Using an Inline dishwasher Element in Central Heating system idea

Andy From Sligo

Hello all - sorry for this post I am bored at the moment and my mind just started racing away so if you don't want to answer then no problem and sorry if you think its a stupid Idea.

just wondering if something like this would physically work in a central heating setup and actually heat up the central heating radiators on the system , or would it just not be gutsy enough? - or not work because of some other reason?

So, my idea then, Using a Dishwasher electrical Heating element instead of a conventional oil or gas boiler in the system

The Element is rated at 230v AC and has 1800w of power - I understand the normal central heating boiler has what is it something like 90 BTU of power which I think is about 24kw (24,000w) of power, but the dishwasher heater heats up at 1800w in such a small space inside the element housing what about if one was not powerful enough then using 2 heater in series (3,600w on a 20amp switch)? I know its still a fraction of what a conventional boiler would put out- a dishwasher when in operation the water inside seems to get scalding / boiling after just a short amount of time because the water is circulating through a pump and being re-heated again and again.

What do you reckon (especially seasoned heating engineers) would it work ... even if it was partially?

from what i can see the volume of water is not that big in a central heating radiator system, the pipes in the system are only 22mm and the pipes going to the rads are about 15mm and I couldnt see the modern radiator themselves holding much water?

cnocbui

Stupid idea, just run your CH pump directly from a socket and turn on your HW cyclinder booster, so the HW cylinder is heating the water in the CH coil instead of vise versa.

I am of course, being facetious. In both cases, neither a 1800w DW element, nor a 3600w cyclinder element has anything like enough oomph, compared to a 24,000w CH burner.

And as if that's not enough, getting your heat from kero is cheaper than from electricity anyway.

Andy From Sligo

Thanks for just poo pooing that 😁

If it did heat up the water the same though 1800w electricity - vs 24,000w kerosene must be more economical and a hell of a lot cleaner than kerosene and more convenient?

jimf

oh jaysus lads andy has dismantled the dishwasher and has parts left over

big difference andy that i can see is static water in appliances as opposed to circulating water in central heating systems

10-10-20

Of course it could partially work, but to further what specific goal, Andy?

If you told me that you had bucket-fulls of left over solar energy which you could pump into the heating system on a cold winter's day, then I'd tell you to invest in an eddi or an iBoost and divert it into a heat-store and use that to partially heat the house.

But the fact is that the 1800w element is probably only sized for the equivalent of around one of your medium sized radiators, and your house probably demands 11kWh to maintain the losses, so the gain from the small heater is minimal if you just end up paying the ESB for electrons instead of BG for methane.

Plus, your diswasher is a contained and insulated unit, so it does heat up quickly and the plates and crockery hold over some of that heat into each of the wash cycles, further reducing the power consumption. So 1,800w is more than sufficient to heat it up.

But keep thinking in similar threads, it's not a bad hobby.

Andy From Sligo

https://www.boards.ie/discussion/comment/120188644#Comment_120188644

hiya jim - no, in a dishwasher with one of those inline heaters the only way it heats up the water for washing is by circulating the water through the element - as it passes through the cylinder it heats up the water and then hot water gets pumped into the dishwasher cavity.

Sure on some of the older dishwashers I think theydid have a large round heating element at the base of the dishwasher that heated up the pool of water but these days they use them inline heater now for some years

Andy From Sligo

https://www.boards.ie/discussion/comment/120189151#Comment_120189151

the specific goal being really is to cut out fumes from boilers and getting kerosene delivered etc , and all needed is a switch put on, and many more positives I dare say over having a oil boiler.

however ... Idea number 2 if an inline dishwasher was used 'ALONG' with an oil boiler to see how much kerosene use it would save , using the inline heater as a secondary heater to 'suppliment the heat to the boiler so it doesnt have to heat up the water from dead cold, therefore reaching desired heat quicker and surely must be more economical to heat 'warm/hot' water rather than cold water?

jimf

https://www.boards.ie/discussion/comment/120189253#Comment_120189253

im sure you could connect up the microwave too andy if you put your mind to it

Lenar3556

There are proper electric boilers that work on that principle Andy - if you look up Amptec.

1.6 or even 3kw would really be lost in the overall heating system. You would be much better buy an electric room heater.

Andy From Sligo

https://www.boards.ie/discussion/comment/120189927#Comment_120189927

ah right thanks for that - might have guessed someone else had thought about it / invented it

cnocbui

https://www.boards.ie/discussion/comment/120189369#Comment_120189369

If you push your car 2km - your heating warm water bit, you have injected energy into your commute, say, and then you climb in and drive the rest of the way, yes you probably will save money and reduce CO2 output, but there might be cost to you and your energy levels, so the overall cost might end up being higher than just driving the whole way.

If your electricity is free from the sun - because you have no better use for it, fine, but if you are paying for electricity, then you are right back at the electricity costing more than kerosene truth and it costing you more than just doing all the heating with kerosene.

10-10-20

https://www.boards.ie/discussion/comment/120189369#Comment_120189369

I think you'd be better of trying to come up with a way of making your boiler more efficient either by monitoring and managing short-cycling, or by managing the water-flow to keep your boiler in condensing mode for longer. Far more gains there I would think than what would come out of a 1.8kW element.

Good articles here:

https://www.theheatinghub.co.uk/articles/turn-down-the-boiler-flow-temperature

https://www.theheatinghub.co.uk/boiler-efficiency-guide-and-energy-saving-tips

https://www.boards.ie/discussion/comment/120190301#Comment_120190301

Yes, I always like the vehicle analogies. 👍️