Development of the Modified Hot Box: A Convective Heat Transfer Device for Measuring the Steady State and Transient Thermal Properties of Non-homogenous Building Materials

The literature data on fired clay brick and other building materials is limitedin scope, necessitating better data for more accurate modeling. A convective heattransfer device for measuring the thermal properties of building materials wasdesigned based on the existing hot box method. This new device is suited tomaterials whose heterogeneous structure does not allow the use of existingdevices such as laser flash or transient plane sensor apparatuses. This device,known as the Modified Hot Box, uses Peltier thermoelectric modules to create aclimate-controlled environment in highly insulated dual chambers. The ModifiedHot Box was calibrated to acquire data that can be used to calculate the thermalconductivity, heat capacity and thermal diffusivity of materials which have athermal conductivity ranging between 0.1 W/m*K to 3.0 W/m*K range. The devicewas designed to test samples with dimensions of 20 cm2 by 0.5 - 5 cm thick. Heatflux transducers in the device were used to measure heat flow through eachspecimen, while resistance thermometer detectors monitored the temperature ofthe sample faces. Statistical methods, such as linear regression, were used tocalibrate the Modified Hot Box. Component data acquired by the Modified Hot Boxwill be used in future research for high resolution computer modeling of wallsystems, allowing for more energy efficient building design