Thermal energy use for dehumidification of a tomato greenhouse by natural ventilation and a system with an air-to-air heat exchanger

Authors

• Katarzyna Maslak Swedish University of Agricultural Sciences (SLU), Dept. of Biosystems and Technology, P.O. Box 103, SE-230 53 Alnarp, Sweden
• Sven Nimmermark Swedish University of Agricultural Sciences (SLU), Dept. of Biosystems and Technology, P.O. Box 103, SE-230 53 Alnarp, Sweden

DOI: https://doi.org/10.23986/afsci.58936

Keywords:

Thermal energy use, greenhouses, humidity, dehumidification, ventilation, rotating heat exchanger

Abstract

The aim of the study was to estimate the amount of thermal energy used for dehumidification of a naturally ventilated tomato greenhouse and to estimate how mechanical ventilation with the use of a heat exchanger recovering heat from the exhaust to the supply air may decrease the energy use. Measured use of thermal energy in a naturally ventilated tomato greenhouse was compared to modelled values using Powersim® software. By the help of the model an estimation of the amount of energy used for dehumidification was made for the months April – September. A non-hygroscopic rotary air-to-air heat exchanger was studied, and its temperature and moisture efficiencies were measured. Modelling for leaf area index (LAI) 3.5 and 4.0 m² m^-2 indicated that 23 and 29% of the total thermal energy was used for moisture removal respectively. Modelling for the heat exchanger indicated thermal energy savings of 15 and 17% for the same LAI respectively.