Last week the R. L. Deppmann Monday Morning Minute gave an example of a pump selection for which we applied the margin multipliers to arrive at 24.5 feet of net positive suction head required or NPSHR. Now let’s turn our attention to the cooling tower pump suction piping and net positive suction head available or NPSHA. [Read more…]
It’s all about Pressure – Cooling Tower Pumps and Piping
Last week the R. L. Deppmann Monday Morning Minute left you with a multiplier of 1.3, 1.5, or 2.0 to use with the pump NPSHR. Let’s look at an example this week using the suction energy formula we introduced last week and add one more margin to the formula.
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.
It’s All About Terms! – Cooling Tower Pumps and Piping – Part 1
Most cooling tower designs and installations are commissioned without any issues. The few percent of times where problems arise will cause multiple meetings, emails, finger pointing, and added costs. The issues are not caused by bad luck or bad Karma; tower water pumping issues are typically caused by air, dirt, or improper application. [Read more…]
Absorption Distance In Action
In the last couple Monday Morning Minutes, we showed how the type of humidifier dispersion method could affect the absorption distance. Let’s look at an example. Ex: 5000 CFM at 55OF Duct temperature to provide a room RH at 35% at 70OF with 50% outside air. [Read more…]
Humidifier Dispersion Choices And Absorption Distance
Last week, we described the criteria that may affect absorption distance. This week we look at how your choice of humidifier dispersion assembles may affect that absorption distance. Call your R.L. Deppmann sales representative to assist you in selection of the best dispersion method for your application.
Humidifier Placement In Airstream is Critical
Absorption or non-wetting distance is the dimension downstream from the leaving side of the steam dispersion assembly to the point where wetting will not occur, although wisps of steam may be present. Solid objects at duct air temperature, such as coils, dampers, fans, etc., downstream of this dimension will remain dry. Location A is the best choice. [Read more…]
Factors That Affect Absorption – Humidification Part II
Duct or AHU temperature. Cool air absorbs less than warm air and requires a longer absorption distance. When equal amounts of steam are introduced into equivalent ducts but with different air temperatures, the lower temperature systems of 50 °F to 55 °F are more difficult to ensure absorption than systems with higher temperatures.
How to Design for Proper Steam Humidification Steam Absorption
Humidification of buildings helps provide a healthy and comfortable work environment. The next several R.L. Deppmann Monday Morning Minutes will examine steam absorption humidification and provide solutions to some of the common issues we see on a regular basis. Dri-Steem Corporation provides a variety of products to solve the many needs in this area of the HVAC
FAQs on Expansion and Compression Tanks – Part 2 of Series
Here we answer the questions:
Can I use a bladder tank and a steel compression tank in the same system? Adding on to my system, need to increase my compression tank/expansion tank capacity? How do I put another tank in parallel with the existing? Or my existing tank is too small, how do I increase capacity? What happens if the bladder type tank air charge is not increased to the proper fill pressure?