PERFORMANCE PREDICTION OF A FLOOR HEATING SYSTEM U

This study examines the optimum design and control of a floor heating system using buried electric heating panels. The system makes a significant contribution to electric power load leveling bye the thermal storage using soil as storage medium. Also, it is a very economical system in Japan because it can use the nighttimepower rate, which is discounted about a quarter of that during daytime.

The system performance and thermal environment in the building are strongly affected by various design conditions ( e.g., number of panels, depth of buried panels, condition of the thermal insulation surrounding the storage medium, control strategy, physical properties of the storage medium, etc,), so there are a number of problems that need to be solved or clarified to established the optimum design and control strategies.

In order to estimate the system performance and the storage effect accurately, it is necessary to estimate the thermal behavior of the system, not only in winter season but also in other seasons, because the soil has an extremely large thermal storage capacity. Furthermore, in the analysis procedures, the system operation and the thermal behavior of the building should be analyzed simultaneously.

In this study, a system simulation program was developed for this purpose and the system behavior was analyzed under several design conditions. In conclusion, it was clear that not less that 10 M2 floor in a building can be air-conditioned by one buried panel, which has 0.975 m2 area and 320W output, at depth of 0.1m below the slab. And then , the annual heat recovery rate was about 90%.