Any thoughts on the future of heating?

[vulcancontinental]

Whatever the future holds will be dictated by politicians who often have no idea about how things work and are easily influenced by various industry people who may have different agendas. An example of this is the introduction of condensing boilers where much of the performance data was compared with cast iron boilers when low water content 'standard efficiency' was almost as high and had less complications. Certainly condensing technology in oil appliances produced nowhere near the claimed improvements.
Regulation of heating controls has overcomplicated their use for many people and taken away the facility for individual control options.

I don't think low water content SE boilers were particularly close to a condensing boiler efficiency, a large reduction in the flue gas temp would confirm that plus better mixing of gas/air premix adding to savings, I would postulate 10% possibly 15 with cast iron.

What is interesting is how people believe the very act of getting the boiler to condense will result in a huge leap in efficiency again, it cannot. If half the water vapour was collected that would be 4.5% improvement and the plume at the flues indicate a lot of vapour escapes the boiler.

The other problem with low water content was cycling and poor modulation; even with a limited modulated output, nowhere near today's levels, as the output went down to try to match a reduced load the inefficiency increased.

 

[fixitflav]

I believe Hydrogen burns at a higher temperature than natural gas and this higher temperature could produce more NOx

That's what I meant about excess air, to lower the flame temperature.

the more air there is the more un-used Oxygen there will be available to be reacted with Nitrogen

NOX limit I found is 56mg/kWh, and assuming that's as NO2, ~ 39mgO2/kWh. I estimate O2 for complete combustion 0.26kg/kWh and with typical 10% excess air 26gm O2/kWh. So NOX production isn't limited by O2 availability, and as you say it can't be controlled that tightly in practice.

 

[vulcancontinental]

That's what I meant about excess air, to lower the flame temperature.

NOX limit I found is 56mg/kWh, and assuming that's as NO2, ~ 39mgO2/kWh. I estimate O2 for complete combustion 0.26kg/kWh and with typical 10% excess air 26gm O2/kWh. So NOX production isn't limited by O2 availability, and as you say it can't be controlled that tightly in practice.

Excess air simply means more volume through the flue carrying heat, cool the burner to lower nox.

56mg/ kW is upper limit, boilers can be as low as 18. Generally with natural gas excess air is around 30% on premix.

 

[plugwash]

If we are going to stop burning fossil fuels in winter, a big challenge is going to be balancing supply with demand. Batteries can help with short term fluctuation over the course of a day, but it becomes prohibitively expensive to use them for balancing longer term weather and seasonal fluctuations.