The ‘Bio-optimaal’ greenhouse of the tomato enterprise of Ruud van Schie in Ens is the first greenhouse in the Netherlands with a system enabling anyone to monitor the climate in the greenhouse via internet (www.aircokas.nl). This experimental greenhouse has a unique air cooling system in combination with atomization for climate optimization: the Airco greenhouse concept. This combination means that windows less frequently require opening than in a conventional greenhouse. This enables a more accurate match between greenhouse conditions and crop needs. Another aspect is a considerable cost saving in comparison with other (semi) closed greenhouse concepts.
The Aircokas is a joint project of researchers of Applied Plant Research (PPO) of Wageningen UR and the specialists of Wilk van der Sande technical contractors and Hoogendoorn Automatisering. PPO acts as crop consultant and is responsible for the climate settings. The researchers also perform all plant measurements, they register the microclimate, and process and interpret the results. Wilk van de Sande provides the heating and cooling expertise while Hoogendoorn Automatisering provides broad knowledge and experience for optimization and automation of all processes.
Cooling by evaporation
A grower wants to keep the largest possible amount of CO2 in the greenhouse. This is why he wants to keep his windows closed as much as possible. This, however, rapidly results in the temperature becoming too high. This is why recently closed greenhouses are constructed with an advanced but expensive cooling system where cold water is pumped up from the below-ground aquifers.
The partners in the Aircokas project now investigate the perspective of a new, complementary cooling system that utilizes the cooling effect of water evaporation. In a (semi) closed greenhouse this system saves on pumping capacity, and thus on costs.
The Aircokas is fitted with a high-pressure atomization system that brings a fine water mist above the crop in case of much sunshine. This mist evaporates and then has a cooling effect on the environment. This means that windows need to be opened much less than in a conventional greenhouse. This reduces CO2 loss by ventilation resulting in higher CO2 concentrations in the greenhouse under conditions with much light. This benefits crop growth, resulting in higher yields.
A production increase of ten per cent is expected at a thirty per cent reduction of CO2 emission and twenty per cent energy saving.
The Aircokas project will be running for two years. The partners will regularly inform growers and other interested parties about crop development and climate via the website and a newsletter. A number of Open Days will be organized as well.