# What are good insulation materials?

Types of metals, plastics and others like fiber glass.

Also I have another question.

How do I calculate how long it takes to heat liquid up with different amounts of energy.

Say from -40c, how long does it take to heat oil to 71c with a 120volts. This is bare bones, but I just want to know what I'd be looking at.

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Fiber glass is an excellent overall insulation for pipes, heat exchangers, and so on. It has a low thermal conductivity, easy to form, and relatively inexpensive.

If you need something more solid and strong, calcium silicate is a good choice.

If you have a constant heat input into a tank, apply this 1st law of thermo:

Qnet = mass X cp X (T-final - T-initial) / time

Qnet = power input - heat loss through insulation. Other variables self explanatory.

Solve for time.

You will need to convert your heater voltage into power (e.g. watt) units.

Hmm so I feel like I'm missing something.

I'll just make something up.

540w source.
0 Heat loss through storage:
Initial temperature of oil: -40
Final temp: 70 degrees

Qnet is in what units or, what is it exactly? Where do I make up a qnet number so that I can find time? I see how to get it when I do have time or how to get time when I do have qnet.

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For the sample numbers you listed:

Qnet = 540 watts - 0 watts = 540 watts.

Next, you need the mass of oil in the tank. You can figure this out from the operating (or design) volume of your tank and the density of the oil:

mass = density X Volume.

Now solve the equation I listed above for time. Note that T-final = 70 degrees and T-initial = -40 degrees. Check if you are working in Fahrenheit or Celsius. It makes a difference.

This will be the time required to heat your oil bath from -40 degrees to 70 degrees.

Try it, and see what you get.

Thanks for the information... quite helpful!! :)