HYDRONIC HEATING AUTHORITY
AS HUMBLE BEINGS on the face of this fine planet of ours, it is important for all of us as citizens to seek out ways to reduce our environmental impact on the face of the Earth. This applies not only to our corporate positions, but more so to our daily lives. Use only what's necessary, and avoid wasting our precious, non-renewable resources.
Most snow-melt systems in my climatological region are fairly energy intensive, typically requiring peak energy loads of about 150 Btuh per sq. ft. Compared to a typical residential radiant floor-heating system, that is five times the energy needed to maintain a poorly insulated home operating at design condition. When we start talking about snow-melted areas approaching 10,000 sq. ft., we are talking about some serious firepower to make these systems work. Whole mechanical rooms are dedicated to the operation of the snow-melt system alone.
Speaking as a businessman, these jobs make the world go 'round; as a dedicated citizen of the world with energy conservation foremost on my mind, I have to say that it does not do my soul good to see this energy wasted for the sake of not having to shovel snow. It makes me want to find some alternatives to conventionally fueled systems to lessen the carbon impact on the world. A significant amount of research on the Internet has proven that I am not alone.
A whole bunch of like-minded people is out there, thinking outside the proverbial box, looking for ways to lessen our impact on the Earth. Their testing and research have found other ways of being able to maintain a reasonably safe paved area during the majority of typical snow events without creating much extra pollution.
In this next series of columns, we will look at these methods and educate ourselves about the potential of these off-the-shelf technologies and their applications to the typical energy intensive snow-melt system. We'll start by discussing all the different alternative energy sources and then go back and discuss their potential applications.
These alternative sources include, but are not limited to, waste heat recovery, solar thermal systems, groundsource heat pump systems, deep earth energy storage systems, unassisted geothermal applications, biomass conversion systems and energy conserving control logic.
We'll start with waste heat recovery systems.
Although rarely practical for the typical residential system, the potential application for commercial buildings, shopping centers and office buildings is virtually untapped. Most of the aforementioned buildings have a cooling system installed, and most of these buildings spend a significant amount of their annual operating time rejecting heat to maintain reasonable indoor environments.
These cooling systems mostly consist of remote, rooftop cooling units that reject their heat directly into the atmosphere. Even in those situations where there is a central chilled water plant, the rejected heat is sent directly to the atmosphere, yet again contributing potential heat energy to the flywheel movement known as global warming.
Regardless of your views about the reasons behind global warming, a consensus among knowledgeable scientists is occurring and we need to deal with it. Why not recycle heat into other points of use, such as domestic hot water pre-heating or deep earth energy storage systems to be used at a much later date to augment the needs of space heating demand or snow-melt system operation?
Many documented systems are out there with proven track records showing that this technology is sound and that it makes sense to do it. Why, then, is it the exception and not the rule?
Because, other than conserving energy, no other incentives offset the significant costs of implementation. If world governments have their way about it, there will be a carbon tax, which will act as a significant monetary incentive to promote the additional use of these wonderful technologies. These systems will then become the norm.
I am personally aware of many energy-saving systems that are used to perform snow melt. One is a transportation system located in the heart of a major city that uses the waste heat from the condensate from the surrounding buildings' district steam system to produce the energy required for snow-melting operations. Another is a commercial office building in the mountains that uses the snow-melt system to reject the cooling load of the building.
In the case of the transportation center, it not only makes sense from an energy conservation standpoint but also saves water. Before the residual heat was used for snow melting, the condensate had to be cooled down to less than 180°F before being discharged into the sanitary sewer. This required the addition of cold, potable water to the condensate stream in order to comply with the code requirements.
This waste of a precious resource is no longer required now that the waste heat is used in the snow-melt system. Double bonus to the environment!
The hot condensate had to be collected and then piped to a central plant to convert it to a hot glycol solution, but it made sense to do it. It not only provides a safe, slip-and fall-free environment for the transportation facility, but it also saves manpower in snow removal.
All these aspects have to be considered when doing the economic analysis of these potential systems. Or, it may not make sense to do them.
Tune in next month as we continue our journey to reduce the carbon footprint on Earth from snow-melt systems. Until then, Happy Environmentally Sound Hydronicing!
Mark Eatherton is a Denver-based hydronics contractor. He can be reached via e-mail at [email protected] or by phone at 303/778-7772.