Several dairy farms still have old multi-span barns which are encountering several problems in summer and they are: low ventilation rates, non-uniformed air distribution, heat stress and high indoor concentrations of harmful gases. A solution has been suggested, in this study, which is refurbishing the roofs of old multi-span dairy barns by modifying the roof design, increasing the cowshed height and the roof slope angle. In order to implement this new roof design, rigorous experimental measurements and theoretical calculations were carried out to evaluate the indoor environment before and after refurbishment which was determined by measuring and estimating the following parameters: air exchange rate, indoor temperature, gaseous concentrations (NH3, CH4,... |