Development and evaluation of a greenhouse dehumidification technique based on heat mass exchange and vapour recompression

Main research question/goal

The focus of this PhD research is to develop a vapour heat pump for greenhouses, which converts the vapour produced by the plant into sensible heat. Thermodynamic analysis (including exergy) of greenhouses combined with technical knowledge leads to the following key technologies: high-insulating screens for nighttime, screens with high light transmittance which are controlled depending on the solar radiation during daytime, exergy efficient air dehumidification (vapour heat pump) and exergy efficient CO2 fertilization (CO2 pump). The combination of these techniques in the greenhouse results in the exergy efficient greenhouse called “ExeKas”.

Research approach

The project starts with a thermodynamic analysis (including exergy) of the greenhouse. For this purpose, a simulation programme is developed for tomato production (climate, mass/energy flows, crop growth, exergy). The thermodynamic analysis leads to the identification of certain key technologies such as exergy-efficient dehumidification of the greenhouse. Our vision for this technique is the combination of a heat mass exchanger and mechanical vapour recompression. For both techniques, a simulation programme is first developed and then a prototype is created and optimized.

Relevance/Valorisation

Glasshouse production accounts for 64% of the primary energy consumption of the agriculture industry. The ongoing rise in price energy prices drives an economic pressure toward energy conservation. Our vapour heat pump and other ExeKas technologies can be an essential contribution to reduced energy use. The trend of increasing energy use is also unsustainable from the environmental and ethical perspectives. The simulation programme for thermodynamic analysis of the production process can also be used in other applications. This would generate more insight into problems of energy use and may present innovative solutions.

Funding provider(s)
ILVO - Instituut voor Landbouw-, Visserij- en voedingsonderzoek

External partner(s)
KHK - Katholieke Hogeschool Kempen
KULeuven - Dept. Biosystemen
Ugent - Fac. Bio-ingenieurswetenschappen
UGent - Fac. Ingenieurswetenschappen en Architectuur