I’m going to take a short break from my string on using condensate pump cycles to determine steam consumption and load profile to share something that I learned yesterday that may be useful to some of you.
You may recall that in a post in May 2008, I shared links to the free fan selection software available from a number of manufacturers. One link that I forgot to include was the link to the Twin City Fan and Blower Company selection software, which can also be downloaded for free.
This is another really great package to have on your laptop out in the field. For one thing, you can generate the fan performance curve for a Twin City fan with just a couple of keystrokes. And, you can generate the performance for not only the design condition. You can also generate it for other conditions as illustrated below.
As you can see, I generated a curve for the design condition for the fan I was working with. But, if you look closely at the dialog window behind and to the lower right of the fan curve, you will see that I can generate the curve for a different speed or a multi-speed curve, look at different fan classes, look at the speed vs. torque requirement and the WR2 requirement, etc.
Out in the field, I typically use the design operating point to define the fan curve for design conditions. Then, I work with that curve to model what is actually going on based on field observations of actual fan speed, flow, etc. I’ve even used this program or others like it to generate a curve for a competitor’s fan based on the field observed wheel diameter and other physical characteristics and figured that geometric similarity would get me in the ballpark at least enough for field work.
I happen to be using this software the other day to develop the fan curves for some air handling units on a project I am working on up in Seattle. But the problem was that I couldn’t find the model number for the fans I was dealing with. Specifically, I was dealing with fans that were part of custom air handling equipment that was fabricated in the 2003 – 2004 time frame; not that far back in time (especially if you are my age and have seen stuff you designed torn out and replaced; very sobering).
Evidence suggested that the fan I was looking for was no longer being manufactured, having been supplanted by an improved version. None the less, I was a bit surprised to find that the selection software did not let me access curves for legacy equipment. So, I called the local rep up to find out what I was doing wrong (I happened to know who the local rep was, but if I hadn’t I could have discovered who it was with a couple of clicks on the Twin City Fan and Blower web site).
Jim, the sales person I ended up talking to, was just about as surprised as me but promised to get back to me with an answer after calling the factory, which is several time zones east of us (I called late in the day on Friday). True to his word, Jim called back first thing Monday to say that the curve I was looking for was in fact in the software package, but that you had to access it in a different way from the approach I was using, hence my decision to write this post to share what we learned.
When you run the Twin City software, you get an opening screen that looks like this.
I had been using the “New Job” entry point then creating fan curves using the quick selector or “Fanulator” feature (gotta love that; kind of a cross between ‘ductolator’ and the nick-name for the governor of California) from inside the job file structure, which looks like this.
From this screen if, for instance, you selected the “Fanulator” option, you got a window with a drop down menu that had a whole bunch of different product lines.
My (and after my initial call, Jim’s) problem was that the legacy product line I was interested in (the APF series) was not on the list.
That’s the bad news. The good news is that if you enter the “Fanulator” option directly from the opening menu, with out creating a new job or opening an existing job, then the product line I was looking for was available for selection.
I’m not sure why one entry point lets you get to legacy equipment while the other doesn’t, but my theory is that since the product is no longer manufactured, you can’t select it for a new project and the software, wisely, prevents you from doing that.
But for us field folks working with older systems, it sure is handy to know that you can get to the information you need and benefit from the flexibiltiy and insights provided by this very nice, free software package from Twin City.
Senior Engineer – Facility Dynamics Engineering