The line between industrial and consumer/residential applications is blurring as green energy technologies continue to migrate across all sectors. Is what’s good for the factory floor good for the home when it comes to energy efficiency? Swimming pools are a case in point. Allow me to explain.
I recently moved back to Austin, Texas, from an assignment in California and purchased a home with a swimming pool. With the extremely hot summers that we have in Central Texas, my family and I see the pool as a great way to help make the season more bearable. But as a first-time pool owner, I was surprised to learn how much energy a pool pump consumes.
An average size pool pump can consume more than $1000 a year in electricity. That’s a pretty significant portion of a home’s energy budget. I had assumed that heating a pool would be a significant expense (which it is) but was unaware that filtering one would be as costly as it is. So how could I save money and still keep cool in the summer?
One solution is to install a variable-speed pool pump. A pump is an example of an application that can benefit from a reduction in horsepower and torque. The horsepower of a motor drops off as the cube of the speed of the pump, and the torque of a pump drops off as the square of the speed. So if the pump can run at a lower speed, a significant power reduction can be achieved.
For example, running a pump at one-half the flow rate will require only one-eighth the horsepower of running at full speed. Thus, if the pool water is cycled at a much lower flow, the overall power can be greatly reduced.
You may still need to run at a much higher flow rate to operate a pool vacuum or spa jets. However, the duty cycle of high-flow operation to low-speed operation is such that most of the time will be spent at the lower flow rate.
Manufacturers are now offering ac drives for pool pumps that feature a variable-speed controller to greatly improve their efficiencies. While these motors are more expensive than a standard fixed-speed ac motor that connects directly across the ac supply lines, the energy savings over the life of the pump will quickly allow the variable-speed pump to pay for itself.
From Pools To Products
The purpose of this article isn’t to be an advertisement for variable-speed pool pumps. Rather, it’s to highlight a trend that’s already underway and continuing to gain momentum—the expansion of high-end energy-efficiency techniques into mainstream applications.
The technology to turn an ac motor into a variable-speed motor has been widely used in industrial applications for many years. These motors, most often ac induction motors, are frequently high-horsepower motors that can offer significant energy savings by bringing speed or torque control to their applications. By some estimates, electric motors consume about 30% of all electrical energy produced in the world. So, the ability to reduce their overall power consumption offers huge potential savings.
The installation cost of a variable-speed control system for an industrial application is clearly very different from the price points that residential consumers are willing to pay. However, many of the same technologies that drive those industrial applications are migrating into the consumer market. This shift is driving lower price points and more highly integrated solutions as vendors adapt controllers to the residential and consumer market.
More Fun In The Sun
Consider another example—solar panels. Most residential solar panel installations are grid-tied systems in which the electricity from the panels flows back into the grid. These systems need to take the dc voltage from the solar panels and convert it into ac before injecting it into the grid. An ac inverter handles this conversion. These ac inverters are relatively high power and may need to handle several kilowatts of power depending on the residential installation.
High-power ac inverters are another example of a mainstream industrial technology that’s increasingly finding other uses in the residential market. Like residential motor control, high-power inverters for residential applications require reduced cost and smaller size. Additionally, the equipment must last for 15 to 20 years, requiring increased life expectancies from all the system components.
These requirements are driving innovations from semiconductor suppliers in numerous areas including lower-cost microprocessors and microcontrollers with embedded analog peripherals, high-power transistor drivers, and improved isolation technology.
The migration of these green energy technologies “down market” into consumer/residential applications is one of the most exciting market trends. As energy costs and environmental concerns continue to rise, these industrial-proven technologies are providing additional tools to consumers to help them address their energy usage.
By replacing our pool pump with a high-efficiency model and using solar panels on my house, my family can stay cool in the hot Austin summers while reducing our energy bills. That’s one hot deal.