Towards Sustainable Greenhouse Design: A Numerical Study on Temperature Control in Multi-Span Hoop Structures

A greenhouse with properly managed temperature can provide 5 to 10 times greater yield than conventional methods for crops such as blueberries, cucumbers, and tomatoes; the yield is also of higher quality. However, existing designs in Australia often follow practices developed for cooler regions, making them less effective under local high-radiation conditions. To determine the design parameters for the local condition, this study develops and validates a numerical model of a commercial blueberry greenhouse, applying it to examine how structural parameters, including overall height, arch height, and number of spans, influence indoor temperature distribution in multi-span hoop structures. Results show that increasing greenhouse height by 0.40 m reduced average temperature by up to 0.62%, whereas raising arch height by the same increment led to a marginal increase of 0.15%. In contrast, expanding span numbers from 2 to 12 resulted in a maximum temperature difference of 6 °C (approximately 20% above ambient temperature) across the structure, posing significant risks to plant growth. These findings provide a theoretical basis for optimising design parameters that minimise heat stress while reducing reliance on fossil-fuel-based cooling. The study highlights how tailoring greenhouse design to local conditions can improve productivity and support both environmental and economic sustainability.