HVAC engineers

Pumping Configurations When it comes to chiller plant design, there's a surprising amount of research and experimentation that went into it. Decades of trial and error took the entire industry, worldwide, in quite a few different directions. The oldest chilled water systems had a pump for every chiller. The purpose of the pump was to overcome pressure loss in the piping and supply the required flow rate to the cooling coils. The general rule of thumb was that chillers are best kept at a constant water flow rate. This simplified control and design and protected chiller evaporators. To allow for load variation, a bypass line would be placed at each fan coil or air handling unit, allowing for flow control at the load level. However, this presented a problem, which is that as the heat load decreased (at night for example), keeping all chillers operational would cause a severely low delta T. Solution: turn a chiller or two off. But having one pump per chiller meant that chiller sequenci...