I have equipment in my shop that can rust. So, I can’t use your products.

We disagree! You CAN use our evaporative coolers, you just have to use them correctly. The key here is that you are going to have to 1. Keep a door or multiple windows open, and 2. Sacrifice some cooling efficiency to ensure you keep the humidity levels as low as possible. You can successfully use an evaporative cooler even in shops where rust is a concern.