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Energy/Conservation

DYNAMO CUTS ENERGY-WATER-EMISSIONS-COSTS BY 50%

The Importance of Green & Clean Technologies for Indoor Swimming Pools


Recycling  -  Commercial swimming pools are by design highly efficient water recycling systems.  Generally using chlorine and automated pH/ORP controllers, commercial year-round indoor pools operate under infinitely variable conditions, including swimmer load factors ranging from dozens to thousands per day.  Keeping this water continuously clean and healthy is what well-run pools are all about.  It is recycling the water efficiently to filter and oxidize all forms of contaminants.  Depending on how well the chemical balance is managed, a pool may operate for 10 years without essentially changing this water.  However, due to high rates of evaporation, considerable fresh make-up water must be added.

Evaporation  -  Because heat loss is integral to the physics of evaporation, indoor pools are constantly working to maintain fresh, healthy air with proper ventilation, while simultaneously trying not to exhaust undue heat out of the building.  Evaporation requires huge amounts of energy loss to occur, resulting in water loss, humidity gain, chemical loss, and possibly increased corrosion.  Dynamo is a big energy consumer with its six pools needing to be heated year round, so we have undertaken a big energy savings project with the idea that what’s good for the environment must also be good for us financially.  The fundamentals of this project are alternative energy (solar) and energy conservation (pool blankets).  The objective has been to cut energy and water consumption.  Only with hindsight have we realized how successful our efforts have been.

Environmental  -  Call it green, call it eco-transformation, consider it Dynamo’s contribution to reducing global warming.  Dynamo has become acutely aware of the need, particularly for indoor swimming pools to integrate alternative energies and energy efficiency practices.  And we have successfully put these objectives into practical practice.  Here’s the magic unique to indoor pools.  The problem for any alternative energy technology is what to do about energy storage and retention.  What Dynamo has discovered and been validating over the past four years is that our pools, with nearly 2 million gallons of water, have remarkable storage capacity for heat (Btu’s).  The “magic” is two forms of pure physics.  One is alternative energy creation using solar thermal panels covering our rooftops.  The other is real energy efficiency using pool energy blankets to cover all water surfaces at night.  Creating a vapor barrier and covering the water surface actually stops the transformation of water from a liquid to a gas, otherwise known as evaporation.  Same principle as putting a top on a teapot.  This blanket prevents evaporative cooling (70%) and ventilation/air movement (27%) which account for roughly 97% of an indoor pool’s total heat loss on a year round basis.

Energy  -  Another analogy  -  leave one cold pot of water on the counter, leave another pot of boiling water on the stove.  Study the difference in the rates of evaporation.  The hot pot evaporates its heat and water much, much more quickly.  This same relative physics phenomenon happens with our heated pools.  All temperatures naturally seek equilibrium.  The greater the temperature differentials, the greater the rate of change.  Warmer pools evaporate faster and in greater volumes.  The colder and drier the outdoor air, the greater the evaporation differential.  Nighttime temperatures are always colder, so the rate of evaporation at night is greater.  The longer and more efficiently you cover the water surface, the less evaporation can occur, and the less heat is lost.  

Dynamo pools are maintained at a year-round temperature of 80-degrees (competition) or 86-degrees (training).   When generally the outside air temperature drops and as the relative humidity drops, the amount of evaporation increases.  On a rainy day, rising humidity may virtually stop evaporation.  Contrary to general opinion, the greatest amount of evaporation does not occur on hot summer days, it occurs in greater volume on cold dry winter nights.

Outdoors around Atlanta, its pools, lakes, or waterways all lose an average an average 50 inches of surface water to evaporation per year every year.  But as water temperatures and air temperatures equalize, evaporation is slowed.  Factoring in wind (air movement), the evaporation loss outdoors in Atlanta is more like 1-1/2 inches per week annualized.  However, indoor pools will create even higher evaporation losses in the neighborhood of 2 inches or more per week.  This is due to generally higher temperature differentials between the warmer pool water and the colder nighttime outside air temperatures in fall, winter, and spring seasons.

Big Renewable Energy & Really Big Energy Efficiency  -  Dynamo believes it has conducted the largest “natatorium energy conservation study” of its kind in the U.S. employing both alternative energy creation (27,000 square feet of solar panels) and energy efficiency (28,700 square feet of pool blankets) over the past four years.  Our objective was to gain a better understanding of evaporative heat loss and to track complex climate variables and difficult-to-monitor evaporation conditions.  We simply took a baseline year (2002), an energy project launch year (2003), and then tracked utilities consumption (gas and water) for the next four years (2004 – 2007).  What we found surprised us  -  solar, with a capital investment of $210,000, only contributed 30% of annual savings.  However the blankets, which cost $25,000, actually accounted for 70% of total savings.  For the past four years, natural gas consumption was reduced by an average of 139,000 therms and water conservation has been reduced from 9 million gallons to 4.6 million gallons annually.

Economics  -  Saving money has been the biggest driving force.  In summary, Dynamo has managed to cut natural gas heating consumption by 50% and water consumption by 50%.  As indicated, roughly 30% of the total energy savings came from alternative energy, the solar thermal hot water heating systems employed on each pool.  But an amazing 70% of total energy savings comes from improvements in energy efficiency or conservation of existing heat.  Just as with preventing heat loss, 100% of water savings comes from stopping evaporation using pool energy blankets 7 hours each night.  Total financial savings each of the past four years for our five pools has averaged close to $200,000 for gas, $27,000 for water, and $10,000 for chemicals.  Cumulative four-year savings are about $950,000.

With the opening of our 6th pool in Alpharetta, savings for the coming year are projected to be $300,000.  Our attention to managing the combined solar and blanket energy programs more efficiently is clearly a high priority.  This $300,000 is a direct bottom line cost savings to our operating budget every year.

Emissions  -  With the 50% reduction in gas consumption comes a 50% reduction in CO2 greenhouse gas emissions.  While energy conservation efforts reduce consumption by 139,000 therms yearly, this means 1.6 million pounds (812 tons) of CO2 are eliminated every year.  The U.S. EPA calculates this as being equivalent to taking 142 passenger cars off the road each year.  Or the equivalent of carbon sequestered by 19,000 tree seedlings grown for 10 years.  From an environmental standpoint, we feel this emissions achievement is an enormous contribution indoor swimming pools can make toward directly reducing global warming and setting a positive example for the community.

Green & Clean  -  Dynamo members see themselves as a new breed of green investor, promoting their small part in improving the swimming world while also improving the global environment.  Dynamo is proud to have developed substantial achievements in multiple areas  -  water conservation, alternative energy creation, energy efficiency, energy storage, and emissions reduction.  In the scheme of things, this has been a pretty big energy savings achievement and financial windfall.  Perhaps the cutting edge of improving natatorium operations.

Bottom Line  -  We have invested our own money, no subsidies, no incentives, no grants, and no rebates.  Along with our desire to be responsibly green, we made it work financially.  We have adapted a simple solar heating technology.  And we have developed our own ultralight, vapor barrier, energy blanket materials and innovative handling system technologies.  We paid back the original capital investment of $235,000 in a little more than a year as utility savings were realized and energy costs began to skyrocket.  Payback on blankets alone is less than two months.  Now each year’s annual savings of $250,000 to $300,000 goes straight to the bottom line.  A great way to prevent offsetting dues increases.  A great way to run your business smarter.

This green & clean energy project has been a great challenge, yielding energy performance and financial benefits far beyond expectations.  We have clearly proven that solar hot water is viable, but the greater impact of energy efficiency using pool energy blankets for indoor pools should be top priority because it yields exceptional economic and environmental returns.  It’s the kind of change in our operations and management philosophy that allows us to compete on a whole new level  -  and become a unique energy example for natatoriums nationally and globally.

Conclusion
  -  Indoor pools cannot afford not to use energy blankets.  This isn’t exactly about saving the environment.  Foremost, it makes good business sense, and it is financially-driven.  It is all about rethinking energy efficiency to consistently save big money year after year by reducing operating expenses.  Saving energy and saving water are by-products of saving money.