Parameter analysis of Earth-air heat exchangers coupled to galvanized bridges

Resumo

Due to the thermal inertia of the soil, it can be warmer or colder than the ambient air. Therefore,
Earth-air heat exchangers (EAHE) connect the ventilation system of a building to buried ducts. Such research is
valuable because EAHE use a renewable thermal source, and they consume little electricity. EAHE heating and
cooling capacities depend on many factors, like the local climate, duct design, and soil properties. This study aims
to evaluate the thermal performance of EAHE coupled to galvanized bridges with high thermal conductivity; the
idea is to increase the overall heat exchange with the surrounding ground. This work analyses the settings of a
subtropical climate, specifically, the southern Brazilian town of Viamao ̃ . The simulations use the validated 1D
GAEA model, and they estimate the soil temperatures (without the ducts) by solving 2D heat transfer equations
with finite element methods. The methodology considers the soil, galvanized bridges, and dynamic boundary
conditions that vary throughout the year. As the thermal potential of EAHE improves with galvanized bridges, this
article examines the reduction of the duct length, keeping high annual efficiency rates.