A buffer vessel, also known as a buffer tank, is a component of a hydronic heating or cooling system that helps regulate the system temperature. Installing a buffer vessel improves system efficiency by reducing how frequently the system needs to turn on and off.
Short cycling is a term used to describe the problem of a heating or cooling system turning on and off frequently in response to inconsistent demand. Short cycling is more common when the demand on the water heater or heat pump system is much lower than the system capacity. Short cycling increases energy costs and decreases maintenance intervals.
In a chilled or hot water system, a buffer vessel solves this problem by acting as a holding tank for precooled or preheated water. When there is a demand on the system, it pulls from the buffer vessel and the refrigeration or heating unit only has to turn on when the demand exceeds the volume of the buffer vessel.
A buffer vessel may also be installed within a heat pump system. The buffer vessel may be equipped with heat exchange coils that increase the thermal exchange rate in both heating and cooling modes.
In commercial applications, a buffer tank may be installed between multiple heating or cooling units to reduce the demand on the individual units, while delivering a consistent supply of temperature-regulated water to the system.