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The present investigation is oriented to determine the potential of solar energy as a renewable source for a swine center established in the "El Guayabal" University Farm, belonging to the Agrarian University of Havana, Cuba. For this, the number of animals is considered, as well as the movement of the herd, which would make it possible to determine the energy demand, based on the diagnosis of the energy carriers existing in the scenario. Among the main results obtained, it was evidenced that for the existing conditions, it is pertinent to introduce photovoltaic solar energy technology as a renewable source for driving the electric motor of the mill, the water pump and lighting, which implies an initial investment of 645 500 peso (25 820 USD). On the other hand, the introduction of a solar heater is viable, for the sanitation actions of the workers of the pig center, with the budget required for the acquisition of this technology being 9 650 peso (386 USD). The introduction of both technologies contributes directly to caring for the environment by stopping the emission of CO2 and other greenhouse gases into the atmosphere and its corresponding negative impact on the environment. Finally, it is evident that, with only the commercialization of the pigs to the carcass of the first group, the total amount required for the acquisition of the photovoltaic system and the solar heater is recovered and it is possible to obtain a benefit that amounts to 478 850 pesos (19 154 USD), this element demonstrates the economic feasibility of this investment. [ABSTRACT FROM AUTHOR]

The present investigation is oriented towards the determination of the economic, environmental and energetic feasibility of the anaerobic biodigestion technology suitable for a dairy agroecosystem, established in "El Guayabal" University Farm, belonging to the Agrarian University of Havana. For this, animal species existing in the scenario is determined, since it will contribute the organic waste to the biodigester. The number of animals is also determined, considering the movement of the herd, which would make it possible to determine the biomass generated daily with the purpose of establishing the sizing of the appropriate biodigester technology and knowing the behavior of the economic and energy parameters. Among the main results obtained, it was evidenced that the installation of a tubular polyethylene biodigester is more feasible than the installation of a fixed dome biodigester, meaning an economic saving of 19,796 pesos for the concept of technology selection. The necessary volume of this technology must be 20 m³, making it possible to produce 190 kg/day of biofertilizers, which represent an economic contribution of 2,375 pesos (95 USD) constituting an added value, in addition to the energy and economic benefits to be obtained. Moreover, with the introduction of the selected anaerobic biodigestion technology, it is possible to generate electrical energy to drive a fodder mill, a refrigeration system, a mechanical milking system, lighting, electric fencing and a water pumping system, all which require the acquisition of a 35 kW biogas generator. [ABSTRACT FROM AUTHOR]

The energy analysis accompanied by economic indicators constitutes a valuable tool for the comprehensive and systemic evaluation of ecosystems, which estimates the values of energies incorporated in products, processes and economic responses, as well as the impact of human activities on ecosystems.. In the present work, the behavior of energy and economic efficiency indicators is analyzed in a dairy unit with a conventional management system, located in the Mayabeque province, Cuba during the years 2018 and 2019. The energy indicators were determined: energy produced and consumed, energy balance, protein produced and consumed, energy cost of protein production and people who feed the system with energy (Pe) and protein (Pp); and economic indicators: net income, net benefit and benefit/cost ratio. The total production per surface unit expressed in terms of energy, showed values of 3.04 and 2.61 GJ.ha-1, while the protein was 38.94 and 33.36 kg.ha-1. The energy balances were below the unit (0.25 and 0.44 MJ/MJ), with high energy costs to obtain protein and low capacity to feed people (0.71 Pe/ha and 1.53 Pp/ha, 2018; 0.61 Pe/ha and 1.31 Pp/ha, 2019); even so, the benefit/cost ratio of 2.29 and 1.81 CUP/CUP revealed the profitability of the system. Although greater energy efficiency was obtained in 2019, the economic benefit was lower due to the reduction in food inputs that, in the absence of alternative sources, affected productivity and income. [ABSTRACT FROM AUTHOR]

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This research is oriented towards determining the energy potential of a biodigester installed on the Santa Bárbara farm, which is located in the Sumapaz province, Colombia. For this, the existing animal species in the scenario is determined, which will contribute organic waste to the biodigester, the number of animals is also determined, considering the herd movement, which would make it possible to determine the biomass generated daily, with the purpose of establishing the sizing of the appropriate biodigester technology and knowing the behavior of the energy parameters. Among the main results obtained, it was evidenced that the biodigester installed by the producer is not capable of assimilating the biomass generated daily, due to the number of existing animals; noting that despite the fact that only approximately 35% of the energy potential is used, due to the dimensioning of the anaerobic digestion technology (tubular polyethylene biodigester) installed in the Santa Bárbara farm, despite this it is shown that it contributes to saving energy and the conservation and preservation of the environment. However, if the biodigester designed in the research were installed, the energy potential would be used 100%, validating that the adequate dimensioning of the anaerobic digestion technology is proportional to the energy savings to be obtained in agricultural units. [ABSTRACT FROM AUTHOR]

The present investigation was carried out in "Héctor Molina Riaño" Base Business Unit, with the objective of determining the rational organization of the sugarcane harvest-transport-reception system, through the integration of mathematical models, which guarantee the stability of the flow in the system. The rational conformation of the harvest-transport-reception-system was determined using the following methods: linear programming, queuing theory for a single service station and for stations in cascades. When analyzing the stability of the compositions with the Markov chain model, it is found that the most stable variant is when the queuing theory is used in cascades when working in fields of 75 t/ha, with two CASE IH 8800 Harvesters and four Tractors BELARUS 1523 + four VTX 10000 dump trailers, four HOWO SINOTRUCK aggregates + two trailers and three reception centers with a probability of 53.79% that the cycle will not be interrupted and a cost of system stops of 33.05 peso/h, being possible to reduce the costs by stops in more than 30%, observing a marked influence when increasing the number of collection centers. [ABSTRACT FROM AUTHOR]

This work deals with the foundation and proposal for the dimensioning of a photovoltaic solar park destined to satisfy the demand for electrical energy in the facilities of the Center for Agricultural Mechanization (CEMA) of the Agrarian University of Havana. For this, a study of the behavior of electricity consumption was carried out in CEMA, as it is considered a high consumer. It was determined that, to satisfy the energy demand, the photovoltaic solar park must have 323 solar panels of the BS18055 model, an accumulation system composed of 47 Trojan monoblock batteries, two Victron Energy model current regulators (input current of 2054.28 A and 1135.09 A output), as well as a 1000 kWh inverter. An analysis of the economic and environmental impact of the proposed installation was carried out, which showed that it will allow an electrical energy saving of not less than 29,421.72 kWh per year. Likewise, it was determined that, due to this unconsumed energy, at least 33.24 t of CO2per year would cease to be emitted into the atmosphere. Then, at least 7.7 t of fossil fuel would stop being consumed in the same period, thus representing a total saving of at least 57,368.23 CUP, for energy not consumed annually. To undertake the proposed installation, the preliminary cost estimate of the investment was calculated, which is around 244,583,376 CUP, if the energy storage system is included, and 935,376 CUP, not including the energy storage system. [ABSTRACT FROM AUTHOR]

The present investigation is oriented towards the design of a solar dryer for botanical seeds of pastures and forages. For the fulfillment of the proposed objective, the theoretical-methodological bases referred to the subject were established. It was evident that the proposed theoretical foundations allowed carrying out the design and simulation of a prototype for the solar drying of botanical seeds of pastures and forages. With the use of the Solidworks software (2018 version), the prototype design was carried out and with the Flow Simulation tool, the analysis of fluid kinetics and temperatures was carried out, reaching air velocity values of 0,25 m/s and temperatures of 8 above room temperature in the drying chamber. On the other hand, with the Simulation tool, a finite element study was carried out to evaluate the structural strength of the prototype, using the von Mises maximum tension criterion, which demonstrated its strength and stability. [ABSTRACT FROM AUTHOR]

The research was guided in establishing a methodology to evaluate the thermodynamic and agronomic quality of the process of solar drying of seeds, for it were considered the different methods and technologies of solar drying used in the postharvest handling of seeds. For the establishment of the proposed methodology was considered from the thermodynamic point of view, the energy retention inside the drying installation, being evaluated starting from the different forms of heat transfer (conduction, convection and radiation), the selection of the most appropriate materials for the construction of this type of facilities, as well as the régime of hot air to introduce or humid air to extract. Among the basic thermodynamic aspects considered, were observed the influence of the type and shape of the solar collector, the airflow and the seed type to process about the technological efficiency of the process. For the agronomic analysis were considered the quality characteristics of the seeds, among those the physical quality of the seeds of a specific sample; the physiologic quality, which refers to aspects of the performing of the seed (vigor and germination); the genetic quality, which is related to the specific genetic characteristics of the seed variety and the sanitary quality of the seeds, which refers to the presence or absence of illnesses or plagues inside the samples of seeds. [ABSTRACT FROM AUTHOR]

Solar crops drying as a process has currently become a decisive factor to improve the efficiency in the industrial, residential and farm sectors. Given its considerable importance, different researchers have proposed and developed a great number of theoretical and experimental models to predict the drying kinetics of the process, including the machine and the product. In the use of solar thermic driers, there have been great advances on developing models; however, the major part of these works has concentrated in driers of industrial scale. The unified models that allow predicting temperature profiles and moisture content for many types of crops, using handmade driers to small scales have been less applied. It has been mainly due to the wide diversity of products and the big differences between the existing processes. The purpose of this research is offering a panoramic about the state of the art related to models and present the basic theoretical foundations to develop a model for solar seed drying. [ABSTRACT FROM AUTHOR]

This research was carried out on areas of the Agrarian University of Havana, with the objective of determining the power used in traction and gases emitted product of combustion in the plowing labor with the tractor set MTZ-82 and universal moldboard plows of three bodies. To achieve this objective the theoretical and methodological foundations were considered and the necessary measuring instruments were used to determine the reactions of the road on the wheels, the tractor dynamics of traction and the gases emissions produced by the combustion. Starting from the above stated, it was obtained that the biggest road reactions occur on the front wheels of the tractor reaching a value of 6,82 kN, being superior to those of the rear wheels 1,11 kN and wheel field 4,1 kN; the average depth of the work was 16 cm, reaching a mathematical expectation of the speed of 1,34 m/s and a mathematical expectation of the force exerted by the hook of 5,54 kN, being 28,4 L/ha the amount of fuel consumed; hook power reached a value of 7,42 kW, equivalent to 35% of the traction efficiency. In addition, 0, 67 kg of CO, 1,17 kg of CO2 and 0,98 kg of water vapor were ejected to the environment per liter of diesel fuel consumed (C12H26). [ABSTRACT FROM AUTHOR]

The drying process in grains is a principal activity in postharvest operations; with the goal of economizing on energy sources and reducing pollution of the environment, it is possible to develop solar grain dryers. For that reason, the fabrication and testing of a solar grain dryer was done. The following show the main results for the grains of soybeans and black beans: the average moisture content before the drying of the soybeans was 15% and after the process it was 10, 24%. In the case of black beans the average moisture content before their drying was 16% and after the process it was 12,15%, being the moisture content reduction rate 1,58%/h and 0,54%/h for both grains soybeans and black beans respectively. Before drying, the mass of soybeans was 116 kg and after the drying process, it was 104 kg, therefore 12 kg of water were removed; in the case of black beans the initial mass was 150 kg and after, it was 142 kg, therefore 8 kg of water were removed; the fuel consumption was null as well the emission of gas. The structural shape of this prototype supports the loads, and the heat transference laws validate that the prototype have characteristics of drying machines. It was also determined the operation cost being of 2,71 peso/h. [ABSTRACT FROM AUTHOR]

The present research was carried out on the Agroindustrial Rice Complex "Los Palacios", on Pinar del Rio province. The investigation had as main goal the study of the means stop probabilities, on the base of stochastic process, considering economical features that appear during the work of the complex rice harvest-transport with the harvester machine New Holland TC-57 and the joint tractor New Holland TS-6020 with trailers RA-6, looking for its rational organization. For the solution of this problem was used the Queueing Theory, taking the economical criteria of itsoptimization the minimum added expenses in one hour by harvester machines and means of transport stops in service, besides it is determined the quantity means of transport for a harvester brigade under probabilistic basis. [ABSTRACT FROM AUTHOR]

This research is aimed at determining the feasibility of introducing a photovoltaic solar system in 021 Dairy Farm of "El Guayabal" University Farm belonging to the Agrarian University of Havana. The consumption of electrical energy was evaluated and the feasibility of three variants was determined in terms of the number of solar panels (342, 126 and 128) that the photovoltaic solar system must have to satisfy the energy demand. An analysis of the economic and environmental impact of the proposed installation was carried out, which showed that it will allow a saving of electrical energy higher than 43,781.75 kWh/year. With the three variants analyzed, savings were obtained in terms of energy not consumed, avoiding the emission of at least 49.47 t of CO2 into the atmosphere annually, and the consumption of at least 11.47 t of fossil fuel. The preliminary cost to establish the installation proposed was estimated at: 386,255.2 CUP, 419,586.6 CUP and 1,048,290 CUP, according to the variants: without considering the current pumping system, considering the current pumping system and assessing the introduction of the solar pumping system PS2-150 C-SJ5-8, respectively. The energy storage system was not included in any of the variants. [ABSTRACT FROM AUTHOR]

The depletion of fossil fuels is eminent over time due to its non-renewable nature. The use of biodiesel is a viable option to stop its decline since it is obtained from biomass. Due to the importance of the percentage of biodiesel that can be added without affecting the operation of the MWM International model 6.10T engine coupled to a Worthington vertical deep well pump. This research was developed in the Department of Engineering and Environment, of the Institute of Animal Science. The pumping system used in the water supply for the institute and the community was evaluated. Biodiesel-diesel blends (B-0, B-5, B-10, B-15, B-20, B-25 and B-30) were handled with three rotation frequencies (1350, 1550, 1750 min-1). The hourly consumption (Gh) did not show statistically significant differences in the rotation frequencies 1350 and 1550 min-1, only at 1750 min-1 the highest consumption is obtained when using 30% biodiesel. The specific fuel consumption (ge) at 1750 min-1 showed statistically significant differences only in B-30 and at 1350 min-1 the highest consumption was observed in B-5 and B-30. When the engine is running for 1000 hours of work, the B-20 and B-25 blends obtain the most economically efficient values, with 9 780 and 9 070 pesos, respectively. By studying all the blends analyzed, it can be stated that B-20 and B-25 are the most recommended to use. [ABSTRACT FROM AUTHOR]

The research was carried out in the conditions of harvest and repair of "Sierra Maestra", Agricultural Base Business Unit (UEBA) in New Holland L-521, L-624, L-626 rice harvesters, in the daily technical maintenance operations, every 30 h periods, with the objective of estimating their maintainability. Through mathematical analysis, average time of daily and periodic technical maintenance every 30 h was determined. In the research, the estimation of maintainability for real operation conditions is made for the first time. Among the most significant results is that for the harvesters evaluated, the maintainability curve shows that there is between 95.8 and 97% probability that the daily technical maintenance will be carried out in two hours; while in technical maintenance every 30 h the probability is between 74 and7 8% in the same period of time. [ABSTRACT FROM AUTHOR]

The research was carried out under the conditions of harvesting and repair of the Agricultural Base Business Unit (UEBA) "Sierra Maestra", in the New Holland L-521, L-624, L-626 rice harvesters. The objective was estimating and checking the maintainability of the rice harvesters during daily technical maintenance, every 30 hours and during the harvest period under the conditions of "Los Palacios" Agroindustrial Grain Company (EAIG). Through mathematical analysis, average daily and periodic technical maintenance time every 30 h was determined. In the investigation, what the same authors did in 2017 was validated. Among the most significant results is that: for the harvesters evaluated, the maintainability curve shows that there is between 95.8...97% probability that the daily technical maintenance is carried out in two hours; while in technical maintenance every 30 hours the probability is 74...78% in the same period. [ABSTRACT FROM AUTHOR]

To evaluate the operating parameters and economic and energy costs of two sets: tractor BELARUS 510- cultivator "Camajuaní" and animal traction (by oxen)-cultivator "Criollo" in beans cultivation on Ferralitic Red soil, belonging to Farmhouse "Las Papas", National Institute of Agricultural Sciences (INCA), technological times, depth, width and working speed and fuel consumption were measured to both technologies. Using NC: 34-37 and NC: 34-38 and the software TECEXP and CEE, operating parameters, economic and energy costs for each set were calculated. As a main result it was determined that the useful operating time of tractor-cultivator is 6% higher than animal traction. Comparing sets, it was obtained that ha/h productivity, increases 4.23 times; the lowest economic cost transferred corresponds to the small power tractor with a value of 10.01 peso/ha, saving 34% and 48% compared to Belarus 510 and animal traction, respectively. The lower energy cost transferred also corresponds to the small power tractor with a value of 194.33 MJ / ha, saving 49% and 58%, compared to Belarus 510 and oxen animal traction, respectively. [ABSTRACT FROM AUTHOR]