The word “green” is now unavoidable during an average day in North America. You’re likely to first read this word on the front page of the morning newspaper. Later, you’ll see it repeatedly used in trade journals as well as consumer magazines. That afternoon you will notice it on product labels at the local store. By the end of the day, chances are you’ll hear it used as the focus of a new government job-incentive program.
Our culture interprets “being green” as having achieved a heightened sense of consciousness about how we should relate to and protect our environment. We are being relentlessly conditioned to view “green” as something we should aspire to, a never-ending quest to minimize any adverse impact we may impose on our planet.
Going green can be anything from installing a bike rack at a public building, to using glass mulch made from crushed bottles for landscaping, to adding insulation to one’s attic. The word green has become an envelope for older terms such as recycle, conserve and reduce. Going green also describes actions such as increased use of renewable energy, planting grass and flowers on your roof, or bringing your own bags to the grocery store.
Within the context of mechanical systems, I see “green” categorized as follows:
How Green Are You?
I recently attended a session on solar water heating at an international conference on solar energy use. One speaker began the session by asking how many in the audience had a solar water heating system installed in their home. By a show of hands I estimated no more than 10 percent of the people in that room lived with solar water heating.Granted, some of those present were new to the subject and wanted to get more involved. Some also may have lived in rented quarters where such a commitment was not theirs to make. On the other hand, modern solar domestic water heating systems have been available in North America for more than three decades. Government-based financial incentives for such systems have also been in place for several years. Fuel prices, especially that of oil, didn’t just become unstable last year.
The speaker’s implication was that many of those present have had ample opportunity to demonstrate what they advocate and, in many cases, what they hope to profit from. In short, he was implying that those in attendance should practice what they preach!
Over the years I’ve had the opportunity to do this by installing a wide range of what are now considered “green” energy systems in our home. They include solar energy systems (active thermal, passive thermal and photovoltaic), a ground-source heat pump, a heat recovery ventilator and a wood-burning stove.
I can tell you that living with these systems has exposed their benefits as well as their weaknesses in ways I would never have discovered by reading literature, surfing Web sites or making occasional site visits. The knowledge gained from this experience has been invaluable in influencing how I currently design systems.
Convenience At Any Cost
One lesson I’ve learned through all this experimentation is that conscious adjustments in lifestyle always have an impact on energy use. For example, if you partially base your use of hot water on sunny days when your solar collectors are performing well, you will reap more savings from the solar DHW system compared to a scenario where any interaction between hot water usage and weather is completely ignored.Unfortunately, most Americans consider self-convenience, instant gratification and the right to consume as extremely important, easily trumping any concern over energy conservation. This attitude has been reinforced over many years and is not easily altered, even when the potential benefits are profound and the return on investment is far beyond anything that banks or Wall Street now offer.
Imagine, for example, asking a potential customer the following question: Exactlywhendo you want your new energy-efficient domestic hot water system to be able to supply hot water to the faucet on your lavatories, showers and tubs?
Most Americans would likely respond with body language suggesting that what you just asked them was a pretty stupid question. After all, isn’t it obvious that everyone expects hot water to be available, and in abundant supply, whenever a faucet is opened, 24 hours a day?
This response certainly agrees with common practice in most North American homes, but it’s not universally accepted around the world. Those of you who have travelled in Europe may know what I’m talking about. If you plan to take a shower at 4 a.m. in some European hotels, don’t be surprised if it’s a bit brisk. Over there, domestic hot water temperature is often lowered at night to reduce use of very expensive fuel. The European culture seems to accept this as being both rational and beneficial. The hotel managers don’t apologize for it. It’s just part of living in (or visiting) some areas of Europe.
Could this concept ever take root in America? We’re about to see. Controls products have recently appeared for North American gas-fired water heaters that allow domestic hot water temperatures to be reduced during periods of low or no demand. One manufacturer offering such controls claims they can reduce domestic water heating energy use by up to 36 percent.
Although most North Americans are familiar with nighttime thermostat setbacks as a way to reduce heating energy use, applying the same idea to domestic water heating is not currently in their cultural mindset.
From a technical standpoint, this idea is certainly sound. It lowers fuel use by reducing standby heat loss from the storage tank. Savings can also occur as the result of reduced delivery temperature during low demand periods, such as from 11 p.m. to 5 a.m. (An example of this would be hot water supplied to washing equipment programmed to operate at night.)
A temporary override function, similar to that used on most automatic setback thermostats, allows for recovery to normal DHW delivery temperatures within a matter of minutes. Waiting a few extra minutes before taking a previously unplanned shower at 4 in the morning is the only compromise.
If this concept works for gas-fired water heaters, it could also be applied to the indirect water heaters used with hydronic heating, or be a standard control feature on solar domestic water heating systems.
After reading this, perhaps you’re worried that customers would complain about having to push a button and wait five to 10 minutes if they want to take a last-minute shower or bath in the wee hours of the morning. Herein lies the opportunity to challenge them about their “greenness.”
Rather than complaining about a very minimal compromise, customers who really want to be green should embrace such a scheme once they understand the benefits and minimal inconvenience. This is a way for people who profess a green lifestyle to demonstrate their commitment and influence others to do the same.
Eventually, the American cultural mindset about having convenience at any cost will be changed to champion responsible energy use with minimal compromise.
