3715 -- Analysis of Stability of Livestock Building Heating/Ventilation Control Systems PDF

An important issue related to control systems is stability. In the future, as humidistats become available for use in livestock buildings, temperature-humidity control strategies will be used. Simulation results reported in this paper show that temperature control (TC) is absolutely stable and temperature-humidity control (THC) is conditionally stable. Two THC systems, humidistat-controlled heater and thermostat-controlled second-stage fan (THC1) and thermostat-controlled heater and humidistat-controlled second-stage fan (THC2), were investigated. An upper temperature limit to deactivate the heater for THC1 control should be devised - otherwise instability may occur when the weather is both warm and wet. A lower temperature limit to deactivate the second-stage fan for THC2 should be devised - otherwise instability may occur when the weather is cold. A THC system would likely give a wider temperature fluctuation than temperature-based control systems.

KEYWORDS: analysis, livestock, animal housing, humidity, temperature control, controls, humidistats, heating, ventilation, calculating, models, thermostats.