If both heating and cooling heat transfer are beneficial, both can be considered, though this is usually denoted as a combined COP.** A cooling or heating element made of pipe or tube that is used to encourage heat transfer to (cooling) or from (heating) the fluid, to the air passing over/through it.Coils can be very large as with a centralized air handling unit (AHU) cooling coil, or much smaller in a localized terminal unit (VAV) coil.
The formation of vapor pockets (cavities) in a liquid.
Cavitation is a phase transition between the liquid and the vapor condition.
The vapor pockets can cause excessive rapid wear of pump impellers, as well as noise.
Suction diffusers, and proper system design and pump selection, can prevent this condition.
Removes heat from the chilled water loop and transfers it to the condenser water loop (if water cooled), or directly to the outside air (if air cooled).
Consists of a compressor, condenser, and evaporator (cooler).
Other hydronic systems that use pumps include (1) condensing water circuits to cooling towers, (2) water-source heat pumps, (3) boiler feeds, and (4) condensate returns.
Centrifugal pumps can also be found in water treatment and service water heating systems.** A key piece of mechanical equipment in chilled water systems.
The process of starting-up, verifying, and documenting the performance of buildings and systems to meet the owner’s specified requirements.
This can also include training operations personnel on long-term operation and maintenance of systems.
Devices that provides the primary force, to distribute and recirculate hot and chilled water, in a variety of space-conditioning and plumbing systems.