geem
Well-Known Member
How much electrity needed to heat fresh water.
- Thread starter Beneteau381
- Start date
ean_p
Well-Known Member
Have you a link please for the requirement to be signed off by a ' registered plumber ' ?
geem
Well-Known Member
A non-registered person may carry out 'wet work', ie install water pipes and radiators for a heating system, but any work on the gas boiler itself and the final connection of the water pipework to the boiler, must be done by a Gas Safe registered engineer.
Unless regs have changed in the last few years, there is nothing to stop you working on an oil fired boiler installation
ean_p
Well-Known Member
Yeah I'm cognisant of the gas regs but don't know anything ref the need for oil systems etc to be signed off which seems implied in the post.
Beneteau381
Well-Known Member
Beneteau381
Well-Known Member
Veryinteresting this, given that 5kw Spacher type gizmos claim half a ltr per hour consumption, the figure for kerosene in pence per hour gives some credence to the fact that they are wirth considering as an auxiliary heater. The wild west youtube vids also show some of them burning waste oil which opens up another acenario!
ylop
Well-Known Member
The chlorine level in drinking water is not generally enough to kill Legionella bacteria. No problem for drinking it, only for breathing it (like in your shower). It made worse because once you warm the water you remove the chlorine and so if one bacterium survives then a little while later you have two, and then four... hence the attention on getting hot water tanks properly hot, the right size and distributing that heat to everywhere it might be used at a temperature that kills any bugs in that pipework.
However I think the OP has made a bit of an unusual assumption in his design calculations. His question has been answered correctly - how much to heat a tank of this size. I don't know how efficient the oil heater he is proposing using is, but the headline "5KW" figure and the energy that actually get into the tank are likely to be different even if its only from the energy lost to heating the recirculating circuit itself etc. But my real issue is he's heated that water and then treats it as though it is 65deg C forever with no more energy input. Firstly, turn the heater off and it will start to cool, so you will need to fire the boiler periodically to keep it warm. How often will depend on the design of the tank and how warm the house is. Secondly, as soon as you use some of the hot water from the tank, fresh cold water arrives. Again you'll need to heat this water if you want to have access to lots of hot water. Thirdly, your combi boiler brings efficiency by not heating a tank of water (unless you don't actually have a combi?) and only heating what you need, when you need it. if you actually need 60L for the family ablutions every morning, then you only heat 60L - with your approach you heat all 60L and then probably at least partly heat some of the replacement 60L (unless you have a routine where the later users of the water prefer much cooler showers etc). If you need hot water for morning showers and how water for doing the dishes etc at the end of the day you heat the tank twice (well insulated it may last most of a day but probably is just losing heat to the surroundings).
geem
Well-Known Member
I think the OP has a brand new well insulated calorifier. I would be more inclined to install a load of solar panels on the house to deal with the electrical base load then use a smart bit of kit that will dump any excess electricity that might otherwise be returned to the grid, into the calorifier. A kW or 2 of PV would do the trick. Install a strap on temperature sensor to the calorifier to switch a 3 port valve to select the hot calorifier water when it's up to temperature or the combi when it isnt.
Graham376
Well-Known Member
Will you survive long enough to make all this cost effective? Every time I look at solar for home and other cost saving exercises, looks like I'll be six feet under before it's payed for itself.
geem
Well-Known Member
It used to be like that. Average payback a few years ago was about 23 years. Now electricity prices have risen sharply and panel costs have dropped payback is much quicker, circa 5 of 6 years if you self install, when I last did the calcs. A lot depends on future electricity prices and to some extent gas costs but sometimes these projects are great just for the fun of it?Will you survive long enough to make all this cost effective? Every time I look at solar for home and other cost saving exercises, looks like I'll be six feet under before it's payed for itself.
Graham376
Well-Known Member
FUN?
That's what I thought when I started to rip the bathroom out! Walk in shower base installed which entailed digging through reinforced concrete floor for the drain, now re-plastered and I'm half way through tiling. < 3 weeks before we head back to the boat so 'er indoors has the whip out
.I did some costings on solar a few months back but bearing in mind we're away for more than half the year, our gas & elec prices are half the norm and feed-in tariff fairly low. Not sure whether DIY is allowed if connected to the grid and I think it has to be an approved installer to get the VAT free grant.
geem
Well-Known Member
You don't need the feed in tariff. You won't get paid much if you export the lecky. A box of tricks will divert the solar power you don't use to heat the domestic hot water. In summer you won't need your boiler on or the immersion heater. Solar can do it for you. The box of tricks monitors the lecky flow at the meter. If it starts to see flow in to the grid it then diverts to domestic hot water heatingFUN?
I did some costings on solar a few months back but bearing in mind we're away for more than half the year, our gas & elec prices are half the norm and feed-in tariff fairly low. Not sure whether DIY is allowed if connected to the grid and I think it has to be an approved installer to get the VAT free grant.
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