How Can We Save 2-Trillion Gallons of Water?

YOU'D BE SURPRISED HOW MUCH WATER...

MANY COMMERCIAL AND RESIDENTIAL COMPLEXES use cooling towers to effectively aid in cooling.  An average public high school’s* cooling tower uses about 30,000 gallons of fresh water per day when it’s hot outside. That’s enough to fill a good sized back-yard swimming pool. Twice.  

A major airport can consume close to a million gallons of fresh water on a hot summer day, just for cooling tower operations. It’s great that we are honoring watering restrictions, fixing drips in faucets and leaky toilet valves; however there are billions of gallons of fresh water being evaporated and discharged into the sewer from cooling towers every day.

Cooling towers use the process of evaporative cooling to increase the energy efficiency of the air-conditioning equipment that serves the building. In the process, a lot of water is evaporated, and nearly as much more is flushed down the drain to purge out impurities.

The US had about 81 billion square feet of commercial space in 2010, served by 300 million tons of cooling capacity (based on floor space estimates from DOE report). This represents between 5-billion and 15-billion gallons of fresh water consumption each day. 

Buildings + Geothermal = More Fresh Water for US!

Industry has begun to embrace geothermal (elimination of cooling towers) for all the right reasons:

• Elimination of water consumption associated with cooling towers
• Elimination of tower related noise
• Elimination of chemical treatment for cooling towers
• Reduction in annual maintenance costs for HVAC system
• Storm proofing through elimination of outdoor equipment (the cooling tower)
• Impressive federal tax incentives
• Reduced capital expenditures for regular cooling tower replacement

The advantages that can be cited that make a geothermal sourced building more sustainable are many. With a reduction of water consumption (which can be close to half of all the freshwater consumed by a building), your client is saving money and doing a good thing for the environment.

Cooling towers can be rather noisy, and most will agree that elimination of this outside noise would be of benefit to both the public and occupants of the building.

Geothermal is Renewable and Energy Efficient, Too

Geothermal sourced chiller plants and heat pumps are more efficient by design, because the condenser water is cooler than can be supplied from an evaporative cooling tower, increasing the EER (Energy Efficiency Rating) substantially.

The average life of a chiller is about three decades, and most chiller plants live through two or three cooling tower replacements. With the geothermal source, these expensive planned expenses go away.

By placing a chiller plant, or any cooling tower-sourced building using water source air-conditioners/heat pumps on a geothermal source, you have created an entirely geothermal sourced building, making the entire building’s HVAC system eligible for federal tax credits. This means that when upgrading chillers and water sourced heat pump, they may be eligible for the current tax credits for geothermal systems.

Most regions of the country and the world have storm events periodically such as hurricanes, tornadoes, blizzards, etc. These storm related events can destroy outside equipment. Many insurance companies will provide credits for elimination of this equipment. The New York Times said, “Geothermal Systems Arise as a Storm-Proof Resource”.  Additionally, outside equipment often needs to be winterized, and properly installed geothermal sources may save you these seasonal costs and headaches.

The federal government gives a 10% federal tax credit, and five year depreciation through the Maximum Accelerated Cost Reduction System (MACRS) on commercial geothermal systems.  With 50% bonus depreciation the first year, a $1 million upgrade can net federal tax incentives amounting to 48% of the entire cost, or federal tax incentives of $480,000.

A Helping Hand for the California Drought (and everywhere else)

The USGS says that the average American uses 80 to 100 gallons of water each day.   Cooling towers use as much fresh water as 50,000,000 US residents each day. I think that California could put that water to good use. This is in the neighborhood of 20% of the volume of water that flows over Niagara Falls each day (65 Billion gallons of water flow over Niagara Falls each day).

• Geothermal HVAC technologies save our energy and water resources. Get Ready to GEO
• New York New York Approves Landmark Thermal Network 
• Presentation on the Utility Thermal Energy Network and Jobs Act: A Renewable Transition https://youtu.be/l1BEQCH47Hc  
  

*based on national average of 752 students per high school, 2000 https://nces.ed.gov/pubs2001/overview/table05.asp 

Save Precious Water With Geothermal Heating and Cooling

Geothermal-Sourced Chillers Save
Billions of Gallons of Fresh Water

Think about the types of building materials that have endured. For example, cement, concrete block, gypsum, and good old fashioned wood/lumber. These have all endured as building materials favored by many. Water has certainly endured as a medium for heating and cooling. Commercial buildings pump the lifeblood of cooling and heating systems through a building in the form of chilled or heated water, depending on the needs of the building. 

Geothermal heating and cooling (HVAC) completes this wonderful cycle by coupling buildings with the shallow Earth, just like a tree’s root system. Closed loop piping filled with life-giving water circulates, transferring the heat to and from the Earth, similar to the way tree roots transfer the essentials of life from the Earth through their branches and leaves. This is perfect symbiotic sharing of energy with the Earth, and is as close to nature as one can get in the process of heating and cooling of building.

Like a Tree's Root System, Geothermal Couples a
Building with the Shallow Earth to Transfer Energy

With respect to refrigerants, water is called "R–718". It has impressive thermal properties, and can be engineered through the established fluid flow practices to efficiently transfer heat to and from a building, using far less energy than forced air systems, and significantly less energy than is needed for refrigerant flow based systems. I mentioned refrigerant flow, because there seems to be a fad of sorts involving equipment with multiple evaporators in homes and commercial buildings. Whether these variable refrigerant systems with multiple evaporators are geothermal sourced or not, the fact remains that pumping refrigerant through building uses more energy, is not natural, and you might wonder what the long-term effects are, as well as the energy efficiency aspects.

Fact is that recent studies prove unequivocally that refrigerant flow takes more energy per BTU than just pumping water. Commonly use refrigerants (other than R-718, water) must be pumped at high velocity to keep the compressor oil en-trained within the stream running through the refrigerant piping. This high velocity pumping wastes significant power when compared with hydronic (water based) heating and cooling systems.

Greg Cunniff, co writer of the book, "Modern Geothermal HVAC Engineering and Control Applications McGraw-Hill 2013”, has done significant research on the subject, some of which can be seen in results from comparisons at the headquarters of ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) in Atlanta.

Water seems limitless, especially when looking at the oceans, which cover about 2/3 of the planet.  Fresh water is not as abundant.  Most of it is in our aquifers, and it’s important that we conserve this resource. Used for drinking water is OK, but using water for things like cooling a building might be a little reckless. 

Commercial buildings, hotels, airports, factories, schools, shopping centers, high rises and power plants use cooling towers to cool down their air-conditioning, refrigeration, and process loads in their facilities. Cooling towers use evaporative cooling principles to decrease equipment size and increase energy efficiency.

Cooling Tower Consumption of Fresh Water is
Eliminated By Geothermal-Exchange

These commercial facilities have a many needs for fresh water that include sanitary, irrigation, and cooling tower.  According to the EPA, about 25% of the water used in office buildings is for the cooling load.  In process cooling applications like laboratories and manufacturing, the consumption for cooling towers is more than 50% of the total consumption of fresh water.

To put this into terms of gallons of water, a typical 50,000 square foot high school will use about 30,000 gallons of water per day; enough to fill two basic swimming pools.   Indianapolis International Airport can use a million gallons of fresh water just for cooling on a summer day.

Geo Saves Fresh Water and Increase Longevity and Resiliency

The US had between 71 and 81 Billion square feet of commercial space in 2010, served by 2 to 3 billion tons of cooling capacity.   [based on floor space estimates from DOE report] This represents between 1 Billion and 3 Billion gallons of fresh water consumption each day.

In our efforts to conserve Earth’s water resources, geothermal sourced heating and cooling will save billions of gallons of fresh water. Some locations can use surface water, others will use ground coupled exchangers, and many will use aquifer thermal exchange

Summary:

Hydronic (water-based) geothermal heating and cooling systems are the most energy efficient HVAC systems in the world today. Less is more; simple is better.

More information on Geo? Just use #GeoDay2015 for social media, and checkout the Geothermal Day Website , IGSHPA and the Geothermal Exchange Organization. 

Jay Egg is a geothermal consultant, writer, and the owner of EggGeothermal. He has co-authored two textbooks on geothermal HVAC systems published by McGraw-Hill Professional. He can be reached at jayegg.geo@gmail.com .