Periodic Reporting for period 3 - TheGreefa (Thermochemical fluids in greenhouse farming)
Periodo di rendicontazione: 2023-06-01 al 2024-05-31
This project is aimed at a new technology for heating, cooling, air humidity control and water recovery in greenhouses and for drying of agricultural goods using thermo-chemical conversion principles based on the use of salt solutions (TCF). The common effect is the hygroscopic property of TCF, allowing an uptake of water vapor from air thus releasing sensible heat involved in the phase change.
The technology allows
- the use of unexplored potentials of solar- and residual heat at farm level
- the conversion and storage of the heat in form of thermochemical potential without thermal losses, also for long time (seasonal storages)
- the use of this potential through re-conversion into heat for heating, cooling and humidity control.
- a circular economy for water: watering of crops, transpiration of crops, absorption through thermochemical fluids, evaporation, condensation, watering
- an effectiveness for capital and operative costs
The greenhouses are assuming more and more importance. In the developed countries a high quality of life concerns especially the diet, which must be fresh, healthy and varied. Long transport routes are often necessary. The transport of fresh fruit and vegetables causes high CO2 emissions. The poor regions with adverse conditions for cultures cannot afford the import of food. For both cases, the greenhouses with dryer and water recovery, operating with renewable energy, will be representing a right solution.
Thermochemical applications in agriculture have the potential to reduce the energy consumption in greenhouse climate control as well as in crop drying and will provide an alternative to energy intensive water desalination in arid regions.
The project demonstrated the technology and preparing a path to the market. The project consists in 4 objectes:
1) demonstration of technology; 2) Development of improved knowledge on modelling of the involved processes and the development of control strategies; 3) economic and environmental s assessment; 4) develop strategies to bring the technology to market as well as appropriate policies.
The technology allows
- the use of unexplored potentials of solar- and residual heat at farm level
- the conversion and storage of the heat in form of thermochemical potential without thermal losses, also for long time (seasonal storages)
- the use of this potential through re-conversion into heat for heating, cooling and humidity control.
- a circular economy for water: watering of crops, transpiration of crops, absorption through thermochemical fluids, evaporation, condensation, watering
- an effectiveness for capital and operative costs
The greenhouses are assuming more and more importance. In the developed countries a high quality of life concerns especially the diet, which must be fresh, healthy and varied. Long transport routes are often necessary. The transport of fresh fruit and vegetables causes high CO2 emissions. The poor regions with adverse conditions for cultures cannot afford the import of food. For both cases, the greenhouses with dryer and water recovery, operating with renewable energy, will be representing a right solution.
Thermochemical applications in agriculture have the potential to reduce the energy consumption in greenhouse climate control as well as in crop drying and will provide an alternative to energy intensive water desalination in arid regions.
The project demonstrated the technology and preparing a path to the market. The project consists in 4 objectes:
1) demonstration of technology; 2) Development of improved knowledge on modelling of the involved processes and the development of control strategies; 3) economic and environmental s assessment; 4) develop strategies to bring the technology to market as well as appropriate policies.
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.
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.
Innovations:
- Use of TCF for air conditioning in greenhouses: air de-humidification can be provided by absorption processes with increase of the indoor air temperature. Turning aerification is replaced by closed air circulation. A further application allows to remove heat during daytime weather with re-direction of the heat during night or during colder periods of a day.
- Closed greenhouse climate control for water recovery and production with highly elevated CO2 concentration: irrigation water is evaporated by the vegetation and related water vapor is taken up by the TCF releasing heat. Water and heat can be stored together. Condensed water can be collected from the inner side of the greenhouse roof, while using the cool of the night to drive the phase change back to water and by releasing heat to the environment. The greenhouse operates in closed mode, with elevated CO2 for increased photosynthetic activity.
- Drying process at low temperature for food: the air is dried by the TCF but is not necessarily heated, as heat could harm the vegetables and affect their quality.
- Use of thermo-chemical fluids in a district network: Greenhouses or dryers based on absorption processes are not necessarily stand-alone applications. The TCF can be transported in district network. This allows shifting energy potentials in space, time and provides seasonal storage for smart energy systems.
The potential impacts are:
Energy savings:
• Reduction of energy consumption in air conditioning for greenhouses.
• Competitiveness of the food producers and food safety in times of growing energy prices.
• Less energy demand for food transport, if more food is produced locally.
• Higher productivity, e.g. reduced energy and water per kg of food.
• Increase the use of low temperature heat, which otherwise will be lost.
Water savings
• Reduction of water demand up to 80% compared
• Reduction of saline groundwater, the condensed water can be used to dilute the salinity content of water externally provided.
• Use of impure water, like pre-treated greywater from cities for irrigation and conversion to clean and hygiene condensation water
Reduction of pesticides
• Reduction of the use of fungicides thanks humidity control
• Less insects due to closed greenhouse
• High safety of labor conditions, no use of pesticide
- Use of TCF for air conditioning in greenhouses: air de-humidification can be provided by absorption processes with increase of the indoor air temperature. Turning aerification is replaced by closed air circulation. A further application allows to remove heat during daytime weather with re-direction of the heat during night or during colder periods of a day.
- Closed greenhouse climate control for water recovery and production with highly elevated CO2 concentration: irrigation water is evaporated by the vegetation and related water vapor is taken up by the TCF releasing heat. Water and heat can be stored together. Condensed water can be collected from the inner side of the greenhouse roof, while using the cool of the night to drive the phase change back to water and by releasing heat to the environment. The greenhouse operates in closed mode, with elevated CO2 for increased photosynthetic activity.
- Drying process at low temperature for food: the air is dried by the TCF but is not necessarily heated, as heat could harm the vegetables and affect their quality.
- Use of thermo-chemical fluids in a district network: Greenhouses or dryers based on absorption processes are not necessarily stand-alone applications. The TCF can be transported in district network. This allows shifting energy potentials in space, time and provides seasonal storage for smart energy systems.
The potential impacts are:
Energy savings:
• Reduction of energy consumption in air conditioning for greenhouses.
• Competitiveness of the food producers and food safety in times of growing energy prices.
• Less energy demand for food transport, if more food is produced locally.
• Higher productivity, e.g. reduced energy and water per kg of food.
• Increase the use of low temperature heat, which otherwise will be lost.
Water savings
• Reduction of water demand up to 80% compared
• Reduction of saline groundwater, the condensed water can be used to dilute the salinity content of water externally provided.
• Use of impure water, like pre-treated greywater from cities for irrigation and conversion to clean and hygiene condensation water
Reduction of pesticides
• Reduction of the use of fungicides thanks humidity control
• Less insects due to closed greenhouse
• High safety of labor conditions, no use of pesticide