Solar DIY and Stove - Plumbing setup

[SimonM]

Hi  I have just started a self build and have accumualted several questions any tips would be much appreicated

What size water cistern recomended for 4 bed Dormer bungalow (2 upstairs)

Hot water cylinder (approx 300 litres)  will be upstairs

Cistern will be in upper  part of roof  - Any tip / pointers

Also on cylinder (Navitron package) I see there is the option option of having 28 or 22 connectors fitting for upper coil and 15 or 22 for lower Solar coil –28 seems best as will have log stove with boiler (for gravity). Is is best to kepp showers downstairs - I do not want to spend a lot on a nice shower only to find it dribbles out

Solar panels will be outside in garden or next to house is ther any benefits to having 15 or 22 connectors  on  solar coil at base of tank  – Distance from outside wall to upstairs cylinder  approx 12 metres.

When garage built it is possible soalr panels could be moved but concerned high pitch bungalow may cast a shadow over garage will have to wait and see – Garage South Facing bungalow East to West 

Has wind energy been used for an immersion heater on a hot water cylinder  ?

Finally can anyone give me a rough idea of  what a handsome output of  KW / BTU is and how long it would take to warm a 300L cylinder on a cold winters night

Any pointers appreicated good luck all with achieving your goals

Cheers SimonM

[dhaslam]

The usual water tanks in the attic are 50 gallon, I have two because the house is at the top of a hill and they are slow to fill after the water is off. Make sure some heat from the house can rise into the tank in winter and that it is well insulated, you don't want water at 0C to heat in winter.   Pipes used for solar panels are normally 10 mm unless the pipe run is very long. You will need a fairly big solar panel area for 300 litre cylinder, preferably 60 47mm tubes but 10mm should do.   I assume you are not thinking of gravity flow.  28mm pipe is fairly standard for a gravity fed stove.   If bedrooms are upstairs there should be at least one shower upstairs.   It may be OK if the water tank is high up in the attic, say water surface  two metres above the shower head  but you could use a small pump for the upstairs shower.   I have all pumped showers, set to lowest setting.     The energy needed, in KWh,  to heat a 300 litre tank from say 10C to 60C   is 50C X 300 /860 =17.5  and you can expect about 3kwh per day cooling losses.  In practice you may get away with a bit less than a full cylinder per day and in summer quite a lot less.    I use about 15KWh in winter, 10Kwh in summer per day for four showers etc.

[SimonM]

To dhaslam

Your comprehensive reply is a great help I have since printed it off and shown others in my family - Thanks for tying up a few loose ends. I shall no doubt keep my fingers crossed that I am able to catch you again latter in my build Cheers Simon

[Richard Owen]

It's quite easy to have a mains water set up that requires no cistern in the loft, just a small header tank for the heating system.

[SimonM]

Hi Richard

I am currently waiting for confirmation to see I need to proceed with a Well installation not too sure about pressure I would get  but I hope that can  be tweeked on the pump. I see what you mean about linking to mains  I imagined setup would have to fully installed by engineer as mains pressure source would mean boiler would fall into the unvented classification ??   - I am about to put down Radon  Barrier so still have some time to learn more (Newbie) and study other installations - Would you be able to send / add a diagram. Do you also happen to know if a recess in a suspended concrete floor works well for pipes or is it better to fit pipes in insulation - Weather has been poor - My thinking was I would have more time to work with pipe layout on concrete rather than rush floor to cover floor insualtion. Your thoughts appreciated cheers Simon

[Richard Owen]

It's all down to pumps really.

For a mains connected system, a mains pressure system simply means you are using the water company's pumps rather than yours.

For a well sourced system, I'd ere on the side of header tanks in the loft. To directly pump mains pressure water from a well requires you to measure the maximum extraction rate from the well to ensure that it's sufficient for your maximum demand (x showers, bath and washing machine, that sort of thing), then you'll need a big pump, appropriately sized expansion vessel etc.

With header tanks, you can get away with a small pump that can run as slowly as you want.

If you use a thermal store (as we have) all the sources (heat pump, wood burner, boiler etc.) all run at atmospheric pressure. The only component at mains pressure is the water that's consumed in the house. No need for fancy certificates or qualified heating engineers (at least as regards the pressure of the system.)

Not great on diagrams. Sorry. You might be able to glean something useful from this dross.

[Justme]

We pump our water from a borehole (like a well only deeper) into a bowser that is about 2 foot higher than our ground level booster pump. From there it gravity feeds to the pressure ground level booster pump with a pressure vessel. This then supplies all our hot & cold water needs at "mains" pressures.

[SimonM]

Thanks all for your suggestions / input  very helpfull. Fingers crossed I  will soon be in position to price up what I need and what needs to be done unless turning over another stone reveals something completely different

Thanks Simon