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CONTENTS
Volume 8, Number 1, March 2022
 


Abstract
The application of Photovoltaic (PV) power in the building sector, is expanding as part of the ongoing energy transition into renewables. The article addresses the question of sustainability of energy generated from PVs through an environmental assessment of a building-integrated PV system (BIPV) connected to the grid through net metering. Employing retrospective life cycle analysis (LCA), with the CCaLC2 software and ecoinvent data, the article shows that the carrying structure and other balance of system (BOS) components are responsible for a three times higher energy payback time than the literature average. However, total environmental impact can be lowered through reuse or reinstallation of PVs on the same building structure after the 30-year interval. Further ways to improve environmental efficiency include identifying the most polluting materials for each LCA parameter. The results of this study are of interest to researchers and producers of PVs and organizations investing and promoting decentralized power production through PVs.

Key Words
building-integrated photovoltaic systems; life cycle analysis; CO2 emissions; EPBT; sustainability

Address
Demetrios N. Papadopoulos, Constantinos N. Antonopoulos and Vagelis G. Papadakis: Department of Environmental Engineering, School of Engineering,University of Patras, Seferi Str 2, 30100, Agrinio, Greece


Abstract
In this study, the first law of thermodynamics was used to establish a one-dimensional (1-D) thermal model for parabolic trough receiver (PTR) taking into account the pressure drop and kinetic energy loss effects of the heat transfer fluid (HTF) flowing inside the absorber tube. The validation of the thermal model with data from the SEGS-LS2 solar collector-test showed a good agreement, which is consistent with the previously established models for the conventional straight and smooth (CSS) receiver where the effects of pressure drop and kinetic energy loss were neglected. Based on the developed model and code, a comparative study of the newly designed parabolic trough Scurved receiver versus the CSS receiver was conducted and solar unit's performances were analyzed. Without any supplementary devices, the S-curved receiver enhances the performance of the parabolic trough module, with a maximum of 0.16% compared to CSS receiver with the same sizes and mass flow rates. Thermal losses were reduced by 7% due to the decrease in the temperature of the outer surface of the receiver tube. In addition, it has been shown that from a mass flow rate of 9.5 kg/s the heat losses of the S-curved receiver remain unchanged despite the improvement in the heat transfer rate.

Key Words
1-D thermal model; conventional straight receiver; kinetic energy loss; pressure drop; S-curved receiver

Address
Yassine Demagh: LESEI, Mechanical Department, University of Batna 2, 05000 Batna, Algeria

Abstract
Electrochemical double-layer capacitors (EDLCs) based on solid polymer electrolytes (SPEs) have gained an immense recognition in the present world due to their unique properties. This study is about preparing and characterizing EDLCs using a natural rubber (NR) based SPE with natural graphite (NG) electrodes. NR electrolyte was consisted with 49% methyl grafted natural rubber (MG49) and zinc trifluoromethanesulfonate ((Zn(CF3SO3)2-ZnTF). It was characterized using electrochemical impedance spectroscopy (EIS) test, dc polarization test and linear sweep voltammetry (LSV) test. NG electrodes were made using a slurry of NG and acetone. EIS test, cyclic voltammetry (CV) test and galvanostatic charge discharge (GCD) test have been done to characterize the EDLC. Optimized electrolyte composition with NR: 0.6 ZnTF (weight basis) exhibited a conductivity of 0.6 x 10-4 Scm-1 at room temperature. Conductivity was predominantly due to ions. The electrochemical stability window was found to be from 0.25 V to 2.500 V. Electrolyte was sandwiched between two identical NG electrodes to fabricate an EDLC. Single electrode specific capacitance was about 2.26 Fg-1 whereas the single electrode discharge capacitance was about 1.17 Fg-1. The EDLC with this novel NR-ZnTF based SPE evidences its suitability to be used for different applications with further improvement.

Key Words
electrochemical double-layer capacitors; natural graphite; natural rubber; single electrode specific capacitance; solid polymer electrolytes

Address
Nanditha Rajapaksha, Kumudu S. Perera and Kamal P. Vidanapathirana: Polymer Electronics Research Group, Department of Electronics, Wayamba University of Sri Lanka, Kuliyapitiya, Sri Lanka

Abstract
Increasing cost of electricity due to rising price of fuel is one of the local community's main issues. In this research, switching of grid dependent system to the grid-tied Photovoltaic (PV) system with net metering for a residential building is proposed. The system is designed by considering the maximum energy demand of the building. The designed system is analyzed using RETScreen on technical, economic and environmental grounds. It is found that the system is able to produce 12,000 kWh/year. The system is capable to fulfill the electricity demand of the building during day time and is also capable to sell the energy to the local grid causing the electric meter to run in reverse direction. During night time, electricity will be purchased from grid, and electric meter will run in the forward direction. The system is economically justified with a payback period of only 3 years with net present value of PKR. 4,758,132. Also, the system is able to reduce 7.2 tons of CO2 not produced in the entire life of the project.

Key Words
economic analysis; grid-tied PV system; residential building; RETScreen

Address
Asad A. Naqvi, Talha Bin Nadeem, Ahsan Ahmed, Muhammad Uzair: Department of Mechanical Engineering, NED University of Engineering and Technology, Karachi, Pakistan
S. Asad Ali Zaidi: School of Computing Engineering and Digital Technology, Teeside University, Middlesbrough, Tees Valley, UK

Abstract
Focus on climate change and extreme weather conditions has received considerable attention in recent years. Civil engineers are now focusing on designing buildings that are more eco-friendly in the face of climate change. This paper describes the research conducted to assess the impact of future climate change on energy usage and carbon emissions in a typical supermarket at multiple locations across the UK. Locations that were included in the study were London, Manchester, and Southampton. These three cities were compared against their building performance based on their respective climatic conditions. Based on the UK Climatic Projections (UKCP09), a series of energy modelling simulations which were provided by the Chartered Institute of Building Service Engineers (CIBSE) were conducted on future weather years for this investigation. This investigation ascertains and quantifies the annual energy consumption, carbon emissions, cooling, and heating demand of the selected supermarkets at the three locations under various climatic projections and emission scenarios, which further validates annual temperature rise as a result of climatic variation. The data showed a trend of increasing variations across the UK as one moves southwards, with London and Southampton at the higher side of the spectrum followed by Manchester which has the least variability amongst these three cities. This is the first study which investigates impact of the climate change on the UK supermarkets across different regions by using the real case scenarios.

Key Words
building simulation; climate change; energy performance; future weather; sustainability

Address
(1) Agha Usama Hasan, Ali Bahadori-Jahromi:
Department of Civil Engineering and Built Environment, School of Computing and Engineering, University of West London, W5 5RF, London, UK;
(2) Anastasia Mylona:
Research Department, The Chartered Institution of Building Services Engineers (CIBSE), SW12 9BS, London, UK;
(3) Marco Ferri:
LIDL Great Britain Ltd., 19 Worple Road, SW19 4JS, London, UK;
(4) Hexin Zhang:
School of Engineering and the Built Environment, Edinburgh Napier University, 10 Clinton Road, Edinburgh Scotland, EH10 5DT, UK.


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