A thermal array was a heating element used in cooking food.
In 2372, the thermal array in Neelix's kitchen aboard USS Voyager overloaded, vaporizing an entire pot roast. Samantha Wildman identified the problem as the anodyne relays. (VOY: "Deadlock")
In 2373, Neelix had the idea to inject sirillium into his thermal array to improve cooking time, but B'Elanna Torres told him he'd blow up half the kitchen in the process. (VOY: "Flashback")