To maximize efficiency and achieve the proper turnover for a standard 20,000-gallon residential pool with an automatic pool cleaner using a variable-speed pump, a strategic programming approach is essential. The goal is to ensure that an amount of water equal to the entire volume of the pool is circulated and filtered at least once every 8 hours, while taking advantage of the energy savings offered by the variable-speed technology.
For optimal efficiency, the pump should run 24/7 but at different speeds throughout the day. During the daytime, when the pool is more likely to be in use and when solar energy (if applicable) is available, the pump can run at a moderate speed to ensure adequate filtration and water circulation. For example, running the pump at 40 GPM for 10 hours during the day would circulate 24,000 gallons, exceeding the turnover requirement. This not only keeps the water clean but also maintains better chemical balance and clarity when the pool is most likely to be in use.
During the nighttime, the pump can be set to run at a lower speed, such as 20-25 GPM, which is sufficient to maintain basic filtration and circulation. Running the pump at 25 GPM for 14 hours would circulate an additional 21,000 gallons, ensuring continuous filtration and further improving efficiency by using less power at lower speeds. This approach leverages the pump affinity law, where reducing the speed of the pump significantly lowers energy consumption, resulting in considerable cost savings.
For pools with a pressure-side cleaner, which typically requires a booster pump, the variable-speed pump can indeed replace the booster pump under certain conditions. Many modern variable-speed pumps are powerful enough to handle the additional load required by pressureside cleaners. By programming the variable-speed pump to run at a higher speed during the times when the cleaner is scheduled to operate, the need for a separate booster pump can be eliminated. For instance, if the pressure-side cleaner is set to run for 2 hours daily, the variablespeed pump can be programmed to increase its speed to the necessary level (e.g., 60 GPM) during this period to provide adequate pressure for the cleaner to function effectively.
For suction- side cleaners, the variable-speed pump can be programmed similarly, ensuring that the pump operates at a speed sufficient to power the cleaner during its scheduled run times. Typically, suction-side cleaners require less pressure than pressure-side cleaners, so the pump may not need to run as fast as it would for a pressure-side cleaner.
In summary, the best way to maximize efficiency with a variablespeed pump for a standard residential pool with an automatic pool cleaner is to program the pump to run 24/7, adjusting the speed at different intervals.
During the day, run the pump at a moderate speed for enhanced filtration and circulation, and at a lower speed during the night for basic filtration.
This approach ensures proper turnover, leverages the energy-saving benefits of variable-speed technology, and can also eliminate the need for a separate booster pump for pressureside cleaners by increasing the pump speed during cleaner operation times.
This method achieves both energy efficiency and effective pool maintenance.
Comparing Costs
To compare the cost of running a variable-speed pump as described to the cost of running a single-speed pump, we need to consider the power consumption of each pump type and the national average price of electricity. As of June, 2024, the average price of electricity in the U.S. is approximately $0.178 per kilowatthour (kWh).
Variable Speed Pump
Let's break down the variable speed pump operation: 1. Daytime Operation: 40 GPM for 10 hours 2. Nighttime Operation: 25 GPM for 14 hours 3. Cleaner Operation (if needed): 60 GPM for 2 hours Assuming the power consumption at different speeds (using typical variable speed pump data):
• At 40 GPM: ~500 watts (0.5 kW)
•At 25 GPM: ~150 watts (0.15 kW)
• At 60 GPM: ~1,000 watts (1 kW) Day Operation Cost: 10 hours × 0.5 kW = 5 kWh Night Operation Cost: 14 hours × 0.15 kW = 2.1 kWh Cleaner Operation Cost: 2 hours × 1 kW = 2 kWh Total Daily Energy Consumption: 5 kWh + 2.1 kWh + 2 kWh = 9.1 kWh Total Daily Cost: 9.1 kWh × $0.178/kWh = $1.62 Monthly Cost (assuming 30 days): $1.62 × 30 = $48.60 Single-Speed Pump Single-speed pumps typically run at one high speed (let's assume 3,450 RPM) and consume around 2,000 watts (2 kW). These pumps often run for 8 hours a day to achieve the necessary turnover.
Daily Energy Consumption: 8 hours × 2 kW = 16 kWh Daily Cost: 16 kWh × $0.178/kWh = $2.848 Monthly Cost (assuming 30 days): $2.848 × 30 = $85.44 Cost Comparison
• Variable Speed Pump Monthly Cost: $48.60
• Single-Speed Pump Monthly Cost: $85.44 Monthly Savings with Variable Speed Pump: $85.44 − $48.60 = $36.84 Annual Savings: $36.84 × 12 = $442 In summary, running a variablespeed pump as described costs approximately $48.60 per month, while running a single-speed pump costs around $85.44 per month. This results in monthly savings of about $36.84 and annual savings of approximately $442 when using a variable-speed pump.
This demonstrates the significant energy and financial benefits of using a variable-speed pump over a singlespeed pump.
