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solenoid
06-04-2011, 10:04 PM
G'day Gentlemen.
This is my first post on this nice and intresting site.

I'm in the progress of calculating the needed cooling power for cooling down 20000kg dough from 25 degree celsius to 12 degree celsius within 8hour. I have been told that the most important thing to consider is the amount of water and fat in the dough and from that point calculate the specific and latent heat in the dough.

Im using two diffrent software for calculating cooling demand and both program have a default parameter for dough. My issue is that this default parameter is not reliable since dough can consist of so many diffrent substances.

Is there anyone who can give me the fomula how to calculate specifik and latent heat for dough by using the amount of fat and water ? Your help would be more than appreciated.

BR Solenoid

mikeref
06-04-2011, 11:42 PM
This won't answer your question, but why are you looking at latent heat as there is no change of state, say , water freeze when going from 25 to 12c? (Looking around to see if Brian Uk is on the same page)

NoNickName
07-04-2011, 04:42 PM
You must first determine how much water vapour the dough will lose during cooling.
The baker will be able to give you a rough idea of the loss of weight and this is the mass of latent heat removal in terms of water vapour.

cool runings
07-04-2011, 08:05 PM
.

I found this

Short summary from this article:
Specific heat above freezing 2.73 J/g degC (0.652 Btu/lb degF).
Spec heat below freezing 1.65 J/g deg C (but varies with temp,
especially just below freezing). Enthalpy of fusion 81-90 J/g.
Samples tested were 42, 43 and 44% water by mass. Higher water
content was associated with higher enthalpy of fusion. Freezing point was -5 deg C.


Or

Try this

http://pqi.poli.usp.br/lea/docs/cigr2006d.pdf

coolrunnings

.

mikeref
07-04-2011, 11:35 PM
You must first determine how much water vapour the dough will lose during cooling.
The baker will be able to give you a rough idea of the loss of weight and this is the mass of latent heat removal in terms of water vapour.
Ahhh, thanks NNN, latent heat with moisture removal. Guess 20k of dough would be significant.

Sandro Baptista
08-04-2011, 12:33 AM
You must first determine how much water vapour the dough will lose during cooling.
The baker will be able to give you a rough idea of the loss of weight and this is the mass of latent heat removal in terms of water vapour.

That will implicate less external cooler needs.

Tesla
08-04-2011, 11:15 AM
Hi Solenoid and welcome to our forum.
I am pretty sure the Cleland brothers (Professors) in NZ at Massey Uni have extensive information on this subject. If I find time in the weekend I will look up their calculation and SHC's for the percentages of fat verses water then post it.