For decades, heat and moisture balance models have been an integral part of common practice in designing livestock houses in order to achieve a suitable microclimate in the AOZ. Models based on the animals’ energy balance have also long been used as support to determine appropriate thermal conditions for different categories of housed farm animals. CFD modelling provides almost unimaginable possibilities for predicting how different designs of livestock housing affect the microclimate among the animals. However especially for CFD modelling, the development has shown that it goes relatively slow to take advantage of the great potentials that the technology provides. This has several causes: (1) CFD models that satisfactorily reflect the condition in livestock housing has to include so many aspects and details that they become very time-consuming to develop and solve; (2) it is time-consuming to obtain the required expertise to build a CFD model that reflects the real conditions in animal housing; and (3) the required validation of the different parts of the CFD models is comprehensive and often requires conduction of experimental studies that target the methods used in the modelling.

There is still a large need to develop modelling methods that can improve the design of the microclimate in AOZ. These methods may lead to design of livestock housing which at the same time (1) takes into account the expected outdoor climate where the facility is intended to be located, (2) is cost-effective, and (3) ensures appropriate microclimate in the AOZ. In addition, especially in pig housing, there is a large potential to obtain benefits by designing microclimates that motivate the animals to behave in a desired way. One example is in farrowing pens where it is crucial to have an area – away from the sow – where the conditions is so attractive for the piglets that they move away from the sow and thereby minimize their risk of being squeezed to death when the sow lies down. Another example is the design of pens for group-housed pigs that ensure that the deposition of manure and urine occurs only in a small area of the pen from which it can be quickly removed. A successful solution to that challenge has many benefits, e.g., (1) the air quality will be better; (2) the emission of, e.g., ammonia, methane, and odor becomes smaller; (3) the hygiene gets better; (4) the working conditions become better; (5) the housing may be cheaper to construct because slatted floor areas may be replaced by solid floor; and (6) the use of solid floors may potentially improve animal welfare by preventing contaminated air from leaking from the manure pit up through the floor and into the animals’ lying area and by making it easier to ensure that there is bedding in the lying area.