Off The Grid - Running pool pump on solar

[Mr_B]

Hi All,

We've recently purchased a (larger) house, with a much increased energy bill of course. I've been busy with all sorts of interventions to reduce this Eskom bill, led lighting throughout the house, replacing 500w floods outside with 10w led floods, fitting a solar heated geyser system and replacing the elec stove top with a gas top. Now I've been thinking, the other item that chows tons of electricity is the pool pump. It's a 0.75kw 5.1amp unit. So first thing I did was install an electronic timer and optimise the operating time of the pump. Winter, 2 hours a day suffices, summer 4 hours a day seems enough. The pool filter system includes a salt chlorinator which I believe draws very little current, can't find tech info, but it's protection fuse is rated 1.25amp.

Ok, so now the questions for all the elec fundi's...

1. Can I setup a reasonably priced DIY solar system to power the pool pump.

2. If I intend running the pump during daylight hours, say 9am to 1pm, is it necessary to have storage batteries, or would it be ok to do a grid-tie(hope that's the right name) system? I wouldn't stress too much about cloudy days... I'd then just run it longer on sunny days.

3. Batteries obviously have benefits and disadvantages. If I did go with a battery array, then I'd would probably be able to connect the houses LED lighting it the battery array(bearing in mind all lighting will/almost is LEDs)? Right or wrong?

Is a solar solution feasible for something like this, or am I barking up the wrong (green) tree?

Mr B

[Stef]

Hey Bretton,

Not with your current pool pump....you need a solar pump like this one http://www.solar-solutions.co.za/produc ... 00+cs+15~1

[Hangover]

Very interesting Stefan. It seems that you need this pump and unit with 3x250W solar panels and that it can run on a very low voltage factor without overheating like normal pumps...

[Johan Kriel]

http://www.alternagy.co.za/shop/grundfo ... panel-kit/" onclick="window.open(this.href);return false;

I like Grundfos pumps

[Donkey]

Interesting conversation

[JamesC]

Lorentz PS600 is not a pool pump per se bu they do manufacture pool pumps.
It is not smart to convert normal DC appliance to solar - better to purchase solar pump.

You can contact KG Elctric in Kya Sands JHB as they are the importer of Lorentz.

Speak to Uwe Klingenberg.

[JamesC]

...and no, you won't be able to run your lights off of two batteries nor your pump...

[Mr_B]

Thanks guys. I got a quote for the Lorentz system with 2 pv panels...R 30k.... eina!

For now I'm going to do a solar geyser system... i'll manage the pool pump running time carefully for until these solar pool pump setups are a bit more reasonable in cost!

[Mud Dog]

The big energy guzzlers are of course primarily the geyser/s and all things with heating elements - stove, kettle etc, even microwave ovens. Then there's fridges / freezers and air-cons that are also energy hungry. Lights are low on the list unless you're talking about incandescent spots like the halogen type - of course it also depends how many incandescent bulbs are running continuously, but ja, they also add up, so every little bit you do helps.

The solar geyser will probably be your biggest energy saver if you fit a timer that only allows for electrical heating in the early morning for showering, off during the day and then again in the evening to provide for bathing / showering.

Best of luck with the project.

[jacol]

Why don't you consider a gas geyser under corection they cheaper and very economical and totaly off the grid

[JamesC]

which solar geyser?

[Huismoeles]

Why don't you consider a gas geyser under corection they cheaper and very economical and totaly off the grid

Gas geyser se running cost is die selfde as krag
Gas geyser kos net minder om te instaleer

Solar geyser is die way to go

Met n solar geyser en n gas stoof gaan jy amper jou krag rekening halfeer

En moenie n dishwasher weg gooi met krag gebruik nie

[Mr_B]

Why don't you consider a gas geyser under corection they cheaper and very economical and totaly off the grid

Gas geyser se running cost is die selfde as krag
Gas geyser kos net minder om te instaleer

Solar geyser is die way to go

Met n solar geyser en n gas stoof gaan jy amper jou krag rekening halfeer

En moenie n dishwasher weg gooi met krag gebruik nie

If I try toss the dishwasher I'll be a single man in no time! I am going to go with our current kwikot 150L geyser + another kwikot 150L geyser, running off a 15 tube evacuated tube collector. With solar heating is it important to have reserve heated water capacity, hence going for 300L in total. A 150L unit can easily run close to empty on a 'busy' day, which means you have a large volume of cold water entering the system, which means electrical backup kicks in often. The evacuated tubes are more efficient than flat panel designs, and are able to heat water on overcast days as well, where flat panels fall short. If an evac tube cracks or loses vacuum for whatever reason just the damaged tube can be replaced.

I'm looking at contracting ITS(http://www.itssolar.co.za) to do the install.

Mr B

[Stuart Baak]

Why not look at heat pumps? Not sure what they cost but I know it saved the company millions per annum. (massive hospitality company - hence millions)

[JamesC]

Nothing beats solar...

Heat pumps:
a. noisy
b. maintenance contract - needs to be serviced yearly
c. three year warranty
d. no more rebate

I can supply you with a technical analysis of why you should not go for heat pump nor gas geysers...

[Mr_B]

Why not look at heat pumps? Not sure what they cost but I know it saved the company millions per annum. (massive hospitality company - hence millions)

Hi Stuart,

I did investigate the heat pump root. Under ideal conditions a heat pump converts 1 unit of electrical power into 3 units of heat. This equates to a 67% saving in water heating costs all year round. But, it's still totally reliant on Eskom as it still continuously requires electricity supply. A heat pump is also sensitive to water hardness and needs to be serviced once a year to maintain it's efficiency.

For the sake of not being reliant on Eskom I decided to go the solar route using the new evac tube technology. I can, in future, convert the system to hybrid by including a heat pump in the setup.

Mr B