When it comes to energy efficiency, there's often a gap between the system designed for a building and the actual performance of it. Reading an article on Facilities Net about HVAC performance today, I was reminded of a presentation that one of Seattle's leading green architecture firms gave where they analyzed the performance of a high rise office that they designed. The LEED Gold building's energy use was fairly much as expected when it came to lighting usage, and pretty close when it came to environmental usage (heating, cooling, ventilation), but plug loads.... they were way higher than modeled by the company--almost double.
Plug loads account for everything that is plugged into the wall, whether it is a server room fully of electronics or a laptop in a cubicle. LEED and other green building standards all look to ASHRAE for baseline assumptions about how much power is likely to be used in, for example, an open office space. The assumptions--in the case of the building the architects analyzed and, I imagine, most others--can be way off as plug loads are fickle things, influenced by employee behaviors, workplace norms, and proliferating electronics. Who among us hasn't plugged in their cellphone at work? And in every office I have seen, there's at least a couple of people with incredibly inefficient fan heaters by their feet and just as many with little cooling fans on their desks (I'm guilty of the latter).
Green building technology is an exciting industry at the moment, with smart control systems taking on the challenge where human judgement isn't always the best thing. Cutting edge companies that have caught my eye of late include startups Building IQ, which presented at the NREL Industry Growth Forum when we did, and Daintree Networks, as well as established players Siemens and Johnson Controls, just to name a few.
While giving occupants some control over the environment is important for workplace satisfaction, giving all employees insight into actual power usage is beneficial too, if your want them to make the right decisions and not override all of the smart control systems that exist to improve energy efficiency. Better still, giving employees insights by areas (e.g. floor-by-floor in a high rise office building) to generate some friendly competition on top of the awareness has been shown to be effective. The same has been found in dorms. While energy modeling will only ever approximate real energy use, smart controls combined with occupant empowerment seems to be the key to keeping green buildings performing as designed.
I'm passionate about sustainable architecture + energy + food and how advances in their technology can help save the planet.