M.M.K. Khan

Energy conservation in buildings: cogeneration and cogeneration coupled with thermal energy storage

Energy-conservation opportunity in an institutional building is studied through cogeneration with double-effect absorption chiller. Both, technical and economical feasibility is evaluated and presented. The typical electrical energy and cooling-load demand profiles of the buildings concerned are determined. Payback period, internal rate-of-return (IRR), net present value (NPV) and net profit of the Institute is determined through cash-flow analysis. Then, cogeneration coupling with thermal energy storage (TES) is studied and its technical and economical feasibility is evaluated and compared with that of cogeneration. On-site cogeneration with a double-effect absorption chiller provides a potential of at least 13% peak-demand reduction and about a 16% savings in energy consumption. It provides IRR greater than 21% but the saving potential is limited by the low demand of co-generated chilled water within the community of the Institution. Cogeneration coupling with thermal energy storage offers a simple and economically more attractive approach for maximizing the utilization of co-generated chilled-water and shows 23% reduction in peak demand and a 21% savings in energy consumption. It provides a higher IRR, greater than 25%.

Environmental pollution generated from process industries in Bangladesh

The sources of environmental pollution in process industries in Bangladesh are discussed. Total pollution load into environment (i.e., into air, water and land) generated from process industries is determined and presented using industrial pollution projection system (IPPS) developed by the World Bank. Most polluting industries in Bangladesh are identified and ranked. The projection of this pollution load for year 2011–2012 is estimated and discussed. It was found that the food industry was the worst air polluter, whereas pulp and paper was the worst water polluter, and tanneries and leather industries were worst polluter of toxic chemicals. Industrial pollution control measures are recommended.

Study on Australian energy policy, socio-economic, and environment issues

This article deals with the Australian total energy consumption related to economic growth and carbon dioxide (CO2) emission in which total energy consumption is sub-divided into renewable and non-renewable energy consumption. The aim of this study is to determine the nexus between all energy elements with gross domestic product and CO2 emission using the Cobb-Douglas equation. The study is based on the Australian panel data over the period from 1976–1977 to 2012–2013. Vector error correction model and generalized method of moments were used to estimate the variables for the relationship between energy variables. The proposed model shows good agreement with the data available on the bioenergy production and consumption in Organization for Economic Co-operation and Development countries. In this model, oil price, oil consumption, carbon tax, renewable energy technology, population growth, urbanization, etc., have been considered as model variables or governing factors. The results show the bidirectional re...

A review on socio-economic aspects of sustainable biofuels

Biofuels are renewable eco-fuel, produced from biological resources. They are classified into 1st, 2nd and 3rd generations based on their feedstocks. The 2nd and 3rd generation biofuels are called advanced and sustainable biofuel. The study reviewed and discussed about socio-economic aspects of the sustainable biofuel in Australia because economy is seen to be a key driver for use of biofuels. Recent researches focused on sustainable biofuel production, their commercialisation worldwide. The world biofuel scenario is presented in this study which shows that total biofuel production is progressively moving towards advanced biofuels. Australian total biofuel production, consumption and available present production facilities are also outlined. The study briefly discussed about Australian energy economy such as energy export, import and trades etc. The study concluded that the 2nd generation biofuel can be considered as sustainable alternatives to petroleum fuel in transport sector providing great economic and environmental benefits to Australia.

Review on Renewable Energy Potential in Australian Subtropical Region (Central and North Queensland)

In Australia the future demand for energy is predicted to increase rapidly. Conventional energy resources soaring prices and environmental impact have increased the interest in renewable energy technology. As a result of that the Australian government is promoting renewable energy; such as wind, geothermal, solar and hydropower. These types of energy are believed to be cost-effective and environmentally friendly. Renewable energy availability is controlled by climatic conditions such as solar radiation, wind speed and temperature. This paper aims to assess the potential of renewable energy resources, in particular wind and solar energy in an Australian subtropical region (Central and North Queensland) namely, Gladstone, Emerald, Rockhampton, Yeppoon, Townsville, and Cairns. Analysis is done by using the latest statistical state of Queensland energy information, along with measured data history of wind speed, solar irradiations, air temperature, relative humidity, and atmospheric pressure for those sites. This study has also shown that national assessments of solar and wind energy potential can be improved by improving local climatic data assessments using spatial databases of Central and North Queensland areas.

A study of the flow phenomenon of water in a channel with flat plate obstruction geometry at the entry

The flow ina parallel walled test channel, when obstructed with a geometry at the entrance, can be forward, reverse and stagnant depending on the position of the obstruction. This interesting flow phenomenon has potential benefit in the control of energy and various flows in the process industry. In this experiment, the flat plate obstruction geometry was used as an obstruction at the entry of the test channel. The parameters that influence the flow inside and around the test channel were the gap (g) between the test channel and the obstruction geometry, the length (L) of the test channel and the Reynolds number (Re). The effect of the gap to channel width ratio (g/w) on the magnitude of the velocity ratio (V1/V0 : velocity inside/ velocity outside the test channel) was investigated for a range of Reynolds numbers. The maximum reverse flow observed was nearly 20% to 60% of the outside velocity for Reynolds number ranging from 1000 to 9000 at g/w ratio of 1.5. The maximum forward velocity inside the test channel was found 80% of the outside velocity at higher g/w ratio of 8. The effect of the test channel length on the velocity ratio was investigated for different g/w ratios and a fixed Reynolds number of 4000. The influence of the Reynolds number on the velocity ratio is also discussed and presented for different gap to width ratio (g/w). The flow visualisation photo-graphs showing fluid motion inside and around the test channel are also presented and discussed.

REVERSE FLOW PHENOMENA OF A POLYACRYLAMIDE SOLUTION IN A CHANNEL WITH AN OBSTACLE AT THE ENTRY: INFLUENCE OF OBSTRUCTION GEOMETRY

This study investigates the reverse-flow phenomena of a polyacrylamide solution in a channel referred to as a “test channel” with obstruction geometry at the entry placed in another wider parallel-walled channel. The influence of various obstruction geometries (i.e., shapes and sizes) plays a very important role in controlling reverse-flow behavior and is investigated in this study. The obstruction geometries used in this research were: flat plate, semicircle, circle, triangle, and rectangle with various aspect ratios. Experimental investigation and numerical simulations were carried out with a non-Newtonian 0.03% (by weight) polyacrylamide solution that obeys a power-law behavior for a fixed Reynolds number of 2000. The non-Newtonian fluid results are compared with that of water. The flat plate produced the maximum reverse flow at a gap-to-width (g/w) ratio of 1, whereas the triangle produced minimum reverse flow at a g/w ratio of 0.5. The circular geometry produced the maximum forward flow, and the flat plate produced the minimum forward flow at a g/w ratio of 8. Good agreement has been observed between the experimental results and numerical simulations.

Exergy Analysis and Efficiency Improvement of a Coal Fired Thermal Power Plant in Queensland

Energy security and CO2 emission reduction are two major concerns of today’s world. Improv‐ ing efficiency of the energy systems is an essential option for the security of future energy and the reduction of CO2 emissions. With the growing prosperity of the civilization, our consump‐ tion of energy is growing very rapidly. Fossil fuels remain the world’s dominant primary energy supply, with its use as a versatile primary source of energy in power generation, transport and industry. However, we have finite sources of these non renewable fossil fuels and we are consuming them at a rate that cannot be sustained, leading to the risk on energy security in the future. The Intergovernmental Panel on Climate Change (IPCC), in its Fourth Assessment Report [3], identified carbon dioxide (CO2) emissions from burning of fossil fuels as the primary contributor to climate change. Therefore, the prudent use of energy is imperative and the importance of improving energy efficiency is now very well realized by all.

Numerical Modelling for the Extreme Flood Event in the Fitzroy Basin, Queensland, Australia

Fitzroy Basin is the second largest catchment that drains to the coast in Australia. Fitzroy Basin is capable of producing severe flooding from tropical cyclone with heavy rainfall due its immense size and fan-like shape. Analysis shows that the historical peaks of different tributaries in different sub-basins of the Fitzroy River occurred in different years and their contributions are different for each flood event. However a scenario might happen when the flood peaks of different tributaries would synchronize and its consequence will be mass devastation indeed. The impact of combination of extreme flood peaks of different tributaries in different sub-basins to the total flood magnitude of the Fitzroy river is presented in this study using an integrated hydrological and hydrodynamic model. The discharge found from the synchronized extreme flood event was about 36% higher than the most severe historical flood that occurred in 1918.

Simulation and Optimization of Residential Grid-Connected PV System in Queensland, Australia

The use of solar photovoltaic (PV) in residential electricity generation is encouraged by Australian governments incentive. However, what extent of residents benefit from installing a grid-connected PV system is not fully understood yet. The purpose of this study is to investigate and optimize the economic, technical and environmental performance of grid-connected PV system in Queensland, Australia. Using the price of PV devices and accessories, grid electricity tariff and sale-back tariff as economic analysis inputs, and global solar irradiation as solar energy resource data, the system is simulated and optimized by HOMER software. The optimized system not only satisfies the typical residential load of 23 kWh per day but also meet the requirement of minimizing the total costs of system investment and electricity consumption during the system life (20 years). It is found that under the weather conditions of the eleven main cities of Queensland, a PV system is an effective way to reducing electricity bills and mitigating carbon dioxide emission.