SWIMMING POOL
Silvercreek Development Company (Silvercreek Pools©) partnered with the green team to innovate around traditional pool design. The pool evolved from its original inception of a biologically filtered natural swimming pond to a "traditional" swimming pool with separate biological wetland bogs along its border.
Pool/pond design evolution
- In green building the number one issue that typically trumps all else is energy consumption. Nothing affects footprint, carbon emissions, climate –whatever you are measuring – in the way energy does.
- Late in the game, extensive modeling determined that in our climate (with natural air conditioning from the fog and the resulting nightly drop in temperatures) the energy requirements to heat the pond due to the need for continuous flow (pumps) and the mass of water flowing through uncovered bog spaces (causing both heat loss and evaporation) to ensure bio filtration and safe swimming were just too massive.
- Nightly energy loss also overstressed our originally planned pond heat source, the thermal mass of the sport court. (A detailed energy analysis comparing all options produced by Rumsey Engineers is available upon request.) As a result the sport court was replaced with a regulation Bocce Court and more native meadow more in keeping with the aesthetics of the project.
- It was determined that a more “conventional” pool leveraging the latest ozonation technology would reduce the need for chlorine by 50% to 75% from a normal pool (original goal was zero chemicals). The alternative was to stick with the natural swimming pond model using zero chemicals but that model would require the addition of 100 more solar panels to heat it to a swimmable temperature given the above heat loss challenges. In green building, energy trumps everything and it was determined that the moderate use of chlorine was far more sustainable than adding significantly more solar. The natural bogs remained the same as originally designed both in terms of creating habitat and maintaining the “natural pond” aesthetic.
- A salt swimming pool was also considered but research uncovered that California is slated to eliminate them as options in the near future because of ground pollution and premature metal corrosion.
Swimming pool innovations.
Display More [+]In addition to using the ozonation technology, many other innovations went into the design of the pool.
- We eliminated the use of PVC pipe by using only High Density Polyethylene (HDPE) pipe and UL Approved electrical conduit to plumb the pool. HDPE is non-chlorinated, requires fewer additives, and has a much higher recycling rate and is thus considered a more benign plastic. We used a local supplier in South San Francisco. This is the first time we have ever used or ever heard of using HDPE for plumbing a swimming pool.
- From HDPE pipe to recycling our form material, to trying to use USA made steel, to California sand in our gunite, to locally made hand crafted tile from Sonoma, we have tried to reduce the carbon footprint of the pool construction. Sonoma Tilemakers have a mission statement to be "Greener Every Day". They are committed to eliminating waste from the production process, utilize clean energy practices and protect the environment. Sonoma Tilemakers are also the largest solar energy creator in their hometown of Windsor, California.
- We are using the most energy efficient pool equipment on the market. We are using a Pentair IntelliFlo variable speed pump for the pool filtration. The IntelliFlo employs exclusive permanent magnet motors (used in hybrid cars) which are a fundamentally more energy-efficient design compared to traditional induction motors. It includes a variable drive that allows the pump to be programmed to operate at a lower optimum speed so we can exploit a fundamental pump law: by going slower, power consumption is reduced.
- The Pentair Clean & Clear Plus Cartridge Filter has an efficient water flow path that ensures optimum filtration while reducing overall back pressure and using a lower speed on the pump. We are using a cartridge filter in lieu of a traditional sand filter. A sand filter requires backwashing the sand to clean the filter. Backwashing requires the water to be sent to waste. With a cartridge filter, the cartridge inside is removed and then rinsed. This will save hundreds, if not thousands, of gallons a year.
- The pool is being heated by a geothermal system composed of six bores/wells at 300ft depth, 20ft apart. The geothermal heat is pumped through a heat pump which is then sent to the heat exchanger. The heat from the heat pump is then transferred to the pool water at the exchanger. We have used an automatic safety cover to help minimize the water and heat loss.
- We anticipate the future development of a thermal pool cover that is also an approved safety cover, so we have built an oversized pool cover vault to accommodate the thicker thermal cover. According to DOE, “almost all of a pool’s heat loss—about 95 percent—occurs at the surface, mostly through evaporation to the air and radiation to the sky.” Today you can buy either a safety cover or an insulating bubble blanket but there is no product that serves both ends. Again our hope is to help create a market for green goods by helping to fund and be the beta site for new technologies and products such as this next generation pool cover.
- The lights used in the pool are IntelliBrite 5g LED Lights. The IntelliBrite LED lights need only 30 watts to create the same light output as traditional incandescent and halogen lights at 161 watts - more than 81% less.
- For the pool sanitizing system, we went with the Del Ozone Eclipse ozone sanitation. Ozone sanitation provides the cleanest water for the pool with a significant reduction in chlorine (60 - 90%) which translates into less money, less time balancing water chemistry, fresher water and reduced environmental impact. Ozone is created by a corona discharge then introduced into the pool water return system. It will kill up to 99.99% of bacteria, viruses, molds, algae, and other unwanted particles. The only by- product from Ozone is Oxygen. It is 100% environmentally safe!
- Since the bogs are no longer part of the pool filtration design, they are now their own separate entity. They are their own ecosystem. Different type rock media was layered in the bog areas on top of an HDPE filtration cover which creates clear open suction. Specialty native aquatic plant life is planted atop the bog areas creating a wetlands area. All the bogs are connected. The small bog at the entrance of the pool acts as the water return wetland. The larger bog areas on the sides of the pool are the suction sides of the wetlands. Water is returned to the smaller bog and the larger bogs draw the water through the wetlands. We have equipped the wetlands/bogs with its own filter pump, filter and ozone system. The filter is plumbed to be completely bypassed so as not to lose any vital nutrients the plant life may need but is equipped in the event it needs to be filtered. The filter is filled with "Bio-beads" which is designed for koi pond and wetland applications. The idea of the wetlands is to create habitat and to enhance the illusion of a swimming hole in the middle of the field, as if one body.
- The Project
