SE—Structures and Environment: Design of a Low-Energy Dehumidifying System for Greenhouses

✍ Scribed by J.B. Campen; G.P.A. Bot

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 274 KB
• Volume: 78
• Category: Article
• ISSN: 0021-8634
• DOI: 10.1006/jaer.2000.0633

✦ Synopsis

A concept for a greenhouse dehumidi"er has been designed. Important constraints for the design are low-energy consumption and homogeneous greenhouse climate. From a survey of dehumidifying methods, condensation to a cooled surface was selected as most promising. Low-energy demand is achieved by natural air circulation through the system and by recovering sensible heat. A homogeneous climate can be realized by decentralized local dehumidi"cation in the greenhouse. Applying a computational #uid dynamics (CFD) program to simulate #uid #ow and heat exchange enabled great improvements in the design. A vertical geometry was chosen "rst in a double-chimney approach to exploit the vertical distance between inlet and cold surface and that between cold and hot surface for natural convection air circulation. However, CFD calculations indicated stagnating #ow in this vertically oriented system. Orienting the system horizontally greatly enhanced the systems performance.

A separate model for condensation has been created to complement the CFD programme that did not include condensation. A prototype of the designed dehumidi"er was built and tested. Calculations and experiments were in fair agreement and demonstrated the potential for practical application.