Use of BUFFER tanks within a solid fuel wood boiler system

TomOnBoard

I have access to loads of free (??) wood. I have a solid-multi fuel boiler house unit that has a separate but attached oil burning chamber. It was state of the art in 1980, but needs replacing now.

I'm looking at alternatives and am putting in a separate oil burning boiler for emergency / short-term use, but intend to rely on a new wood burner for most of the house's heating.

I'm considering a basic multi fuel boiler that would be lit and fed as needed as one option. Another option would he one of the 'fill it up' ceramic wood boilers that only burn for a few hours and heat buffer tanks that are then used to heat the house over a 12-36 hour period depending on the need for heat in the house.

A few years ago these buffer tank based wood gasification systems were all the rage, but I'm wondering how have people found them to work out over time?

TomOnBoard

Maybe I need to move this to a Plumbing/Heating forum?

I have a thermal store and a 1000 litre buffer tank, I do find that they do hold the "spare" heat from the turf boiler and I can often light the fire in the evening and there is sufficient stored heat the system to run the heating in the morning as well as the previous evening. But I do find that it's best to light a fire in the afternoon as well when the weather gets really cold.

The quality of the insulation is key to how long it will hold the heat but the way I have my system configured the oil boiler is in series with the output of the buffer tank with a bypass valve that bypasses the oil boiler if the temperature leaving the buffer tank is high enough, otherwise the oil has the warm water to heat up. It uses far less energy to raise water from 35C to 65C than from 15C to 65C. So if the buffer tank has cooled down the energy left in it isn't wasted.

Water John

AFAIK, really good insulated buffer tank would only lose one degree C in 24 hours, idle. That's from research in a previous job, not personal experience.