Air temperature measured by embedded sensors adopted by pig transporting vehicles in a scaled compartment model

To regulate fans and shutter openings of pig transport vehicles highly depends on the monitoring of indoor air temperature by embedded sensors to ascertain the proper indoor air temperature. It was observed in previous measurements conducted in a weaner transport vehicle that the temperature difference of air (∆T_air) measured by embedded sensors and thermocouples installed by researchers could be up to 20 ºC. The objectives of this study are (1) to study if the current installation manner of embedded sensors in lorry and trailer can reflect the air temperature inside compartments, and (2) to propose feasible approaches to install embedded sensors. A scaled compartment model with dimensions of 122 cm (L) x 122 cm (W) x 70 cm (H) was constructed. The length and width were half of the dimensions of a full compartment and the height was maintained the same as the one of a full compartment. Experimental scenarios mimicking winter and summer conditions were tested. The hypothesis was that ∆T_air could be reduced by insulating the walls near embedded sensors or by forcing the indoor air to pass over the embedded sensor as much as possible. The results showed that insulation had limited influence on ∆T_air for both winter and summer scenarios although insulations could increase the surface temperature of surrounding walls by about 6.0 ºC. Forcing the indoor air of the scaled compartment to pass over the embedded sensors could reduce ∆T_air to be less than 0.5 ~ 1.0 ºC.