how long to heat?

[AceMcAce]

Hi all

Just wondering how long it takes you all to get your water up to temp? Been making sure my AG kit doesn't leak before I make a brew in it. Took me about 90 minutes to get 50L of water from cold tap temp to 70 degrees. Is this normal speed? Fast? Slow?

I'm cooking on gas by the way.

[jack_c]

About 45 mins for 30l, 2.6kw electric heater. Although I realised I have a mains fed combi-boiler, so next time will start with hot tap water to reduce this wait...

[AceMcAce]

Never thought of that. Do any/many of you start from the hot tap?

[alexlark]

I do it. Saves LOADS!!! of time. Haven't noticed any difference in my beer. Absolutely best thing I've done since AG brewing.

[JamesF]

Hmmm. It takes 4.2 joules to raise 1cc of water by 1C. So to raise 50,000cc of water by, say, 60C takes 12.6 MJ which I think is about 3.5kWh.

With a 2.4kW electric heater I'd not be surprised if it took ninety minutes on those figures. Gas is harder to work out because you don't know how efficiently the heat from the burning gas is transferred to the water, but perhaps it's not unreasonable to suggest that unless you have some hefty burners that it would be in the same sort of ballpark as electric?

James

[sbond10]

Are you heat sheilding in any way ?

[AceMcAce]

No shielding. The burner says the "max output" (aka - cycling downhill with the wind behind you) is 7.5kW.
The burner is the same as the one the malt miller sell I believe.

Water was 13 degrees to start.

The hlt is made out of an old sankey keg.

Any advice on how I can get it going quicker?

[JamesF]

I bet 7.5kW is based on the calorific value of the gas being burned, not how much of it can get transferred to the contents of the pot. I'd not be at all surprised if two thirds of that 7.5kW just disappeared into the air, leaving around 2.5kW actually heating the water. I'm not sure there's any real way to improve on that unless you're working outside and the burner isn't shielded.

Starting with domestic hot water does seem like the best way.

James

[sbond10]

Get some sort of sheilding around there is the way I've been told. I'm using cheap breeze blocks and will find out if that works in a few weeks.

[JamesF]

Unless you're working outdoors then my understanding is that shielding adds little more than a few percent to the efficiency. Still worth a go though. I could be entirely wrong

James

[sbond10]

As it's a gas burner I'm hoping he's using it outside or in a extremly ventilated space

[AceMcAce]

Yeah, I wouldnt use that in my kitchen!

[Aleman]

Unless you're working outdoors then my understanding is that shielding adds little more than a few percent to the efficiency. Still worth a go though. I could be entirely wrong

My Heat Shroud adds considerably more than a few % to the efficiency. I get something like 1/3 of the rated output of my burner with no shield . . . with the shield it's close to 96%. . . . The last time I monitored the rise , it was something like 40 minutes to go from ambient (~10-12C) to 76-80C . . . that's 60 odd Litres of water and a 11KW burner.

>>>Here<<< is a link to what I did, and if I ever moved it into the 'inside' I still think I'd get the same sort of effect

[GrowlingDogBeer]

Never thought of that. Do any/many of you start from the hot tap?

I use water from the Hot Tap, It is also a mains fed combi boiler. I wouldn't use it if it was from an immersion tank and there was a header tank in the loft full of dead mice.

[sbond10]

Unless you're working outdoors then my understanding is that shielding adds little more than a few percent to the efficiency. Still worth a go though. I could be entirely wrong

My Heat Shroud adds considerably more than a few % to the efficiency. I get something like 1/3 of the rated output of my burner with no shield . . . with the shield it's close to 96%. . . . The last time I monitored the rise , it was something like 40 minutes to go from ambient (~10-12C) to 76-80C . . . that's 60 odd Litres of water and a 11KW burner.

>>>Here<<< is a link to what I did, and if I ever moved it into the 'inside' I still think I'd get the same sort of effect

That's one scary heat sheild wish I could make one