Numerical sensitivity analyses for identifying rate-limiting factors influencing total energy exchange efficiency in energy recovery ventilator

2019 ◽  
pp. 1420326X1989037 ◽  
Author(s):  
Hajime Sotokawa ◽  
Juyeon Chung ◽  
Sung-Jung Yoo ◽  
Kazuhide Ito
Keyword(s):  
Total Energy ◽  
Energy Recovery ◽  
Energy Exchange ◽  
Sensitivity Analyses ◽  
Limiting Factors ◽  
Factors Influencing ◽  
Rate Limiting

scholarly journals Energy Recovery Potential in Industrial and Municipal Wastewater Networks Using Micro-Hydropower in Spain

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 691
Author(s):  
Aida Mérida García ◽  
Juan Antonio Rodríguez Díaz ◽  
Jorge García Morillo ◽  
Aonghus McNabola
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Energy Recovery ◽  
Energy Production ◽  
Municipal Wastewater ◽  
Distribution Networks ◽  
Total Power ◽  
Energy Potential ◽  
Total Energy Consumption ◽  
Recovery Potential

The use of micro-hydropower (MHP) for energy recovery in water distribution networks is becoming increasingly widespread. The incorporation of this technology, which offers low-cost solutions, allows for the reduction of greenhouse gas emissions linked to energy consumption. In this work, the MHP energy recovery potential in Spain from all available wastewater discharges, both municipal and private industrial, was assessed, based on discharge licenses. From a total of 16,778 licenses, less than 1% of the sites presented an MHP potential higher than 2 kW, with a total power potential between 3.31 and 3.54 MW. This total was distributed between industry, fish farms and municipal wastewater treatment plants following the proportion 51–54%, 14–13% and 35–33%, respectively. The total energy production estimated reached 29 GWh∙year−1, from which 80% corresponded to sites with power potential over 15 kW. Energy-related industries, not included in previous investigations, amounted to 45% of the total energy potential for Spain, a finding which could greatly influence MHP potential estimates across the world. The estimated energy production represented a potential CO2 emission savings of around 11 thousand tonnes, with a corresponding reduction between M€ 2.11 and M€ 4.24 in the total energy consumption in the country.

Kinetic model of hybridoma cultures for the identification of rate limiting factors and process optimisation

1996 ◽  
Vol 42 (2-3) ◽  
pp. 197-205
Author(s):  
A. Lourenço da Silva ◽  
A. Marc ◽  
J.M. Engasser ◽  
J.L. Goergen
Keyword(s):  
Kinetic Model ◽  
Limiting Factors ◽  
Process Optimisation ◽  
Rate Limiting

Is Cognitive Psychopathology Plausible? Illustrations from Memory Research

1996 ◽  
Vol 41 (7) ◽  
pp. S5-S13 ◽  
Author(s):  
Jean-Marie Danion ◽  
Herbert Weingartner ◽  
Leonard Singer
Keyword(s):  
Cognitive Remediation ◽  
Preliminary Evidence ◽  
Limiting Factors ◽  
Specific Rate ◽  
Memory Impairments ◽  
Central Processing ◽  
Elementary Computation ◽  
The One ◽  
Functional Mechanisms ◽  
Rate Limiting

Objective: To examine the strengths and weaknesses of cognitive psychopathology through the specific examples of the memory impairments associated with the administration of benzodiazepines, with schizophrenia, and with depression. Method: These examples are analyzed with reference to a model of memory based on the principle of division between specialized and central processing structures. A basic contention is that it is useful to consider 2 broad classes of processes—automatic, associative, or sensory/perceptual processes on the one hand and intentional, strategic, or reflective processes on the other hand—as being separate. Results: The functional mechanisms of the memory impairments associated with these conditions are beginning to be identified, and there is preliminary evidence that a deficit in an elementary computation may have dramatic consequences on highest cognitive functions. There is also evidence that certain memory impairments are linked to specific dysfunctional outcomes in everyday life. By showing that specific rate-limiting factors of cognitive performance can be identified and are amenable to cognitive interventions, existing data open the door for theoretically and empirically based cognitive remediation of mental disorders. Conclusion: The bulk of available evidence (albeit limited) makes the enterprise of cognitive psychopathology quite plausible and convincing.

Investigation of Effect of Biomass Torrefaction Temperature on Volatile Energy Recovery Through Combustion

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Oladapo S. Akinyemi ◽  
Lulin Jiang ◽  
Prashanth R. Buchireddy ◽  
Stanislav O. Barskov ◽  
John L. Guillory ◽  
...  
Keyword(s):  
Total Energy ◽  
Energy Recovery ◽  
Treatment Process ◽  
Hydrocarbon Composition ◽  
Low Molecular Weight ◽  
Mass Losses ◽  
Pretreatment Temperature ◽  
Pine Wood Chips ◽  
Mild Pyrolysis ◽  
Conservation Evaluation

Biomass torrefaction is a mild pyrolysis thermal treatment process carried out at temperatures between 200 and 300 °C under inert conditions to improve fuel properties of parent biomass. Torrefaction yields a higher energy per unit mass product but releases noncondensable and condensable gases, signifying energy and mass losses. The condensable gases (volatiles) can result in tar formation on condensing, hence, system blockage. Fortunately, the hydrocarbon composition of volatiles represents a possible auxiliary energy source for feedstock drying and/or torrefaction process. The present study designed a low-pressure volatile burner for torrefaction of pine wood chips and investigated energy recovery from volatiles through clean co-combustion with natural gas (NG). The research studied the effects of torrefaction pretreatment temperatures on the amount of energy recovered for various combustion air flow rates. For all test conditions, blue flames and low emissions at the combustor exit consistently signified clean and complete premixed combustion. Torrefaction temperature at 283–292 °C had relatively low volatile energy recovery, mainly attributed to higher moisture content evolution and low molecular weight of volatiles evolved. At the lowest torrefaction pretreatment temperature, small amount of volatiles was generated with more energy recovered. Energy conservation evaluation on the torrefaction reactor indicated that about 27% of total energy carried by the exiting volatiles and gases has been recovered by the co-fire of NG and volatiles at the lowest temperature, while around 19% of the total energy was recovered at the intermediate and highest torrefaction temperatures, respectively. The energy recovered represents about 23–45% of the energy associated with NG combustion in the internal burner of the torrefaction reactor, signifying that the volatiles energy can supplement significant amount of the energy required for torrefaction.

Analysis of Rate-Limiting Factors in Thick Electrodes for Electric Vehicle Applications

2018 ◽  
Vol 165 (3) ◽  
pp. A525-A533 ◽  
Author(s):  
Byoung-Sun Lee ◽  
Zhaohui Wu ◽  
Victoria Petrova ◽  
Xing Xing ◽  
Hee-Dae Lim ◽  
...  
Keyword(s):  
Electric Vehicle ◽  
Limiting Factors ◽  
Rate Limiting

scholarly journals Co-Combustion of Waste Tires and Plastic-Rubber Wastes with Biomass Technical and Environmental Analysis

2020 ◽  
Vol 12 (3) ◽  
pp. 1036 ◽  
Author(s):  
Luís Carmo-Calado ◽  
Manuel Jesús Hermoso-Orzáez ◽  
Roberta Mota-Panizio ◽  
Bruno Guilherme-Garcia ◽  
Paulo Brito
Keyword(s):  
Energy Recovery ◽  
Calorific Value ◽  
Thermal Conversion ◽  
Pollutant Emissions ◽  
Limiting Factors ◽  
Gaseous Emissions ◽  
Waste Tires ◽  
Feeding Difficulties ◽  
Stable Conditions ◽  
Combustion Tests

The present work studies the possibility of energy recovery by thermal conversion of combustible residual materials, namely tires and rubber-plastic, plastic waste from outdoor luminaires. The waste has great potential for energy recovery (HHV: 38.6 MJ/kg for tires and 31.6 MJ/kg for plastic). Considering the thermal conversion difficulties of these residues, four co-combustion tests with mixtures of tires/plastics + pelletized Miscanthus, and an additional test with 100% Miscanthus were performed. The temperature was increased to the maximum allowed by the equipment, about 500 °C. The water temperature at the boiler outlet and the water flow were controlled (60 °C and 11 L/min). Different mixtures of residues (0–60% tires/plastics) were tested and compared in terms of power and gaseous emissions. Results indicate that energy production increased with the increase of tire residue in the mixture, reaching a maximum of 157 kW for 40% of miscanthus and 60% of tires. However, the automatic feeding difficulties of the boiler also increased, requiring constant operator intervention. As for plastic and rubber waste, fuel consumption generally decreased with increasing percentages of these materials in the blend, with temperatures ranging from 383 °C to 411 °C. Power also decreased by including such wastes (66–100 kW) due to feeding difficulties and cinder-fusing problems related to ash melting. From the study, it can be concluded that co-combustion is a suitable technology for the recovery of waste tires, but operational problems arise with high levels of residues in the mixture. Increasing pollutant emissions and the need for pre-treatments are other limiting factors. In this sense, the thermal gasification process was tested with the same residues and the same percentages of mixtures used in the co-combustion tests. The gasification tests were performed in a downdraft reactor at temperatures above 800 °C. Each test started with 100% acacia chip for reference (like the previous miscanthus), and then with mixtures of 0–60% of tires and blends of plastics and rubbers. Results obtained for the two residues demonstrated the viability of the technology, however, with mixtures higher than 40% it was very difficult to develop a process under stable conditions. The optimum condition for producing a synthesis gas with a substantial heating value occurred with mixtures of 20% of polymeric wastes, which resulted in gases with a calorific value of 3.64 MJ/Nm3 for tires and 3.09 MJ/Nm3 for plastics and rubbers.

Effects of atropine on synthesis and secretion of pepsinogen in the rat

1960 ◽  
Vol 198 (1) ◽  
pp. 108-112 ◽  
Author(s):  
Basil I. Hirschowitz ◽  
D. K. O'Leary ◽  
I. N. Marks
Keyword(s):  
Water Loss ◽  
Indirect Evidence ◽  
Atropine Sulfate ◽  
Body Water ◽  
Limiting Factors ◽  
Subcutaneous Injections ◽  
Pylorus Ligation ◽  
Pepsinogen Secretion ◽  
Water Secretion ◽  
Rate Limiting

Simultaneous measurements of gastric juice pepsin and stomach mucosal pepsinogen were made in groups of pylorus-ligated rats at intervals from 2 to 24 hours to examine the effects of atropine sulfate (20 mg/100 gm/8 hrs.) on pepsinogen secretion and synthesis. Animals given subcutaneous injections of water served as controls. Atropine caused a marked reduction in pepsinogen secretion and a concomitant accumulation of pepsinogen in the mucosa which increased with time to a plateau; pylorus ligation had the opposite effect, indicating that atropine effected the reduction in secretion of pepsinogen by blocking the release of pepsinogen from peptic cells. In untreated rats the hematocrit increased proportionately to presumed body water loss, but in the atropine-treated rats the hematocrit failed to increase to the same degree for equivalent body water loss. Indirect evidence is presented to suggest that the rate of water secretion may be one of the rate-limiting factors in pepsinogen secretion. Although synthesis of pepsinogen can proceed without secretion, correlation of the rates of synthesis with those of secretion suggested that the rate of synthesis could be increased by an increased rate of secretion.

Sensitivity Analyses of NOx Formation in Micro-Pilot Ignited Natural Gas Engines

2004 ◽  
Author(s):  
Huateng Yang ◽  
S. R. Krishnan ◽  
K. K. Srinivasan ◽  
K. Clark Midkiff
Keyword(s):  
Sensitivity Analysis ◽  
Natural Gas ◽  
Relative Error ◽  
Reaction Rates ◽  
Sensitivity Analyses ◽  
Combustion Model ◽  
Valuable Insight ◽  
Nox Formation ◽  
Rate Limiting ◽  
Formation Paths

A sensitivity analysis of NOx formation in micro-pilot ignited natural gas dual fuel engines is performed based on a phenomenological combustion model. The model’s NOx formation mechanism incorporates a super-extended Zel’dovich mechanism (up to 43 reactions). The sensitivity analysis compares the contribution of each major reaction to NOx formation, and identifies the rate controlling NOx formation reactions. The formation rates for reactions involving NOx are also investigated to reveal the primary NOx formation paths. Results show that there are two main NOx formation paths both in the packets zone and the burned zone. The rate limiting reactions for the packets zone are identified as: O+N2=NO+NN2+HO2=NO+HNO Rate limiting reactions for the burned zone are: N2O+M=N2+O+MN2+HO2=NO+HNO Since the aforementioned reaction significantly influence the net NOx prediction, it is important that the corresponding reaction rates be determined fairly accurately. Finally, because the quasi-steady-state assumption is commonly used for certain species in NOx modeling, a transient relative error is estimated to evaluate its use. The relative error in NOx prediction with and without this assumption is of the order of 2 percent. Clearly, sensitivity analysis can provide valuable insight into understanding the possible NOx formation pathways in engines and improve the status of current prediction tools to obtain better estimates.

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