Try This at Home! Please!

This post was inspired by a question from Alicia Breen, one of the students in a monthly retrocommissioning/ongoing commissioning class that I teach at the Pacific Energy Center with  Ryan Stroupe  and Tony Pierce.  The class is a one day a month plus homework commitment for 12 months on the part of the students, so its not a causal undertaking.

Over its course, the students get lecture and hands on experience with commissioning
techniques using the systems at the PEC, culminating in a functional test targeted at addressing an issue identified earlier in the year in the facility. In addition, the students work on a project in their home facility (where they work, their house, or a facility requiring some sort of commissioning attention and volunteered by someone like Virginia Waik,  the Utilities Marketing Engineer for the City of Palo Alto, who has a passion for commissioning, efficiency and generally making the world a better place that few could

In any case, for the December session, the homework assignment was to perform some sort of test using some combination of data loggers, trend analysis and discrete measurements on the student’s project system or, lacking that on some other system, like their house.

Much to her dismay, Alicia found that she could not get sufficient access to her project system during December and January to allow her to do the testing she had hoped to do. So she was considering testing something in her house and e-mailed me to ask for suggestions and council.

I’ve actually learned quite a bit by working on my house, including how to run conduit, how to run pipe, how to frame, how to run ductwork, how to landscape, etc. I might add that I’ve also learned a lot  about how not  to do those things.

These lessons have been really valuable for me because while, for instance, my little half inch conduit run is pretty piddly compared to what the “big boys” do on commercial and industrial projects, running it gave me a lot of insights into and an appreciation of the challenges they face, the skills they have, and the fundamental mechanics behind the task. These lessons not only made me a better designer and engineer, they also gave me some insight into some one else’s world.

These insights are invaluable for those in the commissioning field because while in theory, commissioning is, at its heart about performance and integrating machinery, my experience has been that about half of that hinges on integrating the team that is putting the project together and operating it. If the team isn’t integrated and on the same page,
then its a lot harder to get the machines to that point.

And, the reality is that, in most cases, we are all just people trying to do a good job, pay the bills, have some time with the ones we love. Ultimately, the more I know about the buildings I work on and the folks that build and operate them and their skills (and visa versa) the better off we will all be.

So, as I typed back to Alicia I realized that what I was suggesting to her might also be worthy of suggestion to a broader audience. So here I am and there you are (I hope).

In general terms, what I am suggesting in the following paragraphs is that you use the place where you live as a little laboratory to gain insight into the things you do at work in this industry. Granted, its on a smaller scale and probably a much less complex scale. But the reality is that the underlying principles are the same and, as Jay Santos would say nature doesn’t lie”.

I’ve found that learning things from a “discussion” with nature on a smaller more manageable scale (represented in the context of this blog post by your house) is a lot better than having the same discussion in a high rise or industrial complex. In that context, here are some things that you might investigate.

Ask your self if there is any problem with your home that has bothered you. For instance, is there a room that is uncomfortable relative to the others? Is the HVAC system noisy when it runs? Do you wish that your utility bills were lower and is that a realistic wish?

As a side note, I suspect that everyone wishes that their utility bills were lower, But, for instance, my worst case heating bill is about $50 for gas. That’s probably because Kathy (my bride) and I have a small house, reasonably tight and well insulated in a mild climate with a high efficiency gas furnace; probably not much that I can do to meaningfully reduce the bill.

That doesn’t mean there aren’t meaningful things I can do to improve the way I use
gas, which is a non-renewable resource that generates atmospheric carbon when I burn it. But, given the modest cost (currently) to heat my home, the perspective driving the desire to improve things will need to be more holistic rather than economic – a lesson I think for our current bottom line driven society.

Anyway, the point of these questions is to find out if there is something you want to target a test at. Probably 50% or more of the tests performed by commissioning providers in the field are targeted at solving a specific problem or verifying a specific level of performance.

But, that doesn’t mean you can’t learn something if you don’t have a problem to target with your test. You can do an information gathering test and find out exactly how your house performs. Here are some ideas that come to mind.

Compare What’s Going On Inside to What’s Going On Outside

Deploy a data logger outside that tracks relative  humidity (RH) and temperature and then deploy several loggers inside tracking the same thing along with maybe some indication of occupancy like light level or the operation of an electric light, and maybe one that tracks furnace operation.

Then plot concurrent data to see how the environment inside your house responds to changes in the ambient environment and the use patterns. For instance:

  • What happens to the RH inside when you take a shower?
  • At night, if your furnace has night set-back, how fast does the temperature in the house drop off relative to how fast the temperature outside drops off. How about RH?
  • How does RH compare to specific humidity or dew point which is a more absolute indication of moisture level? (Some data loggers will calculate dew point an specific humidity based on the parameters they measure.  But if not, you can figure it out from a psych chart).
  • How does absolute humidity inside and outside compare and track?

Compare How Different Electrical Appliances and Loads Use Power

Deploy a current or kW logger on your power panel and on some critical (large) loads like the your dishwasher or your washer and dryer or your water heater (if it’s electric) and plot concurrent data to see how much of an impact on total load each appliance has. Add more loggers to other circuits serving light loads and plug loads to see how you use energy in your house.

Only do this if you feel comfortable putting CTs on your circuits or if you know someone who is an electrician or who is comfortable doing that for you if you aren’t.  Electricity,
even at the voltages we use in our homes can be dangerous
if you don’t know what you are doing or aren’t comfortable working around it.  Never do anything with electrical wiring
that you are not comfortable doing and/or have not been properly trained to do.

Measure and Analyze The Performance of Your Furnace

Put a logger on your furnace to measure differential temperature and pick up fan operation. Or deploy or add another one to monitor filter pressure drop. Deploy another outside to track ambient conditions or download the data from the web using one of
the techniques/sites discussed in the Functional Testing Guide.  Use a rotating vane anemometer to traverse your return grilles and get an idea of air flow.

Then, simply log the operation of the system and see what it tells you. For instance:

  • How does the actual capacity of the furnace compare to the rated capacity?
  • How does the cycling time vary with changes in outdoor temperature?
  • If you have a night set back thermostat, how does that impact the operation of the
    system vs. the way it operates once the house is warmed up or, at
    night once the house has cooled off?
  • How long does it take your filter to load up? (Generally, filters should be changed
    on pressure drop
    , not appearance or time ).

Explore Conservation of Mass

Use a rotating vane anemometer to traverse your return grills and get a feel for total system flow. Then traverse your supply grills and see how the flow is distributed.

  • Is it fairly uniform on a cfm per square foot basis, or are their areas with a lot of air and areas with less?
  • If the distribution is not uniform, is that because of the loads in the areas served? Or does your system need balanced? (Maybe there is a reason that one area is always hot or cold!)

Explore Alternative Approaches for Heating Water

If you have an electric water heater log its power consumption and then use that data to compare what would happen if you heated your water using one of the  heat pump based technologies that’s out there or using a conventional gas water heater or using one of the high efficiency instantaneous type heaters. Look at both the source and site energy implications and the atmospheric carbon implications.

Some of you may be thinking “that’s all well and good, but what if I don’t have a data logger?” If you live in California in one of the public utility service districts, you are in luck. You can borrow a logger from the Pacific Energy Center’s  tool lending library .

This is (as us 60’s generation folks would say) a “free to the people” resource that is available to you as a utility customer. Many of the private utilities in California and other states offer a similar service.

Another option is to simply buy a logger. For under $100, you can be off and running. For $300 – $400, you can be logging just about anything.

I wouldn’t be surprised if you discovered you didn’t need the new DVR if you bought a logger instead because you will be having so much fun learning things about your house or the building you are working on (and making the world a little bit better at the same time) that you won’t have time for a lot of TV.

I also realized that your kids and significant other might have a different perspective on this. The trick there is to make the first problem you solve with your new tool – a.k.a. toy – be something that has been driving your significant other crazy.  And to let the kids use your new tool for their science project; they’ll probably blow away the competition.

So, bottom line, do a science experiment on your home. You may be surprised by what you learn. And I’ll guarantee that what you learn will make you a better technical person in the buildings industry, no matter what your role is.

This entry was posted in Data Logging, HVAC Fundamentals, Mentoring and Teaching. Bookmark the permalink.

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