Which Hot Water cylinder for Pellet Boiler

[Tetrarch]

I had a Winhager BioWin pellet boiler installed in December 21. At the time, pending a planning appeal we had it connected only to the upstairs rads and the UFH that has been installed so far. I am using an immersion heater for hot water and a basic 8.5kw electric shower. The heating is plumbed ready for HW delivery but it is not yet connected.

 

The planning appeal is dragging on interminably so I'm now looking at potemtially another Autumn/Winter under these conditions. 

 

Knowing that the run cycle for the pellet boiler is fairly long I was thinking that a larger HW store with the HW run every other day would be more efficient than a small store/daily run when the heating is off during the summee.

 

The question is how do I optimally size a megaflo (or similar - open to recommendations) to accommodate this kind of arrangement? Our household is just two persons so just a couple of showers and hot water for washing and washing up.

 

Regards

 

Tet

 

 

[SteamyTea]

Generally, with highly polluting burners like these, it is normal to put a lot of energy, in as short a time, into a thermal store.

Then draw what you need from that.

The calculation are fairly basic, just your needs divided by the power input.

Edited June 28, 2022 by SteamyTea

[Trw144]

The Biowin is actually a very good boiler - emissions of less than 2.5mg/m3 so I certainly wouldn't say it was highly polluting.

 

@Tetrarch How is the boiler installed - I am assuming it isn't currently connected to a buffer? A run time of a minimum of one hour is recommended, which sits somewhere between 200-500 litres, depending upon which output you have (10-26kw on the Biowin I think?).

[SteamyTea]

6 minutes ago, Trw144 said:

The Biowin is actually a very good boiler - emissions of less than 2.5mg/m3 so I certainly wouldn't say it was highly polluting

In a lab. Bet it breaks the WHO guidelines in everyday usage (5 μg/m3 for PM2.5 and 15 μg/m3 for PM10).

It is fudged by allowing a higher limit for 24 hours.

 

[Trw144]

Yes, in a lab but then everything is tested in a lab. No different to how an oil boiler is tested. They are tested annually on site for emissions in Germany though for this reason, and are moving over to electro static filters on most new installs to ensure continued low emissions.

 

[Tetrarch]

Thank you for the replies.

 

I chose the 15kw Biowin to replace a 1950's oil boiler in an area that is nor connected to the mains gas grid. We live in a rural setting and so I am sanguine about our contribution to pollution from our boiler, and indeed our wood burner.

 

My intention is to go for a 300L Megaflo and run the boiler every other day. First things first will be fitting a water softener.....

 

Regards

 

Tet