During the project, technology based on absorption processes using desiccant, also called TCF, was applied to control the temperature and humidity of the air in agricultural greenhouses as well as to recover pure water from the air's humidity. This technology was also used to dry herbs for food purposes.
Throughout the project, systems were designed for application in two greenhouses located in different climatic regions. Data was collected during demonstration periods, lasting over a year in one case, to analyze air quality and energy consumption. In continental climates, it was possible to maintain temperature and humidity within the required range. TheGreefa provided a portion of the required thermal energy, achieving over 60% savings in thermal energy.
For the system in Mediterranean climate, collected data from springtime and early summer 2024 partially shows a good performance of cooling and dehumidification but not for the whole period. Also, in a daily cycle, cooling was partially interrupted due to insufficient absorption capacities. The results were surprisingly good in comparison with a (state of art) ventilated open greenhouse under hot ambient conditions. This shows the high potential of a storage system, providing cool collected during the night in combination with TCF humidity absorption, helping the vegetation to improve evaporative cooling. The technology started at low (Technology Readiness Level), and several obstacles have been identified that indicate the technology is not yet market-ready.
An environmental and economic assessment was conducted based on data collected from two greenhouses in mid-continental and Mediterranean climate zones. It considered 15 years of greenhouse operation and showed a big improvement in terms of reduction of negative impacts on environment, use of resources and human health. Heat- and electricity consumption are responsible for most environmental loads. In the techno-economic evaluation long-term operation of the greenhouses was considered to calculate the return of investment period using the system of TheGreefa. Results show visible cost savings in greenhouses operation, giving an estimated return on investment period of 18 years for the Swiss greenhouse. This may be less under higher energy costs and/or more improved standards for the new system.
During the 44 months of TheGreefa project, the achieved results have been disseminated in events, on the project website, on social media, along publications in scientific journals and by release of press information. TheGreefa was presented during 35 events such as workshops, webinars, conferences, etc. Several workshops were organized, also jointly with other projects from the AREA ZERO cluster. The website as well as social media accounts on LinkedIn and X (Twitter) were created and continuously fed with new content. A set of dissemination material has been developed, such as brochures, a project short video, 30 practice abstracts and an extensive training manual.
