Pool


Garden &Global Warming &Lighting &Pool20 Feb 2013 12:03 pm

Discovery Magazine

GreenerHouse in the post box

The latest issue of Discovery magazine has arrived in my post box, and I was pleased to see that my insurance company has been perusing GreenerHouse. A cover article titled 31 Ways to Make a Difference to our Earth quotes liberally from GreenerHouse, especially in the section giving suggestions for what you can do to make your home “more ecofriendly.” It’s clear and compact, so I have reprinted it here. If you want more detail, the information is extracted from more comprehensive posts on composting, LED lighting and pool pumps.

Pool11 Nov 2012 12:46 pm

Viron P300 variable-speed pool pump

Giving the green light to variable-speed pumps

For more than a decade, I’ve been gradually improving the efficiency of my appliances and driving down my electricity consumption. One device had defied me, however. As hard as I looked, there did not seem to be a greener alternative to my 750 watt pool pump. Until now.

For the past 12 months, I have been testing the Viron P300 variable-speed pool pump, courtesy of the South African distributor, Fluidra . What makes this pump different is that it operates on a DC motor, so it can run at different speeds as needed. At the slowest setting, Eco, my Watts Up meter tells me the pump is using a mere 175 watts, less than a quarter of the consumption of the old pump. (A sixth, compared to the widely used 1.1 kw pumps.)

But does it work? The principle of a variable speed pump is that because a slower water flow is much more efficient, longer hours at lower speeds are the most economical way to pump enough water through the filter each day. But I have not significantly increased hours. For my 31,000 litre pool, I leave the Viron P300 on the Eco setting 8 hours a day, spring, summer and fall. And my pool stays clean. (As I have written here before, I radically cut back on pumping hours in the winter.)

The flow on the Eco setting is somewhat weaker than that of the old pump, but my Zodiac Genius still climbs the walls as long as the weir basket is clear. I think the slightly lower flow does make it more sensitive to a leaf-clogged weir, so I check it more often now. I am told that the Gemini and Kreepy Krauley pool cleaners might work even better with the lower flow because they use a hammer action, rather than a diaphram. I have not tested them on on this pump, however.

The Eco setting is not strong enough for backwashing, but that is the joy of a variable-speed pump. Just push a button and the Clean setting sends a surge of water through the filter. My measurements indicate the Clean setting uses 505 watts, still significantly less than a 0.75 kw or 1.1 kw AC pump, and with a stronger flow than a 0.75 kw can create. Beyond Eco and Clean is the Turbo setting, more suited to a fire engine than to anything I need to do with my pool.

I calculate that I am saving 4.6 kilowatt hours every day and R150 each month with the Viron P300. For someone like me who was sitting on a daily consumption just a little above Johannesburg’s magic cutoff point of 16 kWh a day, the savings could be much greater. The municipality offers a Lifeline Tariff as well as affordable rates for prepaid meters for those who keep their average consumption below 500 kWh hours a month, or 16 kwh a day. Qualifying for the lifeline tariff could save me about R3000 a year.

These savings come at a cost, however. A new Viron P300, manufactured in Spain with an Australian motor, sells for about R8300. By comparison, an ordinary AC pump from Speck costs about R2200 for the 0.75kw version. Leaving aside the Lifeline Tariff, it would take a few years of savings on utility bills to cover the difference, but there is no doubt that it is a good long-term investment. With a larger pool requiring more hours of cleaning per day, the DC pump would pay for itself more quickly.

Unfortunately, I did encounter one unexpected cost replacing my dead AC pump with a more environmentally friendly version. The Viron pump is larger, a few centimetres too large to fit in my existing pump box. A larger enclosure set me back R1800. If your box has little room to spare, check the measurements of any pump you might buy.

The Viron P300 is not the only variable-speed pump available now in South Africa. The IntelliFlo by Pentair costs more than double the price of the Viron P300, but has an extremely sophisticated controller. The pump can be programmed to run at different speeds at different times of the day. I have spoken to pool owners who splurged on the IntelliFlo pump and they were completely satisfied. Zodiac has also introduced the variable-speed FloPro ePump, which is worth investigating.

All of these pumps are astoundingly quiet compared to ordinary pumps. Standing at the far side of my pool from the pump box, I can only be certain the pump is operating if I can see the hose is pulsating.

I would love to say that I am finally at ease with the energy consumption that goes into my pool, but alas, I am a perfectionist. The ideal solution is so obvious, and yet no one offers it. A major expense of solar photovoltaic systems is the batteries that store the power for evenings and cloudy days and the inverter that converts the DC power produced by solar cells and batteries into household AC current. My pool pump has a converter to change AC current into DC for the motor. DC-AC, AC-DC—let’s call the whole thing off. Why shouldn’t solar panels send DC power directly to the pump’s motor, eliminating costly and troublesome components? (And getting Eskom out of my pool entirely.) It won’t worry me that the pump operates fewer hours under the winter’s low sun; that makes perfect sense. And if the pump slows down on cloudy days and stops at night, that’s fine too.

I’m not resting by the pool yet.

Pool22 Sep 2009 03:12 pm

Pool full of Coal

Swimming season’s here; start shoveling coal

I didn’t mean to wait until spring had fully sprung before restarting my pool pump, but I forgot to turn it on in August. Even though September is well under way, the water is still not green after leaving the pool pump off for 110 days. Compared to running the 0.75 kilowatt pump for 3 hours a day—as I previously did in the winters—I have saved myself nearly 250 kilowatt hours and spared the atmosphere a similar number of kilograms of carbon dioxide. Financially, I saved about R140 off my municipal bill. Compared to the conventional wisdom of running the pump 12 hours a day, I saved about R550 and kept a few bags of coal out of the pool. My only expense was R20 worth of algaecide.

I don’t like the idea of using algaecide, or any other pool chemical, for that matter. I know far too little about what happens to these chemicals when I backwash the pool. But the likelihood that the algaecide is still very toxic after more than 3 months in the pool seems rather slim.

So can I declare the experiment a success? Not quite. I should have anticipated that the pool pump was not happy to start after being left idle for so long. I had to physically get it turning with my hands—while the electricity was off—before it would move on its own. In the process I may have strained the capacitor. A new capacitor costs less than a hundred rand, but I hardly want to put my pump through such agony at the end of each winter. Next winter, I will set the timer to run the pump for a half hour each day. (Not during Eskom’s peak morning and evening hours.) I’m sure that a couple of hours exercise once a week would also keep the pump lively, if I trusted myself to remember.

Will this work on your pool? I certainly wouldn’t try it without a pool cover. And my pool cover is particularly suited to protecting the water from sunlight. After years of frustration with the limited durability of ordinary bubble pool covers, I bought a heavy duty bubble cover of the kind used on indoor public pools. It helps prevent algae growth because it doesn’t let through much light or heat.  That isn’t a problem for me in the swimming season since I have solar panels to warm the pool. And after more than 4 years, the cover is still strong.

I would be very interested to hear from others about their experiments with near-zero pumping.

Pool04 Jun 2009 01:29 pm

Pool full of Coal

It’s not coal in the pool today

Those who have read my previous post on pools know that I don’t fall for the usual advice that pool pumps should run 12 hours a day, year-round. Still, reducing my pumping schedule to just 3 hours a day in the winter just wansn’t radical enough for me. No one is swimming. The pool cover doesn’t budge. The water’s cold enough to give algae the shivers. I’m turning the pump off.

Yesterday, I backwashed, threw in 3 ½ cups of chlorine and a litre of Pace algaecide into my 30,000 litre pool and ran the pump overnight. Today, I turned it off. I intend to start it again sometime in August. I will report back on the results then.

Those who have read my previous post on pools know that I don’t fall for the usual advice that pool pumps should run 12 hours a day, year-round. Still, reducing my pumping schedule to just 3 hours a day in the winter just wansn’t radical enough for me. No one is swimming. The pool cover doesn’t budge. The water’s cold enough to give algae the shivers. I’m turning the pump off.

Yesterday, I backwashed, threw in 3 ½ cups of chlorine and a litre of Pace algaecide into my 30,000 litre pool and ran the pump overnight. Today, I turned it off. I intend to start it again sometime in August. I will report back on the results then.

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Global Warming &Pool &Water Use/Greywater15 May 2007 01:33 pm

Pool full of Coal

Winter is a tough time to hold down electricity consumption. Days are shorter so lights burn longer. The cold air begs for hot tea, hot meals, hot water, and hot electric heaters. (See this post on heaters.) Even solar-heated water needs an electric boost in the winter. But there is one easy place to save electricity as the days get colder: the swimming pool.

One of the best things anyone can do to make a greener house is to fill in the pool. Swimming pools waste water, use huge amounts of electricity, and require toxic chemicals. But my kids would kill me if I filled in the pool, and there are ways to mitigate the environmental cost of a pool.

The first priority is to get a pool cover that keeps out dirt and ultraviolet and prevents evaporation. If it’s a bubble cover, it will keep your pool warmer, too. In Namibia the law insists on pool covers to prevent evaporation. A cover will save thousands of litres a year.

Ultraviolet breaks down chlorine, which is why you have to add cyanuric acid to stabilize the chlorine. Put on a pool cover and you can save on both stabilizer and chlorine. Most important, with less dirt and more effective chlorine, you should be able to reduce your pool pump’s running time.

In most homes with a pool, the pump is the second or third largest consumer of electricity, after the geyser. If I followed HTH’s standard recommendation to run my pool pump 12 hours a day in the summer, and if I hadn’t resisted a sales pitch a couple of years ago to trade in my 750 watt pump for a new 1 100 watt model, I would be using 13 kilowatt hours a day to filter pool water, more than half my current total daily consumption.

Ignore HTH’s 12-hour guideline, and rather follow the suggestions of the California Swimming Pool Industry Energy Conservation Task Force:

Reduce filter operating times to no less than 4 to 5 hours per day during the summer and 2 to 3 hours per day during the winter period. This will reduce annual electrical consumption by 40 to 50 percent. Normal and heavier swimming use may require as much as eight or more hours filtration per day. Should water clarity or chemical imbalance indicate inadequate filtration, immediately operate the filter until acceptable water clarity has again been established. If additional filtration is still indicated, increase filter operating time in one-half hour increments until the water remains clear and properly balanced chemically.

I run my pool six or seven hours a day during the summer. Since cold water inhibits the growth of nasties, yesterday I reset the pump timer to three hours for the winter. Eskom struggles to keep up with peak winter demand in the morning between 6 and 10 a.m. and in the early evenings between 6 and 9 p.m., so make sure the timer is not set to run the pump during those hours.

All of this inspired me to do some calculations. A cubic metre of coal can produce roughly 3 000 kWh of electricity. My pool holds roughly 30 cubic metres. So if I kept a 1.1 kw pump running 12 hours a day year-round, as many South Africans do, the coal burned over 18 years to keep that pump going could fill the pool to the brim. Better a green pool than a black one.