Anthuriums hebben warmte nodig: de temperatuur mag liever niet onder de 19° Celsius komen. In de winter kan die temperatuur alleen bereikt worden door de kas goed te isoleren en te stoken: dat gebeurt tot op heden met fossiele brandstoffen. Een meer duurzame methode is warmte in de zomer 'oogsten' en te bewaren in een koude-warmteopslag. De Business Unit Glastuinbouw van Wageningen University & Research onderzocht dit systeem met snijanthurium.
In the summer a greenhouse often has (far) too much heat, in the winter there is a lack of heat. That difference can reach a factor of 10. With a heat exchanger, the heat can be harvested in summer and transferred to water: that water can then be stored in an underground aquifer. This heat can be used again in winter: the water that is stored has a temperature of 12 to 15° Celsius.
The underground water that is pumped up in the winter provides a heat pump with heat, cools down a few degrees and is stored in the aquifer again. This cold water can be used in the summer to cool the greenhouse and is heated again for the coming winter. If all the heat from the greenhouse was 'harvested' in summer, there would be enough heat for the following winter.
This system of harvesting heat and storing it underground is used in various crops. WUR has investigated whether it can also be used with Anthuriums a tropical crop that needs a constantly high temperature throughout the year. That is why growers use several screens and sometimes also a foil screen.
For this experiment WUR used a simple installation for harvesting the latent heat, namely one that is actually intended to dehumidify the greenhouse air. The installation has an electrical capacity of 15 W / m2. That was sufficient capacity to harvest enough heat to keep the greenhouse temperature above 19° Celsius during the winter. To achieve this, the heat pump required 42 kWh / m2 green electricity in 2020.
An important research question was whether the Anthurium would lose quality by cold air around the roots when harvesting latent heat from air. That was not the case. On the contrary, the quality of crop and flowers was very good most of the year. In order to harvest as much heat as possible, in the first summer we allowed high temperatures (24 h average of 26°C and higher; this caused in some of the flowers harvested in the winter a quality remark known as “green lobes". By keeping a lower temperature in summer, it seems possible to avoid this problem.
The project “Climate neutral cultivation of Anthurium" is funded by the Program Greenhouse as Source of Energy.