A Field Guide for Engineers

In my previous post, I looked at using MotorMaster to take a life cycle cost perspective on the motor selection for a 5 hp chilled glycol pump serving an ice storage system. In doing that, I looked at upgrading from a Title 24/Energy Policy Act compliant motor to a premium efficiency motor as defined by NEMA. But, as you can see from the list below, there are a lot of choices, including motors with efficiencies that exceeds the NEMA definition of premium efficiency. 

The motors I contrasted previously are highlighted in green and yellow in the table above. In this post, I will take a look at some of the peak efficiency options, specifically, the ones highlighted in lavender ...Read More

Yesterday, I was using DOE's MotorMaster software tool (illustrated below;  page down if you hit the link and you'll find it) as part of an interactive exercise in a class at the Pacific Energy Center and got to thinking that it might be a good idea to expose some of the tool's capabilities to a broader audience.

Details on the capabilities of the tool can be found in the descriptive brochure that you can download from the web site, but in general terms, MotorMaster is a database of electric motor performance data representing an significant portion of the actual s...Read More

Earlier this week, while deploying loggers to monitor filter performance in the Kaiser Building in downtown Portland, Oregon, I noticed that the original building control panel was still in place in the current engineering office/control room as illustrated in Figure 1.

Figure 1 - A 1960's/W's Vintage Central Control Panel

This building, and the control panel, date back to a point in time where direct digital controls (DDC) were not in the mainstream in the commercial buildings industry, although the technology could be found emerging in the process control industry. Instead, control systems were built up from discrete pneumatic and electric control elements, typically mounted in panels located near the equipment se...Read More

There are typically a lot of components to the accuracy specification for the sensors we use in our HVAC systems, as illustrated in Figure 1, which was extracted from the data sheet for a sensor I was working with a while back.

Figure 1A - A Typical Process Grade RTD Temperature Transmitter Specification Sheet - Page 1

Figure 1B - A Typical Process Grade RTD Temperature ...Read More