Direct Glycol Cooling Solution

[Goose]

hi Goose,

their Glycol system works on a refrigeration circuit, so the Coefficient of Performance is above 3:1, therefore your 3kW power in would result in over 9kW of cooling capacity.

at the temperatures we are talking (100degree wort down to 12degC) and on a mild day that efficiency would be much higher, say 6:1 plus.

This is why the refrigeration circuit is such a popular way of heating and cooling

Good stuff thanks, but this assumes that i have a sufficient "reservoir" of low temperature to begin with, and that the "pump" does work to move the heat from one reservoir to the other.

My calculation just works out the total amount of heat that needs to be moved out of the wort....

 

[Truman42]

Are you not concerned about wort oxidation ? I understand its ok for the no-chillers because they have zero airspace in their cubes while they wait for them to cool ?

The wort won't oxidise sitting in a fermenter inside a fridge dropping down to 21C overnight. Likewise I've never had an infection problem doing this. I must admit it was a concern but after being advised to do this by a few fellow brewers on here I've tried it without any problems. Also im confident with my sanitary practices.
Often I make up my starter from the wort so it's not ready until the next day anyway. Saves having to pour off the beer from a 2 litre starter made from ldme which may change the taste of a stout I've just brewed.

My plate chiller is one of those smaller ones (12 plate I think it's called). So in summer even with the water running fast it sometimes only drops to just below 30C.

It works for me. YMMV

 

[Goose]

The wort won't oxidise sitting in a fermenter inside a fridge dropping down to 21C overnight.

In the literature the generally accepted temperature cutoff where the oxidation is unlikely to occur is below 80F (27 Deg C) which suggests the risk is in the time it takes you to cool from pitching temperature to around 27. Below that and its just infection risk.

If you are just below 30 you are probably ok.

Anyway, like u say, what works for you works for you

 

[mikk]

Although the same could be achieved by recirculating back to the boiler... first using tapwater as the coolant then iced water... thugh not as elegant of course.

I think this would take much longer to cool, as maximum cooling occurs when there's a big difference in temp between the wort & the cooling liquid.

Initial cooling when recirculating back to the boiler would be ok, but the cooling rate would slow markedly as the wort gets closer to the cooling water temp. Cooling water usage would also need to increase considerably if recirculating.

 

[Goose]

I think this would take much longer to cool, as maximum cooling occurs when there's a big difference in temp between the wort & the cooling liquid.

Initial cooling when recirculating back to the boiler would be ok, but the cooling rate would slow markedly as the wort gets closer to the cooling water temp. Cooling water usage would also need to increase considerably if recirculating.

An excellent point.

Which is why I just ordered me a Blichmann Therminator for a first stage cooling using tapwater. Reckon its going to look like hose city when its all connected up. :blink:

Should save me a stack of ice and hence freezer space and hence energy (I hope).

Thanks for the discussion lads.

 

[Goose]

2 wort chillers, inline with each other. The first chiller uses tap water to get the wort down to 25-30, the second chiller uses iced water or glycol to get the temp down to 10-15 deg.

Ok got the additional piece and hooked it up for a trial run yesterday..... worked a dream, wort out of first exchanger 30 degrees using tapwater on the other side, then into second heat exchanger and wort out at 10 deg C using chilled water from ice bath.

45 litres of wort 100 deg C down to 10 deg C in 20 mins... cant complain.

Here's a couple of pix, excuse the direction of the wort out thermometer and proximity of power socket

 

[Mardoo]

Nice thread guys. Thanks.

 

[mikk]

Nice work! Any idea how much tap water & iced water you ended up using during the process?

 

[Goose]

Nice work! Any idea how much tap water & iced water you ended up using during the process?

Yeah thanks for the tip mikk

I used half the ice I normally use, ie 15 litres odd, as much as I can squeeze into one shelf of a dedicated freezer, (approx. 4x 4 litre food storage containers) but then then it wasn't fully melted so just loaded containers up with ice + cold water from bath for a freeze ready for the next batch.

On the water side hard to say, though the benefit is that the water coming out of the first exchanger is 60 degC +, so this got recycled back into the HLT for later cleaning of my 3V system. The HLT was full before the cooling had finished, the rest I had to put to the drain. My HLT is 50 litres, I'd estimate maybe 75 was used in the cooling.

In the past I had to add water into the HLT and heat it .... this process saving me LPG and electricity at the expense of a bit more water...

Interesting though, I'd transferred a shedload of heat from my boiler back to my HLT in this process.

 

[Laura Houra]

Generally if the cooling result is too much difference with the reasonable range, there may be two reasons: a. There may be some mistakes with the internal structure of the heat exchanger b. The city water flow capacity is not big enough. But the probability of an error on heat exchanger is too small.. So let us analyze as below:

1. When the glycol water temperature exceed 20 celsius, how many hours it will need for the chillers reduced it back to -4. If it could reduce 4-5 celsius/Hr, just mean the chillers works normally.
2. How about the flow capacity of your city water? Generally for the 15bbl system, the city water flow cannot less than 3T/hr. If the water flow is enough, the city water temperature should raise to above 50 celsius after it cooled the wort, now a effective heat exchanging occured. And now the wort temperature should at about 40-50 celsius.

more details, please help to check the link: http://microbrewerysystem.com/Blog/Why_our_glycol_system_cannot_make_our_wort_cold_enough__829.html

Laura Houra