EVALUATION OF THE THERMAL ENVIRONMENTS OF TWO SINGLE-SPAN TRIPLE-LAYERED GREENHOUSES EQUIPPED WITH CIRCULAR AND HORIZONTAL AIRFLOW FANS

Abstract

The microclimate of indoor production systems is highly dependent on the macroclimate of the ambient. As a result, the microclimate fluctuates with time with respect to the macroclimate and eventually making it have higher measurable climate parameters than the macroclimate. This study was carried out at Sangju Smart Farm Innovation Valley, Sangju-si to compare and analyse changes in the thermal environment in two adjacent single-span tunnel greenhouses covered with two layers of polyethylene films (200 μm thick) and a layer of thermal curtain (3.5 mm thick). While one greenhouse was equipped with five circular airflow fans (HUMITEM-GH), the other had five horizontal airflow fans (Conv-GH). The Seolhyang variety of strawberries was used as the test crop. The greenhouse temperature (Ta), relative humidity (RH), vapour pressure difference (VPD), solar radiation (SR), and carbon dioxide (CO2) data were collected using standard methods and data was analysed using MINITAB software. The statistical tools used for data analysis were descriptive statistics, analysis of variance (ANOVA), and t-Test. The total yield and marketable yield in the HUMITEM-GH was higher than the Conv-GH by 116.33 kg and 97.69 kg, respectively. There were significant differences between the two greenhouses microclimate both in the daytime and night-time with the HUMITEM-GH having higher and near-optimal climate parameters. This result has shown that the newly developed HUMITEM air circulation fan has a superior air circulation and flow capability than the conventional air circulation fans. This information may be of interest to farmers, horticulturists, and researchers who are involved in protected vegetable production.