# Estimation of the Energy Consumption of the Rice and Corn Drying Process in the Equatorial Zone
## 1 Introduction  
Drying is one of the processes where the highest percentage of energy is consumed at the agroindustrial level [1]. The types and methods of drying used have significant effects on the quality of the final product. In practice, the energy requirement for drying food grains has two components; firstly, the energy required to evaporate the water vapor and secondly, the energy required to remove the water associated with the raw material [2, 3]. According to Food and Agriculture Organization, there are different ways to define the drying process, considering the theoretical aspects of the energy and mass transfer mechanisms [4]. On this regard, we can define it as a natural or artificial process, which have an asynchronous exchange of heat and mass between the air existing in the drying process and the grains. In other words, we can define drying as the process capable of reducing the moisture content of a product to a minimum and safe level so that it can be consumed and stored. In this way, the respiratory activity of the grain is reduced, avoiding the insects, fungi, and holds to decrease the grain quality, produce toxins, and prevent its commercialization and consumption [2, 3, 5]. For the drying process, it is necessary to determine the energy consumption, therefore it is estimated the energy required to dry grains, depending on the drying temperature, ranges between 3000 to 8000 kJ/kg of water removed [5; 6; 7]. That would mean an approximate energy consumption of 0.8 to 2.2 kWh for each kilogram of dry product. On the other hand, there is a relationship between the product to be dried and the energetic consumption required in the process. Therefore, it is essential to analyse the energy requirements to minimize the energy losses as well as use the energy input efficiently. Likewise, it is necessary to take into consideration technological variables associated with the drying system, as well as, the grain quality and initial humidity, which can considerably affect the energy demand of the process [3; 5; 6; 7; 8]. In our particular case, the Republic of Ecuador is located in the northwest of South America, and the Pacific Ocean bathes its coasts. It has 277 thousand km\({}^{2}\) and a population of 17 million inhabitants [9], where the topography plays an essential role in the distribution of the country's climates. The Andean Mountain Range, which is the leading mountain chain of South America, crosses our continental territory from North to South, dividing it into three natural regions with very different climatological characteristics. These regions are called: Coast, Highland, and Amazon. The mountain range affects the formation of cold air masses that modify the precipitation patterns and acts as a wall that prevent air masses from the Pacific Ocean and the Amazon to exchange. Moreover, the \"El Nino Current\" plays an important role in the Andean region climate [10]. In summary, all these factors affect local meteorological variables' behaviour, thus contributing to the presence of areas with very particular microclimates throughout the continental territory, which leads to crops sectorization and production areas with different degrees of agroindustrial development [11; 12]. The Ecuadorian agricultural production was about 4524.00 billion US dollars in 2013 and contributed with 13.8% of the total GDP. It is worth mentioning that the crops that guarantee food sovereignty (rice, corn, potatoes, vegetables, fruits, milk, meat, among others) are not considered in the GDP analysis [13]. Now, concerning per capita consumption of food products prepared within the Food Balance 2000-2012 by MAGAP, it is cited that the products with the highest national demand are: corn and rice with an annual average increase of 47 and 9 kg/(person per year) respectively [14]. On the other hand, it is important to mention that 70% of corn production comes from family farming and it is a crucial sector to guarantee food security and poverty eradication [15].