Thermal Model of a Passive Solar Greenhouse
Authors: Ghose, Shreya; Lubitz, William David; Zheng, Youbin; Kong, Yun; Scroggins, Martha Gay; Llewellyn, David; McDonald, Mary Ruth; Van Acker, Rene; Martin, Ralph C.; Elford, Evan
Description: High tunnel greenhouses are ideal for growing small fruits and vegetables in a protected environment. When compared to horticulture in open fields, the regular growing season of a crop can be extended as temperatures inside a high tunnel are higher than temperatures recorded in open fields. Organic high tunnel horticulture can improve the yield, quality, prevent disease and lead to better pest control of the crop.
Variables such as air and soil temperatures, solar insolation, airflow and wind speeds have been measured inside the high tunnels, and in open fields for two growing seasons (2015 and 2016) at Guelph, Ontario. A one-dimensional energy model has been developed and validated for Quonset style passive solar high tunnels using the measured variables to understand how they influence the microclimate inside the tunnels. Analysis of the data collected from previous seasons have shown lower than expected frost resistance inside the high tunnels. The insect screening has significantly lowered the ventilation inside the tunnel, leading to higher temperatures and humidity levels when compared to unscreened tunnels. Some stratification has been observed qualitatively.
The model and data collected is part of a longer study that will be beneficial to farmers. It will help them choose the type of crop best suited for the microclimate inside the tunnels and extend the duration of the growing season. Developing system models using these data can also help identify methods of reducing energy costs through structural changes and by modifying operating methods.
Keywords: High tunnel, Microclimate, Energy Model, Passive Solar
Conference name: CSBE/SCGAB 2017 Annual Conference, Canad Inns Polo Park, Winnipeg, Manitoba, 6-10 August 2017.
Session name: Poster Session
Publisher: Canadian Society for Bioengineering
Language 1: en
Rights: Canadian Society for Bioengineering