Is ‘green’ really new?
Green … It's the color of a well-manicured lawn, the trees during summer, and money. Now we use green to define energy-efficient and environmentally sensitive buildings. Why not orange, purple, or even white (although technically it is the absence of all color) to signify purity?
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Green… It’s the color of a well-manicured lawn, the trees during summer, and money. Now we use green to define energy-efficient and environmentally sensitive buildings. Why not orange, purple, or even white (although technically it is the absence of all color) to signify purity?
For many of the more seasoned engineers this may seem like dejà vu of the late 1970s and early 80s. The oil embargos, high fuel costs, and escalating energy costs created a need for energy and environmental specialists to develop conservation methods and to raise the public’s awareness that, indeed, there are limits on the world’s energy resources and there is a need to develop methods to live within those constraints.
New technologies were developed, equipment efficiencies were mandated, and new societies such as the Assn. of Energy Engineers (AEE) and Certified Energy Manager (CEM) were created to establish a knowledge base and to certify technical credentials.
All of the infant technologies were considered then: Hydronic solar systems with storage tanks, air solar systems with rock storage, geothermal, biofuels, wind power, and heat pumps. There were some successes, some failures, and often too many Rube Goldberg Designs, but that’s progress. The cost of energy started to recede, and after a time, public acceptance and the initiatives were diminished or forgotten.
Some may recall the government mandate during the Carter administration; officials required buildings to have the thermostats set to 68 F for heating and 78 F for cooling in an effort to reduce energy consumption. A simple idea that makes sense, except if you have a closed-circuit heat pump system that has a balance point of 70 to 72 F.
These building systems consumed more energy because the heat pumps would attempt to cool the building to 68 F during the heating season. Today’s technology allows a greater degree of flexibility in setpoints and operation. Any of this sound familiar?
Move forward about 30 years to the present, and we again have an acute awareness of our environment. Global warming, ozone depletion, airborne toxins, and rising energy costs–we should all be concerned, but we should also be cautious. Terms such as “green,” “sustainable,” and “high-performance buildings” are great buzzwords that mean many things to many people. We have created new organizations such as the U.S. Green Building Council (USGBC) to establish guidelines and certification programs such as LEED, which may certify an individual’s ability to provide energy- and environmentally efficient designs.
So once again we strive for a better world, efficient and clean. There is a greater awareness from a global perspective. Technology has improved and a plethora of innovative designs are flooding the market place.
Is ROI worth it?
In the past, most decisions were based on return on investment (ROI). Basically, ROI is the measure of how fast a company could recover the costs of an additional investment for upgrading to a more efficient design over the more traditional systems of the era. This still exists to some extent today, but there is something different, a new spin, a sense of urgency, social responsibility, political correctness, and public image. All of these comprise a somewhat intangible, softer side of the decision making process.
In some instances, decisions are being made because it feels good, not because it makes sense technically or financially, but because it presents a good image. This can be a recipe for disaster.
How often have you made a purchase or did something because it felt good at the moment, only to regret your actions? That potential exists today, and as design professionals we have an obligation to provide sound judgment and guidance to our clients regarding the appropriate design application. We need to provide advice regarding whether it work, how well will it work, whether it is practical, and the financial implications. Ultimately the client is the final authority; design professionals are responsible for providing sound advice that will aid the owner’s decision-making process. This serves two purposes. First, professional ethics demands an honest and open dialogue based on available facts, and second, to limit the liability exposure for inaccurate advice.
Perception is everything
The perceived authority/guideline is LEED. The manuals provide a list of measures that can be implemented with a ranking system that assigns points. The total number of points provides an indication of how successfully the building meets the environmental and energy efficiency guidelines set forth by the USGBC. This has the appearance of an acceptable guideline for the profession.
However, LEED guidelines are not specific; they do not outline systems, components, or methodologies. LEED is more a list of suggestions regarding environmental considerations and energy efficiency and relies on industry standards such as ASHRAE to establish benchmarks. Design documents, narratives and point data sheets are submitted to the USGBC for a subjective review, subsequent award of points, and eventually a plaque to be placed on the building.
There is a potential for feel good versus practical. Inevitably there may be circumstances in which the driving force will be to maximize points rather than the technical practicality or financial considerations for an appropriate functional design.
Generally speaking, anything will work if enough money is thrown at it. Obviously this needs to be discussed with the owner. There is a fine line between leading technology and bleeding technology. There is nothing wrong about pushing the design limits. However, does the client want to be a research project?
Years ago, a medical facility wanted to have a state-of-the-art heating and cooling system, and geothermal systems were being presented as the latest and greatest technology. Getting heat from the earth, a virtually unlimited supply, for the building was a substantial task and would require approximately 1,700 tons of cooling. Utility rebates and other financial incentives justified the first cost. In lieu of wells, a small lake was created as the heat sink. Geothermal heat pump systems work because there is a continuous cooling load. Mechanical energy used to do the cooling is recovered for heating. A requisite component is a continuous cooling load in the winter months. The lake was built, heat exchangers installed, several hundred heat pumps were installed, and the system was commissioned and monitored.
A strange thing occurred: The circulation pumps and heat exchangers associated with the lake rarely operated in the winter. When the system did operate, heat was rejected during the heating season because of rising loop temperatures. This was a result of heat pumps serving interior spaces, continuously cooling them and rejecting the heat to the loop. Further analysis indicated that there were large enough cooling loads in the interior spaces to sustain the loop water temperatures to meet the heating requirements at the exterior of the complex during the heating season. With a little more insight and possibly a dose of skepticism, the additional costs might have been avoided. The final justification was that the lake avoided unsightly cooling towers and exposed mechanical equipment on the property. Bottom line, the system worked but the additional costs to be “geothermal” were not necessary.
Another consideration regarding geothermal systems: heat pumps traditionally consume more than 1 kW per ton of cooling. The overall efficiency is a factor of the amount of recoverable heat used in the process of producing that one ton of cooling. The net operating costs are a factor of dollars per BTU for electricity versus that of some other fuel, such as natural gas. From a totally holistic environmental view, the consumer sees 3,413 BTU/kW. The actual energy expended by the utility is approximately 11,300 BTU/kW. Heat pumps require electrical energy to operate. Most areas in the country have moratoriums on developing any type of new power plant. One could argue that wind or solar could provide the necessary power; however, the costs and long-term reliability of these technologies are factors. This is not an attack on geothermal systems, heat pumps, or other green or sustainable technologies. The point is to substantiate the use of any new technology to the end user. Because it is sleek, shiny, or slick does not always mean it is appropriate.
The outcome will be beneficial for all of us and future generations. We, as design professionals, have a duty to be analytical, to challenge, and to differentiate between sound judgment and emotionally driven perceptions.
It is refreshing to observe the next generation of engineers—enthusiastic, bright, innocent, and filled with new ideas. However, the real world is filled with consequences, and that youthful enthusiasm has to be balanced by the practicality of the experienced cynic. Our industry is headed in the right direction. The environment and energy efficiency seem to be less of a fad and are accepted as practical realities. As professionals, we need to ensure this momentum with sound design concepts and not just fashionable perceptions. Remember, it is failures that are highlighted and remembered, even if they are a small percentage, and it is those failed projects that will inhibit any positive progress.
|Zak is principal with Graef Anhalt Schloemer and Assocs. Inc. and is a dedicated environmental curmudgeon. He is a member of Consulting-Specifying Engineer’s editorial advisory board.|