Browsing by Author "Asfand, Faisal"
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Item Open Access Data for: Thermo-economic Analysis, Optimisation and Systematic Integration of Supercritical Carbon Dioxide Cycle with Sensible Heat Thermal Energy Storage for CSP Application(Cranfield University, 2021-08-12 14:18) Thanganadar, Dhinesh; Fornarelli, Francesco; Camporeale, Sergio; Asfand, Faisal; Gillard, Jonathon; Patchigolla, KumarUnderlying data for the paper "Thermo-economic Analysis, Optimisation and Systematic Integration of Supercritical Carbon Dioxide Cycle with Sensible Heat Thermal Energy Storage for CSP Application"Item Open Access Design optimization of supercritical carbon dioxide (s-CO2) cycles for waste heat recovery from marine engines(American Society of Mechanical Engineers, 2021-01-29) Hossain, Md. J.; Chowdhury, Jahedul Islam; Balta-Ozkan, Nazmiye; Asfand, Faisal; Saadon, Syamimi; Imran, MohammadThe global climate change challenge and the international commitment to reduce carbon emission can be addressed by improving energy conversion efficiency and adopting efficient waste heat recovery technologies. Supercritical carbon dioxide (s-CO2) cycles that offer a compact footprint and higher cycle efficiency are investigated in this study to utilize the waste heat of the exhaust gas from a marine diesel engine (Wärtsilä-18V50DF, 17.55 MW). Steady-state models of basic, recuperated and reheated s-CO2 Brayton cycles are developed and optimised for net work and thermal efficiency in Aspen Plus to simulate and compare their performances. Results show that the reheated cycle performs marginally better than the recuperated cycle accounting for the highest optimised net-work and thermal efficiency. For the reheated and recuperated cycle, the optimized net-work ranges from 648–2860 kW and 628–2852 kW respectively, while optimized thermal efficiency ranges are 15.2–36.3% and 14.8–35.6% respectively. Besides, an energy efficiency improvement of 6.3% is achievable when the engine is integrated with an s-CO2 waste heat recovery system which is operated by flue gas with a temperature of 373 °C and mass flow rate of 28.2 kg/s, compared to the engine without a heat recovery system.Item Open Access Energetic, exergetic and environmental (3E) analyses of different cooling technologies (wet, dry and hybrid) in a CSP thermal power plant(Elsevier, 2021-10-08) Cutillas, C. G.; Ruiz, J.; Asfand, Faisal; Patchigolla, Kumar; Lucas, M.This paper deals with the comparison of three condensation systems for the heat dissipation in a solar power plant: wet system, dry system and hybrid system based on the pre-cooling of the air in an adiabatic panel located in the entrance section of a dry system. Energy, exergy and environmental (3E) analyses were conducted to assess the influence of the condensation system on the power plant performance. The Andasol I plant located in Granada (Spain), with a net power capacity of 50 MWe, is used as a real reference case of a concentrated solar power station. The cycle refrigerated with a cooling tower achieves a lower pressure of condensation, followed by the hybrid and dry system. As the pressure decreases, the efficiency of the cycle increases and also the power generated, being 12.60% in the case of cooling tower and 4.65% in the hybrid system with respect the dry condenser. A 71.74% of water usage savings by the hybrid system carries a 7.06% of net power production with regard of the cooling tower configuration. The exergetic performance of the plant is 73.77% for the wet system, 69.21% for the hybrid and 68.46% for the dry system.Item Open Access Experimental assessment of a pilot scale hybrid cooling system for water consumption reduction in CSP plants(Elsevier, 2021-12-22) Palenzuela, Patricia; Roca, Lidia; Asfand, Faisal; Patchigolla, KumarThe new challenge of the European Commission is to limit water consumption in Concentrating Solar Power (CSP) plants, especially significant in the cooling process. Hybrid cooling systems are presented as a potential solution to achieve water consumption reduction since they also avoid a high penalty of efficiency loss in the power block. In this work, a hybrid cooling pilot plant installed at Plataforma Solar de Almería is evaluated experimentally. The system has been tested under different ambient and operating conditions to analyze their influence on the water and electricity consumption. The results reveal that significant water savings were achieved in comparison with the conventional only-wet configuration. Concretely, a maximum water consumption saving of 67% was found at high ambient temperatures (between 25 and 30 °C) and for a thermal load of 80% when a hybrid configuration was used. The optimal operating strategies that achieve a tradeoff between low water and electricity consumption have been identified by two efficiency indexes: the specific electricity and water consumption. The parallel configuration was the optimal one in most of the cases. At high ambient temperatures and 80% thermal load, the electricity and water consumptions of this configuration were 0.033 kWe/kWth and 0.071 L/kWth, respectively.Item Open Access Off-design and annual performance analysis of supercritical carbon dioxide cycle with thermal storage for CSP application(Elsevier, 2020-11-18) Thanganadar, Dhinesh; Fornarelli, Francesco; Camporeale, Sergio; Asfand, Faisal; Patchigolla, KumarSupercritical Carbon Dioxide (sCO2) cycles can achieve higher efficiency compared to steam-Rankine or Air-Brayton cycles, therefore they are promising for concentrated solar power applications. Although sCO2 cycles show higher design efficiency, the off-design efficiency is highly sensitive to the ambient conditions, impacting the power block net-power and heat input. In the present work a recompression sCO2 cycle is connected to a central-tower solar field with two-tank thermal storage delivering molten chloride salt at 670 °C. The temperature of the molten-salt exiting from the power block and returning to the cold storage tank increases by 46 °C with respect to the design value when the compressor inlet temperature is raised by 13 °C relative to the design condition of 42 °C, which implies that the capacity of the thermal storage reduces by 25%. The main focus of this work is to investigate the off-design performance of a sCO2 recompression cycle under variable ambient temperature, molten-salt inlet temperature and molten-salt flow rate. Multi-objective optimisation is carried-out in off-design conditions using an in-house code to explore the optimal operational strategies and the Pareto fronts were compared. Since the power cycle can either be operated in maximum power mode or maximum efficiency mode, this study compares these two operational strategies based on their annual performance. Results indicate that the capacity factor of the concentrated solar power can be increased by 10.8% when operating in maximum power mode whilst the number of start-ups is reduced by about 50% when operating in maximum efficiency mode.Item Open Access Performance analysis of indirect sCO₂ cycle integrated with different heat sources and thermal energy storage.(2020-09) Thanganadar, Dhinesh; Patchigolla, Kumar; Asfand, FaisalIncreasing the efficiency of the power conversion cycles are crucial in order to reducing global carbon emission. Supercritical carbon dioxide (sCO₂) cycles can achieve higher efficiency than steam Rankine cycle at higher turbine inlet temperatures (>550 °C) with a compact plant footprint (up to tenfold). This PhD study focused on investigating the thermodynamic performance of sCO₂ cycle configurations for three different heat sources: coal-fired, natural gas and concentrated solar power (CSP) plants. The proposed configurations have not only increased the efficiency compared with the state-of-the-art power cycle but also shows cost reduction potential for some heat sources. ❖ For natural gas based combined cycle power plant, the efficiency of the novel sCO₂ cascade cycle has increased by 1.4%pts compared to a triple-pressure steam Rankine cycle (base case efficiency is 58.4% LHV) for a commercial SGT5-4000F gas turbine. The CO₂ emission is reduced by 26,774 tons/year (2.3%). ❖ The proposed novel sCO2 cycle configuration increases the efficiency of coal-fired power plant has increased by 3-4%pts compared to the state-of-the-art NETL baseline steam Rankine cycle (B12A efficiency is 40.7% HHV). This corresponds to a reduction of 6-8% in the cost of electricity, however, this falls within the uncertainty range of the equipment cost functions. The increased efficiency reduces the CO₂ emission by 204,031 tons/year (6.4% reduction). ❖ For a concentrated solar power plant, the sCO2 cycle efficiency is increased by 3.8-7%pts compared to steam Rankine cycles and the novel proposed cycle can reduce the capital cost up to 10.8% compared to the state-of-the-art sCO₂ recompression cycle, which is equivalent to a reduction of about 12-26% compared with the steam Rankine cycle. The performance of sCO2 cycle is more sensitive to the variations in ambient temperature. In a CSP plant, operating the plant at high ambient temperatures, not only penalises the performance of the sCO₂ cycle (i.e., net power output and efficiency), but also the sensible heat storage capacity. For instance, the storage capacity reduces by 25% for a 13 °C increase of the ambient temperature from its design value (i.e., 42°C) when maximising the power cycle efficiency. Therefore, these effect on the levelised cost of electricity is investigated in detail, which guides the effect of different plant operating modes. The transient heat exchanger model informs that the first-order characteristic time of the recuperators is faster (20-90 secs) when using compact heat exchangers,indicating the potential of fast load ramping.Item Open Access Techno-economic analysis of supercritical carbon dioxide cycle integrated with coal-fired power plant(Elsevier, 2021-05-30) Thanganadar, Dhinesh; Asfand, Faisal; Patchigolla, Kumar; Turner, Peter J.Supercritical carbon dioxide (sCO2) cycles can achieve higher efficiencies than an equivalent steam Rankine cycle at higher turbine inlet temperatures (>550 °C) with a compact footprint (tenfold). sCO2 cycles are low-pressure ratio cycles (~4–7), therefore recuperation is necessary, which reduces the heat-addition temperature range. Integration of sCO2 cycles with the boiler requires careful management of low-temperature heat to achieve higher plant efficiency. This study analyses four novel sCO2 cycle configurations which capture the low-temperature heat in an efficient way and the performance is benchmarked against the state-of-the-art steam Rankine cycle. The process parameters (13–16 variables) of all the cycle configurations are optimised using a genetic algorithm for two different turbine inlet temperatures (620 °C and 760 °C) and their techno-economic performance are compared against the advanced ultra-supercritical steam Rankine cycle. A sCO2 power cycle can achieve a higher efficiency than a steam Rankine cycle by about 3–4% points, which is correspond to a plant level efficiency of 2–3% points, leading to cost of electricity (COE) reduction. Although the cycle efficiency has increased when increasing turbine inlet temperature from 620 °C to 760 °C, the COE does not notably reduce owing to the increased capital cost. A detailed sensitivity study is performed for variations in compressor and turbine isentropic efficiency, pressure drop, recuperator approach temperature and capacity factor. The Monte-Carlo analysis shows that the COE can be reduced up to 6–8% compared to steam Rankine cycle, however, the uncertainty of the sCO2 cycle cost functions can diminish this to 0–3% at 95% percentile cumulative probability.Item Open Access Thermal performance and economic analysis of supercritical carbon dioxide cycles in combined cycle power plant(Elsevier, 2019-09-13) Thanganadar, Dhinesh; Asfand, Faisal; Patchigolla, KumarA closed-loop, indirect, supercritical Carbon Dioxide (sCO2) power cycle is attractive for fossil-fuel, solar thermal and nuclear applications owing to its ability to achieve higher efficiency, and compactness. Commercial Gas Turbines (GT’s) are optimised to yield maximum performance with a conventional steam Rankine cycle. In order to explore the full potential of a sCO2 cycle the whole plant performance needs to be considered. This study analyses the maximum performance and cost of electricity for five sCO2 cascaded cycles. The plant performance is improved when the GT pressure ratio is considered as a design variable to a GT to optimise the whole plant performance. Results also indicate that each sCO2 Brayton cycle considered, attained maximum plant efficiency at a different GT pressure ratio. The optimum GT pressure ratio to realise the maximum cost reduction in sCO2 cycle was higher than the equivalent steam Rankine cycle. Performance maps were developed for four high efficient cascaded sCO2 cycles to estimate the specific power and net efficiency as a function of GT turbine inlet temperature and pressure ratio. The result of multi-objective optimisation in the thermal and cost (c$/kWh) domains and the Pareto fronts of the different sCO2 cycles are presented and compared. A novel sCO2 cycle configuration is proposed that provides ideal-temperature glide at the bottoming cycle heat exchangers and the efficiency of this cycle, integrated with a commercial SGT5-4000F machine in lieu of a triple-pressure steam Rankine cycle, is higher by 1.4 percentage point.Item Open Access Thermo-economic analysis, optimisation and systematic integration of supercritical carbon dioxide cycle with sensible heat thermal energy storage for CSP application(Elsevier, 2021-08-16) Thanganadar, Dhinesh; Fornarelli, Francesco; Camporeale, Sergio; Asfand, Faisal; Gillard, Jonathon; Patchigolla, KumarIntegration of thermal energy storage with concentrated solar power (CSP) plant aids in smoothing of the variable energy generation from renewable sources. Supercritical carbon dioxide (sCO2) cycles can reduce the levelised cost of electricity of a CSP plant through its higher efficiency and compact footprint compared to steam-Rankine cycles. This study systematically integrates nine sCO2 cycles including two novel configurations for CSP applications with a two-tank sensible heat storage system using a multi-objective optimisation. The performance of the sCO2 cycles is benchmarked against the thermal performance requirement of an ideal power cycle to reduce the plant overnight capital cost. The impacts of the compressor inlet temperature (CIT) and maximum turbine inlet temperature (TIT) on the cycle selection criteria are discussed. The influence of the cost function uncertainty on the selection of the optimal cycle is analysed using Monte-Carlo simulation. One of the novel cycle configurations (C8) proposed can reduce the overnight capital cost by 10.8% in comparison to a recompression Brayton cycle (C3) for a CIT of 55°C and TIT of 700°C. This work describes design guidelines facilitating the development/ selection of an optimal cycle for a CSP application integrated with two-tank thermal storage.Item Open Access Thermodynamic performance and water consumption of hybrid cooling system configurations for concentrated solar power plants(MDPI, 2020-06-10) Asfand, Faisal; Palenzuela, Patricia; Roca, Lidia; Caron, Adèle; Lemarié, Charles-André; Gillard, Jon; Turner, Peter J.; Patchigolla, KumarThe use of wet cooling in Concentrated Solar Power (CSP) plants tends to be an unfavourable option in regions where water is scarce due to the high water requirements of the method. Dry-cooling systems allow a water consumption reduction of up to 80% but at the expense of lower electricity production. A hybrid cooling system (the combination of dry and wet cooling) offers the advantages of each process in terms of lower water consumption and higher electricity production. A model of a CSP plant which integrates a hybrid cooling system has been implemented in Thermoflex software. The water consumption and the net power generation have been evaluated for different configurations of the hybrid cooling system: series, parallel, series-parallel and parallel-series. It was found that the most favourable configuration in terms of water saving was series-parallel, in which a water reduction of up to 50% is possible compared to the only-wet cooling option, whereas an increase of 2.5% in the power generation is possible compared to the only-dry cooling option. The parallel configuration was the best in terms of power generation with an increase of 3.2% when compared with the only-dry cooling option, and a reduction of 30% water consumption compared to the only-wet cooling optionItem Open Access Underlying data for the paper "Off-design and Annual Performance Analysis of Supercritical Carbon Dioxide Cycle with Thermal Storage for CSP application "(Cranfield University, 2020-11-13 16:51) Thanganadar, Dhinesh; Fornarelli, Francesco; Camporeale, Sergio; Asfand, Faisal; Patchigolla, KumarUnderlying data for the journal paper "Off-design and Annual Performance Analysis of Supercritical Carbon Dioxide Cycle with Thermal Storage for CSP application "Item Open Access Underlying data for the paper "Thermal performance and economic analysis of supercritical Carbon Dioxide cycles in combined cycle power plant"(Cranfield University, 2019-09-09 10:17) Thanganadar, Dhinesh; Asfand, Faisal; Patchigolla, KumarUnderlying data for the journal paper 'Thermal performance and economic analysis of supercritical Carbon Dioxide cycles in combined cycle power plant.'Item Unknown Underlying data for the paper Techno-economic analysis of supercritical carbon dioxide cycle integrated with coal-fired power plant""(Cranfield University, 2021-05-26 14:31) Thanganadar, Dhinesh; Asfand, Faisal; Patchigolla, Kumar; Turner, PeterUnderlying data for the journal paper "Techno-economic analysis of supercritical carbon dioxide cycle integrated with coal-fired power plant"Item Unknown Waste heat recovery integration options for commercial bakeries in a thermo-economic-environmental perspective(Elsevier, 2023-11-11) Chowdhury, Jahedul Islam; Asfand, Faisal; Ja’fari, Mohammad; Mukherjee, Sanjay; Balta-Ozkan, NazmiyeIn commercial bakeries, a substantial amount of heat is exhausted which is not only a waste of useful resource, but also contributes to higher fuel consumption and carbon emissions, if not recovered. In this study, waste heat from a single oven is considered and five potential heat recovery options are investigated in a techno-economic-environmental perspective to provide essential results for integrating an appropriate technology for waste heat recovery in the commercial bakeries sector. Waste heat recovery options were selected considering the temperature profile, the waste heat source, quality and quantity of heat and the heat energy demand for the various processes in commercial bakeries. Thermodynamic, economic, and environmental models are developed to assess the heat recovery performance, cost savings and emission reduction at both design and off-design conditions. Results show that up to 286 kW of waste heat can be recovered and reused in the case of air pre-heater, which can save up to 161.93 t/year of natural gas and an equivalent cost and emission savings of $ 93,594/year and 412.5 tCO2e/year, respectively. Moreover, the earliest payback period of 0.77 years was estimated for the air pre-heater option with an estimated capital investment cost of $71,631, whereas a maximum payback period of 4.59 years was estimated for the electricity generation by the organic Rankine cycle having an estimated capital investment cost of $304,040. These results reveal that air preheating is the most energy-efficient and cost-effective option to recover the waste heat from the ovens in the bakery industry.