Valves and flow equipment for air conditioning and chilled water circuits

Chilled water air conditioning systems are used in office buildings, hotels, hospitals, shopping centres, industrial areas and technical facilities. Their operation is based on chilled water production by chillers, distribution through pumps and pipework, and cooling delivery through fan coils, air handling units, heat exchangers and central air treatment units.

Valves in chilled water and glycol circuits are selected according to flow rate, supply and return temperature, operating pressure, differential pressure, fluid type, branch function and control system requirements. Correct sizing helps limit insufficient flow to terminal units, hydraulic instability, valve noise and temperature deviations in variable-demand loads.

Typical applications

• Chilled water circuits on chillers, pumping stations and distribution networks.
• Glycol circuits for lower operating temperatures or outdoor installations.
• Supply and return lines to fan coils, AHUs, air conditioning units and heat exchangers.
• Condenser water networks on water-cooled chillers, condensers and cooling towers.
• Filling, draining, venting, bypass and recirculation lines.
• Hydraulic balancing points on branches, headers and terminal units.
• Variable-flow circuits with differential pressure regulation.
• Auxiliary automation, instrument and actuator networks.

Equipment selection criteria

• Design flow rate, minimum flow rate and allowable pressure drop.
• Chilled water or glycol supply and return temperature.
• Operating pressure, design pressure and valve differential pressure.
• Material compatibility with water, glycol, treatment chemicals and condensation conditions.
• Isolation, control, non-return, balancing or protection function.
• Valve behaviour at part load and variable flow conditions.
• Modulating control, position indication, response time and fail position requirements.
• Connection to BMS, PLC, DDC controller or local automation panel.
• Access for inspection, branch isolation, cleaning and maintenance.

Indicative equipment

• Isolation valves for chilled water, glycol and condenser water circuits.
• Two-way or three-way control valves for flow and temperature regulation.
• Balancing valves for hydraulic adjustment of branches and terminal units.
• Differential pressure regulators for stabilising variable-flow circuits.
• Check valves for pump protection and backflow prevention.
• Safety and relief valves for closed circuits, vessels and heat exchangers.
• Line strainers for protection of control valves, pumps, heat exchangers and instruments.
• Air vents, drain valves and network drainage equipment.
• Electric and pneumatic actuators for connection to automation systems.

For each application, the cooling load, flow rate, temperature difference, differential pressure, terminal unit type, water quality, available installation length and control logic should be reviewed. These data define the valve type, nominal size, pressure class, construction materials, sealing arrangement and suitable actuation method.