Identification of energy-efficient solutions for broiler house envelopes through a primary energy approach

One of the main concerns regarding intensive broiler production is the high use of energy for climate control. An improved design of broiler house envelopes could decrease this energy consumption. Current evaluation methods only consider the delivered energy, which is misleading because it does not consider the entire energy supply chain. By contrast, primary energy encompasses all forms of direct energy, e.g. thermal and electrical, that are supplied to the broiler house, including the energy losses along the energy supply chain. In this work, delivered energy and primary energy approaches are adopted to identify the most energy-efficient solution for envelopes in typical European broiler houses. This work evaluates 18 scenarios characterized by three different envelope types and six different outdoor weather conditions. Financial aspects are evaluated through global cost analysis. The results of this study show that a high-insulated envelope is suitable in the considered outdoor weather conditions, but it is not sustainable from a financial point of view. By contrast, a medium insulated envelope shows a favourable energy performance and its global cost is similar to that of a non-insulated envelope. A comparison of the results reveals that the delivered energy approach considerably underestimates the broiler house energy consumption compared to the primary energy approach. These results strongly suggest that a primary energy approach is well-suited for the assessment of the energy performance of broiler houses and livestock houses. This is because it accounts for the total direct energy supplied to the broiler house considering the specificity of the energy mix of the analysed country and the considered energy carrier. The proposed approach lays the groundwork for future research regarding the assessment of the energy performance of livestock houses.