Analysis of Heating Characteristics Using Aluminum Multi-Layer Curtain for Protected Horticulture Greenhouses

Purpose: The purpose of this study was to investigate the energy saving effects and characteristics of plant growth in a greenhouse with an aluminum multi-layer curtain compared to a greenhouse with non-woven fabric. Method: The dimensions of both greenhouses 43m×3.6m×8m(L×H×W) , and both used hot air heater systems for maintaining a constant temperature 15∘C . Heating characteristics such as solar intensity, inside and ambient temperatures, and fuel consumption were measured and analyzed. Results: The changes of average temperature of both greenhouses during a 15-days (December 06 - 20) showed approximately 26∘C at around 2 pm when the ambient temperature was highest. The greenhouses were set by the heater to keep a temperature of 15∘C from 4 pm to 8 am the following day. The average heat loss (for 15 days) from the greenhouse with an aluminum multi-layer curtain was 161.2-268.4kJ/m²·h during the daytime and 152.3-198.1kJ/m²·h during the nighttime. The average heat loss (for 15 days) from the greenhouse with non-woven fabric was 155.7-258.9kJ/m²·h during the daytime and 144.9-207.0kJ/m²·h during the nighttime. The total heat loss (for one day) from the non-woven fabric system was 7,960kJ/m² ( 2,876kJ/m² during the daytime, 5,084kJ/m² during the nighttime). The heat supply over 36 days for the non-woven fabric system was higher than the aluminum multi-layer curtain system by 616.3-65,079.4kJ/m² . Conclusions: These results suggest that a greenhouse with an aluminum multi-layer curtain could save energy usage by 35% over a greenhouse with non-woven fabric.