How Much Dry Steam Is Required to Melt Ice in an Open System?

[chopper]

I need a kick start for the following question. We're studying open/closed systems at the moment.

"450kg of ice at -18 degrees C is to be removed from a freezer using a jet of steam. How much dry steam at 100 degrees C is required if the final temp of the effluent is 5 degrees C?"

This is what I've sussed out so far.. because mass is being added to the system (the mass of the steam) I assume this is an open system problem. I haven't been given any information regarding enthalpy of either the ice or the steam so I'm assuming it's a simple matter of working out how much energy I need to bring the ice up to 5 degrees and introducing that energy into the freezer in the form of steam that will be giving up energy as it cools down to 5 degrees.

Can anyone point me in the right direction?

Cheers
Chopper

 

[Andrew Mason]

I need a kick start for the following question. We're studying open/closed systems at the moment.

"450kg of ice at -18 degrees C is to be removed from a freezer using a jet of steam. How much dry steam at 100 degrees C is required if the final temp of the effluent is 5 degrees C?"

This is what I've sussed out so far.. because mass is being added to the system (the mass of the steam) I assume this is an open system problem. I haven't been given any information regarding enthalpy of either the ice or the steam so I'm assuming it's a simple matter of working out how much energy I need to bring the ice up to 5 degrees and introducing that energy into the freezer in the form of steam that will be giving up energy as it cools down to 5 degrees.

It should be a simple matter of algebra. Just set up the expression for heat h needed to raise the temperature of 450 kg of ice to 5 degrees and the heat lost by a mass m of stream. Equate the two and solve for m.

AM

 

[kyle8921]

Based on the information given, it seems like this is a problem involving the transfer of heat energy. To start, you will need to calculate the energy required to bring the ice from -18 degrees C to 5 degrees C. This can be done using the specific heat capacity of ice and the change in temperature.

Next, you will need to determine the amount of energy that the dry steam at 100 degrees C will give off as it cools down to 5 degrees C. This can be calculated using the specific heat capacity of steam and the change in temperature.

The difference between these two energies will give you the amount of energy needed to melt the ice and bring it to 5 degrees C. This energy can then be converted to the amount of steam needed using the enthalpy of vaporization of water.

It is important to note that this calculation assumes ideal conditions and does not account for any losses in the system. Additionally, it is important to consider the efficiency of the freezer and the steam jet in order to determine the actual amount of steam needed.

I hope this helps guide you in the right direction for solving this problem.