single to 3 phase inverter

[Dray]

Hi all.
I need some direction to supplying power to an electric boiler that requires 3 phase. boiler output is 36kw. I have had a bit of a search on tinterweb and only motor supplies seem to be coming up. I'm assuming that the boiler has Three heaters and each needs it's own phase. If any of you could point me in the right direction that would be great. Thanks

 

[Deleted member 105166]

In my experience, the single to three phase inverters I've encountered have been used for machines with much smaller and less constant draw than the 157A that your boiler needs, assuming it is 100% efficient (which many claim to be, or as near as). Have you asked the DNO to quote for a 3 phase supply?

 

[The Ghost]

You mean one element draws 36kw? or is it an array of elements. What is it as a matter of interest. Anyway I have looked into the idea of converters before and could not get any where near that draw and as you say they are usually for motors. The only other possibility is the wiring has provision for changing links for single phase and three phase. Or as @TonyMitchell says, get a three phase supply.

 

[dmxtothemax]

DITTO !
The cost of a unit of that capacity will be enormous,
You would be better off getting a three phase generator
Or a Three phase supply.
Why an invertor ?
tell us more ?

 

[freddo]

Is the 36KW just the heat output rather than the electrical requirement? We often use inverter units to power 3 phase biomass boilers. If it really is an electric boiler an inverter would not be a good idea, the single phase current draw would be enormous.

 

[Wilko]

Hi - I've never seen a static convertor anywhere near this capacity, so it'll need to be a rotary one. Biggest on the linked site is 22kW, limited by 100A single phase I guess. I'm not sure this is going to be cost effective on single phase, just saying .
Single to 3 Phase Converter > Rotary - https://www.simplypowersupply.com/Single-to-3-Phase-Converter/Rotary/default.aspx

 

[Lucien Nunes]

This sounds nonsensical. An ordinary electric boiler is a bunch of elements, which are single-phase. The converter would cost more than the boiler, to do nothing except waste maybe 15% of the energy consumption.

However, it's unusual to have a large enough single-phase supply to power a 36kW load (160A) so the manufacturers might not have bothered to make provision to reconnect as single-phase internally in their standard units. Need to RTFM and maybe contact them. Is this a remote installation with only single-phase HV available?

An electrode boiler is a different kettle of electrodes though.

 

[snowhead]

And send whoever specced a 3ph boiler in a single phase building on a long 1 way journey.

 

[Intoelectrics]

This sounds nonsensical. An ordinary electric boiler is a bunch of elements, which are single-phase. The converter would cost more than the boiler, to do nothing except waste maybe 15% of the energy consumption.

However, it's unusual to have a large enough single-phase supply to power a 36kW load (160A) so the manufacturers might not have bothered to make provision to reconnect as single-phase internally in their standard units. Need to RTFM and maybe contact them. Is this a remote installation with only single-phase HV available?

An electrode boiler is a different kettle of electrodes though.

Yes I agree, it sounds like a 3 phase instant hot water boiler. I have fitted loads of these over the years. If there is no 3 phase supply then it would be un-economical to try and install these using a generator/converter. Depending on the application it would make more sense to install a/couple of single phase stored hot water cylinder/s.

 

[Dray]

thanks for all the replies, I have dug a bit further into what will be needed should the boiler be installed to run this system. But I think I'll give you the full story so you all have a better picture....My mother in law purchased a property over a year ago in a small rural village. The property consists of two old listed cottages joined together with a modern "extension" so it is now a 5 bed, 3 reception room, 1 huge kitchen/dinner/lounge area (the new bit joining the two cottages) and all the other little nooks and crannies that come with the house. The heating (underfloor) and hot water system is a thermal store which is fed from two separate heat sources/types. A- the back boiler fire and B two electric heaters. The thermal store needs a minimum of 32kw by design for this size house to work correctly (as informed by the thermal store engineer) , however the two electric heaters are only 9kw each, these both work together when heat is called for and the fire isn't lit, and the fire only puts out 7kw to the back boiler. These two inputs run separately from each other. So the design of the system is flawed from the start and this is why she has heating and hot water problems. We ..or I, have been trying for over a year to get companies in to solve the problem, or install a system that will work, and it has been time after time that they have pretty much either left screaming or rubbed their hands together and put forward a quote that would wipe out their mortgage payments in one go. We have had quotes in to change to gas, but with the listings on two sides of the house, and the logistics with regards to public spaces and neighbours and other bits and pieces, having a fuelled system that requires flue'ing isnt an option. So I am back to basics...what do I have? power..check what would suit my needs...this 36kw electric boiler..check how do I supply power to the boiler....ehhhh turns out install 3phase supply to the property. right got the ball rolling on that this morning, only from an enquiry side of things to start as I dont know the ins and outs of 3 phase into a domestic property. so thats the story. Dont hate me, it is what it is, and I'm just a baggy --- spark trying to please the mother in law. If I'm going about this the wrong way, then shine me a light so I can start going the right way

 

[DPG]

A property like that is going to cost a fortune to heat using electricity. Sorry for stating the obvious! Not very constructive.

 

[snowhead]

Someone may need very deep pockets if, there isn't a 3 phase available locally or the local 3phase transformer doesn't have enough spare capacity or if the single phase supply is to be upgraded instead, the single phase transformer doesn't have the capacity.

L.P.G with an external boiler and bottles may be a possibility, subject to complying with the listing.

Or heat pump, correctly specced and designed of course.

What have the neighbouring properties got for heating?

 

[Deleted member 105166]

An oil fired solution is worth serious consideration. We installed one last year to replace an inefficient old LPG (Calor) boiler.
You can shop around for oil to get the best deal, which we couldn't previously, as the Calor tank was theirs and the contract prohibited replenishing it by other suppliers. I did the sums and an electric boiler would have been more expensive to run.

 

[Wilko]

I vote for external boiler too (gas or oil). It may need planning approval due to being listed, but that might be straight forward if they recognise that it's not a permanent building and avoids having to install flue on side or through roof. MIL could make an email enquiry to Planning Dept for advice perhaps?

 

[marconi]

Have you considered using two 16 kW (= 32 kW) thermal output heat pumps? The electrical input is circa 5-6 kW for each pump and single phase so about 10-12 kW electrical load. See for more details:

Panasonic Aquarea MDC - H Generation High Performance (55°C) Monobloc - Easy Heat Pumps - https://www.easyheatpumps.com/product/panasonic-h-generation-high-performance-55c-monobloc/?attribute_models=WH-MDC05H3E5&gclid=CjwKCAiAqOriBRAfEiwAEb9oXXvihAYMqvhhGm1aP-vidF_fceVeT47wObnlU9wcuYKZfxRk3tHVAhoCtx4QAvD_BwE