Analysis of Development in Solar Greenhouses (Published)
The move towards a de-carbonised world, driven partly by climate science and partly by the business opportunities it offers, will need the promotion of environmentally friendly alternatives, if an acceptable stabilisation level of atmospheric carbon dioxide is to be achieved. This requires the harnessing and use of natural resources that produce no air pollution or greenhouse gases and provides comfortable coexistence of human, livestock, and plants. This study reviews the energy-using technologies based on natural resources, which are available to and applicable in the farming industry. Among these are greenhouses, which are necessary for the growth of some plants (i.e., vegetables, flowers, etc.) in severe climates. However, greenhouses require some air conditioning process to control their temperature and relative humidity to suit specific plants. To achieve this, a novel air humidifier and/or dehumidifier systems using mop fans had been designed and employed in an experimental greenhouse to evaluate its performance under a controlled environment. This device helped to reduce the energy consumption of the greenhouse whilst providing a pleasant environment for the plants inside the greenhouse. The system was designed taking into account the meteorological conditions, which affect the environment inside the greenhouse. The performance of the system was monitored over a period of time by measuring the temperature and relative humidity of the greenhouse. Results of the monitoring have shown that the system was able to provide comfortable conditions (temperatures of 16-26oC and relative humidity of 65%) suitable for the plants grown in the experimental greenhouse. It also enabled the minimisation of temperature variation and, hence, avoided the hazard of any sudden climatic change inside the greenhouse.
Keywords: Solar Energy, Solar Radiation, global radiation, greenhouses
Analytical Studies of Energy Efficiency Development of the Greenhouses (Published)
The move towards a de-carbonised world, driven partly by climate science and partly by the business opportunities it offers, will need the promotion of environmentally friendly alternatives, if an acceptable stabilisation level of atmospheric carbon dioxide is to be achieved. The use of natural resoucses that have not any air pollution or greenhouse gases and provides comfortable coexistence of human, livestock, and plants. The greenhouses require air conditioning process to control their temperature and relative humidity to suit specific plants. To achieve this goal, a novel air humidifier and/or dehumidifier systems using mop fans had been designed and employed in an experimental greenhouse to evaluate its performance under a controlled environment. The mop fan help to reduce the energy consumption of the greenhouse whilst providing a pleasant environment for the plants inside the greenhouse. The system was designed taking into account the meteorological conditions, which affect the environment inside the greenhouse. The performance of the system was monitored over a period of time by measuring the temperature and relative humidity of the greenhouse. Results of the monitoring have shown that the system was able to provide comfortable conditions (temperatures of 16-26oC and relative humidity of 65%) suitable for the plants grown in the experimental greenhouse. This device enable to minimse the temperature variation and, hence, avoided the hazard of any sudden climatic change inside the greenhouse.
Keywords: Solar Energy, Solar Radiation, global radiation, greenhouses
Global Solar Radiation Modeling on a Horizontal Surface Using Polynomial Fitting (Published)
An attempt has been made to use a polynomial fitting to model global solar radiation on a horizontal surface that was observed by using Pyranometer at University of Ghana Legon, (U.G), situated in Accra, Ghana. The observed solar radiation data was filtered by using fitting and smoothing methods. The polynomial data fitting method was tested by using different degrees of polynomial curve fittings. The root mean square error (RMSE) was used to calculate the error and the R2 (coefficient of determination) value was also determined. The polynomial fittings were carried out for various periods (pre- harmattan, early harmattan and late harmattan period) of the year.
Keywords: Coefficient of Determination, Curve Fitting, Error, Polynomial, Pyranometer, RMSE, Smoothing, Solar Radiation
Global Solar Radiation Measurement in Abakaliki Ebonyi State Nigeria Using Locally Made Pyranometer (Published)
This research work focused on the variability of global solar radiation over the area of Abakaliki, Ebonyi State (6o20’N, 8o06’E) located in South Eastern part of Nigeria for the rainy and dry seasons. The Pyranometer used for this measurement was locally developed and calibrated against a standard pyranometer, it competed favorably with the standard Einstrain Lungs Sensor. The global solar radiation was measured every five minutes from 08:00hours to 18:00hours during the dry season 2011 and rainy season in 2012. The measurements were carried out near the New Physics Laboratory Complex Ebonyi State University Abakaliki, Nigeria. Maximum Irradiances of 1095.10Wm-2 and 689.48Wm-2 recorded in Abakaliki during dry and rainy seasons respectively occurred between 12:00 – 14:00hours local time, whereas the minimum values of 9.20Wm-2 and 9.86Wm-2 respectively are recorded during the sunrise and sunset. Partly cloudy conditions in Abakaliki cause conspicuous oscillations in global solar radiation. This can be attributed to multiple reflections by nearby cloudy layers. The seasonal difference in the observed global solar radiation was 405.62Wm-2. Therefore solar energy devices can operate continuously in Abakaliki for up to 10 hours in a solar day from 8:00hours to 18:00hours which was the period covered during this investigation.
Keywords: Irradiance, Measurement, Pyranometer, Solar Energy, Solar Radiation
THE INFLUENCE OF VEGETATION ON MICROCLIMATE IN HOT HUMID TROPICAL ENVIRONMENT-A CASE OF ENUGU URBAN (Published)
Controlling direct solar radiation and increasing wind velocity to its Optimum capacity are part of planning strategies employed in the design of urban open spaces especially in hot humid tropical environment. Vegetation has the ability to reduce excessive air temperature through sunlight interception. Its geometric configuration influences the amount of solar radiation, air temperature, humidity and wind velocity on microclimate of a given area. Panning strategies aimed at reducing solar heat through application of vegetation were discussed. It also discussed the problem of thermal heat stress affecting the residents of Enugu Urban. The results were analyzed and solutions recommended
Keywords: Open Space, Planning Strategies, Solar Radiation, Tropical Environment, Urban Microclimate.