ABSTRACT
Achieving the optimal energy balance in hydroponic greenhouses is a critical challenge in modern agriculture. This involves managing energy resources to create an environment conducive to robust crop growth. Researchers are exploring advanced thermal models and innovative technologies to enhance energy efficiency and establish a harmonious equilibrium in these controlled environments. Various studies have addressed the optimization of energy consumption in hydroponic greenhouses, with a focus on the greenhouse covering materials and real-time energy monitoring. This study aims to enhance the conventional model by optimizing the form and cover material of the greenhouse and considering new heat gain and loss parameters, including the direct and indirect lighting effect. This study demonstrates that the emitted light and energy consumption of the lighting system directly influence the energy balance. This innovative approach refines the understanding of the interplay between lighting systems and energy consumption, leading to more efficient and sustainable hydroponic greenhouse practices. Collectively, the contributions of esteemed researchers have significantly enriched the understanding of energy consumption dynamics in hydroponic greenhouse environments, setting new standards for energy efficiency, sustainability, and productivity in hydroponic agriculture.
Key words:
cooling; energy project; heating; lighting
HIGHLIGHTS:
Optimizing lighting systems leads to substantial energy savings and improved production in hy-droponic greenhouses.
The interplay between lighting, heating, and cooling enables more efficient energy consumption and enhanced crop yield.
Hydroponic greenhouse design and choice of cover material significantly influence energy bal-ance and environmental impact.
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W - Width of the greenhouse (m); H1- Eaves height of the greenhouse (m); H - Ridge height of the greenhouse (m); L - Length of the greenhouse (m)
U-statique - Static overall heat transfer coefficient (W m-2 K-1); SGH - Hydroponic greenhouse area (m2); Tin - Inner air temperature (°C); Tout - Average outdoor temperature (°C); R - Number of air changes per hour (m3 s-1); Rau - Density of internal air (kg m-3); Ca - Specific heat of air (J kg-1 K-1); Vgh - Volume of the hydroponic greenhouse (m3); Kp - Thermal conductivity of pipe (W m-1 K-1); A1 - Inner area of pipe (m2); A2 - Outer area of pipe (m2); D2 - Outer diameter of pipe (m); D1 - Inner diameter of pipe (m); L - Length of pipe (m); p - Density of the fluid (kg m ̵ 3); u - Dynamic viscosity of the fluid (kg m-1 s-1); Pr - Prandtl coefficient; Ka - Thermal conductivity of water (W m ̵1 K ̵1); Cp - Specific heat (J kg ̵1 K ̵1); Tn - Temperature of solution (°C); Q - Water flow (m3 s ̵1); Af - Greenhouse floor area (m2); Tau - Transmissivity of the greenhouse cover; Isr - Solar radiation on the horizontal surface (W m-2); Sf - Floor surface (m2)
Vw - Wind velocity (m s-1); W - Width of the greenhouse (m); Vi - Indoor air speed (m s-1); Isr - Solar radiation on the horizontal surface (W m-2); Tex - Average outdoor temperature (°C); L - Length of the greenhouse (m); H - Height of the greenhouse (m); τ - Transmissivity of the greenhouse cover; Tin - Inner air temperature (°C); Rh - Relative air humidity (%)
Sgh - Hydroponic greenhouse area (m²); Tin - Inner air temperature (°C); Tout - Average outdoor temperature (°C); Vw - Wind velocity (m s-1); R - Number of air changes per hour (m3 s-1); rau - Density of internal air (kg m-3); Ca - Specific heat of air (J kg-1 K-1); Vgh - Volume of the hydroponic greenhouse (m3); Kp - Thermal conductivity of pipe (W m-1 K-1); A1 - Inner area of pipe (m2); A2 - Outer area of pipe (m2); D2 - Outer diameter of pipe (m); D1 - Inner diameter of pipe (m); L - Length of pipe (m); p - Density of the fluid (kg m ̵3); u - Dynamic viscosity of the fluid (kg m-1 s-1); Pr - Prandtl coefficient; Ka - Thermal conductivity of water (W m ̵1 K ̵1); Cp - Specific heat (J kg ̵1 K ̵1); Tn - Temperature of solution (°C); Q - Water flow (m3 s ̵1); Af - Greenhouse floor area (m²); Tau - Transmissivity of the greenhouse cover; Isr - Solar radiation on the horizontal surface (W m-2); Sf - Floor surface (m2); Rh - Relative air humidity (%)
M1 - Glass covering; M2 - Low emissivity glass covering; M3 - Polyethylene film covering; M4 - Polycarbonate covering; M5 - Polyvinyl chloride covering; M6 - Ethylene-vinyl acetate copolymer EVA covering
M1 - Glass covering; M2 - Low emissivity glass covering; M3 - Polyethylene film covering; M4 - Polycarbonate covering; M5 - Polyvinyl chloride covering; M6 - Ethylene-vinyl acetate copolymer EVA covering
QG - Total heat gain inside the greenhouse (W); Qsr - Solar radiation heat gain (W)
Qinf - Infiltration heat transfer (W); Qevap - Evapotranspiration heat transfer (W); Qlw - Long-wave radiation heat transfer (W); Qcd-cv - Conduction and convection heat transfer (W); Qf - Floor heat transfer (W); Qwater - Water heat transfer (W); Qp - Perimeter heat transfer (W)
Fan - Actuator of cooling; Heater - Actuator of heating; Humidifier - Actuator of humidification; Dehumidifier - Actuator of dehumidification; DHT11 - Temperature and humidity sensor; Lighting - Actuator of lighting; CO2 - CO2 generator; Raspberry Pi - Controller
T Measured - Measured inner temperature; T simulated - Simulated inner temperature
IBGH with lighting - Developed greenhouse within the direct and indirect effect of lighting; IBGH without lighting -Developed greenhouse without the direct and indirect effect of lighting; Traditional model - Literature greenhouse model