Last week I discussed the need to simplify energy codes to disallow the variable air volume systems that (1) 95% of design and construction professionals don’t understand from an energy perspective, or (2) require constant babysitting by the other 5%. This week the topic is commissioning; another critical function to achieve real energy performance.
Commissioning has become the rage for energy codes, and before long, it will be required along with all the other things that are required and not achieved.
Quickly, to douse the risk of losing readers, commissioning is an oversight role that should be fulfilled by an independent third party to ensure the architects, engineers, general contractors, mechanical and electrical contractors are doing a good job, especially with regard to energy efficiency. The cops. Ok?
At this point, I will refer back to last week’s post to say something for which I did not have space. Another major benefit of the unitary, anti-variable-air-volume system, design is simple systems are infinitely easier to commission properly, at least from an energy perspective. There are at least two orders of magnitude (that is 100 times) more things that can go haywire with a variable air volume system compared to a design featuring unitary equipment. You have dozens, if not hundreds, of mechanisms that vary flows, temperatures, and ventilation every minute of the day. As a result, only a small fraction of this junk can be affordably tested.
All this stuff needs to sequence in a symphony to achieve the energy performance as advertised. Ever teach a cat to play a central role in a symphony orchestra? Here is your chance – or you get a variable air volume system to work right. Take your pick.
With the simple unitary design, there are only a handful, if any, central pieces of equipment that vary their output; those being makeup air units to provide tempered fresh air to the building, and possibly exhaust, depending on the facility. Exhaust volumes should vary for spaces like laboratories, as one example. The other equipment has binary control – on or off. The compressor runs or it doesn’t. The fan runs or it doesn’t. About the only things that modulate (vary) may be hot water or chilled water valves if the heating and cooling are of these types. If valves don’t work, the facility manager will know because temperature control will be lost. The notifications are self-evident in these simple systems.
One Problem Painted Over by Another
My former supervisor in the Navy introduced me to the term “pig in a poke”. Essentially, it refers to the need to make sure you know what you are buying before paying. Ha. From an energy performance perspective, the vast majority of new-building owners are getting pigs in pokes.
The problem is derived by the market itself, which calls for cheaper and cheaper first cost plus a big dose of buyer naiveté. I’ve said this a billion times: buying buildings is not like buying a Honda Civic from dealer A versus dealer B across town. The chance of getting energy performance within two percentage points for either Civic is very high. Comparatively, the chance of getting equal energy performance out of a building that looks the same on the surface, and is the same under the hood, is sheer coincidence – random chance. I am not kidding, at all.
So, the code world discovers commissioning as a way to ensure Honda Civic quality control. The problem I see happening already is the market is beating commissioning pricing into the deeply compromised territory. First, the market beats QA/QC out of the design and construction phases over the past 40 years, and it will continue through commissioning as that too becomes a requirement. Take my word for it.
We have already seen commissioning agents essentially quit when the budgeted money runs out. Does the owner know this? Of course not. The brick façade, double pane windows, terrazzo floor, and solar panels on the roof look wonderful.
The ultimate metric is actual energy performance compared to similar buildings. This would hold the design, construction, and commissioning industry accountable for actual results; a little bit like the EPA’s fuel economy ratings for automobiles, although buildings will always be less similar than automobiles.
The cost to achieve this fuel economy rating is only $1000-$2000 per building. The service would involve essentially the same steps as ENERGY STAR® for commercial buildings, where a licensed engineer validates building energy consumption and square footage for the energy intensity calculation. In addition, the engineer verifies the design/construction/commissioning team is not cheating by providing lower than recommended lighting levels and ventilation, or comfort levels that fall outside recommended limits.
Ultimately, we need to get out of hand waving, hoop jumping, pay-for-nothing merry-go-round, and into “show me the money, Jerry”. Don’t tell me; show me, the money Jerry!
 Unitary equipment includes your home air conditioner or a heat pump.