Recent content by joaquinjbs

Well I'm back! I would like to resolve this exercise so... For example, applying this formula to a solution with 10 wt% NaCl (0.17 mol NaCl), which has a T0 = 268 K, ΔT = 1 K and R = 8.31 J/(molK); I have ΔH = 495392 J Now with n = 1 mol, and ΔT = 1 K: Cp = ΔH/(nΔT) = 495392 J/(molK) →...

Ok, this post has clarified me all! All my books and notes are in spanish with a little bit different nomenclature so I was a little bit confuse with those terms. At the end, it's just calculate the equivalent resistance... Thank you so much to all!

My english level is extremely basic, and the hint is a bit difficult to me. :frown: A part of my work is about to define all component in the formula at #1. I looked for in my old heat transfer notes but I didn't find anything like that formula.

I thought the OVERALL HEAT TRANSFER COEFFICIENT was α, and k was the HEAT-TRANSFER RESISTANCE... Thank you!

I've just checked my problem and I think all it's OK now. Thank you for your time and for responding quickly!

Ok, thank you! And If I have two liquids and between them I have a copper plate. I must use 400 W/(m2 K) ;) as this website says: http://www.engineeringtoolbox.com/overall-heat-transfer-coefficients-d_284.html It's true? I'm obtaining incoherent results... :(

Hi everyone! I would like to confirm if heat-transfer coefficient α units in SI are W/m2 K. I have to use heat-transfer coefficient α in this formula: Heat-transfer resistance: 1/k = δ/λ + 1/α Where δ is material thickness and λ is thermal conductivity Thank you!

Thank you, but I'm going to do with an practical experiment. Even so I'll try to resolve the formula.

I have been thinking about this all day, but I'm not able to resolve the problem. If you don't mind, could you show me an example? Than you.

Ok, thank you very much!

Well, thank you BvU. But for me it's interested what happened on the left of eutectic point. I could calculate the latent heat of fusion of ice+brine?

Thank you DrDu. I guess that heat of fusion will be at -21ºC, but If I have 10% of NaCl, would I have another different heat of fusion at -5ºC, or it would be the same?

It's possible to calculate the latent heats of fusion and the specific heat of a solution of H2O and NaCl? In some cases, it would have two latent heats of fusion? For example, at 10% NaCl, one at -21ºC and another at -5ºC? Thanks!

I tell you what I have do at the time. With specific heat of the mixture, the mass and the temperature difference between exit refrigerator temperature and -15ºC I calculate the heat. On the other way, I obtain the heat of convection and conduction with the equivalent resistance (in a...

Hello everyone, first of all, thank you very much for reading. I have to design a container (100 mm of height and 80 mm of interior radius of XPS) to keep a cryogenic mix (water and salt ice) at -15ºC at least for 40min. And my problem is to calculate the optimum thickness of XPS. I've been...