Design, simulation, prototyping and IoT-Based testing of an innovative tropical greenhouse with an energy efficient cooling system powered by a standalone Hybrid HAWT-Solar PV energy system: Case study of DR Congo-Kinshasa /Plateau de Bateké weather conditions (savannah tropical climate).

Abstract

Greenhouse is an agricultural structure that creates an optimal growth environment (microclimate) for the crops (especially vegetables and fruits). This work is geared towards identifying the current challenges that exist within the greenhouse sector in the savannah tropical climate and developing a new type of greenhouse more adequate, energetically efficient and affordable for small as well as large farmers thus, to boost their yield which remain low due to several reasons including the exclusive dependence on natural climatic factors such as rain and seasons. A meticulous design and simulations were carried out using Software, Ansys Fluent, helioscope and HOMER Pro respectively for an in-depth study of thermo-physical parameters distributed in the proposed greenhouse and for the design and sizing of the greenhouse energy supply system. The proposed greenhouse uses a new energy efficient cooling method designed and tested for savanna tropical climates in emphasizing more on the simplicity of technology, use of local materials, affordability and energy efficiency. It is mainly based on natural ventilation sustained by a misting system, a shading system and 6 exhaust fans. An effective and efficient coordination of the proposed cooling configuration was developed for an economical use of water and especially energy in the entire greenhouse. This configuration based on the designed energy usage planning saves significantly the entire greenhouse energy consumption; resulting in only 5.8382 KWh/day in summer months and 1.7KWh/day in winter months (for 24 hours). To optimize the energy consumption of the greenhouse, a specific timing was set for different cooling components (natural ventilation, misting system, shading system and exhaust fans). The first concept of the prototype was built in Kinshasa / Plateau de Bateké-Menkao in the Democratic Republic of Congo in the miniaturized design and provided 1°C to 7 ° C of cooling compared to the outside temperature. The cooling system proposed in this research has shown an increase in relative humidity of 1% to 24% during the testing phase. Design and sizing of a Hybrid Wind-Solar PV energy system with the storage system as a backup were meticulously carried out for the full-scale greenhouse. Finally, the cost of the proposed full-scale greenhouse was estimated to be 3.94 USA dollar per square meter, cost which made the proposed greenhouse affordable