Author Description

Many heating, ventilation and air conditioning (HVAC) systems use heated or cooled water to provide comfortconditions within buildings. Owners, managers and operators rely on these hydronic systems to operate their buildings,to support their processes, or to enable other systems.Hydronic systems in HVAC are designed to deliver pre-calculated amounts of heated or cooled water down sometimescomplexpiped distribution systems, all controlled by dynamic and responsive comfort controls. To have any chanceof performing as the designer intended, these systems must be tested, adjusted and balanced (TAB) after installation -and, importantly, the water distribution quantities must be measured, adjusted and verified against the design.TAB is the process of making an HVAC system perform as efficiently as the designer intended, and it helps HVACsystems operate more effectively, providing maximum comfort at the lowest energy cost possible.The performance of any equipment in centralised HVAC systems is dependent on many parameters, but sufficientwater flow is one of the most significant.To understand the best way to approach a system water balance, the TAB technician must understand how the systemis intended to operate. This knowledge transfer is the responsibility of the system designer, and it is important that thedesigner clearly communicates the intended operation and performance of the system, and how it is to be verified.This is the starting point of the TAB process.This application manual considers the entire water-balancing story. Starting from an explanation of where TAB sits inthe overall commissioning process, the manual takes us through the fundamentals of water flow and measurement,what needs to be done before TAB, how to approach a water balance for a range of different system types, and what todo after the water balance has been successfully completed, including recording and witnessing results.