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- Sustainable Agricultural Practices for the Production of Medicinal and Aromatic Plants: Evidence and RecommendationsPublication . Marcelino, Sara; Hamdane, Samia; Gaspar, Pedro Dinis; Paço, Arminda doAs the demand for medicinal and aromatic plants (MAPs) increases, so does the pressure to intensify production, increasing the risk of overexploitation of these natural resources. Therefore, both consumers and companies must commit to sustainable practices. Since sustainable practices in MAP production are scattered in the literature, this study aims to provide a comprehensive compilation of agricultural practices to improve sustainable performance in productive activities. This study collects recommended practices for cultivation, harvesting, drying, extraction of essential oils, and packaging, based on guidelines published by the World Health Organization, the European Herb Growers Association, and the European Medicines Agency, and presents complementary information from scientific papers and the Food and Agriculture Organization. Since the circular economy is considered one of the solutions to foster sustainability, the potential for valorising residues from MAP processing is also highlighted. This study allowed us to identify a set of key parameters that should be monitored in MAP production, which may be a starting point for designing a sustainability assessment tool for the sector. By presenting examples of circular economy approaches, this research can help producers to identify new business opportunities.
- Evaluating the thermal performance and environmental impact of agricultural greenhouses using earth-to-air heat exchanger: An experimental studyPublication . Hamdane, Samia; Pires, Luís Carlos Carvalho; Silva, Pedro Dinho da; Gaspar, Pedro DinisThe thermal performance and environmental impact of agricultural greenhouses (GH) connected to earth-to-air heat exchanger (EAHE) systems depend on the ambient temperature, soil temperature, EAHE system, and greenhouse specifications. The impact of an EAHE system on the temperature and humidity of a GH microclimate, as well as its effects on CO2 emissions and heating energy consumption, are determined experimentally. Two scaled-down models of agricultural GHs (2 × 1.4 × 1.4 m3) were developed. Each GH was equipped with a heater. A spiral EAHE system was integrated into only one of the GHs. The temperature differences in the microclimate range from 3.5 °C to 7.5 °C, with the microclimates of GH + EAHE and GH being quite similar. In summary, the EAHE system helped to reduce the hourly energy consumption of the heating system by more than 40%. It also reduced emissions to the environment by more than 100 g (CO2)/hour. The EAHE coefficient of performance (COP) for the cooling mode has a higher average value than that for the heating mode. The closed-loop performed better in cooling mode, while the open-loop performed better in heating mode. When the difference between the set temperature in the heater and the air outlet temperature of the EAHE system is smaller, the heater performs better in reducing energy consumption and CO2 emissions of the heater. The COPheating range is between 0 and 3.4 and the COPcooling range is between 0.5 and 7.3. The energy consumption ranges between 0 and 1.41 kWh and the CO2 emissions are between 0 and 359.55 g. Thus, using EAHE in agricultural greenhouses improves thermal performance and reduces environmental impact, providing an overall benefit in terms of energy consumption and environmental sustainability.