Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

Especially in hot climate, heat stress decreases feed intake and performance of animals and leads to an increased mortality. Evaporation of water to the ambient air is generally a cost effective solution to alleviate heat stress, but is also critically discussed due to its effect on indoor humidity. The impact of a high pressure fogging system on ventilation, temperature reduction, indoor humidity, water consumption, and evaporation efficiency was investigated in a research facility for fattening pigs during a total of four fattening periods. Measured reductions of the indoor temperature ranged up to 7C, ventilation rate was reduced by about 22 %, and water consumption averaged on 4 to 5 liters per pig per day at mean daily outside temperatures above 14C. Performance of the animals was reduced during hot periods when no cooling was used, but were in general compensated afterwards. Evaporation efficiency for a fixed pressure (7 MPa) did depend mainly on temperature and saturation deficit and was 67 % for cold and wet indoor conditions (13C; 83 % r. h.) and up to 100 % for indoor temperatures around 28C.

To simulate the effect of the cooling system at different outside conditions, a data-based model was created and used as sub-model part in an established dynamic simulation model. The comparison of indoor temperature-humidity profiles, as well as the consideration of water and energy consumption enabled general recommendations for the settings of ventilation and fogging control, like a reduced maximum ventilation rate combined with shifting the fogging start. Pulse cycles instead of continuously fogging featured minor advantages compared to other changes of settings. An adequate control of a fogging system is generally recommended but depends on the specific outside and facility characteristics.