As operating expenses continue to rise and budgets shrink, finding ways to trim energy costs is even more important today than it was 10 years ago, when variable-speed pumps first came on the pool scene. When it comes to operating expenses, one huge figure never seems to shrink — the cost for electricity.
As one of the largest consumers of electricity in a pool, the equipment pad or pump room is a logical place to start. Luckily, several new “cost calculators” allow pool owners to determine exactly where that power is being used.
Many professionals use the figures generated to reinforce their proposals to upgrade to more efficient equipment. They also can be used to help a homeowner or facility qualify for rebates from the local utility in exchange for using energy-efficient products.
Learning the potential savings from equipment upgrades is the first step in renovating a pump room.
What is the cost calculator?
As the name implies, these programs determine the cost to power one particular piece of equipment. Pumps are a great place to start because they are big electricity users.
With this data, cost calculators identify power demand and energy use per day and, more importantly, the cost each year. Comparing the usage figures of current equipment to those of new, energy-efficient pumps puts the savings in black and white.
The use of these cost calculators is quite simple. Once you have all the data required, it’s just a matter of entering it in.
The calculator will begin by asking questions about the pool system, such as how many gallons of water are in the pool and the pump’s turnover time.
Calculators also ask if there is a minimum required flow rate, the number of days the pool is open each year, and how many hours it operates daily. Be sure to have an electric bill handy to enter the cost per kilowatt hour of electricity and the horsepower of the existing pump. Many people do not know the cost per kilowatt hour, but this is a key figure. It can be located on a utility bill or by calling the power company.
Calculators will even take into consideration the suction and return pipe size and estimated flow rate.
In the case of aquatics facilities, it is important to remember turnover rate. If the local health department requires the minimum flow rate needed to achieve a six-hour turnover 24 hours a day, then remember there’s still potential for savings by using a VFD to clean the power going to the pump, which could result in at least a 5- to 10 percent savings.
Also consider this: If you run the pump at higher flows than needed during operating hours, there could be a case for slowing it down during non-operating hours. This could maintain the turnover rate while still resulting in energy savings for part of the day.
How cost calculators work
Cost calculators have pre-loaded formulas to make it easier and faster to obtain the needed data. Ultimately, the calculator shows how reducing pump speed saves energy by a cube factor. The computation takes kilowatt hours (measuring energy used) and rpm (which measures speed) to determine the savings.
The calculators also have integrated pump affinity laws into the computation. This allows a pool professional to demonstrate that lower pump speeds save energy by a cube factor.
Because of the affinity law, reductions in energy consumption have a larger impact than most people realize. It doesn’t work the same as in other examples. Reducing the speed of a pump by 20 percent automatically results in a flow reduction of 20 percent.
However, energy consumption is reduced by a cube factor! So a 20 percent reduction in flow provides almost a full 50 percent reduction in energy. Even a 10 percent reduction of flow saves more than 25 percent of energy!
Commercial pools and utilities
For pool professionals working with aquatics facilities, using a cost calculator is the first step in convincing operators to consider upgrades to their pump rooms.
It’s an easy tool to close a deal with a facility that might be hesitant to upgrade equipment. By showing the tool in action, you can open their eyes as to how much will be saved. When you can go from a $1,000 power bill to $300 in one year after upgrades, it’s a real no-brainer. Then the question becomes, what will the facility do with that extra money?
Commercial clients stand to greatly affect the landscape through energy efficiency. The electrical grid is stressed. With an aging infrastructure and constrained capacity, utility providers are seeking rapid reductions in the amount of power they must provide. More than 322,000 aquatics facilities pumping 70 billion gallons of water make for a nice target. The aquatics industry could make a huge impact on electrical demands. If every pool saw a 20 percent reduction in pump speed for one hour a day, it would free up four medium-sized power plants. A 50 percent reduction for one hour would spare seven medium power plants.
CPS Energy, in San Antonio, Texas, is an example of a utility looking for quick reductions in power usage. The city of San Antonio worked with CPS Energy to reduce the city’s energy usage. An initial energy audit of the city, using tools similar to those of a typical cost calculator, showed that retrofitting 22 city-owned pools would result in a dramatic reduction in energy demand that would pay the needed renovation in less than one year! The city replaced older pumps and installed variable-frequency drives. The total project cost, including equipment and labor, was $137,000. However the annual electrical savings was $63,000 and CPS gave the city of San Antonio a rebate of $87,000. This gave the city a payback on the project of just nine months and a five-year return on investment of 530 percent.
On the residential side
Cost calculators can be helpful to pool pros working in the residential market, particularly in places where utilities offer rebates to consumers who install products such as LED lights, drives and variable speed pumps. Nevada, California and many other states are offering such rebates to homeowners. Those servicing residential pools should take the time to understand these rebates and include information about them in proposals to upgrade pumps and lighting on residential pools. Southern California Edison currently offers a $200 rebate for all new variable-speed pumps installed on pools. Even without a rebate, LED lights and variable-speed pumps immediately reduce monthly electrical bills for residential pool owners. This can be invaluable to a consumer who already has high electricity bills because of air conditioning in the summer. If you show a consumer how they can reduce their monthly electric bill in July and August, you are more likely to sell them on a new pump or LED lighting.
Remember, it’s best to present the information from the cost calculator as an estimated savings potential. Anything can happen in real time, but what you’re doing is using proven formulas and data to show the effects of bringing these pumps where they need to be instead of using one that’s pumping more water and using more energy than is truly necessary.