Real world gasification log boiler accounts needed

[muttley9050]

Air is much cheaper to fit not more expensive in electricity.
But like an aircon unit in reverse.
I would avoid.
Here's a couple of pics of our System

[muttley9050]

Pics

[difflock]

Per some of the posts above, while I was still running the boiler,

I joked that iffen I hadda sold all the wood I burned,

it would more than have paid for the heating oil needed, and been simpler.

Because.

It is a wile pile o drudgery lighting it and tending it etc.

Or so I found, being constrained to working around full time employment

Also, as said above, Insulation, insulation and insulation.

And then perhaps a GSHP driving underfloor heating for background heat only, with a woodstove in the living room to top-up/fine-tune the heat needed.

Which is essentially how we operate, except the underfloor is oil heated, but IF I had applied for our RHI, it was going to be for a GSHP system to feed into the pre-existing underfloor.

Cheers Mr. Ed.

Marcus

[Mr. Ed]

On 19/03/2021 at 16:56, TuscanPhil said:

I have been using an SHT TDA 25Kw for the last 4 years - heating a 2000L thermal store.  It also has a pellet chamber on the side (not separate burner) and is auto start.  Just load it with logs, press the 'on' button, and wait for it to 'call' for heat and it lights the boiler automatically.  It uses hot air to light the handful of pellets (literally a small handful), which then light the logs, which then heat the thermal store.  Burns once per day in the winter when cold - 1 deg or so, (though I do extend the burn by topping it up with logs while it is still burning) and once per 7 or 8 days in the summer for hot water only.

One thing to be aware of, that wasn't made clear to me, is that my pump system and boiler, like to put 50-55deg C water through the rads, so as we've been renovating the house, all rads are being swapped out for 'oversized' rads - or for us - normal sized rads.  There's a conversion chart online for different water flow temps in rads, but ours are about 1/3 bigger than a gas boiler heated house would use.

One benefit of the SHT TDA is that is also has an internet enabled interface, so I can control the boiler from my phone when out and about.  It has a 'holiday' mode, so you can load it before you go away and it will start itself automatically after X days (whatever you set).

SHT do 4 boilers in that range 15, 25, 30 and 40Kw.

Don't underestimate the amount of logs you'll need, we use about 15-20 M3 per year.

Happy to answer any questions etc.  Oh yes, the ash pan needs cleaning about once per 3-4 weeks over the winter (assuming you are burning good wood and not crap pallets etc)

Not my boiler but it looks like this (boiler, thermal store and expansion vessel)

http://www.efficientenergycentre.co.uk/wp-content/uploads/IMG_3133-800x380.jpg

Thanks for this interesting account. I take it that’s 15-20 cubes of loose packed logs? Softwood/hardwood?

[Mr. Ed]

On 19/03/2021 at 14:43, Woodworks said:

If you cant then as above and go for high levels of insulation and a heat pump. We have a GSHP and a woodburner and can heat the house either way but have a good market for logs so its cheaper to sell the logs and run the GSHP. Also way less faff and does the hot water. We sell logs for a living and supply folk who rely on wood for heating and its not a route I would want to go down given the choice 

Hi Works

 

Many thanks for this. 

 

Is it too personal to ask what order of money the GSHP installation set you back, and whether you use a deep or shallow ground source? 
 

Best

 

Ed

[TuscanPhil]

@Mr. Ed, as part of the 'delivery' process, the installer provided me with a heat requirement based on my EPC (had to have a new one done for the RHI).  From this heat requirement (CH + HW) they then worked on the calorific content of beech / oak to generate the logs required.  I think the amount is based on 'solid' so I've allowed an extra bit for stacked (tightly stacked not loosely stacked).  Here's their calc.

 

The TDA boiler is rated at 25kW and has a seasonal efficiency of 91%.
Fuel type: Beech @ 20% moisture = 4.13 kWh/Kg
Beech bulk density = 500 kgs/m3
From the EPC dated 23 May 2017 the total amount of heat required per year is 27844 kW/hours. This figure includes hot water requirement.
The annual mass of log fuel required per year = 27844 x 1.09 divided by 4.13
= 7348 kgs.
Volume = 7348 divided by 500kgs per m3 = 14.70 m3

 

An old pic of my 'tightly stacked' log store.  I split relatively small so that it seasons more quickly.  The boiler will take big chunks without issue as it is lambda controlled via O2 sensors, primary and secondary air, temperature etc etc. 

[Mr. Ed]

21 minutes ago, TuscanPhil said:

@Mr. Ed, as part of the 'delivery' process, the installer provided me with a heat requirement based on my EPC (had to have a new one done for the RHI).  From this heat requirement (CH + HW) they then worked on the calorific content of beech / oak to generate the logs required.  I think the amount is based on 'solid' so I've allowed an extra bit for stacked (tightly stacked not loosely stacked).  Here's their calc.

 

The TDA boiler is rated at 25kW and has a seasonal efficiency of 91%.
Fuel type: Beech @ 20% moisture = 4.13 kWh/Kg
Beech bulk density = 500 kgs/m3
From the EPC dated 23 May 2017 the total amount of heat required per year is 27844 kW/hours. This figure includes hot water requirement.
The annual mass of log fuel required per year = 27844 x 1.09 divided by 4.13
= 7348 kgs.
Volume = 7348 divided by 500kgs per m3 = 14.70 m3

 

An old pic of my 'tightly stacked' log store.  I split relatively small so that it seasons more quickly.  The boiler will take big chunks without issue as it is lambda controlled via O2 sensors, primary and secondary air, temperature etc etc. 

Cool! Very thorough. Will digest. Great log store. 

[Woodworks]

50 minutes ago, Mr. Ed said:

Hi Works

 

Many thanks for this. 

 

Is it too personal to ask what order of money the GSHP installation set you back, and whether you use a deep or shallow ground source? 
 

Best

 

Ed

Not at all but it was around 15 years ago! The GSHP was £3600 if memory serves me right. There was £1200 grant and I cant honestly remember if that price included that or not. There was a bit of additional kit to add as it includes a built in hot water tank. This needed a higher water pressure than our spring supply had so fitted a tank and pressurising system and dont know the costs of this but would estimate around £500. Ground loop pipe was around £300.

 

It's a ground loop around 1.2m deep and not a borehole. In hindsight I would have put in appreciably more pipe as our ground loop runs cooler than would be ideal but combined with a well insulated barn conversion the UFH does not need to run hot so efficiency is still pretty good. 

 

The GSHP is an IVT Greenline C6.

All self installed but commissioned by the supplier 

Edited March 22, 2021 by Woodworks

[openspaceman]

On 19/03/2021 at 16:56, TuscanPhil said:

I have been using an SHT TDA 25Kw for the last 4 years - heating a 2000L thermal store.  It also has a pellet chamber on the side (not separate burner) and is auto start.  Just load it with logs, press the 'on' button, and wait for it to 'call' for heat and it lights the boiler automatically.  It uses hot air to light the handful of pellets (literally a small handful), which then light the logs, which then heat the thermal store.  Burns once per day in the winter when cold - 1 deg or so, (though I do extend the burn by topping it up with logs while it is still burning) and once per 7 or 8 days in the summer for hot water only.

This sounds similar to the kunzel installation we did for an chap that runs an oak framing company except he had a concrete slab and under floor heating. I think the Kunzel (now out of business) was based on the original Baxi gasification idea (sold as Tarn in US). It burned once per day and used hot air (with a graphite resistance heater) to ignite the logs directly, there was a 3tonne water heat store as the heat store cooled it triggered the burn.

 

The firm also put in a Kob  gasifier boiler at an institution near Petersfield, it  ran the old radiators in the large property, was manually triggered and burned cord wood.

 

Both only needed only annual maintenance and cleaning  unlike the various chip stokers we installed which needed frequent attention.

[openspaceman]

9 minutes ago, Woodworks said:

In hindsight I would have put in appreciably more pipe as our ground loop runs cooler than would be ideal

I've told the story before of the big country house that installed GSHP heating and used the heat for the house, offices, pool and stables (posh horses). The loop was extensive and on a cold day you could trace out the pipe in the lawn because the antifreeze mix in the pipes had cooled the ground so much it had frozen and the heave was visible. This must be over 30 years ago now.