Paper Conference

Proceedings of eSim 2020: 11th Conference of IBPSA-Canada


Proposition of a humidity control strategy for a calibrated greenhouse model with realistic controls in TRNSYS

Timothe William Lalonde, Danielle Monfet, Didier Haillot
Ecole de Technologie Superieure, Canada

Abstract: In this study the impact of different humidity control strategies on the overall energy performance of a small greenhouse was assessed. The existing greenhouse, located in Montreal, was modelled in TRNSYS and calibrated using its monthly gas consumption as well as measured indoor air temperature and relative humidity. Implementation of realistic controls for natural ventilation and for the heater were included. The greenhouse model was then used to compare four humidity control strategies: (1) natural ventilation; (2) forced ventilation with heat recovery; (3) desiccant wheel with solar and electric powered regeneration; and (4) condensation dehumidification unit. The calibration process resulted in a model that predicted the gas consumption of the greenhouse with a CVRMSE and NMBE of 4.21% and 0.69%, respectively. The calibration of the model resulted in a RMSE of 1.65°C on the indoor air temperature. Since few details on the crops cultivated, production cycles and irrigation events were available, the calibration resulted in a high RMSE of 17.34% for the indoor air relative humidity. When comparing the humidity control options, strategies (3) and (4) showed reduced gas energy consumption, but higher operation costs due to the electricity consumption required for air dehumidification. However, considering the energy context of Quebec, there was a reduction of greenhouse gas (GHG) emissions when using strategies (3) or (4) since electricity is mostly produced from hydroelectricity.