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

In my last post, I began to look at the challenges faced by a fairly typical VAV system (Figure 1) operating in a Midwestern climate (Figure 2) on a day where the conditions were no-where near the summer or winter design conditions or extreme conditions (Figure 3).

Figure 1 - System Diagram 

Figure 2...Read More

Frequently, when I encourage operators to consider the loads their systems serve, as I did in my previous post, I'm asked how someone who is not trained in design can go about doing that. I often suggest that they apply rules of thumb and there are a number of great resources out there on this topic. One of my favorites, appropriately titled HVAC Equations and Rules of Thumb is illustrated below.

...Read More

In my previous post, I illustrated how hourly weather data for the most recent 3 - 7 days can be easily obtained from a nearby NOAA weather site.  The screen shot below illustrates another very handy weather-related feature that can be found for some sites that seem to be associated with the Western Regional Climate Center.

Notice the small histogram toward the bottom middle of the screen labeled Recent Area Temperatures.  This simple looking graphic actually is loaded with information regarding the recent climate pattern relative to the n...Read More

If you're like me, there has been more than one occasion where you returned to your office from doing some field work and wished you had taken the time to document the outdoor air conditions better than you had.  Maybe you thought the data was being captured by the facilities control system or data logger, only to discover that the data was bad or missing.  Or, maybe you were trying to recall if it was sunny or cloudy or when it rained or exactly when the marine layer moved out one day and at best, you can only infer those events from the temperature and humidity data logged by the system.   What ever the specifics, with out the data, while it may not be the end of the world, your analysis suffers because you have to make more assumptions than would be necessary if you had the data.

The good news is that the ...Read More