1,549 research outputs found
Steam bottoming cycle for an adiabatic diesel engine
Steam bottoming cycles using adiabatic diesel engine exhaust heat which projected substantial performance and economic benefits for long haul trucks were studied. Steam cycle and system component variables, system cost, size and performance were analyzed. An 811 K/6.90 MPa state of the art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. The costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with aftercooling with the same total output were compared, the annual fuel savings less the added maintenance cost was determined to cover the increase initial cost of the TC/B system in a payback period of 2.3 years. Steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability are considered and the cost and performance of advanced systes are evaluated
Parametric optimization and heat transfer analysis of a dual loop ORC (organic Rankine cycle) system for CNG engine waste heat recovery
In this study, a dual loop ORC (organic Rankine cycle) system is adopted to recover exhaust energy, waste heat from the coolant system, and intercooler heat rejection of a six-cylinder CNG (compressed natural gas) engine. The thermodynamic, heat transfer, and optimization models for the dual loop ORC system are established. On the basis of the waste heat characteristics of the CNG engine over the whole operating range, a GA (genetic algorithm) is used to solve the Pareto solution for the thermodynamic and heat transfer performances to maximize net power output and minimize heat transfer area. Combined with optimization results, the optimal parameter regions of the dual loop ORC system are determined under various operating conditions. Then, the variation in the heat transfer area with the operating conditions of the CNG engine is analyzed. The results show that the optimal evaporation pressure and superheat degree of the HT (high temperature) cycle are mainly influenced by the operating conditions of the CNG engine. The optimal evaporation pressure and superheat degree of the HT cycle over the whole operating range are within 2.5–2.9 MPa and 0.43–12.35 K, respectively. The optimal condensation temperature of the HT cycle, evaporation and condensation temperatures of the LT (low temperature) cycle, and exhaust temperature at the outlet of evaporator 1 are kept nearly constant under various operating conditions of the CNG engine. The thermal efficiency of the dual loop ORC system is within the range of 8.79%–10.17%. The dual loop ORC system achieves the maximum net power output of 23.62 kW under the engine rated condition. In addition, the operating conditions of the CNG engine and the operating parameters of the dual loop ORC system significantly influence the heat transfer areas for each heat exchanger
Waste heat recovery technologies for offshore platforms
none5siThis article aims at finding the most suitable waste heat recovery technology for existing and future offshore facilities. The technologies considered in this work are the steam Rankine cycle, the air bottoming cycle and the organic Rankine cycle.
A multi-objective optimization approach is employed to attain optimal designs for each bottoming unit by selecting specific functions tailored to the oil and gas sector, i.e. yearly CO2 emissions, weight and economic revenue. The test case is the gas turbine-based power system serving an offshore platform in the North Sea.
Results indicate that the organic Rankine cycle technology presents larger performances compared to steam Rankine cycle units, whereas the implementation of air bottoming cycle modules is not attractive from an economic and environmental perspective compared to the other two technologies.
Despite the relatively high cost of the expander and of the primary heat exchanger, organic Rankine cycle turbogenerators appear thus to be the preferred solution to abate CO2 emissions and pollutants on oil and gas facilities.
As a practical consequence, this paper provides guidelines for the design of high-efficiency, cost-competitive and low-weight power systems for offshore installationsrestrictedL. Pierobon;A. Benato;E. Scolari;F. Haglind;A. StoppatoL., Pierobon; Benato, Alberto; E., Scolari; F., Haglind; Stoppato, Ann
Design and optimization of heat exchangers for Organic Rankine cycles
Design of power plant and heat exchangers. Optimization with multi-objective genetic algorithm. Selection of optimal working fluid
Sterilization Assembly Development Laboratory. Personnel procedures for SADL operations - JPL procedure SADL 201.00
Personnel cleaning and clothing procedures for entry and operations in sterilization assembly development laborator
ISHPC 2021 proceedings – online pre-conference 2020
For decades there has been intense research and development on sorption heat pumping and cooling processes; still, looking at the sales numbers, it is mainly a niche technology. The current transition to an energy system based on renewables changes the boundary conditions. Sorption heat pumps will have an indispensable place in this context, especially for its potential to make use of waste heat.
We want to look at the future of sorption heat pumping devices including the newest research developments, as well as reports about pilots and mature technology
Hybrid nuclear-solar power
Nuclear and solar power, in the form of concentrated solar power (CSP), play a significant role in achieving the ambitious global targets of reducing greenhouse emissions and guaranteeing security of energy supply. However, both power generation technologies still require further development to realise their full potential, especially in terms of attaining economic load following operations and higher thermal efficiencies. Therefore, the aim of this research is to investigate and thermo-economically evaluate the available options of upgrading the flexibility and enhancing the thermal efficiency of nuclear and solar power generation technologies (i.e., through the integration with thermal energy storage (TES) and by hybridising both power generation technologies) while providing reasonable economic returns.
The thesis starts with describing the development and validation of several thermodynamic and economic computational models and the formulation of the whole-energy system model. The formulated models are utilised to perform several thermo-economic studies in the field of flexible nuclear and solar power, and to quantify the economic benefits that could result from enhancing the flexibility of nuclear power plants from the whole-energy system perspective. The studies conducted in this research are: (i) a thermo-economic assessment of extending the conventional TES system in direct steam generation (DSG) CSP plants; (ii) a thermo-economic evaluation of upgrading the flexibility of nuclear power plants by the integration with TES and secondary power generation systems; (iii) an investigation of the role of added flexibility in future low-carbon electricity systems; and (iv) a design and operation analysis of a hybrid nuclear-solar power plant.
The most common TES option in DSC CSP plants is steam accumulation. This conventional option is constrained by temperature and pressure limits, leading to lower efficiency operations during TES discharging mode. Therefore, the option of integrating steam accumulators with sensible-heat storage in concrete to provide higher-temperature superheated steam is thermo-economically investigated in this research, taking an operational DSG CSP plant as a case study. The results show that the integrated concrete-steam TES (extended) option delivers 58% more electricity with a 13% enhancement in thermal efficiency during TES discharging mode, compared to the conventional steam accumulation (existing) configuration. With an estimated additional investment of 30.4M/yr and 53.4M/yr, the proposed flexibility upgrades appear to be economically justified with net system economic benefits ranging from 39.5M/yr for the examined low-carbon scenarios, provided that the number of flexible nuclear plants in the system is small.
The concept of hybridising a small modular reactor (SMR) with a solar-tower CSP integrated with two-tank molten salt TES system, with the aim of achieving economically enhanced load following operations and higher thermal efficiency levels, is also thermo-economically investigated in this research. The integration of both technologies is achieved by adding a solar-powered superheater and a reheater to a standalone SMR. The obtained results demonstrate that hybridising nuclear and solar can offer a great amount of flexibility (i.e., between 50% and 100% of nominal load of 131 MWel) with the SMR continuously operated at full rated thermal power output. Furthermore, the designed hybrid power plant is able to operate at higher temperatures due to the addition of the solar superheater, resulting in a 15% increase of thermal efficiency compared to nuclear-only power plant. Moreover, the calculated specific investment cost and the LCOE of the designed hybrid power plant are respectively 5410 /MWhel, which are 2% and 4% lower than those calculated for the nuclear-only power plant.Open Acces
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