Analysis of livestock environment control by simulation technique and field data

A dynamic model based on physical laws and field measurements has been developed to simulate temperature, humidity and gas concentration in livestock buildings and the emission of ammonia from these buildings. The model consists of several sub models and permits to evaluate different control algorithms for heating and ventilation of livestock buildings. For each control algorithm the dynamic evolution of the resulting inside temperature and humidity are calculated together with the corresponding energy use for the specified heating and ventilation system. By using this simulation technique a new climate control algorithm for livestock buildings has been designed, which, compared to a traditional climate control algorithm, has several advantages in terms of energy use, reduced temperature fluctuations and reduced ammonia emission. In a validation experiment is was found that the agreement between the simulated and measured temperature was less than 0.4C, although the difference between the temperature measured at different locations within the building is higher than the difference between the simulated and the measured temperature. It was concluded that simulation technique offers a powerful tool to develop new control strategies, but that more knowledge is needed about the process of three dimensional energy and mass transportation around a living organism.