This reminds me of some vernacular thermally active surfaces that’s adopted by people in the rural part of northern China. Explained by Moe in his another writing, this design is called Chinese Kang, a thermally active bed. “In this system, the living space of the house was a few feet bove the level of the kitchen and fireplace in an adjacent room.” Hot air is channelled horizontally from the fire. There are slots built under the finished floor from the fireplace to and exterior chimney. The floor slab is made of concrete coated with clay. And on top of this are layers of oiled paper and floor mats. When heat warms up the concrete, the space above is heated up as well mainly due to radiant effect. the bed surface is then heated up as well and transfer heat to human body, mainly through conduction. Here, radiation is the main starting process of heat transfer, followed by more direct conduction. The following diagram explains this system.