In this work, friction stir processing using a pinless tool with a featured shoulder was performed to alter the surface properties of Al 6061-O, focusing on the effect of tool traverse speed on ...surface properties, i.e., microstructure, hardness, and corrosion resistance. All processed samples showed refinement in grain size, microhardness, and corrosion resistance compared to the base material. Increasing tool-traverse speed marginally refined the microstructure, but produced a significant reduction in microhardness. Electrochemical impedance spectroscopy, linear polarization resistance, and potentiodynamic polarization were used to evaluate the effect of the processing conditions on corrosion behavior in a saline environment. All corrosion test results are found to agree and were supported with pictures of corroded samples captured using a field emission scanning electron microscope. A remarkable reduction in the corrosion rate was obtained with increasing traverse speed. At the highest traverse speed, the corrosion current density dropped by approximately 600 times when compared with that of the base alloy according to potentiodynamic polarization results. This is mainly due to the grain refinement produced by the friction stir process.
•The thermal performance and environmental aspects were investigated.•A comprehensive mathematical thermal model was developed.•The proposed model was implemented to study two building configurations ...in UAE.•Using solar penetration of 20% proved good feasibility with short payback period.
This paper addresses the viability of using the integrated Solar Heating Cooling (SHC) systems in residential buildings in UAE, by studying the thermal performance and potential energy savings, in addition to the economical and environmental aspects such as payback period and reduction in CO2 emissions. This work involves integration of the absorption chiller with solar thermal collectors to provide a continuous cooling. In the absence of sun, the bio-mass heater is used as an auxiliary heating source.
A comprehensive mathematical thermal model was developed to represent the fully integrated system, which was implemented to determine the useful energy for two selected building configurations based in UAE; fully solar cooling powered one-floor office building and hybrid four-floor residential building at different percentages of solar penetration. The obtained results for the fully solar powered system, showed that about 159kWh and 126ton/year savings were achieved in the Annual Energy Consumption (AEC) and CO2 emissions, respectively. Based on the performed numerical studies on the integrated SHC system of the residential building, the maximum solar penetration of 20% was found to be optimum as it reduced AEC by 176kWh and cut off CO2 emissions by 140ton/year with a payback period of 4 years.
Offshore facilities have high energy demands commonly accomplished with local combustion-based power generators. With the increased commercialization of the marine renewable energy sector, there is ...still a need for research on floating photovoltaic installations on their performance and economic perspective. This paper investigates the techno-commercial feasibility of installing a battery-integrated floating solar photovoltaic (FPV) system for an offshore oil platform facility in Abu Dhabi. The performance analysis of two floating PV design schemes has been evaluated using the PVsyst design tool. The proposed system’s annual solar energy availability from the PVsyst 7.2.21 output was validated with MATLAB Simulink R2022b with a deviation of 1.85%. The optimized solution achieved the Levelized Cost of Electricity (LCOE) of 261 USD/MWh with a Discounted Payback Period of 9.5 years. Also, the designed system could reduce carbon emissions by 731 tons per year. Furthermore, it was recognized that the contribution of the marine sector to the construction of floating platforms influences the success of floating PV systems. Independently authorized floating PV system designs would guarantee insurability from the viewpoints of investors and end users.
•This paper addresses the integration of ice storage system with solar PV panels for space cooling applications.•The proposed system was implemented on two case studies represented by office and ...residential buildings.•The proposed integrated system contributed to significant amount of savings in the annual electricity consumptions for the office and the residential buildings by 33 % and 38%, respectively.•The proposed sustainable model results in reducing the carbon dioxide emissions by almost 154 tons per year.
This paper addresses the potential of integrating a hybrid solar powered cooling system with ice storage for the purpose of space cooling in residential and office buildings. The proposed hybrid system was implemented on two case studies represented by one floor office building located in Abu Dhabi and four floor residential building located in Dubai with peak cooling loads of 70 kW and 366 kW, respectively. The solar powered system was investigated based on hourly solar radiation to fully capture the energy harvested from solar panels utilized to power the ice glycol chiller at different modes of operation. The annual power generated from the solar system was estimated using the monthly average solar radiations. The areas of PV panels installed on the roof of the office and residential buildings were 240 m2 and 400 m2, respectively. A feasibility study was conducted to assess the system’s performance from both economic and environmental perspectives. Based on the obtained results, it was found that the proposed system contributed to a significant amount of savings in the annual energy consumptions in the office building which was estimated to be 38 % less than the conventional cooling systems accompanied with 40 % reduction in CO2 emissions. For the residential building, the annual energy consumption savings were estimated to be 140,160 kWh and resulted in a tangible reduction in CO2 emissions of almost 154 ton/year. The feasibility study showed that the payback periods of the office building and residential building are about 8.8 years and 7.8 years, respectively.
In the current study, friction stir surface processing (FSSur.P) was carried out to alter the surface microstructure of 6061 aluminum alloy using a pinless friction stir tool. The impact of rising ...tool rotational speed from 400 to 1200 rpm while keeping tool traveling speed constant at 250 mm/min on surface microstructure, mechanical properties, and corrosion resistance was explored in detail. The microstructural findings revealed a significant reduction in grain size, in addition to a remarkable improvement in microhardness of processed samples. Approximately 44% increase in microhardness, compared to unprocessed counterpart was achieved at the lowest rotation speed. The corrosion behavior of the processed samples as well as the base sample was evaluated after 15 days of exposure to 3.5% NaCl using several electrochemical methods such as potentiodynamic polarization technique (PDP), linear polarization method (LPR) and electrochemical impedance spectroscopy (EIS) approach. All electrochemical techniques results demonstrated an excellent agreement where the unprocessed sample showed poor corrosion resistance with corrosion current density of (Icorr.) of 3.22 μA, whereas the sample processed at the highest tool rotating speed exhibited superior corrosion resistance with Icorr. of approximately 0.057 μA. Based on results it was found that increasing tool rotational speed has minimum effect on grain size, as well as microhardness; with best improvement achieved at lowest rotational speed or minimum heat input. On the other hand, the corrosion resistance was found to improve with increasing tool rotational speed. The use of pinless tool had a great impact on simplifying the process and achieve required surface enhancement without altering the subsurface material.
•This paper addresses the potential of integrating Parabolic Trough Collectors (PTC) with a double-effect absorption chiller for the purpose of space cooling in residential buildings.•A comprehensive ...mathematical thermal model was developed.•The thermal performance and environmental aspects were investigated.•The obtained model was implemented to provide space cooling for a four-floored residential building based in UAE.•The proposed integrated system proved to be feasible. The payback period of the proposed system was found to be 2.5years only. Moreover; the system reduced the Carbon-dioxide emissions by 304tons/year.
This paper addresses the potential of integrating the Parabolic Trough Collectors (PTC) with a double-effect absorption chiller for the purpose of space cooling in residential buildings. The proposed model was designed such to provide a continuous cooling. During the absence of sun, the bio-mass heater was used as an auxiliary heating source. In this study, the thermal performance of the proposed integrated system was investigated and a feasibility study was conducted in order to assess the system's economic and environmental impacts. The obtained model was implemented on a case study represented by a four-floored residential building based in Dubai with a net cooling load requirement of 366kW. The obtained results from the numerical simulation were analyzed to identify the optimum configuration in terms of feasibility and potential savings. It was found that the hybrid system with 30% solar contribution is the most viable compared to other alternatives in terms of performance and cost. The proposed system achieved Annual Energy Consumption (AEC) savings of about 519322kWh and a reduction by 65% in the annual operating costs. The payback period of the proposed system was found to be 2.5years only. Moreover; the system reduced the Carbon-dioxide emissions by 304tons/year.
Coal-based Integrated Gasification Combined Cycle (IGCC) power plants show obvious gains over conventional pulverized coal power plants by achieving higher efficiency, lower carbon emissions and ...lower energy penalty for incorporating different carbon capture and storage (CCS) technologies. However, due to the lack of standardised designs, current IGCC-CCS projects are hindered by higher capital expenditures limiting their commercial implementation. Therefore, the key challenge is carrying out a techno-economic optimisation of IGCC-CCS power plants to ensure compatible power generation efficiency and accessibility. This study aims to optimise the performance of a coal-based IGCC plant with two different CCS technologies (double-stage Selexol absorption cycle and Ni-based chemical looping combustion (CLC) process) through intensive process simulation, heat integration and economic analysis. Heat integration has increased the net plant efficiency by more than 12% and decreased the levelised cost of electricity (LCOE) no less than 5 cents kWh−1. The CLC technology offered near-zero carbon emissions with higher plant efficiency and lower value of LCOE. Decreasing the CO2 capture rate by Selexol caused a decrease in LCOE and an increase in the corresponding CO2 specific emissions. Therefore, an appropriate decarbonisation scenario depends on a trade-off between the degree of carbon capture and the allowed CO2 specific emissions.
This paper aims to evaluate the potential of heat recovery from the integrated heat exchanger within the exhaust stack silencer baffles in a simple cycle gas turbine. Heat transfer channels were ...incorporated into the upstream (nose) and downstream (tail) sections of the parallel silencer baffles in the exhaust stack. The gas turbine exhaust gas represents the hot side flow across the baffles' sections. The integrated heat exchanger system offered an advantage of extracting waste heat from the exhaust stream, while reducing pressure drop on the flow and improving acoustic attenuation.
In this work, a series of parametric studies were carried out across a range of internal and external heat transfer area configurations within the silencers to maximize the heat transfer. Further enhancement opportunities were introduced and discussed based on the conducted parametric studies and practical aspects borne out of common industry practice. The proposed heat recovery system was implemented to power the gas fuel performance heater which is used to enhance the gas turbine cycle performance through utilization of the extracted waste heat while keeping lower exhaust pressure drop in the stack.
The obtained results showed that the proposed integrated heat exchanger within the silencers has a potential of generating a 5.48 MW net gain from the gas turbine exhaust stacks which are normally lost to the atmosphere from the simple cycle exhaust stack. The proposed heat recovery system proved significant fuel savings that lead to economic benefits and reduction in CO2 emissions.
An experimental study for an inverted trickle solar still was performed. The still was basically composed of an inclined absorber plate painted black on the top. Saline water flowed at the backside ...of the plate and was kept attached to the plate. The water flow rate was kept low so that its temperature was raised to produce vapor. Condensation took place in another compartment where a heat exchanger was placed to provide heat recovery. The still was tested using brackish water of 6000 ppm salinity during the month of November at 47° and 32° tilt angles. The condensate obtained was 2.8 and 2 L/d at the above angles, respectively. This represents an 18% increase in this kind of output over previous work, which is due to reduction in the salinity of feed water. However, the intermediate header production, which is saline water of reduced salinity (3600 ppm), was also reduced by 13%. A computer simulation program was developed to predict the performance of the still.
This paper addressees the technical and economic feasibility of using an integrated solar powered desalination system under the United Arab Emirates (UAE) weather conditions. The proposed system ...consists of the parabolic trough concentrator (PTC) as an evaporation unit and shell and tube heat exchanger as condensation unit. In this paper, the thermal model was derived for the PTC to predict the steam productivity. Also the heat exchanger was designed using HTRI Xchanger software. The performance of the system was simulated for typical summer and winter days in June and January, respectively. The daily fresh water productivity was estimated in June to be 214.5 kg/day and was 140.0 kg/day in January. A preheating effect was implemented to increase the fresh water productivity, due to which the fresh water productivity increased by 7.14% and 8.50% for the selected days in June and January respectively. Furthermore, a flushing mechanism was designed and implemented on the system to eliminate the salt accumulation in the absorber tube which proved to be efficient in maintaining the optimum productivity of the system. Finally, the feasibility study was conducted which showed that the payback period of the proposed system is about 6 years based on PTC area of 60m 2 .
