Comparação numérica-experimental do desempenho térmico de um trocador de calor solo-ar

Abstract

Buildings are responsible for a large part of energy demand worldwide. In Brazil, energy consumption in buildings accounted for 15% of total energy consumption, and 46% of electricity consumption. In commercial buildings, air conditioning systems are responsible for about 70% of this use. In order to collaborate to reduce this demand, this paper aims to present a computational model to analyze the performance of an Earth-Air Heat Exchanger (EAHE). This passive air conditioning system uses the soil as a heat exchanger, heating or cooling the air depending on the climatic conditions. To develop the computational model, simulations based on Computational Fluid Dynamics in Ansys/Fluent®️ software were used, in order to obtain air temperature values along the EAHE, and compare them with values obtained experimentally, collected from sensors installed in a EAHE located at the Universidade Tecnológica Federal do Paraná (UTFPR), Ponta Grossa campus – Brazil (25.1° South, 50.16° West). To optimize the computational time, a reduced model for the soil domain has been used in the simulations. The heat exchanger was installed at a depth of 1.5 meters, where the average temperature of the soil at this depth is 22.8°C. It was observed that for both cases (heating and cooling), the air temperature after circulating through the heat exchanger converged to the average temperature of the soil, in which it obtained a reduction of up to 15°C and an increase by 4.9°C, revealing a good performance of the system.