Water is widely used as PCM material - it is called slurry ice. Paraffin is used for other temperatures.

I've studied PCMs as heat stores for electrical batteries. A paraffin leak from inside an encapsulated PCM is simply a messy situation. A leak of water in a similar situation is a potentially catastrophic hazard.

If i want to store the milk at 4 degree Celsius which would be he best PCM?

I'd go for water but work on the encapsulation thermal insulation so that you maintain 4C in the milk.

Dear Adarsh

you can use the water as a PCM , but you need to simulate the heat transfer for your system .

For my study I build a matlab code to simulate the PCM , then I decided which is the best melting temperature for my design.

I think you have to simulate your system , then you can decide.

regards

hasan alasadi

Agree with Hasan , I use STAR-CCM+ CFD code, much easier than reinvent the wheel in Matlab.

thanks for your comments

Water as PCM fails due to high volumetric expansion. It cannot be considered for a containment problem

Dear Srikanth

the problem of volume expansion for the water can be considered only for the evaporation case. This because when the water transfer from liquid to vapour , it will need a very big volume at same pressure. While during the solidification and melting, the volume expansion of the water is same as other PCMs.

Regards

Hasan

Dear Hasan,

When liquid water is cooled, it contracts like one would expect until a temperature of approximately 4 degrees Celsius is reached. After that, it expands slightly until it reaches the freezing point, and then when it freezes it expands by approximately 9%. . Below 4 °C, the volume increases, and therefore the density decreases . water near the surface loses energy to the ambient, becomes denser, and sinks; the warmer, less dense water near the bottom rises. However, once the colder water on top reaches temperature below 4 °C, it becomes less dense and remains at the surface, where it freezes.

Dear Srikanth

you talked about something is knowing for everyon!!!!!!

we talk about problem while what you mentioned happen with any material but in contras Which mean when it melted the volume expand . If you check the densities of melt and solid of the praffin , you will imagine that .

therefor , this expansion during the melting of the water dose not consider as a problem.

However, the problem of volume expansion for the water can be considered only when the water changed from liquid to vapour.

Regards

Hasan Alasadi