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.
Citation: ASHRAE Trans. 1993, vol. 99, Part 2, Paper number 3715, 237-244, 6 figs, 11 refs.
Product Details
- Published:
- 1993
- File Size:
- 1 file , 850 KB
- Product Code(s):
- D-17410
