Short answer

When designing evaporative cooled greenhouses for hot and arid regions, prioritize induction fan placement at or below crop height and ensure adequate ventilation capacity, considering roof shape for enhanced cooling.

Field: Modelling
Source: Science and Technology for the Built Environment (2019)
Method: Computational Fluid Dynamics (CFD) simulation, validated with experimental data.
Evidence: Strong effect

Computational Fluid Dynamics (CFD) simulations demonstrate that strategic placement of induction fans at or below crop height and increased ventilation rates are critical for reducing internal temperatures in evaporative cooled greenhouses, especially under high solar radiation. This modelling research insight is drawn from a 2019 study published in Science and Technology for the Built Environment. Using Computational fluid dynamics (cfd) simulation, validated with experimental data., researchers explored how this design variable affects real-world outcomes. The key design takeaway: When designing evaporative cooled greenhouses for hot and arid regions, prioritize induction fan placement at or below crop height and ensure adequate ventilation capacity, considering roof shape for enhanced cooling.

Study

ModellingHigh ImpactStrong effect

Optimizing Greenhouse Microclimates: CFD Reveals Induction Fan Placement and Ventilation Rates Significantly Impact Thermal Performance

Science and Technology for the Built Environment · 2019

Key Findings

01Induction fans placed at or below crop height effectively lower the average greenhouse temperature.
02Doubling ventilation rate from 20 ACH to 40 ACH significantly reduces greenhouse air temperature.
03Increased ventilation rates mitigate temperature rise caused by high solar radiation.
04An uneven span roof shape resulted in the lowest average internal temperature compared to other tested roof geometries.
05Aspect ratio had a negligible impact on thermal performance for a given floor area and volume.

Application

Design takeaway

How to apply

When designing or retrofitting greenhouses in similar climates, simulate different induction fan heights and ventilation rates using CFD to identify the most effective cooling strategy.

Project actions

01When designing a greenhouse, think about where the fans will be and how much air they can move.
02Consider using simulation tools like CFD to test different designs before building.

Method & Evidence

AimTo investigate the impact of greenhouse geometry and operational parameters on the thermal performance of an evaporative cooled greenhouse in a hot and arid climate using CFD modelling.

MethodComputational Fluid Dynamics (CFD) simulation, validated with experimental data.

ProcedureA CFD model of a standard greenhouse was developed and calibrated using measured data on internal air temperature, relative humidity, and solar radiation. The model was then used to simulate various design configurations, including induction fan elevation, roof shape, and ventilation rates, to assess their effect on internal temperature.

ContextAgricultural engineering, Controlled environment agriculture, Building performance simulation

Variables

IV["Induction fan elevation","Ventilation rate (ACH)","Roof shape"]

DV["Greenhouse internal air temperature","Relative humidity"]

CV["Greenhouse geometry (aspect ratio, floor area, volume)","Geographical location (solar intensity)","Evaporative cooling system operation"]

Strengths & Limitations

Strengths

+Utilized validated CFD modelling for detailed analysis.
+Investigated multiple design and operational factors.

Limitations

Simulations are models and may not perfectly replicate real-world conditions. The study was conducted in one specific climate.

Reliability & validity

The CFD model's validity was established by comparing its simulation results with experimental measurements of temperature, humidity, and solar radiation, indicating good agreement.

Think critically

How might the findings on induction fan placement and ventilation rates be adapted for greenhouses in cooler climates or those with different crop types that have specific temperature requirements?

Design Principles

"Optimize airflow and heat dissipation through strategic component placement and system capacity."

Understanding how design and operational parameters influence greenhouse microclimates is crucial for maximizing crop yield and quality. This research provides data-driven insights for designers and engineers to create more efficient and effective controlled environment agriculture systems.

What This Means for Your Design

This study shows that putting fans lower down in a greenhouse and increasing how much air it moves makes it cooler inside, which is good for plants, especially when it's very sunny.

How to use in your project

1.Use the findings on fan placement and ventilation rates to justify design choices in your greenhouse project.
2.Reference the simulation methods to explain how you tested different design ideas.

Add to My Project

Quick Cite

Paragraph starter

This research highlights the significant impact of induction fan placement and ventilation rates on greenhouse thermal performance in hot and arid climates. The study's findings, which demonstrate that placing fans at or below crop height and increasing ventilation rates (e.g., from 20 to 40 ACH) substantially reduce internal temperatures, provide a strong basis for optimizing greenhouse environmental control systems to improve crop yield and quality.

Source

Science and Technology for the Built Environment

Experimental and numerical investigation of the thermal performance of evaporative cooled greenhouses in hot and arid climates

journal · 2019

View source

Questions About This Research

What does the research say about optimizing greenhouse microclimates: cfd reveals induction fan placement and ventilation rates significantly impact thermal performance?: When designing evaporative cooled greenhouses for hot and arid regions, prioritize induction fan placement at or below crop height and ensure adequate ventilation capacity, considering roof shape for enhanced cooling. Evidence: Science and Technology for the Built Environment (2019).
Why does "Optimizing Greenhouse Microclimates: CFD Reveals Induction Fan Placement and Ventilation Rates Significantly Impact Thermal Performance" matter for design?: Understanding how design and operational parameters influence greenhouse microclimates is crucial for maximizing crop yield and quality. This research provides data-driven insights for designers and engineers to create more efficient and effective controlled environment agriculture systems.
How can designers apply this research?: When designing evaporative cooled greenhouses for hot and arid regions, prioritize induction fan placement at or below crop height and ensure adequate ventilation capacity, considering roof shape for enhanced cooling.
What were the main findings?: Induction fans placed at or below crop height effectively lower the average greenhouse temperature.. Doubling ventilation rate from 20 ACH to 40 ACH significantly reduces greenhouse air temperature.. Increased ventilation rates mitigate temperature rise caused by high solar radiation.. An uneven span roof shape resulted in the lowest average internal temperature compared to other tested roof geometries.
What research method was used?: Computational Fluid Dynamics (CFD) simulation, validated with experimental data..
How strong is the evidence?: Evidence strength is rated Strong effect, based on a 2019 journal from Science and Technology for the Built Environment.
What should I do differently in my next project?: When designing or retrofitting greenhouses in similar climates, simulate different induction fan heights and ventilation rates using CFD to identify the most effective cooling strategy.
What are the limitations?: The study focused on a specific hot and arid climate (Qatar) and a standard ASHRAE compliant greenhouse; results may vary in different climatic conditions or with different greenhouse designs.