How energy intensive is it to maintain a vacuum?

Question

This is for extracting various alcohols and water from a solution without having to maintain the solution at a very high temperature. I think it might be less energy intensive this way, but I have no data on energy needed to maintain a vaccum. What is the wattage on some of the pumps able to do this? Could it be cost prohibitive compared to just boiling at full temp?

Answer 1

A perfect vacuum, of course, does not exist as far as we know. Approximate vacuums, however, are used in this way quite often to "boil off" liquids from solutions. Some are created by attaching a few pipes to a water faucet. The water reduces pressure in the pipes on its own, and the only energy required is the energy used to turn on the faucet. You can get pretty good vacuums in this way.

Much stronger vacuums can be created with an oil diffusion pump, but this involves boiling oil, and for your purposes you may as well just boil the sample.

Answer 2

If i understand the question right once you create the vacuum you seal it. This would take no energy once you get to that point.

Answer 3

You don't have a wife to ask? I asked mine and she say the only maintenence she does is change the bag every so often, which is only a few bucks.