Alternative to kettle for solar panels

glennevis

I have a two-pronged approach to boiling water. A 1000W mains-powered kettle if there's enough solar output, or a stainless steel teapot on the gas hob (boils exact volume required) for ~6 months of the year.

paul991

i use  the same  under the neo star brand very  good with peek power of 600 watts so no energy from grid to boil and  2 watts  to  keep hot
had  no problems but is cheaper  to  buy under scotts of stow  brand £39.95 for 2,2 ltr version

2nd_time_buyer

Thanks for that the ones on the Scott's of stow website seem well priced

JKenH

paul991 said:

i use  the same  under the neo star brand very  good with peek power of 600 watts so no energy from grid to boil and  2 watts  to  keep hot
had  no problems but is cheaper  to  buy under scotts of stow  brand £39.95 for 2,2 ltr version

Same here. We got the 3.5 litre one from Scotts of Stow. It is great for daytime use when there isn’t enough PV to run a kettle. This time of year we set the Neo to boil on Octopus Go Faster which costs 5.5p/kWh and come down to hot water for a quick cuppa in the morning. It also saves time when you want a quick cup of coffee. No waiting for the kettle to boil and I think it saves energy as you always put more water in the kettle than you need and that just goes cold. There will be some heat loss but it is insulated and the outside never seems to get that hot so it can’t be too bad. 

https://www.scottsofstow.co.uk/neostar-perma-therm-water-boiler-and-dispenser/

Spies

I have a 3kw kettle and it appears to cost between 2 and 3 pence per boil for 2 cups of water at 20p/kwh.

So I'm not really sure I see the attraction of these instant hot water devices. 

2nd_time_buyer

Thanks all for the comments. I have just bought this one. They had a "like new" one on Marketplace for £30. 

https://www.amazon.co.uk/dp/B001XMJ7UI/ref=cm_sw_r_apan_glt_fabc_ZS2DW2H5ASHVJ8HWFEKF

Exiled_Tyke

glennevis said:

I have a two-pronged approach to boiling water. A 1000W mains-powered kettle if there's enough solar output, or a stainless steel teapot on the gas hob (boils exact volume required) for ~6 months of the year.

A few years ago (I reported it somewhere on these boards) I did a test comparing the cost of using mains electricity to boiling a kettle on my (then) gas hob.  Surprisingly for me I found that despite the massive difference in unit price of electricity and gas (electricity being around 4-5 times more expensive at the time) I found that using the gas hob was only 10% cheaper. So I concluded that the wastage in using gas for heating must be the issue. This is further supported by the fact that a hob of a few kilowatts (I can't remember exactly how many) would still take far longer than a 3kW kettle to boil the same amount of water.  Gas seems to be very efficient in central heating boilers but not so when used for cooking. I suspect that now using a gas hob probably provides no cost saving and as we all know, the electric kettle is now (slightly) more environmentally friendly (especially if you have PV or batteries which charge over night on leccy which has a higher non-carbon make up)

silverwhistle

2nd_time_buyer said:

Having hot water ready for a cuppa on the morning is another big bonus.

Any thoughts?

Ugh no! I like freshly drawn water for my pot of Darjeeling (or builder's)!:-)  Having said that I do have a lower powered kettle and make sure I only boil what I need to warm and then fill the pot with whatever is needed.

mickyduck55

My system is listed in my sig.. I have a 2 Kw kettle which keeps the draw below the inverter and battery capacity even if I have something else on at the same time... If I'm feeling really frugal I pour the left over hot water into a steel flask.. the main issue with this is I forget I have a flask containing hot water and start all over again.  It often gets just poured into the sink to help with the washing up....

JKenH

mickyduck55 said:

My system is listed in my sig.. I have a 2 Kw kettle which keeps the draw below the inverter and battery capacity even if I have something else on at the same time... If I'm feeling really frugal I pour the left over hot water into a steel flask.. the main issue with this is I forget I have a flask containing hot water and start all over again.  It often gets just poured into the sink to help with the washing up....

What’s happened to our signatures?

I empty the NeoStar each night into the washing up bowl then fill up with cold water and set the timer for 10 hours. If I am getting up really early I will fill a couple of flasks from the NeoStar then fill it up again while still on the GoFaster rate. 

I have heard that tea doesn’t taste as good with reboiled water but I haven’t noticed a difference myself. I do believe in warming the pot first but I do recycle that hot water. 

In winter any heat loss from the NeoStar just goes into warming the house. You could use it as a 0.64kWh heat battery. Fill it up once on GoFaster or Go and again during the day on solar and you could store around 1.25 kWh of heat. That way you could time shift 12-15p of heat which over say 100 days of winter is around £12-15. Payback on £50 cost is around 4 years which compares well to a battery.If you just used it for 1 litre of hot water at breakfast time over the other 265 days you time shift around 50kWh which could save about £5 on current electricity rates but possibly £10 next year when daytime rates go up. So that’s around 2 years payback. 

You can still save money the rest of the year by using it instead of the kettle when PV is low so you might even get payback sooner.

 (I do expect someone to pull that argument to pieces but it is man maths in action). 

Edit: I forgot to add that in summer I can turn off the hot water heating at the kitchen end of the house completely and just use the NeoStar for hot water (from PV) for washing up in the evening. (We still have separate hot water for bathing at the other end of the house). It does away with heat loss in pipe runs getting the hot water to the sink and actually saves water as you aren’t running cold water through the pipes first to get to the hot.