Lagging the boiler

[The-Engineer-That-Brews]

I lag my mash tun using these convenient plastic coated mineral wool panels from ScrewFix:

Anyhow yesterday I was just bringing the Burco up to the boil and I thought why don't I use them on the boiler ... it's at a higher temperature so the energy loss is higher....?

Anyhow the bottom line is that it worked really well - the wort came up to the boil 5-10 min faster, and I only needed 30% power to maintain the boil instead of the normal 40% so that's a decent energy saving

In retrospect I should have worried about the plastic coating melting all over the outside of the boiler - but fortunately no problem.

 

[Cheshire Cat]

When you say you needed less power is that achieved with the Burco knob or an external controller? Thanks

 

[cushyno]

I need to do something similar with my boiler too. Time to boil doesn't concern me too much, but I want to use less energy where I can and do the right thing.
Maybe a thin layer of the foil backed foam facing inwards beneath the jacket may help protect the plastic cover.

I need a fitted lid cover and tap sleeve too as the tap conducts lots of heat.

 

[The-Engineer-That-Brews]

When you say you needed less power is that achieved with the Burco knob or an external controller? Thanks

That’s a decent question - an external controller. It uses an SSR to pick out a pseudo random pattern of individual mains cycles :-)

 

[Cheshire Cat]

I’m a mechanical engineer I understood external but nothing much after
SSR = solid state relay?

 

[The-Engineer-That-Brews]

I’m a mechanical engineer I understood external but nothing much after
SSR = solid state relay?

Apologies! Yes, SSR = Solid State Relay :-) It's a type of on/off electronic switch. You connect it between the mains voltage and the thing you want to control (just like a light switch) and you can safely turn it on and off with low voltage (e.g. 5v) signals from a simple logic circuit.

SSRs are strictly on/off devices, but there are a couple of ways to use one to get variable power into a load. The first is to only turn it on for a given percentage of every mains cycle - this is called 'phase angle' control. The second is to switch it on for complete half-cycles of the mains (between zero crossings), but only for a selected proportion of the cycles - e.g. one in three. This is sometimes called 'pulse density modulation'. Both types of control rely on rapid on/off switching in order to achieve a variable amount of power over a certain period of time.

Phase angle control is most common and is what you'll find used in e.g. a dimmer switch, but it's probably not the best approach for a big power load like a brew kettle because the sudden switch on current can cause radio interference and may damage the heating element. Pulse density modulation is 'kinder' from that point of view but requires slightly more complex control circuitry :-)


A typical SSR:

 

[The-Engineer-That-Brews]

Maybe a thin layer of the foil backed foam facing inwards beneath the jacket may help protect the plastic cover.

I really should have though of this at the time as it could have made a right mess of the outside of the Burco if it had melted and stuck however there was no sign of any heat damage to the plastic at all. I can only assume that because it's designed for hot water cylinders they used a plastic of a suitably high melting point :-)

I need a fitted lid cover and tap sleeve too as the tap conducts lots of heat.

I see what you mean... although probably the amount of heat energy that escapes from the tap pipework is pretty small compared to what comes off the surface of the boiler due to the larger area.

In general I don't cover the lid completely during the boil because it has a nasty habit of leading to boil-overs - also I am told that it's a good idea to let a fair bit of the steam escape in order to dissipate the effects of any unwanted sulphur compounds in the wort (although this is said to be rare, with commercially produced malts these days) :-)

 

[Cheshire Cat]

Apologies! Yes, SSR = Solid State Relay :-) It's a type of on/off electronic switch. You connect it between the mains voltage and the thing you want to control (just like a light switch) and you can safely turn it on and off with low voltage (e.g. 5v) signals from a simple logic circuit.

SSRs are strictly on/off devices, but there are a couple of ways to use one to get variable power into a load. The first is to only turn it on for a given percentage of every mains cycle - this is called 'phase angle' control. The second is to switch it on for complete half-cycles of the mains (between zero crossings), but only for a selected proportion of the cycles - e.g. one in three. This is sometimes called 'pulse density modulation'. Both types of control rely on rapid on/off switching in order to achieve a variable amount of power over a certain period of time.

Phase angle control is most common and is what you'll find used in e.g. a dimmer switch, but it's probably not the best approach for a big power load like a brew kettle because the sudden switch on current can cause radio interference and may damage the heating element. Pulse density modulation is 'kinder' from that point of view but requires slightly more complex control circuitry :-)


A typical SSR:
View attachment 48105

When I worked for STC in the 80’s I was Quality and Production manager making relays. Electro mechanical then

 

[The-Engineer-That-Brews]

When I worked for STC in the 80’s I was Quality and Production manager making relays. Electro mechanical then

That must have been an interesting job! There’s still a big place for electromechanical relays and to be honest, I think there will be for a long time to come. One of the problems with SSRs is that because of the components they’re based on, they drop about a Volt across them in the ’on’ state; so when they are handling big currents that corresponds to a significant power dissipation.

 

[jayk34]

I wondered if the insulation on my burco gave me a more violent boil on my most recent brew. The last few times I had only put a few blankets around the boiler during the mash and toom it off for the boil.

I put 2 layers of thermawrap on and didn't take it off at all. I had to turn the knob on the burco off several times during the boil as it was spilling out the top of the boiler.