Category Archives: Pool Pumps

Swimming pool pumps category

Variable Speed Pool Pumps

Variable Speed Pool Pumps Enhance Pool Efficiency

Achieving the ideal filtration flow rate for a swimming pool with the least amount of energy consumption is made possible by variable speed pool pumps. Variable speed pool pumps are equipped with Permanent Magnet Motors (PMM) unlike single speed pumps which are driven by Induction motors. These pumps use permanent magnets to create a magnetic field between the rotor and the windings similar to the motors used in hybrid cars. Efficiency is delivered by magnets working to spin the rotor as opposed to a creating a magnetic field in the rotor with a standard induction motor that requires additional electricity.

Installing a Variable Speed Pool Pump

In comparison to single speed pumps which use induction motors, motor designs using PMM can achieve efficiencies of up to 90%. The average single-speed pumps have efficiency ratings between 30% and 70%. As for flow rates, the PMM pumps can produce the same gpm flow rate as single-speed induction motors but use significantly less power.

Energy Efficiency of Variable Speed Pool Pumps

Efficiency is achieved by programming the PMM pump to desired flow rates depending on usage and condtion of the pool A single speed pool pump in contrast is set to operate at a set flow rate even when the required flow rates may be a lot lower. The variable speed pump can be slowed down to the optimum required flow rate thereby conserving energy. The physics behind this efficiency of the PMM pumps is explained by the Pump Affinity Law. The savings are achieved by operating at lower speeds which in turn drops the power consumption. The table below demonstrates the results of this law.

Pump Affinity Law

Speed(rpm)	Flow(gpm)	Power(W)
3450	66	2,000
3000	55^*	1157
2400	44	593
1800	33	250
*A reduction in 450 rpm almost unnoticed in the application, cuts the power almost in half.

An example cited by the Department of Energy Publication “Measure Guideline: Replacing Single-Speed Pool Pumps with Variable Speed Pumps” dated May 2012 illustrates how replacing a single-speed pump with a variable speed pump can create significant energy savings.

The average residential swimming pool contains 25,000 gallons of water and has a suggested turnover rate of 24 hours. A single-speed pump drawing 2,000 watts, operating at 3,450 rpms and generating a flow rate of 66 gallons per minute can turn over the entire 25,000 gallons of water in roughly 6.3 hours.

(25,000 gallons / 66 gpm) /60 minutes = 6.3 hours

At this rate the single-speed pump would consume 12,600 watt hours or 12.6 kWh per day, to turn over the pool.

6.3 hours x 2,000 watts = 12,600 watt hours (12.6 kWh)

However, because of the Pump Affinity Law, slower flow rates create greater energy savings. In the field, a variable speed pump set at a flow rate of 22 gpm will draw 116 watts and turn the pool over in 19 hours but only consume 2.2 kWh of electricity.

(25,000 gallons / 22 gpm) /60 minutes = 19 hours – 19 hours x 116 watts = 2,200 watt hours (2.2 kWh)

This is a savings of 10.4 kWh per day, or approximately 3,796 kWh per year. The average retail price of electricity to residential customers in California, where there are an estimated 1.1 million in ground pools, is 14.8 cents per kilowatt-hour. Following this example, the homeowner could realize a savings of $561 annually on their electric bill.

Selecting Above Ground Pool Pumps

Interesting image of a large swimming pool complex

One complete turnover of water every 24 hours provides adequate pool filtering

Swimming pool pumps can be classified by the location of the pump in relation to the water level of the pool: above ground or in ground. Above ground pool pumps are known as a flooded suction pumps. What this means is that the pump is designed to operate with the water level always being higher than the pump.

The opposite is true for in ground pool pumps. They are designed to work with the water level situated lower than the pump. In other words, an in ground pool pump is designed to draw water up — the water level of the pool being lower than the pump. While there are some design differences between the two types of pump, the major difference is in the plumbing.

Pool Pump and Filter Installation

Residential inground and above ground pool pumps are used to circulate and filter swimming pool water in order to maintain water clarity and sanitation. Pools need to be filtered. How long you should filter your pool depends on:

The size of the pool.
The filtering equipment.
How much you use the pool.
Different environmental factors (such as how much sunlight hits the pool).

As a general rule, one complete turnover of water every 24 hours provides adequate filtering for a single-family pool. The more you use your pool, the more filtering it will need. It is generally recommended that you run your filter for four to six hours a day during the summer and two to four hours a day during the winter.

In houses that have in ground or above ground pool pumps, they are almost always the largest single electrical end-use, using over three times the energy of a new refrigerator. More importantly, they create a diversified electrical demand over 20 times that of a new refrigerator. Residential pump motors range in size from one half to three horsepower (hp), are operated an average of about four hours per day, but in some cases up to 10 hours per day, and draw approximately one kW per nominal horsepower.

A leaf strainer is usually integrated and aids in priming the pump when it is installed higher than the pool surface. Pools may use multiple pumps for pool filtration, bottom cleaning (pool sweep), and for operating water jets for adjoining spas. Bottom cleaning systems are usually integrated with the filtration systems and operate on vacuum or pressure supplied by the filter pump. They either operate on the suction side (vacuum) of the filtration piping (such as the bottom crawler type), or on the high pressure side of the pump (such as floating pool sweeps). Since bottom cleaning (“pool sweep”) systems require full flow to operate properly, low speed operation of two-speed pumps can inhibit their function. High-pressure cleaning systems sometimes employ separate pumps to provide water pressure, but this practice is becoming less common.

Three types of filter media are commonly used. Sand filters remove particles down to 25 microns (μ or micrometers) and are cleaned by back washing. Cartridge filters remove particles down to approximately 15μ and are cleaned by removing the cartridge and spraying it down. Diatomaceous earth (DE) filters remove particles down to 3μ and can also be back-washed (ADM 2001). Sand filters require the most pump pressure, followed by diatomaceous earth and cartridge filters.

Selecting an above ground pool pump or an inground pool pump

Manufacturers offer high efficiency pump-motor combinations for most of their product lines, typically using capacitor start, capacitor run motors, but specific pump efficiency data are not generally published by manufacturers and are not available from other sources. Manufacturers offer above ground and inground pool pumps with the following characteristics:

A) Single-speed Pump: A pump which has an electric motor that operates at only one speed.

B) Multi-speed Pump: A pump which has an electric motor that can operate at multiple, discrete speeds.

C) Variable-speed Pump: A pump which has an electric motor that can operate at continuously variable speeds.

D) Variable-flow Pump: a pump which has an electric motor that can operate at continuously variable speeds, with added controls that automatically adjusts speed to control flow.

Selecting a pump entails picking the pump with the right characteristics that fit the design requirements of the pool and evaluating the performance parameters published by the manufacturer. Most manufacturers provide the following information about the pump-motor:

Rated HP
Actual HP
Service Factor
Volts
Amp Draw
Energy Use (watts)
Annual Cost @ 24 hr filtration
Annual cost @ 12 hr filtration
Pump Warranty
ROI (5 year)
Energy Efficiency Rating
Overall Product Rating

It is important to understand what each of these performance parameters mean in determining the right pump for you. The following is an explanation of the terms listed above:

Rated Horsepower (HP): The motor power output designed by the manufacturer for rated revolutions per minute (RPM), voltage and frequency. May be less than Total Horsepower where the Service Factor is > 1.0, or equal to Total Horsepower where the Service Factor = 1.0. Also known as Nameplate Horsepower.
Service Factor: A multiplier applied to Rated Horsepower of a motor to indicate the percent above Nameplate Horsepower at which a pump motor may operate continuously without exceeding its allowable insulation class temperature limit, provided the other design parameters such as rated voltage, frequency and ambient temperature are within limits. A 1.5 HP pump with a 1.65 service factor produces 2.475 HP (Total Horsepower) at the maximum Service Factor point.
Total Horsepower: The product of the Rated Horsepower and the Service Factor of a motor used on a Pool Pump (also known as Service Factor horsepower, SFHP) based on the maximum continuous duty motor power output rating allowable for nameplate ambient rating and motor insulation class. Total Horsepower = Rated Horsepower x Service Factor.
Volts/Amps/Watts –The energy efficiency of a pump is measured by the electrical consumption of the pump and motor and is dependent on the Amps and Watts.
ROI – Return on Investment & Energy Efficiency are both linked and determine the selection of the pump
Overall Product Rating is very important – review about the pump by experts, by consumers and by agencies that test equipment should be reviewed before deciding on a specific pump.

The following pump makes are currently available in the market with energy efficiency ratings that can qualify for rebates from your local electric company.

Leaf Pumps
Eco Pump
Pentair Intelliflo
Hayward Tristar
Pentair Whisperflo
Hayward Northstar
Sta-Rite Max-E-Pro
Hayward Super 2

Efficient Pool Pump Comparison

Sparkling Pool with Efficient Pool Pumps

Pacific Gas and Electric’s Code and Standards Enhancement (CASE) Initiative for efficient Pool Pump comparison has provided some much needed guidance for understanding and comparing pool pump efficiency and selection of in ground and above ground pool pumps. Pump efficiency varies with flow rate and head. Selecting an efficient pump for your pool means selecting a pump with a flow rate close to the design flow rate for the pool system. The design flow rate should be chosen to be no fewer than 8 hours per day for residential private pools. In addition to applying proper design practice, there are two approaches to improving efficiency. These include high efficiency pump-motor combinations and using pumps with two-speed motors. Using pumps with two-speed motors offer the most significant opportunity for energy savings by taking advantage of pump affinity laws, that state that the power consumed by a pump is proportional to the cube of the flow rate. In example, the power required to pump one half the flow rate is one eighth the power required to operate at the full flow rate. Operating a pump equipped with a two-speed motor at half speed for twice as long therefore moves the same volume of water, but in theory uses only one-quarter the amount of energy.

What’s Pump Efficiency

Unlike motor efficiency, pump efficiency varies substantially with load. Pump (impeller-volute) efficiency can be determined by testing, but is seldom reported and is not regulated by state or federal standards. The efficiency of pool pump and filter systems can also be improved by properly matching pumps to system flow and pressure head requirements. Service factor is a measure of how much a pump motor can be under-sized without overloading the motor. For example, a 1 HP pump with a service factor of 2.0 draws about the same power as a two-horsepower pump with a service factor of 1.0. The reasons for marketing high service factor pumps are unclear, but the practice creates confusion and could be contributing to inappropriate pump sizing.

Design Life and Life Cycle Cost of Efficient Pool Pumps

The average service life of swimming pool pumps is ten years in accordance with data collected by the Department of Energy in Priority Setting for New Products, published on October 26, 2001. Newer technologies and light weight components have not altered this data by much. Testing or labeling would not affect design life. No data are available to determine whether low speed operation extends or shortens motor life. Since motor life is principally determined by speed and heat, one might speculate that a two-speed motor operating at low speed would last longer, since the speed and heat would be reduced. A comparison of the high efficiency and two-speed pool pumps for life cycle cost by the California Energy Commission 2000 Appliance Standards indicated that the 2 speed pumps had a lower life cycle cost than the high efficiency pumps.

Optimizing Operation with Energy Efficient Pool Pumps

Energy Efficient Pool Pumps Deliver Performance

To get the most out of energy efficient pool pumps it is important to understand the critical parameters that govern the pool. As a general rule, one complete turnover of water every 24 hours provides adequate filtering for a single-family pool. The more you use your pool, the more filtering it will need. It is generally recommended that you run your filter for four to six hours a day during the summer and two to four hours a day during the winter.

If you’re filtering more than this, try reducing your daily filtering time by 30 minutes. After a week, if the water clarity and chemical balance show adequate filtration is taking place, try reducing your filtering time by another 30 minutes. Continue this process until water clarity or chemical imbalance indicates more filtering is needed.

In addition to chemical testing, a good way to check your water clarity is that the main drain cover should be clearly visible from the deck.

Automatic pool sweeps (booster pump style): Usually, three to four hours of daily operation during summer and two to three hours daily in the winter are sufficient. Start the pool sweep one hour or more after the pool pump has started and stop the sweep one hour or more before the pool pump turns off. On unusually dusty days, increase cleaning time in half-hour increments until the pool is clean. Use a wall brush and leaf skimmer frequently to help the sweep along.

Filter during off-peak times: You can help everyone by filtering your pool during off-peak hours. Avoid operating your pool filter between the hours of noon and 6 p.m. This will help reduce the demand for electricity, conserve natural resources, and save money. However, if your pool has solar heating, you’ll need to filter when the sun is correctly positioned for your solar panels. However, we recommend that you minimize filtration during the peak period of noon to 6 p.m. as much as possible.

Setting filtering time: A filter time clock is an easy way to manage pool filtering. Just be sure to check it once a month to make sure the trippers are secure. Check your clock’s instruction manual for directions on setting the operation times. Remember to reset the time clock after power outages and for the fall and spring time change.

Preventive maintenance: Follow a regular program of preventive maintenance, including an annual inspection and de-liming of the heat exchanger to help maintain heating efficiency.

Motor and pump assembly: When its time to replace your old motor and pump assembly, consider a new energy-efficient model with a closed impeller and reduced horsepower. It moves more water more efficiently, and may help you reduce your filter operating time by an hour or more. Also consider purchasing a two speed motor with an automatic controller. The high speed is used only when needed for tasks like pool vacuuming, operating the automatic pool sweep and pump operation for the pool/spa combination. Once the heavy work is done, the controller automatically kicks down to low speed for your pool’s daily filtration cycle, which may result in energy and money savings for you.

Energy Consumption: The size and operation time of the pump motor determines operating costs. Example: A pool owner has a 1.5 hp filter pump motor and filters the pool for 12 hours per day, using 552 kWh per month. By reducing the filtering time to 4 hours per day, the pool owner uses only 184 kWh each month, saving 368 kWh monthly, which translates to an estimated net savings of $55 each month.*

* Approximate operating costs are based on 15¢ per kWh. The price you pay may vary depending on market prices, your tiered rate and other factors.

Water temperature: The American Red Cross recommends that the most healthful swimming pool temperature is 78°F–82°F. Be sure to use an accurate pool thermometer, since a variance of just four degrees above 78°F could use as much as 40% more energy. Shelter the pool where possible from prevailing winds by using well trimmed hedges or other landscaping, cabanas or fencing as windbreaks.

Solar heating: Swimming pool heating is a popular application of solar energy. If your pool is in direct sunlight, the sun helps to raise and maintain the water temperature free of charge. Special solar heating pool systems can be installed in your pool to heat water pumped through solar panels. In many cases, you can add a solar system to your existing filter pump and plumbing. Buying and installing a solar-heating system can be a significant investment, so be sure to shop around and get the best combination of price, performance and warranty