Chiriboga Gonzalo, Capelo Santiago, Bunces Pablo, Guzmán Carla, Cepeda Jonathan, Gordillo Gilda, Montesdeoca Diego E, Carvajal C Ghem
Central University of Ecuador, Chemical Engineering Faculty, Jerónimo Ritter S/N and Bolivia Quito, Ecuador.
Heliyon. 2021 Dec 17;7(12):e08608. doi: 10.1016/j.heliyon.2021.e08608. eCollection 2021 Dec.
Globally, the greenhouses' farming area comprises 500 000 ha, and they efficiently produce more than half of the vegetables consumed around the world. Nevertheless, high-yield crops tend to be incredibly energy-intensive. This study proposes designing and building a coupled geothermal heat pump for a 470 m greenhouse in the Andean zone conditions addressing a requirement of 15 °C at night and 30 °C during the day. Firstly, the study determined the energy potential of the solar and geothermal sources employing actual measurements and contrasting the results with theoretical models. Then, it developed an energy balance in the greenhouse to size the geothermal heat pump using the vapor compression cycle. Finally, the comprehensive system was built and evaluated through the Leveled Cost of Heat (LCOH). The operation requires a potential of 29.56 and 65.76 kW for heating and cooling; this is technically feasible when running the system with a heating flow driven by an optimized temperature ramp of 1.64 °C h. Also, the capacity factor (CF) shows that a lifespan between 12 to 14 years is required to reach acceptable LCOH when CF is as low as 0.45. Financially, it is necessary to foster customs exemptions to make it competitive versus more traditional sources such as electricity and LPG since the main components of the heat pump and the geothermal exchanger are not produced locally and represent nearly 70 % of the upfront costs.
在全球范围内,温室种植面积达50万公顷,它们高效生产了全球一半以上的消费蔬菜。然而,高产作物往往能源密集度极高。本研究提议针对安第斯地区条件下的一座470米温室设计并建造一个耦合地热热泵,以满足夜间15°C和白天30°C的温度要求。首先,该研究通过实际测量确定了太阳能和地热能的潜力,并将结果与理论模型进行对比。然后,利用蒸汽压缩循环,在温室中建立了能量平衡以确定地热热泵的规模。最后,通过平准化供热成本(LCOH)对整个系统进行构建和评估。该系统运行时,供热和制冷分别需要29.56千瓦和65.76千瓦的功率;当以1.64°C/小时的优化温度梯度驱动供热流运行系统时,这在技术上是可行的。此外,容量因子(CF)表明,当CF低至0.45时,需要12至14年的使用寿命才能达到可接受的LCOH。在经济方面,有必要促进海关免税,以使该系统相对于电力和液化石油气等更传统的能源具有竞争力,因为热泵和地热交换器的主要部件并非本地生产,且占前期成本的近70%。