They are large ovens not too disimilar to the ones in the kiosks at the amex. How we used to use them was that the food was plated up for a banquet, speed chilled and then 'regenned' on the day.
Could be a reasonable solution as possibly not everyone wants a hot food product but buy one because it is the only thing on offer. This could reduce demand for the pies and negate the need for the additional hardware required in the summer.