Roundtable: Performance Monitoring
Onset recently assembled a roundtable to discuss the current role data loggers play in energy and retro-commissioning applications. Roundtable participants included: Adam Knickelbein of Summit Blue Consulting, Don Gray of US Innovative Green Technologies, and Stephen Pfeiffer of Energy Plus.
How do data loggers play into your overall performance monitoring strategy?
Don: Data loggers allow us to do full baseline testing on a facility before we do any upgrades, changes, or modifications. We work with utilities to get Customer Directed Rebates (CDR) for energy-efficient projects that decrease electrical usage at our clients’ facilities – putting money back in their pockets. With the data loggers, we get extremely high-quality data.
Adam: We do a lot of evaluation work for gas and electric utilities that implement energy efficiency programs. An important part of doing that is to measure the energy savings that they get from various projects. For example, when we are monitoring lighting run-times, we often use light on/off loggers or current-activated switches. When we measure motor run-time we use 4-channel loggers with current transducers to monitor the energy usage and estimate energy savings
There is an increased need for precise and reliable data because we need to verify whether the energy savings is really there.
Stephen: Data loggers play a very big role in my job. I use the loggers mainly for retro-commissioning to measure how efficiently an existing HVAC system and other building systems work. I also use the devices to verify whether or not a system is working properly after a retrofit.
What particular challenges do you face with respect to data collection?
Adam: We have a lot of different monitoring projects going on simultaneously and have to go to a number of different sites to download the data. I know that there are a number of web-based loggers that allow you to get real-time data, but right now, we only use stand-alone loggers that don’t have web access.
Don: One of the main challenges we have faced in the past is sending a tech out to a site to collect the data. Historically we collect high-volume samples. Collecting data with a web-based system, like the HOBO U30, saves us time and money. It gives us the ability to access the data anytime without having to go out in the field.
Stephen: I find that at times it’s difficult to put the loggers on older systems. Another challenge I face is bringing a laptop into the field to activate the loggers.
How do you work with the data?
Adam: We usually export the data into a statistics software program. For example, if we are measuring lighting we will often look at a population of retail stores or office buildings to get a snapshot of the energy usage other buildings are using and then we are able to get an average based on the data.
Don: I export the data files into Excel. Our customers want to see a graphical interface of what’s happening with their data. When I prepare a report, I put the data into graphs to show everything that has happened during the entire lifespan of the project.
Stephen: I always export the data into Excel because it helps me get a clear picture about how a system is working and easily helps me identify problems.
Do your monitoring projects typically require trend logging, real-time data, or both?
Don: We need both. I need real-world data for a lot of our projects. However, in general, trending data is more important to us.
Adam: We are looking at trend logging mostly.
Stephen: I only need to look at trend data.
What are the most important product features you look for in a data logger?
Stephen: The most important feature for me is memory since I need to log a lot of data using short- time sampling rates. I also look for a logger that can withstand harsh environmental conditions. They have to be able to take a beating.
Don: For us, its ease-of-use. The more complicated the test equipment, the longer I have to train our techs to go out and collect the data. Data loggers have been historically created for scientific types, and I think that more work-a-day people are going to be looking for products that are easy to use for their monitoring projects.
Adam: Cost is a big one for us as well as ease-of-use.