Going Green only for the wealthy

[adrianh]

There is a truth in "Going green is for the rich" The rest of us simply save what we can because we have very limited resources to start with.

The Green club is very similar to diets. People go on the latest fad diet in the hope that it would make them thin without going to too much trouble. Spend R10K on a machine, swallow a pill, but don't exert yourself too much. We want to diet and get fit by not inconveniencing ourselves. People want to be seen driving a Prius.

There are ways to save lots of money and save resources but with it comes inconvenience - Take a bus, train create a lift club - you buy the lawnmower and your neighbour buys the weed eater and you share - use one anothers skill and barter rather than spending money - grow food etc...

We are quick to save money by spending money without inconveniece,mut we are not so quick to make real hard differences - and yes I also speak for myself!

[AndyD]

I would like to source a reasonably priced container that can :
1. be used to store hot water from a copper / plastic tubing solar panel circulated via thermosyphon (sp?)
2. can be easily insulated to help retain some heat.

The initial thinking is to erect a small gum pole tower with the solar panel and tank mounted, so it is gravity feed. A toilet cistern style inlet valve would keep it topped up, and it would have a tap fitting to draw hot water from the tank. This could then be adapted to add a shower.

There would be no element. The thinking is not to create hot water 24 hours a day - rather to have a tank ( say, 50 or 75 liters ) of warm / hot water available when they return home from work each day.

There's no reason you can't do this with a slightly larger tank (c.150 litres) and if you go to town on the insulation you could still have hot water in the morning as well.

For insulation I would consider cladding the tank in high impact polystyrene isoboard panels, same as I used in my roof, they can be easily cut and shaped to fit. Armourflex all the pipework as well. You would need to make sure it's all closed cell insulation and not hygroscopic to prevent it becoming sodden in rain otherwise it will require painting or similar. Wet insulation is useless. I'm guessing you would need 100mm thick insulation and the pipework design would need to prevent water circulation or back siphoning during non-sunny times so all the heat won't be lost through the solar panel basically working in reverse.

I think anything copper in this application will be like a flashing neon saying 'steal me'. For a solar panel maybe consider one of those flexible swimming pool types that you can roll out on your roof. I only got close to one once but I think it was made from low density polyethylene which should make it cheap and fairly hardy. You could maybe hang it like a curtain around the pole or from a frame. It would certainly be better than a flat glass covered panel in windy conditions like Cape Town.

I'm already excited. There's no rush, just post on Monday with details on how your prototype performs:-)

[AndyD]

There are ways to save lots of money and save resources but with it comes inconvenience - Take a bus, train create a lift club - you buy the lawnmower and your neighbour buys the weed eater and you share - use one anothers skill and barter rather than spending money - grow food etc...

We are quick to save money by spending money without inconveniece,mut we are not so quick to make real hard differences - and yes I also speak for myself!

This is a valid point, but I see this kind of lifestyle as the next step and one I'm not sure I'm ready to take. I can make further improvements to my impact on the planet without foregoing the way of life which I'm accustomed to.
What you're suggesting is a complete change in lifestyle and even culture. Maybe my childrens children will commute on communal or public transport, not travel for pleasure, live in a small dwelling without extravagances, braai in a microwave and make the 'real hard differences' out of what might be absolute necessity by that time. Hopefully for them they won't miss what they never had....I for one plan to tan a few chops the old fashioned way tomorrow and to hell with the emissions.

[daveob]

There's no reason you can't do this with a slightly larger tank (c.150 litres)

Thanks, and I agree with you on this. I just want to do the experimental project on a slightly smaller scale first.

the pipework design would need to prevent water circulation or back siphoning during non-sunny times so all the heat won't be lost through the solar panel basically working in reverse.

OK. My understanding on the theory is that the water tank sits higher than the panels, and the feed goes from the bottom of the tank to the bottom of the panel, and from the top of the panel back to the tank ( I don't think the re-entry position is as important as the cooler water feed from the tank to panel, as long as they not right next to each other ). The Thermosiphon effect will allow the cooler water to flow from the bottom of the tank to the bottom of the panel, and as it warms, it rises and returns to the tank. When there is no sunlight / UV warming the solar panel, the water in the panel does not rise, and the coldest water in the entire cycle will drop to the lowest point, in this case the solar panel, where it will remain until such time as it again gets warmed to a temperature higher than the coldest water in the tank, and the circulation current starts up again. So during this 'no warming' time, there should not be any circulation, and the warm water would remain at the highest point, in the tank.

I think anything copper in this application will be like a flashing neon saying 'steal me'.

Agreed. I am planning a trip to a few stores to look at the temperature range on some tubing, as well as the connectors available for joining them.

[SilverNodashi]

@daveob,

What kind of panels would you use, and what type of storage take do you have in mind? I'm interested in a similar setup and would like to keep the costs to a minimum as well.

[daveob]

@daveob,

What kind of panels would you use, and what type of storage take do you have in mind? I'm interested in a similar setup and would like to keep the costs to a minimum as well.

Hi Rudi

For the system to be donated to a less fortunate individual, I think that as much of the material as possible should have little resale / scrap value. For this reason, I would be looking at various plastic drums and pipes that could withstand the higher temperatures. I think that as long as the insulation is effective, there shouldn't be any pros / cons between the metal and plastic units.

For my home system, I am thinking of using a standard pressure geyser about 200 / 250 liters and a number of home made panels using copper tubing. The geyser will be in the garage on a robust stand ( 3 m from the house ) and the solar panels either side of a east / west facing wall which gets sun literally from sunrise to about 1 hour before sunset.

My logic is that as we are at home all day, the east facing panels will capture plenty of heat for the daily washing, dishes, etc. The west facing then would top-up the heat for the later afternoon and evening baths / shower / dishes. The length of the wall is about 8 meters, so I have plenty of space to add additional panels. Also, if I can insulate the geyser sufficiently to keep some heat overnight, it may well be worth it to add a second geyser ( and possibly more panels ) to be used in the winter months so that I can do away with the eskom powered geyser completely.

[AndyD]

@daveob,

....what type of storage take do you have in mind?

For a small scale system I'm thinking you can use a storage bin with a clip on lid. I think they're about 70 litres and they sell them at Pick&Pay, Makro etc they're not expensive.

[AndyD]

I was thinking about this type of flexible panel;

[daveob]

I was thinking about this type of flexible panel;

Hi Andy

Do you know if that is available locally ?

Where did you get the pic from ?

Would be a lot easier than a load of T connectors on black plastic piping.

[SilverNodashi]

Hi Rudi

For the system to be donated to a less fortunate individual, I think that as much of the material as possible should have little resale / scrap value. For this reason, I would be looking at various plastic drums and pipes that could withstand the higher temperatures. I think that as long as the insulation is effective, there shouldn't be any pros / cons between the metal and plastic units.

For my home system, I am thinking of using a standard pressure geyser about 200 / 250 liters and a number of home made panels using copper tubing. The geyser will be in the garage on a robust stand ( 3 m from the house ) and the solar panels either side of a east / west facing wall which gets sun literally from sunrise to about 1 hour before sunset.

Are you going to buy a new geyser, or re-use an existing one?

Just some thoughts:

- since you're using a standard geyser it might be easier to use the one already installed (the plumbing already works well), but have the inlet run through the copper pipes on the roof first, then into the geyser? The roof should also help to keep in more heat and a geyser blanket would help as well.
- thicker copper pipes will probably work better, but pipes made of thicker tubing (i.e. the sides, I don't know what you call this) would keep the water warmer for longer since the heat is in the pipes.

But, would lead pipes, or even black corrugation (some can withstand high pressure, but a pressure release valve might be needed) be as effective?

My logic is that as we are at home all day, the east facing panels will capture plenty of heat for the daily washing, dishes, etc. The west facing then would top-up the heat for the later afternoon and evening baths / shower / dishes. The length of the wall is about 8 meters, so I have plenty of space to add additional panels. Also, if I can insulate the geyser sufficiently to keep some heat overnight, it may well be worth it to add a second geyser ( and possibly more panels ) to be used in the winter months so that I can do away with the eskom powered geyser completely.

sounds good, please update us once it's done.

Wouldn't North facing be better all-day round?

[daveob]

- since you're using a standard geyser it might be easier to use the one already installed (the plumbing already works well), but have the inlet run through the copper pipes on the roof first, then into the geyser?

Wouldn't North facing be better all-day round?

Problem I have is that the north facing side of the roof is mostly in the shade due to trees and the neighbours house.

Also, to use the existing geyser I would have to add a pump as the ideal location for the panels next to the garage is higher than the existing geyser, so the thermosiphon effect would not work.

Will do some research about the cost of a new 250 liter geyser. I know most are made by Kwikot, but I would (hopefully) end up throwing the element away. Does anyone know of other high pressure tank manufacturers, pref in the Durban area ?

[AndyD]

Hi Andy

Do you know if that is available locally ?

Where did you get the pic from ?

Would be a lot easier than a load of T connectors on black plastic piping.

I think most of the pool heating companies have their own version of the flexible panels.

http://www.setsolar.co.za/solarheating.htm

And

http://www.vottle.com/home-and-garden-pools-and-spas-buy-pool-heating-diy-solar-panels-new-pool-heating-solar-panels-for-sale_v1567543

Were the web locations of those particular photos.

Most pool solar panels are only rated to around 1 bar pressure so you can't use them on a standard pressure geyser system.

[desA]

If anyone is seriously interested in thermal storage technologies - drop me a PM.

[wynn]

Ooh! now you guys are sounding all 'new agey' next you will be saying cob earth walls and sod roofs.

I believe that all savings on electricity and water is 'green' even if the idea is to save money first, yes, I worry about the repayment period of the investment.

Any water saved is a good thing.

I have just set up a grey water garden watering system for about R150.00

It will only work if your shower outlet is above the level of your garden.

I bought a 'Lay Flat hose 100mmx10M from the hardware store and attached it to my shower outlet, on the other end I installed a 110x50MM eccentric Marley s&v waste pvc reducer, with a Marley 40x1 1/4" female bsp waste s&v pvc adaptor siliconed into the 50mm outlet, ptfe'd and screwed in a 32x20mm threaded galv bush and a 20mm male gardena hose adaptor to which I attached the garden hose and 'voila'

When the wife or I shower the LFpipe fills up, acts as a holding bladder, then gently trickles water into the chosen flower bed.

TIPS:- you may have to cut a tiny air hole into the LF pipe just above the shower inlet to prevent the system creating a vacuum and so that it can drain easily, insert the reducer well into the LFpipe use cable ties to attach, make sure that the reducer is set at the lowest point of the pipe so that it can drain completely, move the LFpipe and hose around the garden and lawn regularly, don't take long showers.

[murdock]

my nieghbour got smart and invested in some irrigation piping which he detoured from his pool pump...up the wall onto his roof made a couple of loops and back down to the pool pump...now he always has a warm pool to swim in...whenever the pool pump runs it circulates the water over the roof and back into the pool.

just the cost of the piping and he did it himself...it been working for about 3 years already.