Last week’s post for Strategic Energy Management was milquetoast calm and civil. This post will provide more of what many Rant readers crave: brash provocation, with concrete reality to back it up. Here begins the fantasy of energy code effectiveness and compliance.
This topic was spawned as I was assessing ACEEE’s 2015 State Energy Efficiency Scorecard, for The Daily, Michaels’ internal daily news blog. The ACEEE state scores are developed from 50 total points, allocated as follows.
My comment was/is that points for code enforcement and level of stringency should be reversed; i.e., there should be four points for enforcement and two for stringency. Ah, let’s just put them all on enforcement and really make it meaningful. Stringency is pointless, and that is the subject of this post.
Let’s start with the humble building envelope. This is as simple as it gets, it would seem. I will demonstrate that stratospheric stringency means NOTHING (yes, I just yelled) without appropriate execution.
Consider a simple roof or wall construction. Assume it is insulated to R-100. This is about three times what code requires for home attic insulation and five times that required for commercial building flat roofs.
I could explain what R-value is, but it is easier to visualize with the following thicknesses of materials to achieve R-100 (see table to the left).
When I see code compliance reports that claim 74% compliance, I don’t know what that means. Does it mean 74% of the criteria are met? Does it mean the building is 74% “as efficient” as a compliant building? Does it mean it uses 1/0.74 as much energy as a compliant building?
It doesn’t matter. To wit:
Assume the builders of our 100 square foot roof insulated to R-100 are 99% perfect. Ninety nine percent perfection for insulating walls and roofs is no trivial matter. I would consider this to be an excellent job.
Simply by having “screwed up” 1% of the job DOUBLES (I’m yelling again) the heat loss from the entire roof.
Loss from the perfect job (the units don’t matter for this demonstration):
Loss from the 99% job:
There it is; 1.99x the heat loss of the perfect installation for 1% error. I will not go into the details, but an uninsulated barrier (roof deck) has an R-value of roughly 1.0, shown in red font, highlighted in yellow in the final equation above.
Widgets including heating and cooling equipment, fans, motors, variable frequency drives, lighting, and building materials, are not the problem. These items are thoroughly tested in laboratory conditions, and are most likely to perform per specifications.
As someone used to say on television when I was a kid, “get a load of this”! What would any code compliance study check for? Widget specifications. This is nearly worthless.
Specifications don’t matter. I just demonstrated that in the envelope section. Implementation matters.
Demons are in the systems. Angels are in the widgets.
The code allows for a “simplified” approach for buildings less than 25,000 square feet. Aside from the angelic equipment efficiency requirements, there are 18 other requirements such as:
- System(s) must serve a single zone
- Shall have air energy recovery per section umpty squat
- Shall be controlled by a manual or automatic changeover thermostat
- A half page of control requirements for supplemental electric toaster heating with an air-source heat pump
- Exclusion requirements for simultaneous heating and cooling
- Another half page of requirements for large hotel room HVAC units
- Optimal start controls
These Energy Rant posts have a Flesch Kincaid grade reading level of 8th grade. Rant posts have a reading ease of about 60 (scale shown below for what this means). It’s as easy to read as Sports Illustrated or USA Today.
The control requirements for an air source heat pump – a stupid, lousy, single zone, piece-of-junk, air-source heat pump, (it reminds me of the wagon wheel in When Harry Met Sally) – has a 22nd grade reading level (like PhD to the fourth power), and a readability score of 12.4. It is twice as complex as a PhD thesis and the Harvard Business Review.
As an energy puke, as I was/am affectionately known, with a MS in Mechanical Engineering, these sequences are a challenge to figure out. Do you think HVAC techs who install this stuff get it?
Now that the simple HVAC requirements are taken care of, let’s abuse ourselves with some of the more complex things. Here are some highlights:
- There are 17 pages of system design and control requirements, not counting the angelic widget efficiency requirements.
- Humidity control requirements consume a half page. This clocks in at a measly reading grade level of 18 but still more complicated than a PhD thesis.
- The avoidance of simultaneous heating and cooling – my favorite, consumes over a half page and nobody gets this one right.
Drive for show, putt for dough.
Drive for show: solar panels, LED lights, chillers with frictionless bearings, 95% efficient boilers, R-50 insulation. In golf, these would be 300 yard drives from the tee box.
Put for dough: air leaks, insulation gaps, simultaneous heating and cooling, poorly sized systems, system types that should have been banned 40 years ago. Ten-putt.
I will get to solutions later.
 A measure of insulation effectiveness.
 For variable air volume systems, to be specific.