Kalina Cycle

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Yiping Dai - One of the best experts on this subject based on the ideXlab platform.

  • Comparative analysis on off-design performance of a novel parallel dual-pressure Kalina Cycle for low-grade heat utilization
    Energy Conversion and Management, 2021
    Co-Authors: Zheng Shaoxiong, Pan Zhao, Yiping Dai, Chen Kang, Gang Fan, Jiangfeng Wang
    Abstract:

    Abstract In this paper, a novel parallel dual-pressure Kalina Cycle system is presented to utilize the low-grade geothermal energy. In order to highlight the performance of the proposed Cycle, the comparison of parallel dual-pressure Kalina Cycle system and the basic Kalina Cycle system is conducted and set at the same boundary conditions. The maximal net power output of Cycle is considered as the single-objective function based on particle swarm optimization algorithm. The exergy analysis and economic cost for both Cycles are investigated at design conditions. Furthermore, as operating at off-design conditions, the variation ranges of geothermal energy mass flux and inlet temperature are 7.5–14 kg/s and 136–150 °C, respectively. The sliding pressure regulation strategy is applied to response to the variations of geothermal energy parameters. The two-levels evaporation pressures in the parallel dual-pressure Kalina Cycle are adjusted to remain the invariable temperature difference between geothermal energy inlet temperature of evaporators and the corresponding turbine inlet temperature. The results show that, at design conditions, the maximal net power output of parallel dual-pressure Kalina Cycle and basic Kalina Cycle is 329.62KW and 274.94KW, the corresponding exergy efficiency is 44.52% and 33.39%. Besides, the condenser contributes to the largest exergy destruction ratio in parallel dual-pressure Kalina Cycle and basic Kalina Cycle, which are 33.96% and 44.94% of overall exergy destruction, respectively. According to the off-design performance investigation, it is shown that the higher geothermal energy mass flux and inlet temperature are in favor of the larger net power output for both Cycles. The thermodynamic evaluation shows that the proposed parallel dual-pressure Kalina Cycle exhibits a more excellent performance in terms of net power output and exergy efficiency than basic Kalina Cycle.

  • a study of the optimal control approach for a Kalina Cycle system using a radial inflow turbine with variable nozzles at off design conditions
    Applied Thermal Engineering, 2019
    Co-Authors: Kang Chen, Yiping Dai
    Abstract:

    Abstract To maximize the exergy utilization efficiency of a Kalina Cycle system with an ammonia-water radial turbine at off-design conditions, this study proposes a novel control approach named optimal control approach. An off-design model for ammonia-water radial-inflow turbine using variable nozzles is constructed. The optimal control approach is realized by changing the outlet angle of the radial-inflow turbine nozzle and the turbine inlet pressure. Design parameters of heat source (waste hot water) are 130 °C and 10 kg/s. To find out the performance advantage for the novel control approach, it is compared with two traditional control approaches. The results show that the proposed novel control approach presents the highest exergy utilization efficiency and net power at off-design conditions. The net power ratio of the optimal control approach to the traditional sliding pressure control approach reaches 111.22% as the heat source mass flow rate declines to 5 kg/s. Compared with the traditional approach for constant pressure control (changing turbine nozzle outlet angle), the optimal control approach has a potential to produce 3.11% more net power. The exergy utilization efficiency is generally declined with the elevated heat source mass flow rate at the approach for optimal control, while the system thermal efficiency is slowly increased.

  • off design performance analysis of a power cooling cogeneration system combining a Kalina Cycle with an ejector refrigeration Cycle
    Energy, 2018
    Co-Authors: Yiping Dai
    Abstract:

    Abstract This paper conducts the off-design performance analysis of a novel power-cooling cogeneration system combining a Kalina Cycle and an ejector refrigeration Cycle for low-grade hot water. Five plate heat exchangers, a separator, an axial inflow turbine, two pumps, an ejector and two throttle valves are adopted. The ejector refrigeration Cycle using R134a is driven by the ammonia-poor solution from the separator. A novel method for predicting the off-design performance of the power-cooling cogeneration system is proposed. Variable hot water parameters, condensation temperature and evaporator temperature are analyzed by the sliding pressure operation approach. The results indicate that the system shows 619.74 kW net power and 71.28 kW cooling at design conditions. As the mass flow rate ratio or the inlet temperature of hot water increases, the net power, thermal efficiency and exergy efficiency increase, while the cooling and cooling exergy decrease. The exergy efficiency reaches the maximum of 39.82% at the saturated evaporator temperature of 6 °C. The cooling is more strongly affected by the hot water inlet temperature than the saturated condensation temperature, while the turbine efficiency, net power, thermal efficiency and exergy efficiency are more strongly affected by the saturated condensation temperature than the hot water inlet temperature.

  • exergoeconomic analysis and optimization of a supercritical co2 Cycle coupled with a Kalina Cycle
    Journal of Energy Engineering-asce, 2017
    Co-Authors: Mingkun Wang, Jianyong Wang, Yiping Dai
    Abstract:

    AbstractA novel combined Cycle system comprising of a supercritical CO2 (sCO2) Cycle and a Kalina Cycle is proposed in this paper. Exergoeconomic comparison between the combined sCO2/Kalina Cycle and the sCO2 Cycle is investigated. The exergoeconomic models are established, and detailed parametric analyses are conducted for both Cycles to reveal the influence of selected decision variables on Cycle performance based on the self-build thermodynamic simulation platform. Besides, the parameters of both systems are optimized utilizing the exergetic efficiency and total product unit cost as the objective functions through genetic algorithm (GA). The results reveal that there is an optimal main compressor pressure ratio, an evaporating pressure, and a Kalina turbine inlet temperature that contribute to better system performance. A lower pinch point temperature difference in evaporator and a higher ammonia water mass fraction are beneficial to operation. The nuclear reactor and the sCO2 turbine are the most and ...

  • off design performance analysis of Kalina Cycle for low temperature geothermal source
    Applied Thermal Engineering, 2016
    Co-Authors: Mingkun Wang, Yiping Dai
    Abstract:

    Abstract Low temperature geothermal sources with brilliant prospects have attracted more and more people’s attention. Kalina Cycle system using ammonia water as working fluid could exploit geothermal energy effectively. In this paper, the quantitative analysis of off-design performance of Kalina Cycle for the low temperature geothermal source is conducted. The off-design models including turbine, pump and heat exchangers are established preliminarily. Genetic algorithm is used to maximize the net power output and determine the thermodynamic parameters in the design phase. The sliding pressure control strategy applied widely in existing Rankine Cycle power plants is adopted to response to the variations of geothermal source mass flow rate ratio (70–120%), geothermal source temperature (116–128 °C) and heat sink temperature (0–35 °C). In the off-design research scopes, the guidance for pump rotational speed adjustment is listed to provide some reference for off-design operation of geothermal power plants. The required adjustment rate of pump rotational speed is more sensitive to per unit geothermal source temperature than per unit heat sink temperature. Influence of the heat sink variation is greater than that of the geothermal source variation on the ranges of net power output and thermal efficiency.

V Zare - One of the best experts on this subject based on the ideXlab platform.

  • employing thermoelectric generator for power generation enhancement in a Kalina Cycle driven by low grade geothermal energy
    Applied Thermal Engineering, 2018
    Co-Authors: V Zare, Vahid Palideh
    Abstract:

    Abstract The Kalina Cycle (KC) is one of the most promising options for power generation from renewable energy and low temperature heat sources such as geothermal energy. Also, employing thermoelectric generators (TEGs) is widely developed recently to convert heat into electricity directly. The possibility of employing thermoelectric generators to utilize the waste heat of a Kalina Cycle is investigated in the present paper. The proposed system performance is modeled, analyzed and compared with the conventional Kalina Cycle performance. To assess the systems’ performances, thermodynamic and economic models are developed and a parametric study is carried out. The results indicated an enhancement of around 7.3% for net output power and energy and exergy efficiencies for the proposed system as compared to the conventional Kalina Cycle, at a typical operating condition. In addition, an economic evaluation of integrating thermoelectric generators with the Kalina Cycle is conducted and the conditions are indicated under which the proposed system is profitable.

  • parabolic trough solar collectors integrated with a Kalina Cycle for high temperature applications energy exergy and economic analyses
    Energy Conversion and Management, 2017
    Co-Authors: V Zare, A Moalemian
    Abstract:

    Abstract As a promising option for future power generation is the concentrating solar power systems with various types, among which Parabolic Trough Solar Collectors (PTSC) are the most proven technology with lowest cost available today. Benefits of this renewable energy source are challenged by means of relatively low energy conversion efficiency. To overcome the dilemma, one approach is employing an efficient thermodynamic power Cycle in order to enhance the overall power plant efficiency. The Kalina Cycle (KC) is considered as an efficient alternative over the conventional or organic Rankine Cycles in last few years. In the present work, the integration of a novel configuration of the KC, which is proper for utilizing high temperature heat sources, with PTSC is proposed and analyzed. Thermal, thermodynamic and economic models are developed to investigate the integrated system performance from the viewpoints of energy, exergy and economics. The results indicate that, exergy efficiencies of around 64% is achievable for power Cycle unit while the overall power plant exergy efficiency reaches to around 14%. The results of economic analysis revealed that if a lower LCOE is to be reached increment of the number of collectors per row is more beneficial than the increment of parallel rows of the collectors.

  • a comparative thermodynamic analysis of two tri generation systems utilizing low grade geothermal energy
    Energy Conversion and Management, 2016
    Co-Authors: V Zare
    Abstract:

    Abstract A comparative thermodynamic analysis and optimization is presented for two different designs of geothermal energy-based tri-generation systems. The two considered systems are distinguished by their power generation units, as organic Rankine Cycle is employed in one system while Kalina Cycle is used in the other system. To provide cooling and heating loads, a LiBr/water absorption chiller and a water heater are coupled to the Organic Rankine and Kalina Cycles. To assess the systems’ performances, thermodynamic models are developed and a parametric study is carried out prior to the optimization with respect to the second law efficiency, as the objective function. Also, an exergy destruction modeling is conducted to identify the major sources of irreversibilities within the components of the considered systems. The Kalina Cycle-based system is found to be more efficient as its maximum second law efficiency is 50.36% while the organic Rankine Cycle-based system has a maximum second law efficiency of 46.51%. The results also indicate that, for a heat source temperature of 120 °C, the Kalina Cycle-based system can produce more power than the other system by around 12.2%, under the optimized conditions.

  • Exergoeconomic comparison of TLC (trilateral Rankine Cycle), ORC (organic Rankine Cycle) and Kalina Cycle using a low grade heat source
    Energy, 2015
    Co-Authors: Mortaza Yari, S.m. Seyed Mahmoudi, V Zare, Ali Saberi Mehr, Marc A. Rosen
    Abstract:

    Recently, the TLC (trilateral power Cycle) has attracted significant interest as it provides better matching between the temperature profiles in the evaporator compared to conventional power Cycles. This article investigates the performance of this Cycle and compares it with those for the ORC (organic Rankine Cycle) and the Kalina Cycle, from the viewpoints of thermodynamics and thermoeconomics. A low-grade heat source with a temperature of 120 °C is considered for all the three systems. Parametric studies are performed for the systems for several working fluids in the ORC and TLC. The systems are then optimized for either maximum net output power or minimum product cost, using the EES (engineering equation solver) software. The results for the TLC indicate that an increase in the expander inlet temperature leads to an increase in net output power and a decrease in product cost for this power plant, whereas this is not the case for the ORC system. It is found that, although the TLC can achieve a higher net output power compared with the ORC and Kalina (KCS11 (Kalina Cycle system 11)) systems, its product cost is greatly affected by the expander isentropic efficiency. It is also revealed that using n-butane as the working fluid can result in the lowest product cost in the ORC and the TLC. In addition, it is observed that, for both the ORC and Kalina systems, the optimum operating condition for maximum net output power differs from that for minimum product cost.

  • on the exergoeconomic assessment of employing Kalina Cycle for gt mhr waste heat utilization
    Energy Conversion and Management, 2015
    Co-Authors: V Zare, S M S Mahmoudi, Mortaza Yari
    Abstract:

    Abstract Exergoeconomic concept is applied to compare the performance of the Gas Turbine-Modular Helium Reactor (GT-MHR) plant with a proposed combined GT-MHR/Kalina Cycle in which the waste heat from the GT-MHR is recovered by the Kalina Cycle for power generation. Thermodynamic and exergoeconomic models are developed to investigate the Cycles’ performance and assess the unit cost of the products. A sensitivity analysis is performed prior to the optimization of the Cycles’ performances from the view points of thermodynamics and economics. The results indicate that, when the performances of the two Cycles are optimized economically, the efficiency and total product unit cost of the combined Cycle is 8.2% higher and 8.8% lower than the corresponding values for the GT-MHR. It is interesting to note that, under these conditions, the total investment cost rate for the combined Cycle is just slightly higher than that of the stand alone GT-MHR.

Fredrik Haglind - One of the best experts on this subject based on the ideXlab platform.

  • thermoeconomic optimization of a Kalina Cycle for a central receiver concentrating solar power plant
    Energy Conversion and Management, 2016
    Co-Authors: Anish Modi, Martin Ryhl Kae, Jesper Graa Andrease, Fredrik Haglind
    Abstract:

    Abstract Concentrating solar power plants use a number of reflecting mirrors to focus and convert the incident solar energy to heat, and a power Cycle to convert this heat into electricity. This paper evaluates the use of a high temperature Kalina Cycle for a central receiver concentrating solar power plant with direct vapour generation and without storage. The use of the ammonia-water mixture as the power Cycle working fluid with non-isothermal evaporation and condensation presents the potential to improve the overall performance of the plant. This however comes at a price of requiring larger heat exchangers because of lower thermal pinch and heat transfer degradation for mixtures as compared with using a pure fluid in a conventional steam Rankine Cycle, and the necessity to use a complex Cycle arrangement. Most of the previous studies on the Kalina Cycle focused solely on the thermodynamic aspects of the Cycle, thereby comparing Cycles which require different investment costs. In this study, the economic aspect and the part-load performance are also considered for a thorough evaluation of the Kalina Cycle. A thermoeconomic optimization was performed by minimizing the levelized cost of electricity. The different Kalina Cycle simulations resulted in the levelized costs of electricity between 212.2 $ MWh −1 and 218.9 $ MWh −1 . For a plant of same rated capacity, the state-of-the-art steam Rankine Cycle has a levelized cost of electricity of 181.0 $ MWh −1 . Therefore, when considering both the thermodynamic and the economic perspectives, the results suggest that it is not beneficial to use the Kalina Cycle for high temperature concentrating solar power plants.

  • thermodynamic optimisation and analysis of four Kalina Cycle layouts for high temperature applications
    Applied Thermal Engineering, 2015
    Co-Authors: Anish Modi, Fredrik Haglind
    Abstract:

    Abstract The Kalina Cycle has seen increased interest in the last few years as an efficient alternative to the conventional steam Rankine Cycle. However, the available literature gives little information on the algorithms to solve or optimise this inherently complex Cycle. This paper presents a detailed approach to solve and optimise a Kalina Cycle for high temperature (a turbine inlet temperature of 500 °C) and high pressure (over 100 bar) applications using a computationally efficient solution algorithm. A central receiver solar thermal power plant with direct steam generation was considered as a case study. Four different layouts for the Kalina Cycle based on the number and/or placement of the recuperators in the Cycle were optimised and compared based on performance parameters such as the Cycle efficiency and the cooling water requirement. The Cycles were modelled in steady state and optimised with the maximisation of the Cycle efficiency as the objective function. It is observed that the different Cycle layouts result in different regions for the optimal value of the turbine inlet ammonia mass fraction. Out of the four compared layouts, the most complex layout KC1234 gives the highest efficiency. The cooling water requirement is closely related to the Cycle efficiency, i.e., the better the efficiency, the lower is the cooling water requirement.

  • Part-load performance of a high temperature Kalina Cycle
    Energy Conversion and Management, 2015
    Co-Authors: Anish Modi, Jesper Graa Andreasen, Martin Ryhl Kærn, Fredrik Haglind
    Abstract:

    Abstract The Kalina Cycle has recently seen increased interest as an alternative to the conventional steam Rankine Cycle. The Cycle has been studied for use with both low and high temperature applications such as geothermal power plants, ocean thermal energy conversion, waste heat recovery, gas turbine bottoming Cycle, and solar power plants. The high temperature Cycle layouts are inherently more complex than the low temperature layouts due to the presence of a distillation-condensation subsystem, three pressure levels, and several heat exchangers. This paper presents a detailed approach to solve the Kalina Cycle in part-load operating conditions for high temperature (a turbine inlet temperature of 500 °C) and high pressure (100 bar) applications. A central receiver concentrating solar power plant with direct vapour generation is considered as a case study where the part-load conditions are simulated by changing the solar heat input to the receiver. Compared with the steam Rankine Cycle, the Kalina Cycle has an additional degree of freedom in terms of the ammonia mass fraction which can be varied in order to maximize the part-load efficiency of the Cycle. The results include the part-load curves for various turbine inlet ammonia mass fractions and the fitted equations for these curves.

  • performance analysis of a Kalina Cycle for a central receiver solar thermal power plant with direct steam generation
    Applied Thermal Engineering, 2014
    Co-Authors: Anish Modi, Fredrik Haglind
    Abstract:

    Abstract Solar thermal power plants have attracted increasing interest in the past few years – with respect to both the design of the various plant components, and extending the operation hours by employing different types of storage systems. One approach to improve the overall plant efficiency is to use direct steam generation with water/steam as both the heat transfer fluid in the solar receivers and the Cycle working fluid. This enables operating the plant with higher turbine inlet temperatures. Available literature suggests that it is feasible to use ammonia-water mixtures at high temperatures without corroding the equipment by using suitable additives with the mixture. The purpose of the study reported here was to investigate if there is any benefit of using a Kalina Cycle for a direct steam generation, central receiver solar thermal power plant with high live steam temperature (450 °C) and pressure (over 100 bar). Thermodynamic performance of the Kalina Cycle in terms of the plant exergy efficiency was evaluated and compared with a simple Rankine Cycle. The rates of exergy destruction for the different components in the two Cycles were also calculated and compared. The results suggest that the simple Rankine Cycle exhibits better performance than the Kalina Cycle when the heat input is only from the solar receiver. However, when using a two-tank molten-salt storage system as the primary source of heat input, the Kalina Cycle showed an advantage over the simple Rankine Cycle because of about 33 % reduction in the storage requirement. The solar receiver showed the highest rate of exergy destruction for both the Cycles. The rates of exergy destruction in other components of the Cycles were found to be highly dependent on the amount of recuperation, and the ammonia mass fraction and pressure at the turbine inlet.

  • Energy and exergy analysis of the Kalina Cycle for use in concentrated solar power plants with direct steam generation
    Energy Procedia, 2014
    Co-Authors: Thomas Knudsen, Fredrik Haglind, Lasse Røngaard Clausen, Anish Modi
    Abstract:

    Abstract In concentrated solar power plants using direct steam generation, the usage of a thermal storage unit based only on sensible heat may lead to large exergetic losses during charging and discharging, due to a poor matching of the temperature profiles. By the use of the Kalina Cycle, in which evaporation and condensation takes place over a temperature range, the efficiency of the heat exchange processes can be improved, possibly resulting also in improved overall performance of the system. This paper is aimed at evaluating the prospect of using the Kalina Cycle for concentrated solar power plants with direct steam generation. The following two scenarios were addressed using energy and exergy analysis: generating power using heat from only the receiver and using only stored heat. For each of these scenarios comparisons were made for mixture concentrations ranging from 0.1 mole fraction of ammonia to 0.9, and compared to the conventional Rankine Cycle. This comparison was then also carried out for various turbine inlet pressures (100 bar to critical pressures). The results suggest that there would be no benefit from using a Kalina Cycle instead of a Rankine Cycle when generating power from heat taken directly from the solar receiver. Compared to a baseline Rankine Cycle, the efficiency of the Kalina Cycle was about around 5% lower for this scenario. When using heat from the storage unit, however, the Kalina Cycle achieved efficiencies up to 20% higher than what was achieved using the Rankine Cycle. Overall, when based on an average assumed 18 hours Cycle, consisting of 12 hours using heat from the receiver and 6 hours using heat from the storage, the Kalina Cycle and Rankine Cycle achieved almost equal efficiencies. A Kalina Cycle operating with an ammonia mole fraction of about 0.7 returned an averaged efficiency of about 30.7% compared to 30.3% for the Rankine Cycle.

Sujit Karmakar - One of the best experts on this subject based on the ideXlab platform.

  • power generation from fluegas waste heat in a 500 mwe subcritical coal fired thermal power plant using solar assisted Kalina Cycle system 11
    Applied Thermal Engineering, 2018
    Co-Authors: Goutam Khankari, Sujit Karmakar
    Abstract:

    Abstract This paper proposes a solar assisted Kalina Cycle System 11 (KCS 11) driven by fluegas waste heat of 500 MW Subcritical (SubC) coal-fired thermal power plant for additional electrical power generation. A computer simulation programme has been developed in MS-Excel and VBA to calculate and optimize system performance at different conditions. Results show that net electric power generation of about 516.52 kWh can be added with main plant generation for improving the plant net energy and exergy efficiencies by about of 0.040% and 0.036% point, respectively. This will reduce the annual CO2 emissions by about 1008.28 ton. Solar assisted KCS11 is more energy efficient but less exergy efficient compared to standalone KCS11. About 0.76 is the optimum ammonia mass fraction that yields the maximum efficiency at the operating pressure of 17.54 bar. System performance increases with increase in cooling water flow rate and is optimum at 92.80 kg/s. Power generation cost and payback period of the proposed system are about of Rs. 2.163 per unit generation and 12.44 years, respectively. The levelized cost of electricity (LCoE) for additional generation by solar heater is about Rs. 10.99 per kWh which is about 8.80% lower than conventional solar thermal power plant.

  • power generation from condenser waste heat in coal fired thermal power plant using Kalina Cycle
    Energy Procedia, 2016
    Co-Authors: Goutam Khankari, Jagannath Munda, Sujit Karmakar
    Abstract:

    Abstract In any thermal power plant the major energy loss takes place in the condenser through its cooling water system. The objective of the present study is to convert this low grade waste heat from a 500 MWe subcritical coal-fired power plant into electricity by integrating Kalina Cycle System 11 (KCS 11) where ammonia-water binary mixture is used as working fluid. A computer simulation programme has been developed by MS-Excel and VBA to analyze the combined Cycle plant configuration and parametric optimization based on thermodynamic equations. The parametric study is carried out based on variation of ammonia mass fraction and cooling water flow rate by keeping saturated vapour condition at turbine inlet. Result shows that the Kalina Cycle is able to add about 13.49MWe electric power with a net Cycle efficiency of 2.58%. There is an optimum cooling water flow rate that yields the maximum net Cycle efficiency for a particular condenser design value in the Kalina Cycle. Effect of ammonia mass fraction variations in the binary mixture is also studied by fixing turbine inlet temperature at 312.308K. The study shows that Cycle performance improves with higher ammonia mass fraction. Effect of temperature rise across the main plant condenser increases the overall plant efficiency. Around 3.3 ton/h of CO2 emission can be reduced by electric power addition with the help of utilizing the condenser heat loss.

Jiangfeng Wang - One of the best experts on this subject based on the ideXlab platform.

  • Comparative analysis on off-design performance of a novel parallel dual-pressure Kalina Cycle for low-grade heat utilization
    Energy Conversion and Management, 2021
    Co-Authors: Zheng Shaoxiong, Pan Zhao, Yiping Dai, Chen Kang, Gang Fan, Jiangfeng Wang
    Abstract:

    Abstract In this paper, a novel parallel dual-pressure Kalina Cycle system is presented to utilize the low-grade geothermal energy. In order to highlight the performance of the proposed Cycle, the comparison of parallel dual-pressure Kalina Cycle system and the basic Kalina Cycle system is conducted and set at the same boundary conditions. The maximal net power output of Cycle is considered as the single-objective function based on particle swarm optimization algorithm. The exergy analysis and economic cost for both Cycles are investigated at design conditions. Furthermore, as operating at off-design conditions, the variation ranges of geothermal energy mass flux and inlet temperature are 7.5–14 kg/s and 136–150 °C, respectively. The sliding pressure regulation strategy is applied to response to the variations of geothermal energy parameters. The two-levels evaporation pressures in the parallel dual-pressure Kalina Cycle are adjusted to remain the invariable temperature difference between geothermal energy inlet temperature of evaporators and the corresponding turbine inlet temperature. The results show that, at design conditions, the maximal net power output of parallel dual-pressure Kalina Cycle and basic Kalina Cycle is 329.62KW and 274.94KW, the corresponding exergy efficiency is 44.52% and 33.39%. Besides, the condenser contributes to the largest exergy destruction ratio in parallel dual-pressure Kalina Cycle and basic Kalina Cycle, which are 33.96% and 44.94% of overall exergy destruction, respectively. According to the off-design performance investigation, it is shown that the higher geothermal energy mass flux and inlet temperature are in favor of the larger net power output for both Cycles. The thermodynamic evaluation shows that the proposed parallel dual-pressure Kalina Cycle exhibits a more excellent performance in terms of net power output and exergy efficiency than basic Kalina Cycle.

  • Assessment of off-design performance of a Kalina Cycle driven by low-grade heat source
    Energy, 2017
    Co-Authors: Jianyong Wang, Jiangfeng Wang, Pan Zhao
    Abstract:

    Abstract Kalina Cycle is a promising power Cycle to utilize or recover the heat of low-grade heat sources. Most of previous works focused on the thermodynamic and thermoeconomic analysis or optimization for the Cycle. In this paper, an off-design mathematical model for Kalina Cycle is established to examine the off-design performance of the Cycle with the variation of heat source mass flow rate, heat source temperature and cooling water temperature. A modified sliding pressure regulation method, which regulates the turbine inlet pressure to keep the temperature difference between heat source temperature and turbine inlet temperature constant, is applied to control the Cycle when off-design conditions occur. The results show that the modified sliding pressure regulation method keeps Kalina Cycle with a good off-design performance. With the increase of heat source mass flow rate or heat source temperate, both of the net power output and thermal efficiency increase. With the increase of cooling water temperature, both of the net power output and thermal efficiency decrease. In addition, the turbine efficiency almost keeps the designed value under the off-design conditions.

  • Thermodynamic analysis of an integrated energy system based on compressed air energy storage (CAES) system and Kalina Cycle
    Energy Conversion and Management, 2015
    Co-Authors: Pan Zhao, Jiangfeng Wang, Yiping Dai
    Abstract:

    High penetration of renewable power sources into power system leads to significant challenge in balancing of power generation and consumption due to the highly erratic nature of renewable energies. Integrating the energy storage system (ESS) with power system can weaken these negative effects effectively. Compressed air energy storage (CAES) system as one of the grid-scale ESS technologies has grown rapidly in the past few years. However, the temperature of exhaust from low pressure turbine during discharge process is still high enough to utilize. An integrated energy system consisting of a CAES system and a Kalina Cycle system 6 (KCS6) is proposed to recover this waste heat. The thermodynamic analyses including energy analysis and exergy analysis are evaluated by using steady-state mathematical model and thermodynamic laws. The second law efficiency of the proposed CAES-KCS6 system can be improved nearly 4% compared to that of the single conventional CAES system. Meanwhile, the parametric analysis is also carried out to evaluate the effects of some key parameters on system performance, such as the turbine inlet temperature (TIT), inlet pressure of low pressure turbine and the air storage cavern temperature. Results show that all of these parameters have positive effect on system exergy efficiency.

  • thermodynamic analysis of a biomass fired Kalina Cycle with regenerative heater
    Energy, 2014
    Co-Authors: Liyan Cao, Jiangfeng Wang, Yiping Dai
    Abstract:

    Abstract The biomass fuel is a renewable energy resource, which is viewed as a promising alternative to fossil energy. This paper investigates a biomass-fired Kalina Cycle with a regenerative heater which is generally utilized to heat the feedwater and to increase the efficiency in coal-fired steam power plant. The mathematical model of the biomass-fired Kalina Cycle with a regenerative heater is established to conduct numerical simulation. A parametric analysis is conducted to examine the effects of some key thermodynamic parameters on the system performance. Furthermore, a parametric optimization is carried out by genetic algorithm to obtain the optimum performance of system. The results demonstrate that there exists an optimum extraction pressure and its corresponding maximum fraction of flow extracted from turbine to maximize the net power output and system efficiency. In addition, a higher turbine inlet pressure or turbine inlet temperature leads to higher net power output and system efficiency. And net power output and system efficiency increases as separator temperature rises. The optimization result of the biomass-fired Kalina Cycle with/without regenerative heater indicates the system is more efficient when regenerative heater is added.

  • Parametric analysis and optimization of a Kalina Cycle driven by solar energy
    Applied Thermal Engineering, 2013
    Co-Authors: Jiangfeng Wang, Zhequan Yan, Enmin Zhou, Yiping Dai
    Abstract:

    Abstract A solar-driven Kalina Cycle is examined to utilize solar energy effectively due to using ammonia–water's varied temperature vaporizing characteristic. In order to ensure a continuous and stable operation for the system, a thermal storage system is introduced to store the collected solar energy and provide stable power when solar radiation is insufficient. A mathematical model is developed to simulate the solar-driven Kalina Cycle under steady-state conditions, and a modified system efficiency is defined to evaluate the system performance over a period of time. A parametric analysis is conducted to examine the effects of some key thermodynamic parameters on the system performance. The solar-driven Kalina Cycle is also optimized with the modified system efficiency as an objective function by means of genetic algorithm under the given conditions. Results indicate that there exists an optimal turbine inlet pressure under given conditions to maximize the net power output and the modified system efficiency. The net power output and the modified system efficiency are less sensitive to a change in the turbine inlet temperature. An optimal basic solution ammonia fraction can be identified that yields maximum net power output and modified system efficiency. The optimized modified system efficiency is 8.54% under the given conditions.