Rainwater water harvesting!

[Agile]

Its not a topic that seems to come up often.

Has anyone compared the saving to be achieved for toilet flushing and WMCs to use rainwater collected at ground level and pumped up to a loft storage after allowing for the cost of electricity?

Part of the problem is finding a suitable reasonably priced pump as the cheap 6 m head pumps would not be adequate.

What annual volume of water is to be expected per m² of collection area?

Tony

 

[ChrisR]

Depends where you live!
Water's a couple of pence a bucket and I'm sure you can look the rest up!
You obvioulsly need a solar powered pump, though the sun has to pour after the rain stops shining.
One problem is that you have to dump any water stored more than a day; it's category 4 water and goes very foul very quickly.

I've often wondered about putting a generator on the water pipe. You're paying for it to be pressurised, so get some of the money back

 

[Redhotferrari]

Could try asking these guys, as its what they do www.espirituswater.com

 

[rssteve]

not worth the cost in electric, let alone the pump etc. how about installing a tank at first floor level, from downpipe to tank, overflow back out, then the toilets could fill by gravity, still the cost of tank would take some years to recover on the savings.

 

[Deleted member 105431]

Depends where you live!
Water's a couple of pence a bucket and I'm sure you can look the rest up!
You obvioulsly need a solar powered pump, though the sun has to pour after the rain stops shining.
One problem is that you have to dump any water stored more than a day; it's category 4 water and goes very foul very quickly.

I've often wondered about putting a generator on the water pipe. You're paying for it to be pressurised, so get some of the money back

you mean a turbine/dynamo on the mains i think.

 

[billy bob]

Rainharvesting will become a must soon, water shortages in the south and rising costs of the supply of water will mean that it will become more widely used, I use www.rainharvesting.co.uk for systems I install

 

[ChrisR]

No no billy I've found a solution to that one.
Just find a neighbour without a meter and use their tap to water your garden.

 

[mattylad]

My neighbours do that already. They provided the hosepipe & I provided the tap

I have in the past wondered about being able to collect the cold water that comes out of the hot tap until it gets hot & having a water butt for the toilets.
But yes, I can see how pumping it will now cost more than the cost of the water. Luckily I live up north where we have plenty.

 

[Paul Barker]

You could keep yourself fit and warm (so saving on heating) and carry it upstairs in buckets.

 

[wilhelm]

Its not a topic that seems to come up often.

thannnnnnnnnnnnnnnnk fekk for that.

 

[Agile]

Those are very useful pointers to success.

Its also reminded me that I have some 12v caravan water pumps somewhere (!). But PV panels are a problem as they are still very expensive! Any suggestions for a cheap source?

I have done some quick calcs and averaging water consumption, my roof area could provide about 1.4 times the daily toilet requirements.

Of course rainfall is not uniform and sufficient storage is vitally important to bridge dry spells as far as possible.

My initial calculations using a 400w 1.5 Bar old shower pump would give a 500% gain in value for water saving over the electricity cost assuming a 10 li/min flow rate when pumping up seven metres.

There is an immediate gain in the value of water because the supply cost is doubled when you remember the sewerage charge is charged on the supply volume!

The more I think about it, the more attractive the idea becomes. Of course it was sparked off by Paul's mention and photos of his storage tanks. Adequate storage is the key and thats an expensive part as I will have to buy most of my storage new and thats about £60 per 250 litres in loft tank format.

Swimming pool tablets might get over Chris''s comment that it goes off quickly anthough that does not seem to be a major factor on the web site linked to above.

Any more ideas?

Tony

 

[Paul Barker]

Funnily enough Tony I will probably only use one bowser for the solar so i had already thought of saving water also.

So are you saying that the water costs 5 times as much as the energy consumption to pump it? or 10 times with sewerage?

in any case if it is a saving it is worth doing.

By the way my hot water situation even though overcast since installing 3 weeks ago as a family of 4 we have relied on solar except last night (immersion on hlaf hour) and one other occasion. Even if there is only 1/2 hr of clear sky bang the cylinder is up in the 70's. Overcast all day and it is 35 degrees. Which is suffcient for strip washing but you need to boil kettle for washing up if like me you like very hot water to degrease.

i have isntalled a plate heat exchanger with secondary pump and bridged it into the central heating. This is an experimental perhaps vain hope that spring and autumn i can get a little warmth from the sky.

There is a phenomenon that if the sun is hidden all day the panels don't get above 35.When the dhw is already 35 you are making no use whatsoever of the free UV energy because it is too low. yet if you were to put water at 30 degrees into your rads you would be better off than not. it wouldn't heat you as central heating would but it is a contribution you are otherwise not receiving.

The remainder required for your cumfort you throw some sawn up pallet on the fire.

Or you buy everybody a continental quilt to throw over themselves.

What you mustn't do is waste any more of theplanets precious resources. We need those to get us from a to b so we can fix otherpeoples' hydrocarbon guzzlers.

the key element in going green is to accept a changed lifestyle. use water when it is available. Shower at 35 rather than 38. I shall be puting a backward tmv on combi to top up buti plan to install a hard switch aswell so that the family have to think first "can i manage with the water at this temperature? Rather than the combi automatically chucking out piping hot water.

Same ways cutting wood and burning it (the wood is already waste merchants have to pay for disposal) you warm yourself cutting it and get fit. Half the evening gone anywya so less time requiring the heat from it. If family don't like it they can join in the cutting of it.

after all they will face these issues for longer at a time resources are far more scarce. So the sooner they learn to adopt changed lifestyle the better.