Aurélien Jean

Natural Materials for Thermal Insulation: Mulch and Lava-Rock Characterizations

This paper reports on the thermal characterization, via the thermal conductivity, of natural materials, such as mulch and lava rock and their usefulness as building insulation. Experiments were carried out using a scale one monitored wall (i.e. heat flux and temperature sensors) exposed to a heating source on one side and to an air conditioned space on the other. The wall system was composed of an 8.85 cm thick cavity, where the mulch and lava rock were placed. The cavity was enclosed between two layers of pine wood (40 mm thick each). After the experiments and statistical data manipulation, the estimated thermal conductivity of the materials were 0.48 ± 0.001 W.m-1.K-1 and 0.129 ± 0.003 W.m-1.K-1 for mulch and lava-rock, respectively. That is, mulch has a thermal conductivity comparable to that of bulk hemp while lava rock has a thermal conductivity comparable to that of hemp brick. These values indicate the usefulness of mulch, compared to the impracticality of using lava-rocks materials for building insulation.

Heating or Cooling Buildings with PV Walls in Reunion Island

In Reunion Island, many buildings have been equipped with PV panels on their roofs in order to produce electricity. These PV systems were built to increase the penetration of renewable energies in the public electricity grid and so reduce greenhouse effect gases emissions. This type of installation was designed just in order to produce electricity but many works have shown that PV systems integrated to walls can also cool or heat the buildings. This paper presents how PV systems integrated to building can be used to help meeting energy needs in two microclimates of the island by cooling or heating the building where it is installed. To show this, a building simulation code able to model BIPV buildings is used.

Vegetalized Complex Partition (VCP): Impact of a Green Roof under a Humid Tropical Climate, Comparison between Hong Kong and Reunion Island

The aim of this paper is to present the experimental results of a specific vegetated complex partition (VCP) and discuss the conclusions found from an interesting study case in Hong Kong, especially the presence of a strong upward heat flux in winter. The experimented VCP configuration has never been tested in Reunion Island. It is located on a small scale building with a sloped roof covered with steel foil and under a humid tropical climate. From March to August, the extensive VCP reduced the global average heat flow by 91.61% and the ceiling temperature by 9.3°C, with a maximum average reduction of 18.9°C at noon. Compares to the results from Hong Kong, three of the four conclusions have been observed or deduced from the experimented VCPs results. The fourth conclusion (about heat flow loss in winter) has not been observed. But, based on the results, a precision of the explanation of its origin is proposed: the evaporation process act like a heat loss amplifier.

Heat transfer in buildings : application to air solar heating and Trombe wall design

The aim of this paper is to briefly recall heat transfer modes and explain their integration within a software dedicated to building simulation (CODYRUN). Detailed elements of the validation of this software are presented and two applications are finally discussed. One concerns the modeling of a flat plate air collector and the second focuses on the modeling of Trombe solar walls. In each case, detailed modeling of heat transfer allows precise understanding of thermal and energetic behavior of the studied structures. Recent decades have seen a proliferation of tools for building thermal simulation. These applications cover a wide spectrum from very simplified steady state models to dynamic simulation ones, including computational fluid dynamics modules (Clarke, 2001). These tools are widely available in design offices and engineering firms. They are often used for the design of HVAC systems and still subject to detailed research, particularly with respect to the integration of new fields (specific insulation materials, lighting, pollutants transport, etc.). Available from: http://www.intechopen.com/books/evaporation-condensation-and-heat-transfer/heat-transfer-in-buildings-application-to-solar-air-collector-and-trombe-wall-design