Centrifugal pumps find open cooling tower applications are the toughest duty there is in hydronic cooling systems. Pumps do best with piping systems that provide …
Hydronic Centrifugal Pumps – Open & Closed System Discharge Piping
The pump discharge is the most turbulent location in a hydronic system. There are simple rules to follow when piping up a pump discharge. Today, …
Variable Speed Pump Motors and Drives
Danfoss VFD Motor Efficiency Terms Bell & Gossett ECM Pump Variable speed centrifugal pumps in building heating, cooling, and plumbing systems use a …
Developing Variable Speed Pump Curves
Most heating and cooling pumps in commercial buildings operate in a variable speed mode. Today, we take your Monday Morning Minutes to explore the variable …
Three-way and Two-way Control Valve Basics in Hydronic Systems
Centrifugal pumps operate at the intersection of the pump curve and the system curve. Last week we developed the system curve for an example closed …
Closed System Curves in HVAC Hydronic Systems
A system curve is a graphical representation of how a heating or cooling system flow rate and system head might change as the load …
Chilled Water Coil Temperature Reset in Cold Winter Months
Many facilities require cooling during the cold winter months. Northern climates such as Michigan or Ohio may not have any latent load in the cold …
Existing Hydronic System Volume Calculations
During a recent visit to a K-12 school hydronic system, I was asked if there was a way to determine the total system volume. My tongue …
Parallel Pumping with Unequal Condensers (Part 4)
Over the last few weeks our Monday Morning Minutes posts have looked at pumping issues with parallel, equal-sized condensers and pumps. This week we will look …
Where Cavitation Begins – Cooling Tower Pumps and Piping
Last week the R. L. Deppmann Monday Morning Minute defined NPSHR, and ended with the Hydraulic Institute (HI) definition as the absolute pressure that will cause the total head of the pump to be reduced by 3%, due to flow blockage from cavitation”. Of importance is the fact that it does not say that NPSHR is where cavitation begins.