Development of a simplified resistance and capacitance (RC)-network model for pipe-embedded concrete radiant floors

Abstract

Pipe-embedded concrete radiant floor system has gained much popularity due to its higher energy efficiency and better thermal comfort. Simplified yet accurate heat transfer models are essential for energy simulation of this system. This study presents the development and validation of a simplified RC-network model for the pipe-embedded concrete radiant floors. A concrete radiant floor mainly consists of three parts which are the cover layer, the pipe-embedded concrete slab and the insulation layer. The cover layer and the insulation layer are simplified as one-dimensional and represented by RC models with two resistances and one capacitance (2R1C). Within the pipe-embedded concrete slab, the complex heat transfer is represented by a coupled RC model which includes two parts describing the heat transfers of the concrete slab and the water loop respectively. In the case studies, the coupled RC model for the pipe-embedded concrete slab has been validated in both numerical and experimental ways. The experimental validation results show that the average relative errors of the coupled RC model in predicting the upper and bottom surface heat fluxes are all less than 5.5%. Validation has also been conducted to demonstrate the accuracy and effectiveness of this developed simplified RC-network model in predicting the dynamic thermal performance of a multi-layer pipe-embedded concrete radiant floor. The developed simplified RC-network model can be beneficial for design and optimal control of the pipe-embedded concrete radiant floor system.