More and more growers gain experience with desiccant dehumidification. In the Netherlands, the first greenhouse companies are already working with the system and soon a new study will start at Wageningen UR Horticulture. In Denmark, kalanchoe grower Knud Jepson has achieved some good results with the new technique. Knud Jepson recently installed 17 machines operating according to hygroscopic principles, thus reaching a 25% energy reduction.
In hygroscopic dehumidifying, humid greenhouse air is sucked through a filter through which a very concentrated salt solution flows. If the moist air comes into contact with the salt solution, the moisture is drawn in the solution, and is then rinsed away. This process also generates some heat. The air is therefore drier and warmer.
Over time, however, the hygroscopic liquid is so diluted it loses moisture suction effect. Hygroscopic dehumidification systems therefore include a process to 'regenerate' the salt solution. For this purpose, there is a number of solutions, usually involving heating and the partial evaporation of the salt solution. This costs energy.
Economy
The efficiency of the regeneration, and the extent to which the energy can also be utilized in the greenhouse, to a large extent determines the economic feasibility of hygroscopic dehumidification.
Source: Energiek2020