Control head is a term used in many different industries. What is the control head in our world of variable speed pumping hydronic and plumbing …
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 …
What’s On a Pump Curve?
Selecting centrifugal pumps for heating, cooling, process, and plumbing systems is easy once you understand how they work and what you are seeing when …
Glycol Pressure Drop Corrections for Hydronic Systems (Part 2)
Last week the article covered pressure drop correction calculations. Today we offer you some handy charts to use for second glycol correction pressure drop. Example: I have calculated the water piping pressure drop through a chilled water system to be 80 feet using the System Syzer. Question: What is the pressure drop if I have 50% Ethylene Glycol/Water with temperatures of 45°F to 55°F? Answer: The average temperature is 50°F, so my factor is 1.47. [Read more…]
Pressure Drop Corrections for Glycol in HVAC Systems (Part 1)
Question: I have selected my piping friction loss based on water, but I am pumping a glycol solution. What correction do I use? Answer: There are three glycol corrections when designing a hydronic or process cooling system; heat transfer correction, pressure drop correction, and pump curve correction. This R L Deppmann Monday Morning Minute defines the second of three glycol corrections. [Read more…]
Hydronic System Pump Selection: Flat vs. Steep Curves
An engineer in Michigan called about a large project with several pumps being selected in parallel for a plant chilled water system. He commented that …
Bell & Gossett Part Load Efficiency Value Part 4: End-of-Curve Selections
When looking at Bell and Gossett pump selections, we often find higher part load efficiency (PLEV) pump choices are to the right of the BEP, or best …
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