ASHRAE Journal - March 2009 - (Page 10)

Why Green Can Be Wash By Joseph W. Lstiburek, Ph.D., P.Eng., Fellow ASHRAE Editor’s Note: Letter s to the editor a re w elcome fo r this column. Send letters to the editor at fturner@ashrae.org. Letters should not exceed 250 words.  I like November’s “Why Green Can Be Wash,” by Joseph should not be ignored. Many researches have been carried out W. Lstiburek, Ph.D., P.Eng., and agree with most of the author’s to explore the cooling impact of green roofs and strategically opinions. However, I believe a green building should not be con- placed plants around buildings at macro level. The urban heat sidered only in energy terms, but also in social, economic and island effect can be mitigated simply by introducing enough spiritual ones. Cities filled with 30% windowgreen roofs and plants in cities. Let’s imagine, to-wall ratio, compact and square buildings are with even a 0.5°C (0.9°F) reduction of ambienergy efficient but boring. It would be very Why Green Can Be Wash ent air temperature in cities, how much energy likely that the stark, unornamented International consumption in buildings can be saved! We M Style architecture comes back again, right? are not talking about biodiversity, or social Some points that I cannot totally agree with and environmental benefits but tangible enare as follows: ergy savings and economic benefits. To my • Using less glass. It is generally right in a understanding, green building should be in temperate climate. But it may not be a good the color of green. idea in tropical countries where natural venYu Chen, Ph.D., Vancouver, BC, Canada tilation through large openings is critical and necessary. The Author Responds • Green roof. For an individual building, The intent of my argument is not to ignore the author is probably right. The direct savsocial and spiritual issues in design but to point ings from a green roof, especially considering out that social and spiritual issues should not maintenance, are not comparable as a well-insulated roof. be used as the justification to ignore energy issues. I am tired But the indirect savings, although it is not easily measurable, of the hypocrisy of the architectural profession that talks any “green” buildings don’t save energy (Figure 1). Why? They have too much glass, they are overventilated, they are leak y to air , they are fraught with thermal bridges and the y rel y on gimmicks and f ads rather than physics. Basically, the cur rent green and sustainability craze can be summed up as architects and engineers beha ving badly. The good news is that most of this nonsense can be easil remedied. y The bad news is that the failures are beginning to bubble to the surface, and we are in danger of ruining the “green brand.”* Before you can have a “g reen” building, you need a b uilding that can stand up, not be b lown away in a hur ricane, not fall down in an ear thquake, not b urn, not leak rainw ater, not be moldy, not rot, not cor rode and otherwise be ab le to meet applicable building codes such as having a basic provision for ventilation like that speciﬁed by Standard 62.1. So what’s with all these “g reen” programs providing “points” for “durability” and “indoor air quality?” I mean it’ s pretty pathetic if we h ave to re ward architects and engineers w hen they provide details and speciﬁcations that should be basic to fundamental practice. If yo u design and install a controlled ventilation system that meets Standard 62, you get points. You get more points if you keep the rain out and design the building to dry if it becomes w et. And, you get still more points if the occupants are actually comfortable. Aren’t these code requirements? Shouldn’t these be “the standard of care?” Have we architects and engineers sunk so low that we now get points if we meet basic building requirements that all b uildings should meet to be called buildings? Green programs waste a lot of time and money on stuff that is obvious and more time and money on stuff that is irrelevant or unimportant. How about focusing on stuf that is important? It’ become all f s about the points and the important stuff gets ignored. Chasing “green points” doesn’ t get yo u good b uildings that are tr uly green. You can get a Leadership in Energy and Environmental Design® (LEED) rating and not save any energy compared to traditional buildings. How can that possibly be green? How to Be Green No points for this. This is what the minimum requirement for a building should be. Now what’s next? That’s pretty easy . It’s energy. What are two of the greatest challenges facing the U .S.? Global warming and energy security. The key to both is ener gy conservation. Architect Edward Mazria lik es to s ay “architects control the global thermostat.” I think he is right. Show me a building that meets code and the standard of care and saves energy, and I will show you a green building. A “real” green building, not a social statement that saps mone time and y, resources from the real problems facing the planet. Do yo u w ant to s ave serious ener gy and serious mone y? That’s easy. Use less glass. Windows and curtain walls are the most expensive component in a building and provide the worst energy performance. The more you use, the more energy and money you burn. Limit the glazing area to appro ximately 30%, and use good glass and frames (Figure 2). Then, don’t overventilate. This idea of getting g reen points by increasing the rates abo those speciﬁed by Standard 62 is just ve madness. Whatever happened to source control? If you don’t use poorly chosen materials in the b uilding, don’t do unwise things in the building and don’t connect the interior to exterior via the parking garage, Standard 62 works very well. Next, b uild an enclosure without big holes. Build tight, ventilate right. Tight is 2.0 L/s/m2 at 75Pa (0.39 cfm/ft2 at 0.3 in. w.c.).1 Right is Standard 62. How complicated can that be? Except, we don’t do it. Moving on, don’t insulate steel stud ca vities, insulate them on the outside. Most of the time all that you will need is R-10 of continuous exterior insulation (that’s between 1.5 in. and 2 in. [40 mm and 50 mm] of rigid insulation). And, don’t use supply or return plenums. Use ducts to avoid air quality problems and to ensure air goes where you want it. How Not to Be Green So let’s start with a basic requirement that we need a building that meets code and the standard of care. That would be a building that is structurally sound, is ﬁre-safe, has a controlled ventilation system, does not leak rainw and is comfortable. ater Once we get an enclosure, we can condition it. Note to architects: before you can control air you must ﬁrst enclose air. The enclosure comes ﬁrst and is more impor than all the systems tant within it. Mechanical engineers call themselv green and claim es to do g reen design. However, when push comes to sho ve, few of them w ant to do the additional w ork necessary to design a mechanical system matched to a high performance enclosure. Of *“Michael Zatz, manager of the commercial building program for ENERGY STAR®, an EPA program to promote energy-eﬃcient products and practices, says ENERGY STAR has a usersupport line that gets calls from green-building owners and managers who are disappointed in their building’s energy performance.”5 ASHRAE Journal ashrae.org November 2008 Griswold Controls Puts You in Control Now and for the Next Generation Griswold Controls’ Next Generation products address the changing environment and marketplace, providing: • Resistance to today’s chemical treatments • Protection from temperature fluctuations following system evening shutdown • External stem accessibility allowing for field servicing without removing the valve You have control for now and for the future with Griswold Controls’ Next Generation products. 1-800-838-0858 or visit our web site at www.griswoldcontrols.com For more information call www.info.hotims.com/23933-39 ASHRAE Journal ashrae.org March 2009 http://www.ashrae.org http://www.griswoldcontrols.com http://www.griswoldcontrols.com http://www.info.hotims.com/23933-39 http://www.ashrae.org

Table of Contents Feed for the Digital Edition of ASHRAE Journal - March 2009

Contents Commentary Industry News Letters Meetings and Shows Special Section 2009 ASHRAE Technology Awards Feature Articles Heat Recovery for Office Tower Air Motion Control in the Hospital Operating Room Anniversary Feature: Five Defrost Methods for Commercial Refrigeration Groundwater Issues: Commercial Open Loop Heat Pump Systems Used Filters and Indoor Air Quality Building Sciences Emerging Technologies Washington Report Products Special Products People Classified Advertising Advertising Index

ASHRAE Journal - March 2009

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