What is psychrometrics? It’s a big and intimidating word to be sure and the common definition, the study of the physical and thermodynamic properties of gas-vapor …
How to Determine Impeller Size with Shut-off Head
Here is a quick way to determine impeller size from the No Flow point on the pump curve. Tools needed: 1) Pump curve. Select the …
Humidification Basics Part 2: Mastering Humidification Terms
Humidification is one of those areas where the terminology can often be a roadblock to understanding the topic. After all, we’re not all meteorologists! Since …
Humidification Basics: Why We Humidify in Building Design
Ever hear the phrase, “It’s not the heat, it’s the humidity”? It’s all about humidification in this Monday morning Minute series. In the commercial HVAC …
Parallel Pumping: 2-Position Control Valves on Multiple Cooling Towers (Part 5)
Over the last few weeks the Monday Morning Minutes posts have looked at pumping issues with multiple condensers and pumps. One of our most-received questions …
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 …
Parallel Pumping in Condenser Applications: Automatic Differential Pressure Control (Part 3)
Chilled water condensers are normally operated as constant-flow devices and the pumps serving them are constant-speed. Why would you ever use a variable-speed drive for …
Selecting the Proper Glycol Concentration for Closed-Loop HVAC Systems
There are two basic types of glycol protection available for your closed-loop HVAC system: “burst protection” and “freeze protection.” Burst protection is sufficient if the …
Parallel Pumps in Condenser Applications: Limiting the Flow Rate (Part 2)
In part 1 of this series we offered an example condenser water pumping system. The design of this example is 800 GPM per condenser for …
Parallel Pumping in Condenser Applications (Part 1)
Applying a single constant-speed pump for each condenser in a chilled water application is a normal design for the HVAC engineer. The chiller manufacturers suggest …