Verbetering van de uniformiteit van het microklimaat in verticale teeltsystemen

Foreword

This is a final report of the graduation project at Hogeschool Inholland (Delft). The project was carried out in the vertical farm of the company Vertify located in World Horticulture Center (WHC), in order to investigate the correlation between air circulation (ventilation) and microclimate, this objective was proposed by Vertify. Two anemometers and one climatic sensor were used to measure the climatic factors within each block in the vertical farm. To conduct this project well, some meetings with my advisor Daniel Scheepens (once a week) were held online (because of the corona virus situation), and some meetings with my commissioner Matthijs Blind (every two weeks) were arranged physically in WHC and online. I would like to thank Daniel for giving me some important and valuable suggestions and supports, and Matthijs who providing me this opportunity to do this project. What’s more, Sjoerd van Marrewijk (an employee of Vertify) was also very helpful, he gave me the technical supports which made this project run smoothly. I learned a lot from him and I cannot finish my project without him.

Summary

Our world faces the challenges of a growing population, a changing climate, and a decline in arable land and clean water. In addition, increasing demand and food waste have put unprecedented pressure on agricultural systems and natural resources, making food supply one of the most serious challenges facing humanity in the twenty-first century. To solve this problem, vertical farming was carried out. But some growers have recently observed significant differences in crops between different vertical farms despite setting the same conditions in terms of temperature, humidity, light formulations and CO² concentrations. So, the project was done on vertical farms where basil is grown to help solving that problem for growers.

The objective of this project is to investigate the influence of air circulation (ventilation) on the microclimate in the containers within the vertical farms by doing the literature study and experiment. To achieve this objective, the main research question is defined as: How does the air circulation (ventilation) influents the microclimate in (the containers within) the vertical farms?

After defining the research question, a literature study was carries out, then made an experiment design based on the knowledge achieved from literature study. The experiment was done in a Vertical farm at Vertify in Naaldwijk, the Netherlands. Hot-wire anemometer, vane anemometer, ruler, and thermohygrmeter were used to measure the wind speed, basic wind speed, plant height and temperature and RH respectively. Then, Excel and SPSS (One-way ANOVA & Correlation) were used to organize the data of measurements during the experiment.

The result includes the correlations between wind speed and temperature and RH, the correlations between plant height and microclimatic factors, the significance test of climatic factors and plant height among modules and within modules, and the diagram showing the wind movement measurement by short pieces of wool.

According to the result, the most significant conclusion is carried out. The climatic factors influence microclimate includes radiation, temperature, relevant humidity and CO² concentration. The climate between blocks is uneven, but almost homogeneous within blocks. The wind speed has significant negative correlation with temperature and RH, which means when the wind speed increase, temperature and RH will decrease. In contrast, air circulation has no decisive effect on temperature and humidity.

Finally, there are some recommendations on choosing suitable techniques to measure the air circulation regards to the range of wind speed within vertical farm (<3m/s). In addition, one option to build homogeneous climate within vertical farm is to twist the ventilation ducts until the wind direction is consistent among blocks. Last but not least, CO² is also an important climatic factor in vertical farm, so, for the following research on climate in vertical farm, the sensor of measuring the CO² concentration within each block is necessary.