Developing a Monitoring Plan; The First Step in Data Logger Deployment

A couple of weeks ago, in a post discussing how I went about field installing a surface temperature sensor for a data logger deployment I promised to follow up with a post showing the rest of the data logger deployment and some of the field issues I had to think through in order to decide what to pick up with the loggers.

This is the first in a series of posts that will cover that topic.  They will be based on recent deployments at the Newport Oregon EPA lab pictured below courtesy of the EPA website.

Newport-EPA-lab

Yes, sadly, I occasionally have projects which force me to go and work for days at a time at the Oregon Coast, leaving me away from home with nothing better to do in the evening than watch sunsets and fly kites with my bride and play on the beach with grandkids and puppy.

Coast-time

Let that be a lesson to you; this is what can happen to you if you have a good work ethic, work in the industry a while, and gain some experience. But enough of my hard luck stories.

The control system serving the lab does not have a lot of trending capability. In fact, one of the goals of the project I am working on is to master plan, purchase and install a control upgrade and then use the commissioning work required to bring the new control system on line to also do some retrocommissioning. But, the Owner did not want to wait until the completion of the control system work to start the retrocommissioning process, so we are
deploying data loggers through-out the facility to allow us to begin to understand where the opportunities are and pick up the easy saving, a process commonly called “harvesting the low hanging fruit”.

From an engineering perspective, the Newport EPA lab is a pretty interesting place that includes:

  • Five major air handling systems and a number of smaller air handling systems;
  • A central heating water system serving both process and HVAC loads;
  • Two chilled water systems, one dedicated to process loads and one dedicated to HVAC loads;
  • A marine water pumping system that moves salt water from the bay through-out the research facility;
  • Numerous specialty systems associated with performing research and laboratory processes.

To fully instrument everything with portable data loggers would have taken a lot more equipment than I had at my disposal. So, my goal initially was to spread the 8-10 loggers that were available (representing the ability to pick up about 30 to 40 data points) across all of the systems in a way that would:

  • Identify the potential opportunities that exist to improve performance, save resources, and/or resolve operating problems.
  • Allow me to begin to quantify the benefits that could be realized by taking advantage of the opportunities identified.

Once I had the opportunities identified and prioritized, I could re-deploy the loggers to focus on specific issues as necessary.

As a first step in the deployment process, I developed a monitoring plan to identify what systems I wanted to log, what data I wanted to pick up from the systems, and about how many points each target would take.  Some of the key points of the plan I ultimately developed were outlined in the following paragraphs.

The utility analysis work I had done initially on the project indicated that while there were likely opportunities to save both gas and electricity, the electrical system likely had more opportunities than the gas system. Thus, I planned to use three or four loggers to sub-meter the electrical distribution system and see where the power was going.

Given the mild weather at the coast, the HVAC chillers did not run very often, a fact confirmed by my observations on previous site visits and discussions with the operating staff. Thus, at least initially, I had decided not to do much logging on the chilled water system beyond what I learned about chiller operation from the electrical sub metering.

Four of the five air major air handling systems in the facility served laboratory areas. These four systems actually worked in pairs to serve the lab areas; i.e. for any given laboratory space, two air handling units operated concurrently, one providing general ventilation, heating, and cooling, while the other provides make up air for the lab hoods. These systems were obvious logging targets because they had the potential to be resource intensive on a number of fronts. 

  • They were 100% outdoor air systems;  handling outdoor air is always an energy intensive process.
  • They ran around the clock; this is a necessary evil of the lab environment, but there may be ways to minimize the impact once we understand the systems an the lab requirements.
  • The filters used were high efficiency filters and thus represented a significant operating
    cost in terms of energy, filter costs, disposal costs and labor to change them.
  • The systems were reheat systems operating at fairly constant flow rates dictated by the air change requirements associated with keep the laboratories safe to work in.

The lab air handling systems have several energy conservation strategies including a run around coil system and the ability to reduce flow rates when hoods were not in use. If these features are not working as intended, then they represent energy savings potential that can likely be realized simply by making the equipment perform as intended.  Savings of this type may represent “low hanging fruit” in contrast to opportunities that might be identified by the retrocommissioning investigation but which will require modifications to the systems to achieve.

The pairs of laboratory air handling systems are fairly similar, so I decided I would dedicate two loggers to one pair of systems and assume that issues identified in one set of systems will likely be reflected in the other similar set of systems.

Since gas consumption is a concern and since the utility analysis indicated that there might be opportunities to optimize how gas is used on the site, I decided to use the remaining loggers to monitor the heating hot water system, which is the only system that uses gas on the site.

The surface temperature sensor installation discussion I mentioned at the beginning of this post was illustrated with pictures from the installation I did to monitor the hot water system at the Newport EPA lab. In my next post, I will look in detail at how I decided what to log on the hot water system with the loggers I had available.  After that, I will look at the details of deploying the loggers on the various systems in the facility and share some of my results.


David Sellers
Senior Engineer – Facility Dynamics Engineering

Click here for an index to previous posts

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