If you want to manufactures air conditioners for vending machine, then ptc thermistor would be your good choice.
Problem --Evaporator Projects for Vending Machines
The purpose of the evaporator heater is to speed up the evaporation of condensed water in the drip tray and prevent the water from overflowing. This project requires a heater/heating element (including the entire assembly) that can be installed in a very compact location inside the tray.
Evaporator heaters for vending machines will be placed in water and need to be submerged, which also means we can't use any fiberglass in the silicone. The drip tray isn't always full of water, though. After draining, the evaporator heater can get very hot. Some kind of temperature regulation method is required. Due to the small space, there is no room for the sensor to connect back to the control system. We can't even put a thermocouple for feedback.
Solutions - PTC Thermistor for Vending Machines
We glue raw silicone rubber (no fiberglass) and seal the edges to ensure it can be submerged in water. We put a PTC thermistor on the surface of the heater and self-adhesive on the bottom for easy installation.
Now we have a small self-regulating silicone rubber heater that automatically shuts off if it gets too hot. Our heaters fit into tight spaces and help water evaporate quickly. On site, technicians can easily install the heater. After installing the vaporizer heater for vending machines, there is no more water flow on the floor and the heater does not get too hot.
