What question did this study set out to answer?

This review aims to summarize and evaluate various passive cooling techniques for greenhouses in hot-arid climates.

February 12, 2026Water3 citationsOpen Access

Integrated Passive Cooling Techniques for Energy-Efficient Greenhouses in Hot–Arid Environments: Evidence from a Systematic Review

HBHamza BenzzineUniversité Ibn-Tofail HLHicham LabrimMohammed V University IAIbtissam El AouniUniversité Ibn-Tofail

Key Points

This review aims to summarize and evaluate various passive cooling techniques for greenhouses in hot-arid climates.
Synthesized evidence from multiple studies on passive cooling techniques
Organized findings into four domains: Airflow & Ventilation, Shading & Radiative Control, Thermal Storage & Ground Coupling, and Structural Design & Geometry
Analyzed outcomes such as temperature reductions relative to control greenhouses
Achieved 3–7 °C daytime reduction with optimized ventilation techniques
Reported 2–4 °C cooling from shading and spectral covers while maintaining photosynthetically active radiation (PAR)
Demonstrated up to 14 °C peak temperature attenuation from rock-bed storage under optimal conditions

Abstract

This systematic review synthesizes passive and passive-first cooling strategies for greenhouses in hot–arid climates, organizing evidence across four domains: Airflow earth-to-air heat exchangers (EAHE/GAHT), rock-bed sensible storage, phase-change materials (PCMs), and sunken or buried envelopes; as well as roof slope and shape, span number, and orientation. Across studies, cooling outcomes are reported as peak or daytime indoor air temperature reductions, defined relative either to outdoor conditions or to a control greenhouse, with the reference frame and temporal aggregation specified in the synthesis. Typical outcomes include ≈3–7 °C daytime reduction for optimized ventilation, ≈2–4 °C for shading and spectral covers while preserving PAR, ≈5–7 °C intake cooling for EAHE with winter pre-heating, and up to ≈14 °C peak attenuation for rock-bed storage under favorable conditions. Structural choices consistently amplify these effects by sustaining pressure head and limiting thermal heterogeneity. Performance is strongly context-dependent—governed by wind regime, diurnal amplitude, dust and UV exposure, and crop-specific light and temperature thresholds—and the most robust results arise from stacked, site-specific designs that combine skin-level radiative rejection, buoyancy-supportive geometry, and ground or latent buffering with minimal active backup. Smart controllers that modulate vents, shading, and targeted fogging or fans based on VPD or temperature differentials improve stability and reduce water and energy use by engaging actuation only when passive capacity is exceeded. We recommend standardized composite metrics encompassing temperature moderation, humidity stability, PAR availability, and water and energy use per unit yield to enable fair cross-study comparison, multi-season validation, and policy adoption. Collectively, the synthesized techniques provide a practical palette for improved greenhouse climate management under hot and arid conditions.

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