Thursday, August 29, 2013

ASHRAE Journal Articles

I have had 4 of the 6 promised “Engineer’s Notebook” articles published in the ASHRAE Journal. I received permission to post these on the Krueger website, which I will do as soon as they send me back the “approved” versions. We’ll update this blog entry with links as soon as they become available.

I have had a lot of very positive feedback from these articles, but today I got my first negative critique. The responder, a consultant (I assume an energy consultant) from Seattle, complained that “this kind of thinking will prevent ASHRAE from progressing the art of design”. I responded with this:

While I fully agree that oversized equipment may lead to occupant dissatisfaction, as the system attempts to operate efficiently at part load (see my most recent article in the Journal ), there are a large number of "energy efficient" buildings where occupant comfort has taken a back seat to energy savings. Following the publication of the article in question, I received a comment regarding a government building in your city, which is going for an energy award with both Underfloor Air Distribution (UFAD) and Chilled Beams. An occupant posted a picture on the internet of a temperature sensor on his desk indicating it was 90°F there. I'm sure they will have low energy use, but at what cost? Supposedly, there are umbrellas duct taped to office dividers to keep the sun off the occupants.  

I fully agree that "Energy efficiency does not make buildings uncomfortable; but the lack of good mechanical engineering design does." Sadly, so does poor understanding of how a building is supposed to operate. Innovative systems need much more building operations training than more traditional ones. Construction of innovative designs is also often compromised by poor construction. As indicated in the recently released ASHRAE UFAD Design Guide, the key to a successful UFAD system starts at the first day of construction in order to avoid issues with leakage in the end, which may be impossible to locate or remedy. 

But, the biggest issue I have with energy efficient designs is the apparent lack of validation of the energy calculations created to get owner and code acceptance (and LEED points). There are plenty of examples of buildings using far more energy than was predicted. Some schools are reporting that their expensive schools (at more than twice the cost/unit area of any prior schools in that area) are the highest energy users (again in terms of energy/unit area). I suggest that validation is lacking in many of these claims. An internet search for peer reviewed cases of proven energy savings of innovative designs will show you there isn't much out there. If these designs are so good, I'd expect the internet to be flooded with glowing reports. Sadly, that doesn't seem to be the case. Maybe all the successful building owners and designers are just bashful?

Authored by: Dan Int-Hout, Chief Engineer Krueger