Development of a New Dynamic Energy Model for Commercial and Small-scale Greenhouses: Validation and Practical Applications

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Authors

Nauta, Alex

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Volume Title

Publisher

University of Guelph

Abstract

A transient lumped capacitance model capable of predicting the greenhouse microclimate based on external weather conditions and site properties was developed and extensively validated using data from several sites in southern Ontario. Both large, complex commercial operations, and small-scale, passive greenhouses were considered in the validation cases. The model considers conductive, convective and radiative heat transfer between internal greenhouse layers, as well as latent heat transfer from crop evapotranspiration. The impact of environmental control technology commonly used at commercial greenhouses, such as supplemental heating and lighting, forced and natural ventilation, dehumidification technology, and curtains (energy and light abatement) are included in the model. To assess the predictive accuracy, the root-mean squared error (RMSE) and mean absolute error (MAE) between measured and simulated values were calculated for each test site. Once validated, the model was used to predict energy savings from running dehumidification technology and switching from HPS to LED lights in the southern Ontario context. A scoping study was conducted to estimate the annual greenhouse heating load at locations across Canada using typical meteorological year (TMY) data, with an emphasis on identifying suitable areas for seasonal energy storage. The impact on greenhouse heating and cooling loads that can be expected by using an earth air heat exchanger (EAHE) at a commercial-size greenhouse was also examined at locations across Canada using TMY data.

Description

Keywords

Greenhouse energy modeling, Convective heat transfer, Heat and moisture balance, Dehumidification technology, Earth-air heat exchanger, Lumped capacitance model, Typical meteorological year data, Solar rooftop test cell, Infrared heat transfer, Crop evapotranspiration

Citation

Nauta, A., Lubitz, W., & Tasnim, S. (2022). Solar Rooftop Test Cell - Experimental Methodology and Results of Multivariable Sensitivity Analysis. Proceedings of 2022 Responsible Engineering and Living Symposium. Windsor.
Nauta, A., Lubitz, W., Tasnim, S., & Han, J. (2021). Development and Evaluation of a New Greenhouse Energy Model with Data from Four Ontario Greenhouses. Canadian Greenhouse Conference. Niagara Falls: Canadian Greenhouse Conference.
Nauta, A., Lubitz, W., Tasnim, S., & Han, J. (2022). Methodology and Validation of a New Climate Prediction Model for Commercial and Small-scale Greenhouses. Proceedings of 2022 Responsible Engineering and Living Symposium. Windsor, Ontario, Canada.
Nauta, A., Lubitz, W., Tasnim, S., & Han, J. (2022). Using a Greenhouse Energy Model to Examine Potential for Maintaining Year-Round Growing Conditions in Off-Grid Greenhouses Across Canada. CSBE/SCGAB 2022 Annual Conference, (pp. CSBE22-129). Charlottetown.
Nauta, A., Lubitz, W., Tasnim, S., & Mahmud, S. (2021). Thermal modelling of greenhouse using 1D lumped capacitance model. 5th International Conference of the International Commission of Agricultural and Biosystems Engineering. Quebec City: Canadian Society for Bioengineering.
Nauta, A., Lubitz, W., Tasnim, S., & Han, J. (2022). Performance Evaluation of a Commercial Greenhouse in Canada using Dehumidification Technologies and LED Lighting: A Modeling Study. SETA-D-22-02937. https://dx.doi.org/10.2139/ssrn.4139225