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The proposed system uses the thermal energy storage characteristic of the solar pond to power a multi-effect desalination (MED) process with a total fresh water production of approximately 14,000 m3 annually. Pressure retarded osmosis (PRO) alongside photo-assisted chloralkali reactor are employed to utilize the brine rejected from the desalination process. The inclusion of PRO is proposed to take advantage of the salinity difference that occurs as a result of the preparation of the solar pond and desalination process. The quest for zero salt discharge in the proposed energy system configuration is undertaken through the introduction of a photo-assisted chloralkali reactor, which is conducted utilizing the power generated from PRO, and solar pond storage arrangement. This solar pond and desalination coupling system will achieve independence from conventional energy sources, which will lead to a significant contribution to the reduction of greenhouse gas emissions caused by fossil-fuel driven desalination. At solar irradiation of 600 W/m2, the overall energy and exergy efficiencies can reach 16.4% and 1.4%, respectively. The annual average overall energy efficiency of 11.4% is achieved utilizing the integrated system, whereas the average overall exergy efficiency is about 0.9%. Parametric studies are performed to examine the impacts of ambient conditions, irradiance, solar pond geometry, brine salinity, and the total number of MED effects on the performance of the overall integrated system. In addition to the sensitivity analysis, the potential to improve overall energy and exergy efficiencies and fresh water production of the proposed system is demonstrated.

This study experimentally investigates the effectiveness of various PV cleaning techniques for potential retrofitting into unmanned aerial vehicles, drones, for large-scale solar power plant cleaning operations in desert climates. The ultimate objective of this study is to improve the efficiency, reduce the cost, time and environmental impact of cleaning techniques by integrating them with autonomous drone cleaning to ensure cost-effectiveness and competitiveness of Solar PV installations. This study considers the following factors: (i) cleaning effectiveness (power output change in W and %), (ii) frequency of cleaning (daily, weekly, and monthly), (iii) overall cost of cleaning (USD/m2), (iv) adaptability to drone, (v) energy consumption, and (vi) weight. The cleaning techniques tested for their effectiveness and overall cost are (1) cloth wipers, (2) brushes, (3) vacuum cleaners, and (4) some combinations. Cleaning frequency is varied from 1-day to 1-month intervals to find the optimal cleaning period. The results of this study show that there is a significant reduction in the PV efficiency, and hence an increase in the cost of produced electricity, for monthly cleaning periods regardless of cleaning technique in desert climate conditions. The microfiber based-cloth wiper is found to be the optimum method from both cost and performance point of view. Microfiber based-cloth wiper achieved on average 7.7% and 3.1% performance improvement (compared to control panel) for weekly cleaning frequency in winter and summer seasons, respectively. The assessment of drone retrofitting was also conducted, which resulted that the brush and microfiber based-cloth wiper with their low weight, small size, and ease of use are best-suited options for drone-based solar panel cleaning. The evaluation factors for microfiber based-cloth wiper are found to be (i) 3.1% for cleaning effectiveness in summer, (ii) 1 week for frequency of cleaning, (iii) 0.41 USD/m2 for overall cost of cleaning, (iv) 9.5 (out of 10) for adaptability to drone, (v) 10 (out of 10) for energy consumption and (vi) 9 (out of 10) for weight.

In this study, a novel approach for energy and exergy analyses of a photovoltaic (PV) cell is presented, and the exergy destructions within the relevant optical, thermal and electrical processes are quantified. The present study uses a holistic approach to cover all processes and their interactions inside a PV cell; such as photonic: photons transmission, reflection and spectral absorption, background (blackbody) radiation emission at cell temperature; electrical: electron excitation to create a photocurrent, electron-hole recombination, electrical power transmission to an external load; and thermal: internal heat generation by shunt and series resistances, and heat dissipation by conduction-convection. A physical model which considers the highly complex interaction and interdependence among these processes is introduced based on energy and exergy balances completed by writing various constitutive equations, including correlations for the convective heat transfer coefficient and the photocurrent dependence of the spectral distribution of the quantum efficiency. The irreversibilities caused by the processes are assessed in terms of their relative magnitudes of the exergy destructions. The largest exergy destruction occurs in PV generator-photo current generation process followed by wafer-light absorption process. The overall energy and exergy efficiencies are then determined based on the novel model for seven different atmospheric and ecological conditions. The lowest and highest exergy efficiencies of the PV cell are calculated as 9.3% and 14% for two sample locations as Oshawa in Canada and Emirdag in Turkey, respectively. Furthermore, the effects of varying ambient conditions, light spectrum, wind velocity and solar intensity on the PV cell performance are investigated for comparative evaluations.

In this study, a combined system for syngas, bitumen, hydrogen and electricity production is developed and analyzed. The proposed system consists of steam assisted gravity drainage (SAGD), underground coal gasification (UCG), solid oxide fuel cell (SOFC), integrated gasification combined cycle (IGCC) and an electrolyser. The present system offers significant practical advantages for the regions, containing both coal and oil reserves such as Alberta region. Coal, as an alternative to natural gas for generating steam, is gasified using high temperature and pressurized steam in underground cavity. The produced syngas is utilized in both IGCC and SOFC systems. By using the excess steam in IGCC, SAGD process is run, and bitumen is extracted as in-situ extraction. In addition, a part of generated power is used in an electrolyser to produce hydrogen. The present system is analyzed in terms of energy and exergy methodologies to assess the performance of the cycles. Additionally, the effects of various system parameters, such as ambient temperature and pressure, syngas temperature, coal and syngas lower heating values, air and steam injection rates on energy and exergy efficiencies of the subsystems and overall system are evaluated. The energy and exergy efficiencies of the overall system are calculated as 19.6% and 17.3%, respectively.

Sustainable development and effective management of resources has become an integral need of future energy systems. This study considers a unique multi-generation system involving ammonia synthesis using electrolytically produced hydrogen from desalinated water, alongside supply of basic utilities like potable water, heating, cooling, and electricity. The integrated system employs a phase change material based-energy storage unit to provide uninterrupted energy supply to the system. Energy and exergy analysis of the overall and sub-systems based on the first and second law of thermodynamics reveal valuable insights into the performance of such a system. A rigorous analysis of external parameters including environmental temperature, direct normal irradiance on the overall and component energy/exergy efficiencies is performed. The analysis reveals that the utilities demand of a remote area can be met in a more sustainable and environmentally friendly manner using the proposed multi-generation system. An overall system exergy and energy efficiencies of 18.9% and 28.0% respectively are obtained, whereas the sub-systems are also found to have energy efficiencies ranging between 15 and 80%. The highest exergy destruction rates of 25 megawatts and 32 megawatts are observed for the multi-stage flash distillation and the steam Rankine cycle sub-systems respectively. An elementary environmental impact assessment of the same system reveals that the proposed system can help reduce the carbon footprint by almost 60% with no significant compromise on the overall exergy and energy efficiencies.