Swimming pool operators know pools can be hogs of both energy and water. Water is lost to evaporation, heat is lost to the surrounding environment, heaters and pumps can be inefficient, and pool chemicals are a toxic hazard.
With the rising cost of fuel, wise pool operators are greening-up their operations--benefiting their pocketbooks, their employees and the environment. "Going green has always been good,” says Tom Lachocki, CEO of the National Swimming Pool Foundation. “With energy costs so high, going green is like gold.”
Pool operators have a multitude of options in becoming more environmentally friendly. These include efficient heating, programmable controls, hydraulics, filters, chlorine generators, variable speed pumps, lighting and dehumidifiers.
Options For Efficient Heating
The electrically powered heat pump captures the heat from the atmosphere and returns that heat to the water. “There is no combustion process, it is just transferring the heat,” says Jeff Farlow, program manager of energy initiatives with Pentair Water Pool and Spa, a global manufacturer of swimming pool and spa equipment and accessories. When selecting a heat pump, check to make sure it uses R410A refrigerant, which will be mandatory in 2010.
“It takes much less electricity to run a heat pump than it does gas to heat a pool with a gas heater,” says Connie Sue Centrella, program director and professor of Aquatic Engineering and Technology at KeiserUniversity. “The key to the heat pump is the coefficient of performance (COP). The higher the COP number, the more efficient the heating will be. So in laymen’s terms, if you have a COP of 4.5, that means that for every dollar of energy, you are going to reap $4.50 in energy because with a heat pump, you are increasing the efficiency.”
Geothermal heating units use the heat from the ground to heat pool water. “It is like mining the earth for heat,” says Centrella. “It takes the earth’s ability to store heat, and transfers it into the pool heater.”
The ultimate pool heater is solar energy; however, it only works in those areas that have sufficient ultraviolet rays and warmer weather. “With a solar heater, you pump the pool water through a series of panels facing the sun,” says Centrella. “The water circulating through the panels warms up, and the warm water is returned to the pool.”
The disadvantage of solar heating is that you need to have the same square footage in solar panels as you have in swimming-pool surface.
Technology has helped improve the efficiency of gas heaters from 75 percent to 95 percent. For example, a 75-percent efficient gas heater will only use 75 percent of the fuel for heat production, so for every dollar of fuel used, you are only getting a return of 75 cents. With a 95-percent efficient heater, you are getting a return of 95 cents for every dollar of fuel used. An energy-efficient heater provides more heat for your dollar, which saves money.
By providing wider pipes, larger filters and fewer bends in the pipe, you can decrease the amount of energy the pump needs to move the water through the system. In addition, by bypassing the water flowing through the heater, you can reduce the amount of energy needed by the pump. “Water pressure drops when it passes through a heater,” says Farlow. “If the heater is plumbed with a bypass, you can avert the flow from the slow down of passing through the heater when the water doesn’t need to be heated.”
“Go with the largest filter size that you can because it will reduce the amount of resistance,” says Centrella. “When you lower the resistance, you also lower the total dynamic head, and that means less horsepower is required to achieve the same flow rate.”
“There is nothing wrong with using an oversized filter,” says Farlow. “With the large surface area, there is less pressure drop over the filter, and you can extend the time between cleanings.”
Sand filters need to be cleaned by backwashing, which can waste between 500 gallons to 1,000 gallons of water unless it is captured in a settling tank. The captured water then can be recycled into the pool once the particulates have been removed.
Cartridge filters can be cleaned by removing and spraying them thoroughly with a garden hose. This method uses between 50 gallons to 100 gallons of water. The cartridge filter has a hydraulic advantage over the sand filter--since the cartridge filter is not cleaned by backwashing, a backwash value is unnecessary. This is another way to reduce the resistance that makes the pump have to work harder.
Most pool operators typically shock the pool because chlorine degrades with time, resulting in fluctuating chlorine levels. A chlorine generator provides a steady level of chlorine by using a small amount of electricity to convert table salt into chlorine.
"You're not exposing the maintenance staff to chlorine fumes," says Centrella. “With this device you literally are continuously generating chlorine with very little electrical energy.”
The automatic chlorine generator is easy to use. Simply set it to the log value that you need to have for the parts per million (ppm) level of chlorine. The generator will maintain that level and will alert you to when you need to add more salt, which is as easy as pouring table salt into the pool.
Variable-speed pumps allow you to change the flow rate. A fundamental law of physics states there is a relationship between speed, flow, pressure and power consumed. The energy-conserving component of this law is that by reducing the pump speed by half, you will get half the flow for one-eighth of the power.
Health departments usually require a minimum of a six-hour turnover rate when the pool is operating. This means that with a variable-speed pump, you have the option of reducing the flow when the pool is closed, which will reduce fuel costs.
Shedding A Little Light
“LED [light emitting diode] lights are very effective, and they take a lot less energy to run than the traditional 500-watt, 125-volt lights installed in most park and recreation pools,” says Centrella. LED selection should be based on the amount of lumens the unit produces to make sure the pool is meeting safety requirements.
Fiber optics are being used as accent lighting to enhance water features, such as laminar jets, waterfalls and bubblers, as well as along the borders of swimming pools. “Fiber-optic lighting is something that should be done during construction,” says Steve Gasperson, vice president of marketing and sales for Fiberstars, a fiber-optic lighting manufacturer. “The majority of our products are used to accent water features such as those you would see at a water park.”
Dehumidifiers remove the humidity from the air and convert it into water, which is returned to the pool. “It is a good cost savings, and you have to have a dehumidifier with indoor pools,” says Centrella. “The issue with the dehumidifier is that you must maintain the pool balance to keep the dehumidifier from eroding.”
“The industry as a whole is working on ways to reduce costs and create more energy-efficient, environmentally friendly pools,” says Centrella.
With various states enacting laws for residential pools to use variable-speed pumps, going green might not be optional for commercial pools in the future. But, by taking a few easy steps now, pool operators can create an energy-efficient, environmentally friendly pool which benefits the bottom line and reduces workplace hazards.
Tammy York is the president of LandShark Communications LLC in Greater Cincinnati. She left her state public-relations position to pursue her passions of outdoor recreation and marketing. Her upcoming book 60 Hikes within 60 Miles of Cincinnati is due out spring 2009. You can reach her at firstname.lastname@example.org