This paper presented an overview of the passive strategies for ventilation and air-conditioning energy saving in underground metro stations. The strategies were relevant to building envelopes, piston effect and natural cold sources. This review found that the building envelopes had made minimal contribution to the research literature and might not be applicable to the underground stations. The piston effect was the most popular passive strategy in research community for its great energy saving potential. The ground cooling strategy was another promising option for air-conditioning energy saving but it was often overlooked due to its high R&D costs. The authors hope that this study can promote the adoption of different passive strategies for the ventilation and air-conditioning energy conservation in underground metro station buildings.
To characterize the operation risk of wind power, the concept of wind power fluctuation costs is proposed, the environmental benefits of wind power integration are calculated from the perspective of wind power, which can reflect the environmental benefits of wind power more clearly. An improved economic dispatch model is proposed based on the comprehensive power generation costs calculated by the operating costs of thermal power units, wind power fluctuation costs and environmental benefits. The planned output of thermal and wind power is taken as the decision variables and solved by particle swarm optimization, and the economic change law of wind power integration is explored. The effectiveness and practicability of the proposed model are verified by IEEE 39-bus, 118-bus system.
In this study, crude Calophyllum inophyllum oil was used as the feedstock for biodiesel production. This feedstock contain high acid value of 56.3 mg KOH/g (28wt%) which is not favorable for direct conversion to biodiesel by transesterification. Therefore, this paper emphasizes the study on the pre-treatment process of degumming and acid catalyst esterification in order to reduce the high free fatty acid for successful transesterification. Single parameter study was conducted to identify the best acid with best concentration to efficiently esterify the degummed Calophyllum inophyllum oil with highest FFA conversion. Among phosphoric acid, hydrochloric acid, and sulphuric acid, 3.0M concentration of sulphuric acid was found to be the best condition for the esterification reaction providing 87.46% FFA conversion.
Utilizing biodiesel from non—edible resources replacing diesel in power generation sector would reduce significant amount of carbon footprint. Biodiesel has lower carbon monoxide (CO) and carbon dioxide (CO2) providing large environmental benefits. This paper aims to study economic feasibility of applying Callophyllum Innophyllum (CI) biodiesel in power generation sector replacing diesel by varying economic factors. Although CI has advantages in technical aspects high production cost due to limited supply still is a disadvantage to CI biodiesel commercialization. A techno-economic assessment for biodiesel production is studied from feedstock acquisition till biodiesel consumption by analyzing its payback period and internal rate of return (IRR). The result shows that CI biodiesel is a feasible option considering influence of selling price, tax incentives as well glycerol selling price.
So far, the role of fossil fuels in future energy systems is still uncertain. To obtain a deeper understanding of how conversion technologies for fossil fuels act in multi-energy systems (MES), we extended our mixed integer linear programming (MILP) modeling framework for MES, first introduced by Gabrielli et al. , by adding gas turbines. This work presents the modeling approach for said gas turbines, focusing on the linear description of the efficiency’s dependency on load and ambient temperature. Furthermore, the model considers the possibility of selecting either natural gas or hydrogen as fuel, which affects the efficiency as well. A series of simple, proof-of-concept simulations were conducted to show the functionality of the model.
The present study examines the feasibility of Solid Oxide Fuel Cell (SOFC) assisted Vapor Absorption Refrigeration System (VARS) for refrigerated transport to replace the conventional TRU, where the heat generated from SOFC can be used to run the VARS. The study investigates and compares the GHG emissions from SOFC assisted VARS, diesel, and natural gas (NG) engine powered TRU, and cryogenic transport refrigeration systems. The operational and production related emissions were considered here to find out the total GHG emissions from the above-mentioned systems. Hydrogen fueled SOFC was considered in this work, and four different hydrogen (H2) production methods (solar based electrolysis, windbased electrolysis, biomass gasification, and NG reforming) were studied to calculate the hydrogen production related emissions. The analysis was then applied to systems for chilled and frozen products over a 10-hour vehicle operation. Finally, to select an optimum system configuration, both environmental and economic aspects were be considered. The mass intensity of the various fuels to obtain the required amount of refrigeration load in the different systems was calculated. The result showed that the considered novel SOFC-VARS emitted considerably lower amounts of GHG (50- 75 % reduction) compared to diesel and natural gas (NG) fueled TRUs, and cryogenic transport refrigeration systems.
Making the heavier components of coal tar into lighter components, which are the raw material for fuel and the chemicals, will improve the economy of pyrolysis. To promote the hydrogenation of heavy components, the co-hydrogenation of heavy components and pine sawdust (PS) was extensively studied in this work. The addition of PS significantly promoted the hydrogenation of heavy components which improved the yield of n-hexane soluble matter from 66.63 wt% to 75.46 wt%. The results of synchronous fluorescence showed that the product has a significant degree of lightening. Addition of biomass increased the aliphatic hydrogen content as evidenced by Fourier transform infrared spectroscopy.
The development of CO2 capture became great of importance in recent years. Apart from reducing the emissions from power generation sector, capturing CO2 from industrial flue gas has not been a popular topic, especially in the cement industries which is quite energy intensive and a main resource of anthropogenic CO2 emission in industries. The main purpose of this work was to systematically conduct techno-economic analysis of CO2 capture based on MEA technology, in which the impactors such as the flue gas flow rate, flue gas CO2 concentration and CO2 recovery rate were studied with the commercialized software Aspen Plus. Meanwhile, the concentration of MEA solutions was studied. The results indicate that 20% MEA is more suitable for practical application. The CAPEX is more sensitive to these selected impactors than OPEX, but still OPEX dominates the major change in the overall cost. In addition, the gas flowrate and CO2 concentration are the major impactors affect the cost rather than the CO2 recovery rate.
The highly energy requirement of rich amine solvent regeneration process is the biggest obstacle for the industrial application of amine-based CO2 capture technology. In this work, to reduce the heat duty of absorbent regeneration, the zeolite Beta/SBA-15 (BS) with different zeolite Beta (β) content synthesized by the hydrothermal method with zeolite Beta (β) as the silicon source were utilized to prepare the novel Zr@BS and FeZr@BS catalysts for amine regeneration. Experiments for CO2 stripping were performed under the temperature of 370.15 K using amine solvent (monoethanolamine (MEA)) with an initial CO2 loading of 0.5 mol CO2/mol amine. Additionally, various techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption–desorption experiment, ammonia temperature programmed desorption (NH3-TPD), and pyridine-adsorption infrared spectroscopy (Py-IR) were adopted to characterize and estimate the prepared catalysts. Also, the catalytic CO2 desorption performances of seven different catalysts (β, SBA-15, three BS catalysts, Zr@BS and Fe-Zr@BS) were investigated and evaluated in terms of the cyclic capacity, desorption rate and energy consumption. The experimental results showed that the Fe-Zr@BS catalysts exhibited best catalytic performance than other catalysts studied in this work, enhancing the desorption factor by 212% and reducing the energy consumption by 33% compared to the blank run. Furthermore, the Fe-Zr@BS catalysts have no influence on the amine absorption performance in terms of the absorption rate and have the advantages of good stability and easy regeneration. Based on the results of characterization and experiments, the possible catalytic mechanism for the Fe-Zr@BS catalysts catalyzed amine regeneration for CO2 stripping were proposed and the reusability of the catalysts were also investigated.
With severe environmental pollution pressures growing, research on fuel cell vehicles is increasing. Compared to electric vehicles, fuel cell vehicles do not have the constraints of driving distances. Meanwhile, the emissions of fuel cell vehicles are cleaner than the traditional vehicles. This paper takes a fuel cell bus as the research object. Based on the characteristics of fuel cell vehicles，the Dynamic Programming algorithm is used to calculate the global optimal process for typical urban conditions. The drawback of the global optimal process is that the operating conditions must be known before.As a result, it is not reasonable to use dynamic programming in real driving condition. Therefore, we propose to use an adapted power management method to deal with the actual driving conditions.