Design And Construction Of An Office Table Solar-Dc Powered Fan

A table fan is a small, portable type of fan that is used in various rooms of a home or office. It is more convenient compared to other types, like kitchen exhaust, window, and pedestal fans because of its portability. It serves a number of functions for home owners and office workers such as conservation of energy compared to using air conditioners, removal of heat and unwanted fumes from indoor areas, cooling a room and generation of mechanical noise that helps to distract a person’s attention from undesirable background noise so he could focus on his task. The idea of a solar fan has been proven to be a very good especially for a country like Nigeria that enjoys an average of 8 hours of sunlight daily. The same sun that causes heat is made to power an object of thermal comfort at a low level of sophistication. In this design, a 3-blade table fan of 25 watt capacity capable of 6 hours of continuous operation was powered with just 1.0 Photo-voltaic (PV) module of 80 watt power rating. Also a minimum of 85% efficiency was designed for and the fan runs at a low torque of 0.95Nm. The fan blade rotates at a tip speed of 500rpm rotates on a 10mm diameter shaft. In order to maintain a constant operation during the night and when the sun is not at its peak, a 75Ah 12V battery has been considered suitable for power storage assessor.

CHAPTER ONE

1.0                                          INTRODUCTION

Solar energy currently represents the most abundant inexhaustible, non-polluting and free energy resources that could be used economically to supply man’s increasing energy demands (Nasir, 2004). Over the years, there has been a great insight into the need to tap into the proper utilization of the renewable energy. As a result, there have been great strides in trying out many electrical gadgets and equipment as to how they could be powered with renewable energy sources like the solar energy.

The share of renewable in electricity generation is around 19%, with 16% of global electricity coming from hydroelectricity and 3% from new renewable. (Renewable Energy Policy Network for the 21^st Century, 2011).One of the most exciting developments in the renewable energy sector in recent years has been the decline in the cost of Photo- voltaic (PV) cells. PV module prices at the start of 2012 were nearly 50% down on a year earlier, and some 76% below their level in the summer of 2008, when the Spanish PV boom was at its height (UNEP, 2012).

As availability of fossil fuel is diminishing due to over-dependence in its use apart from its effects on ozone layer depletion, it is convinced that solar energy can contribute significantly to addressing the current challenges in energy and climate change. There is a notable growing need for countries to reduce their emissions and achieve greater energy independence while facing increasing volatility in fossil fuel prices, significant increase in energy demand and CO₂ emissions in emerging countries and decreased nuclear generation in the energy mix of developed and developing countries. Many if not all day-to-day useful gadgets such as fans, water dispensers, among others should function on the solar energy. Actually, solar DC-powered fan is more convenient compared to other types, like kitchen exhaust, window, and pedestal fans because of its portability.

There are two primary types of fans, namely; centrifugal and axial (U.S. Department of Energy Efficiency and Renewable Energy, 2003). The table fan under consideration is an axial type meant to be powered with a DC source from a solar panel with a 12V battery backup. A typical fan system consists of a fan, an electric motor, a drive system, duct or piping and flow control devices (Department of Energy Efficiency and Renewable Energy, 2003). Fan design is a compromise between the various fan parameters that affect fan efficiency. The capacity is directly proportional to the fan speed; the pressure (static, total, or velocity) is proportional to the square of the fan speed; and the power required is proportional to the cube of the fan speed (BASF, 2006).There The aim of this work therefore is to design an energy efficient 25 watt single user solar table fan that will run for maximum of 6 hours, improves on the performance of previous ones and which can be sustained by the available technology in Nigeria and also meets up ASHRAE recommended thermal comfort range of 50 – 100cfm for fans. This aim is achieved by creating design ideas on the product (solar fan) through product design specifications that could enhance better lifestyles and comfort of the user, designing a solar fan that meets safety requirements of the user in his environment; and modelling the design using an Autodesk Inventor Design tool. Hence, the design of this machine was carried out at the University of Lagos, Nigeria, and should be able to deliver 85% efficiency and rotate at a tip speed of 500rpm. This machine has not been designed to run for a whole day (24 hours) but rather between 4-6 peaks working hours in the office. Also, it has not been manufactured /developed.