fluids used are typically potable water, with glycol or other antifreeze solutions added for freezing protection. Water treatment and corrosion inhibitors are often used to prevent scaling, corrosion, and microbial growth. System materials commonly include copper, steel, and plastics such as PEX or CPVC. Maintenance involves checking for leaks, purging air, ensuring proper pressure, and servicing pumps, valves, and controls.

Hydronics offers efficient heat transfer and flexible zoning, and it integrates well with renewable energy sources. Its drawbacks can include higher upfront costs, space needs for equipment and piping, and the need for ongoing maintenance and leak management.