Human Body Exergy Analysis Model in Building Thermal Comfort Evaluation

Norouzi Nima 대한설비공학회 2021 International Journal of Air-Conditioning and Refr Vol.29 No.4

To explore the application of the human body exergy analysis method in assessing the indoor thermal environment, strictly according to the definition of metabolic exergy, based on the two existing exergy analysis models, a more reasonable calculation method of metabolic exergy was first proposed and established, which is a new two-node exergy analysis model. Then, the experimental data in the ASHRAE database were used to verify the reliability of the established model. Finally, the human body exergy exchange rate and exergy loss rate with indoor and outdoor environmental parameters were revealed. The research results show that the new metabolic calculation method can more accurately analyze the human body’s exergy; the exergy loss rate is larger than the exergy exchange rate in the metabolic exergy rate; when the operating temperature is 25 ∘ C, the exergy exchange rate mainly includes the radiation exergy rate and the convective exergy rate; operation at a temperature of 32 ∘ C, the evaporation rate and respiration rate are the main components of the exergy exchange rate; the human body’s exergy loss rate has extreme values at low or high operating temperatures, and it is used separately for the evaluation of human thermal comfort. Combining the exergy loss rate and the exergy exchange rate can better evaluate the indoor thermal environment, the minimum exergy loss rate and the minimum exergy exchange rate under the given indoor conditions, both occur under outdoor high-temperature and low humidity conditions; outdoor temperature affects the human body exergy loss rate and human body exergy exchange rate more strongly than outdoor relative humidity.

The Pahlev Reliability Index: A measurement for the resilience of power generation technologies versus climate change

Norouzi, Nima Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5

Research on climate change and global warming on the power generation systems are rapidly increasing because of the Importance of the sustainable energy supply, thus the electricity supply since its growing share, in the end, uses energy supply. However, some researchers conducted this field, but many research gaps are not mentioned and filled in this field's literature since the lack of general statements and the quantitative models and formulation of the issue. In this research, an exergy-based model is implemented to model a set of six power generation technologies (combined cycle, gas turbine, nuclear plant, solar PV, and wind turbine) and use this model to simulate each technology's responses to climate change impacts. Finally, using these responses to define and calculate a formulation for the relationship between the system's energy performance in different environmental situations and a dimensionless index to quantize each power technology's reliability against the climate change impacts called the Pahlev reliability index (P-index) of the power technology. The results have shown that solar and nuclear technologies are the most, and wind turbines are the least reliable power generation technologies.

Exergetic design and analysis of a nuclear SMR reactor tetrageneration (combined water, heat, power, and chemicals) with designed PCM energy storage and a CO₂ gas turbine inner cycle

Norouzi, Nima,Fani, Maryam,Talebi, Saeed Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.2

The tendency to renewables is one of the consequences of changing attitudes towards energy issues. As a result, solar energy, which is the leader among renewable energies based on availability and potential, plays a crucial role in full filing global needs. Significant problems with the solar thermal power plants (STPP) are the operation time, which is limited by daylight and is approximately half of the power plants with fossil fuels, and the capital cost. Exergy analysis survey of STPP hybrid with PCM storage carried out using Engineering Equation Solver (EES) program with genetic algorithm (GA) for three different scenarios, based on eight decision variables, which led us to decrease final product cost (electricity) in optimized scenario up to 30% compare to base case scenario from 28.99 $/kWh to 20.27 $/kWh for the case study. Also, in the optimal third scenario of this plant, the inner carbon dioxide gas cycle produces 1200 kW power with a thermal efficiency of 59% and also 1000 m3/h water with an exergy efficiency of 23.4% and 79.70 kg/h with an overall exergy efficiency of 34% is produced in the tetrageneration plant.

Exergy and exergoeconomic analysis of hydrogen and power cogeneration using an HTR plant

Norouzi, Nima,Talebi, Saeed,Fani, Maryam,Khajehpour, Hossein Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.8

This paper proposes using sodium-cooled fast reactor technologies for use in hydrogen vapor methane (SMR) modification. Using three independent energy rings in the Russian BN-600 fast reactor, steam is generated in one of the steam-generating cycles with a pressure of 13.1 MPa and a temperature of 505 ℃. The reactor's second energy cycles can increase the gas-steam mixture's temperature to the required amount for efficient correction. The 620 ton/hr 540 ℃ steam generated in this cycle is sufficient to supply a high-temperature synthesis current source (700 ℃), which raises the steam-gas mixture's temperature in the reactor. The proposed technology provides a high rate of hydrogen production (approximately 144.5 ton/hr of standard H₂), also up to 25% of the original natural gas, in line with existing SMR technology for preparing and heating steam and gas mixtures will be saved. Also, exergy analysis results show that the plant's efficiency reaches 78.5% using HTR heat for combined hydrogen and power generation.

Hydrogen production in the light of sustainability: A comparative study on the hydrogen production technologies using the sustainability index assessment method

Nima Norouzi 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.4

Hydrogen as an environmentally friendly energy carrier has received special attention to solving uncertainty about the presence of renewable energy and its dependence on time and weather conditions. This material can be prepared from different sources and in various ways. In previous studies, fossil fuelshave been used in hydrogen production, but due to several limitations, especially the limitation of theaccess to this material in the not-too-distant future and the great problem of greenhouse gas emissionsduring hydrogen production methods. New methods based on renewable and green energy sources asenergy drivers of hydrogen production have been considered. In these methods, water or biomass materials are used as the raw material for hydrogen production. In this article, after a brief review ofdifferent hydrogen production methods concerning the required raw material, these methods areexamined and ranked from different aspects of economic, social, environmental, and energy and exergyanalysis sustainability. In the following, the current position of hydrogen production is discussed. Finally,according to the introduced methods, their advantages, and disadvantages, solar electrolysis as a methodof hydrogen production on a small scale and hydrogen production by thermochemical method on a largescale are introduced as the preferred methods.

4E Analysis and Design of a Combined Cycle with a Geothermal Condensing System in Iranian Moghan Diesel Power Plant

Nima Norouzi 대한설비공학회 2020 International Journal Of Air-Conditioning and Refr Vol.28 No.3

Considering the new issues human society faces now, environmental issues, and climate change is one of the primary and most essential phenomena which have been caused by the unsustainable lifestyle of men over the last two centuries. Power and energy are some of the leading role players of today’s human lifestyle and one of the most effective in which the environment is affected. This article represents the results of research over the possibility of recovering waste heat and determination of design parameters of a waste heat steam generator for medium speed set of diesel generators, with the rated 42 MW capacity and are used for power generation. The main goals of this study are to manage the waste heat of the engines and to help the severe water leakage of the power plant. In this paper, for managing the waste heat, a combined steam cycle is being designed for this process. This system added 19 MW the overall electricity generation, and the exergy and energy efficiencies of the system are being increased by 29.2% and 32.8%. Moreover, finally, a geothermal condensing system (GCS) is designed to control the water shortages of the steam power unit condensing system. The GCS condensing system developed in this paper helps to reduce the water evaporation losses in the cooling water by more than 79% compared to the wet cooling towers.

Entropy and exergy analysis and optimization of the VVER nuclear power plant with a capacity of 1000 MW using the firefly optimization algorithm

Talebi, Saeed,Norouzi, Nima Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.12

A light water nuclear Reactor has been exergy analyzed, and the rate of irreversible exergy loss and exergy destruction is calculated for each of its components. The ratio of these losses compared to the total input exergy loss is calculated, which shows that most irreversible losses occur in the reactors, turbines, steam generators, respectively, as well as in the downstream operations. The main aim of this paper is to optimize the power plant using an innovative firefly algorithm and then to propose a novel strategy to improve the overall performance of the plant. As shown in the results, the exergy destruction rate of the plant decreased by 1.18% using the firefly method, and the exergy efficiency of the plant reached 29.3% comparing to the operational amount of 28.99%. Also, the results of the firefly optimization process compared to the Genetic algorithm and gravitational search algorithm to study the accuracy of the model for exergy analysis fitness problems in the power plants and the results of this comparison has shown that the results are nearly similar in the mentioned methods. However, the firefly is faster and more accurate in limited iterations.

Exergy analysis and optimization of Natural Gas Liquids Recovery unit

Hossein Khajehpour,Nima Norouzi,Navid Shiva,Reza Mahmoodi Folourdi,Ehsan Hashemi Bahremani 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.1

The Natural Gas Liquids (NGL) recovery unit is one of the processes that requires cooling. The sweetened gas enters this unit after the dehydration stage, and the final product called NGL Product is stored and ready for consumption or export. In this research, the first, one of the NGL units, is simulated with HYSYS software. Three types of processes with different cooling systems are studied using the exergy analysis method. Joule–Thomson’s combination with the expander is selected for its high exergy efficiency, and the exergy efficiency function has been selected as the objective function 1 to optimize this process mathematically based on this study’s findings. The critical term in this objective function is the work of the compressors and turboexpanders in the process. After defining the optimization problem, the problem is optimized by two genetic algorithms and SQP, considering the process constraints and the process’s initial conditions. Finally, using the genetic algorithm’s data application to the simulated process, a 15% increase in the plant’s exergic efficiency was observed.

An exergetic model for the ambient air temperature impacts on the combined power plants and its management using the genetic algorithm

Hossein Khajehpour,Nima Norouzi,Maryam Fani 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.1

4E analysis is used on a Brayton–Rankine combined cycle power plant (CCPP) with a dual pressure heat recovery steam generation (HRSG) system. A multi-objective genetic-based evolutionary optimization has been used to estimate the most optimal exergy efficiency status, exergy cost reduction, carbon emission reduction, and NOx emission reduction. For the validation of the data, the simulation results are compared with the plant’s data. This study investigates the effect of every decisive parameter on the objective performance parameters of the CCPP. The primary estimated results are the emission rates, efficiencies, and the exergoeconomic cost of the system. At the optimum operational state, the exergy efficiency may increase by 10%, while the total emissions may decrease by 14.6%. The conventional technical measures’ effectiveness to improve the combined cycle power plant’s energy performance is applied to the simulated case study. Results have shown that the main source of the exergy destruction in this system is the HRSG and the combustion chamber, and also the overall performance of the plant shows great sensitivity to the ambient air temperature. This fact has shown that climate change and global warming are effective in thermal power plants’ performance. Therefore, the effect of the climate change on the ambient air temperature impact on the power plant and the 4E performance of the simulated combined cycle power plant is also studied. The results show that, due to the global warming effect, the exergy efficiency of the CCPP unit is decreased by over 0.2% in the last two decades, which can be generalized to all thermal electricity generation units throughout the world based on the mean global temperature rise in the last decades

Energy, Exergy and Exergoeconomic Analysis of Solar Thermal Power Plant Hybrid with Designed PCM Storage

Maryam Fani,Nima Norouzi,Molood Ramezani 대한설비공학회 2020 International Journal Of Air-Conditioning and Refr Vol.28 No.4

The tendency of renewable energies is one of the consequences of changing attitudes towards global energy issues. As a result, solar energy, which is the leader among renewable energies based on availability and potential, plays a crucial role in thoroughly filing global needs. Significant problems with the solar thermal power plants (STPP) are the operation time, which is limited by daylight and is approximately half of the power plants with fossil fuels, and the capital cost. In the present study, a new suggested sketch of adding latent heat storage (LHS) filled with commercial phase change material (PCM) to a 500-kW STPP case study has been investigated. Solar system details and irradiation amounts for a case study, including total and beam radiation have been determined. Also, the theoretical energetic and exergetic analysis of adding PCM storage to STTP is conducted, which showed a 19% improvement in the exergetic efficiency of the power plant to reach 30%. Besides, an optimized storage tank and appropriate PCM material have been investigated and selected concerning the practical limitations of the case study. By designing a new cycle, the LHS will be charged during daylight and will be discharged at night, doubling power plant operation time up to 2500h. Finally, exergoeconomic survey of STPP hybrid with PCM storage was carried out using Engineering Equation Solver (EES) program with genetic algorithm (GA) for three different scenarios, based on eight decision variables, which led us to decrease final product cost (electricity) in optimized scenario up to 30% compared to base case scenario from 28.99 to 20.27 $/kWh for the case study. Also, a comparison is made to demonstrate the effectiveness of the proposed new cycle on 250, 500, 1000, and 2000 kW STTPs.