Wind power equipment for small farms and households

V. Beresnevich*, M. Cerpinska, M. Irbe and J. Viba

Riga Technical University, Faculty of Civil and Mechanical Engineering, Institute of Mechanical and Biomedical Engineering, 6A Kipsalas Street, LV1048 Riga, Latvia
*Correspondence: vitalijs.beresnevics@rtu.lv

Abstract:

This article deals with the development of small-sized wind power equipment as a viable solution for decentralized renewable energy production. To improve operational specifications of conventional turbine models with rotating blades, it is proposed to use a new design of wind power plant synthesized on the base of a closed loop conveyor equipped with flat-shaped blades. In this design, blades are mounted on a belt with an opportunity to move together with it in one straight line direction. Air flow interaction with flat blade that performs translation motion is studied by computer simulation using a superposition principle. In accordance with this approach, a fast-chaotic motion of air particles (Brownian motion) is separated from the slow-directed air motion, with the given average velocity. Dynamic analysis of flat blade interaction with air flow is performed for the stationary air flow with constant speed and also for non-stationary flows with wind gusts. Optimization of the system parameters is made using the generated power as a criterion. Simulation results confirm the serviceability and efficient operation of the proposed conveyor type wind power equipment. It can be mounted on the roofs of buildings or rooftops of vehicles, also device is befriended to nature and people.

Key words:

Modelling the effect of sowing date on the emergence, silking and yield of maize (Zea mays L.) in a moderately warm and dry production area

A. Széles¹,* and L. Huzsvai²

¹University of Debrecen, Faculty of Agricultural and Food Sciences and Environmental Management, Institute for Land Utilisation, Regional Development and Technology, Böszörményi út 138, H-4032 Debrecen, Hungary
²University of Debrecen, Faculty of Economics and Business, Institute of Statistics and Methodology, Böszörményi str. 138, H-4032 Debrecen, Hungary

Abstract:

This research focused on accurately modelling emergence (VEEmergence) and silking (R1) dates using 5 cm deep soil temperature (ST) and how sowing date (SD) affects VEEmergence and R1 date of different maturity hybrids and which is the optimum sowing date in the changed climate. Three sowing dates were used between 4th April and 10th May. The same maize hybrids (FAO 290, FAO 350, FAO 420) were involved in the experiment between 2011–2013. The 5 cm deep soil temperature could be used for simulating the date of VEEmergence and R1 and the Percentage of Predicted Deviation (PD) was below 10%. When calculating the effective heat units (HU) at 5 cm depth, setting 6 °C as base temperature leads to better modelling. SD did not clearly affect yield since due to the influence of genotype and crop years. The FAO 290 hybrid had the lowest yield (11.534 t ha-1) and it responded sensitively to sowing date. Its highest yield (12.788 t ha-1; P < 0.05) could be obtained with SD3. FAO 350 and FAO 420 hybrids provided stable yields without any significant effect of SD. The highest yield was provided by the FAO 420 hybrid (13.494 t ha-1) with a wide SD interval (4th April – 10th May). The obtained findings help farmers in making grounded decisions to obtain high and stable yield under the changed climatic circumstances. The obtained findings help farmers in making grounded decisions to obtain high and stable yield under the changed climatic circumstances.

Key words:

air temperature, CERES-Maize model, climate change, computer simulation