Alternative to Gas Boiler ?

[jonm01]

In doing my research I found a few devices but only one that I could buy within the UK. The IoT controller is connected to the boiler PCB and through the controller you can access via its own built-in webpage so use if on a phone or computer. It came with the IoT controller as standard as well as the flue. The downside is that the UK support are no existent but as its a global brand its easy to find someone to answer your questions. Cost wise it was about the same as any big box mass sold items so for what it does, amazing price

Interesting. I wondered what boiler you have; is it possible to switch any condensing combi to operate in this mode? Would Opentherm or Weather compensation achieve the same? Any link available for info to the IoT device you mention?

 

[CBW]

I refer to them as tax jockeys..paying an extended BBC licence fee..to the same company. You are not qualified, you are certified by virtue of the tax you pay. A point easily proven...don't pay the tax..you are no longer competent

Not a clue what you’re on about.

 

[fixitflav]

which weighs more? a kg or NG or a kg of hydrogen?

I suppose that's meant as a joke? A kg is a kg, whether it's NG, hydrogen, feathers or lead.
In replying to your #3, I was doing you the courtesy of agreeing that hydrogen has higher CV, but only on a mass basis. But that's not what matters to find the gas flow, hence do the pipe sizing. For that you need the CV per unit volume (which is given on your gas bill).
Gross CV figures are (approx) -

Hydrogen 142 MJ/kg, 11.9 MJ/m3

NG 55 MJ/kg, 39.3 MJ/m3

 

[vulcancontinental]

explain why that can't be please. An equation would do nicely

Because there is not 40% latent heat in any quantity of NG burned. Google is your friend here. But an old poor efficiency boiler and system may be improved to a 40% improvement, stretch though that may be and excluding maintenance and lifetime costs.

 

[endecotp]

Because there is not 40% latent heat in any quantity of NG burned.

What do you mean by that?

The latent heat in steam, relative to water, is huge.

 

[vulcancontinental]

What do you mean by that?

The latent heat in steam, relative to water, is huge.

Of the potential calorific value in a quantity (e.g cubic metre) natural gas being burned just under 10% can come from latent heat if all the water vapour is condensed the remainder being sensible heat.

 

[fixitflav]

Of the potential calorific value in a quantity (e.g cubic metre) natural gas being burned just under 10% can come from latent heat if all the water vapour is condensed the remainder being sensible heat.

Exactly. It's the ratio of latent heat of vaporisation to heat of combustion which determines how much heat can be recovered by condensing the vapour.

 

[endecotp]

Exactly. It's the ratio of latent heat of vaporisation to heat of combustion which determines how much heat can be recovered by condensing the vapour.

Yes... though its the latent heat of vaporisation of WATER vs. the heat of combustion of METHANE, and you need a factor of two because one molecule of methane produces two molecules of water (if you’re using the molar heats).

So its 2 x 41 / 891 = about 10%, as you say.

 

[vulcancontinental]

Being pedantic I look at it slightly differently; it's the latent heat of condensing that is released, there is no vapourisation of H2O. The H2O is formed as the result of the rearrangement of atoms during combustion unlike say boiling H2O (vapourisation) then condensing it. H2O is created, it's very hot so is a vapour but should it be cooled below its dewpoint it will become liquid releasing energy when changing state. The quantity of energy released is exactly the same anyway.

 

[fixitflav]

Yes... though its the latent heat of vaporisation of WATER vs. the heat of combustion of METHANE, and you need a factor of two because one molecule of methane produces two molecules of water (if you’re using the molar heats).

So its 2 x 41 / 891 = about 10%, as you say.

Yes of course. Only the water vapour will (partly) condense, as the CO2 is a gas at ordinary temperatures. Burning pure hydrogen, possible recovery is about 15%.