Measurement, evaluation and control of the microclimate in rooms for weaned piglets

The Animal Occupied Zone (AOZ), or the microclimate, in a room for weaned piglets is roughly the zone between 0 and 50 cm above the floor of the pen. It is distinguished from the macroclimate, which is the average climate of a pig room. The ability to create and maintain an optimal climate in the AOZ is an important aspect of ventilation system performance, and was studied in this thesis in rooms for weaned piglets. The effectiveness of removal of air contaminants and heat from the AOZ highly depended on the type of ventilation system. It was highest in a room with ground channel ventilation. In a room with door-ventilation, it varied largely over the pens. In the room with porous ceiling ventilation the heat production of the animals resulted in an upward airflow above the lying area, which lowered AOZ contaminant removal effectiveness. For a good insight in thermal environment in the AOZ, air velocities were measured in the AOZ by an ultrasonic anemometer. The location of the anemometer in a pen appeared to be important and in a door-ventilated room there were differences in average air velocity between the pens. To indicate the quality of the thermal environment piglets in a batch are exposed to, two evaluation methods were introduced. The first uses solely AOZ air temperature; the other the kata-value (KV), which combines air velocity and air temperature. The methods result in numerical indicators, based on the duration and the magnitude of excess of AOZ thermal conditions outside the Thermo Neutral Zone. These methods proved to be useful tools in the technical evaluation of climate-systems, and the value of the indicator for ¿too warm¿ conditions significantly affected animal performance. Comparison of both indicators learnt that air temperature is the most critical variable to be measured to characterize the AOZ climatic conditions, but for recognition of ¿too cold¿ conditions KV clearly has additive value. Simulated AOZ climatic conditions were compared with measurements in a door-ventilated room, and showed that the simulation technique is a powerful tool for the design of a ventilation system, but needs to be calibrated with data from real farming situations. In a conventional climate control system in a room with ground channel ventilation AOZ temperature was lower and showed greater fluctuations than room temperature. Model predictive control including AOZ temperature measurement strongly reduced the temperature fluctuations in the AOZ

Bibliographic Details

Main Author:	van Wagenberg, A.V.
Other Authors:	Bot, Gerard
Format:	Doctoral thesis biblioteca
Language:	English
Subjects:	control, evaluation, measurement, microclimate, pig farming, pig housing, piglets, stall climate, ventilation, weaning, biggen, controle, evaluatie, meting, microklimaat, spenen, stalklimaat, varkenshouderij, varkensstallen, ventilatie,
Online Access:	https://research.wur.nl/en/publications/measurement-evaluation-and-control-of-the-microclimate-in-rooms-f
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