An understanding of the dynamics of the thermal environment in heated and ventilated spaces is needed for the selection of optimized equipment systems and control strategies. A simulation model is presented which describes the transient thermal responses within a ventilated livestock building. First, a mathematical model of heat and mass transfer within the airspace was tested for a single heating and cooling event using data from a laboratory chamber and from a pig farrowing room. This model was limited by a need for a better estimate of the convective heat transfer coefficients at the inside surfaces of the building shell. A further limitation was the complexity needed to simulate the rapid changes in pressure that occur in response to sudden temperture changes and, therefore, an inability to simulate accurately the exhaust air flow delivered by propellor fans. The airspace heat and mass transfer model was coupled with a model of an electromechanical temperature controller and the overall model was used to simulate a series of heating and cooling events within a pig farrowing room. The GASP IV simulation software was used because of the facility with which both discrete and continuous events can be modelled. Although the simulated temperature did not agree exactly over a 24 h period with real temperature data, the fit was sufficiently good to conclude that the simulation model is useful for analysing alternative control strategies for livestock building heating and ventilating systems.
ASJC Scopus subject areas
- Aquatic Science