Journal of Bio-Environment Control ISSN:1229-4675(Print) 2765-3641(Online) 생물환경조절학회지

This study evaluated the crop growth environment and energy consumption of a greenhouse clad with high-insulation double-layer vacuum glazing, in comparison with an identically sized single-glass greenhouse (each 8 m wide, 10 m long, 3.7 m to the eaves and 6 m to the ridge) at the Protected Horticulture Research Institute in Haman, Korea. ‘Doterangdia’ tomato, seedlings (sown 13 Oct.) were transplanted on 20 Dec. and grown until 31 May. Eighteen temperature－humidity loggers arranged in a 3×3×2 grid plus one temperature－humidity－CO₂ logger were installed in each greenhouse, and heat supply was metered with a digital integrating calorimeter on each hot-water line. The internal air temperature of the vacuum-glass greenhouse was on average 1.1°C higher than the single-glass greenhouse, and its spatial non-uniformity (0.65－0.79°C) was smaller than the between-greenhouse difference. During 28 Dec.－18 Jan., the single-glass greenhouse remained below the tomato low-temperature limit (10.5°C) for 85.3 h (minimum 8.3°C), whereas the vacuum-glass greenhouse never fell below it (minimum 11.0°C). Transmitted solar radiation in the vacuum-glass greenhouse was 58% of that in the single-glass greenhouse. Early crop growth was faster under vacuum glazing, but growth rate was overtaken by the single-glass greenhouse from mid-March; final plant height did not differ significantly (302.2 vs 304.9 cm, p > 0.05). Heating energy of the vacuum-glass greenhouse was 49.9% of the single-glass greenhouse, while total yield was lower (192.4 vs 229.7 kg). Consequently the vacuum-glass greenhouse achieved a 1.7-fold higher energy-use efficiency (4.60 vs 2.70 kg·MWh^-1). Double-layer vacuum glazing is therefore highly effective for reducing heating energy and carbon emissions, but its light transmittance must be improved before it can be adopted as a general greenhouse cladding.