Thermal evaluation and optimization of a building heating system: radiant floor coupled with a solar system

Abstract

The continuous increase in the building energy consumption impactes negatively on both energy resources and the environment. In this respect, the use of conventional heating systems affects on both energy consumption and the related CO 2 emissions. The present work shows the benefits of using a radiant floor heating system (RFHS) coupled with a solar energy system. In the current study TRNSYS-18 software was used to numerically evaluate the RFHS. To achieve improved efficiency and optimize the performance of this letter, a parametric study was conducted on the solar system characteristics and the heated floor. According to the obtained results the optimal design parameters of the system that lead to a high annual solar fraction (SF=93.72%) are: a parabolic trough collector area of 6 𝑚 2 with a tilt angle 60°, a mass flow rate of 180 kg/h and 410 kg/ℎ for the collector and floor heating respectively, and a thickness of 0.07m for the heating floor slab. Furthermore, the total auxiliary energy consumption of the RFHS is approximately 63.42 kWh, versus 1953.41 kWh for a conventional heating system of reference. The economic results of the studied system show that the cost of energy saving is 244.25 €/year, and becomes 257.52 €/year with the production of solar domestic hot water. The payback period is estimated at around 13 years.