Do you have any friends who run a restaurant? Please tell me how to keep rice warm in winter.

If conditions permit, heat the rice in the microwave oven. It can keep moisture without splashing water. You can also choose waterproof distillation for heating rice. Put the rice in a bowl, wrap it with plastic wrap and steam it. Specific other insulation methods: it may be better than the advanced insulation barrel. A thermos bucket like a water bottle is nice. I hope I can help you.