Ventilation of Piggeries in Cold and Humid Climate

Optimization of the operation schemes of the ventilation devices and their consumption of energy is an important measure from the viewpoints of the animal welfare, the cost reduction, and the environment conservation. Intense scientific research is going on in the world how to ensure microclimate in the animal houses, how to reduce energy consumption and apply various heat retrieval devices in the ventilation systems. Methodology has been elaborated the calculation of energy consumption for various sets of ventilation systems in the air treatment processes using systems optimization. The operation of various air treatment devices is analyzed by the variations in the enthalpy of the outdoor air, the supply air and the exhaust air treatment processes. Using the climatologically data of Latvia about the repetition frequency of the combinations of the outdoor air parameters and recalculating them to the enthalpy of the outdoor air parameters. Using the climatologically data for Rezekne (Latvia) in a five-year period, the values of the intervals of the mean temperatures and relative humidity were calculated for a one-year heating season. With the help of the calculations about the outdoor air temperatures, how often and how long the combinations of temperatures and relative moisture continue in Latvia, we determined the average repetition frequency of the enthalpies of the outdoor air parameters. In this way the possible energy consumption of the air treatment devices was estimated in the animal house for a heating season. On the basis of an assumption about climate as a limited system in the h-x diagram in which every point of the outdoor air parameters has a non-uniform repetition frequency we determine the change in the enthalpies of each interval vs. the enthalpy of the working area. In the further course of investigation, using various ventilation systems and heat exchange apparatus, their application, the most economical way of ventilation systems was searched for in order to make it possible to use the obtained data in a far distant future in planning capital investments and their payback. Energy economy results in financial saving, conservation and safety of the environment, ensuring the animal welfare.