Heating, ventilation and air conditioning systems (HVAC) are widely present in industry. They permit to maintain strict environmental conditions such as in clean room in pharmaceutical and aerospace industries. They also permit to maintain personal health and comfort (e.g., in offices). This article is a case study in an industrial pharmaceutical site in France. HVAC systems represent 57% of siteâs carbon emissions because air must be transported and undergo several different treatments: heating, cooling, dehumidification, and Filtration. Moreover, those systems are generally overdesigned, operate very far to the specification limits and/or regulation are not optimized. To minimize carbon emissions, a specific methodology has been developed for ensuring to make the right choices when implementing a new HVAC or modifying an existing one. This methodology contains 4 steps: reduce quantity of air, reduce air treatment periods, efficient air treatment by design and efficient air treatment by management. Each step includes complex, simple and innovative actions such as electronically commutated motor in place of conventional motor. The methodology developed does not degrade global performance and thermal efficiency of systems and answer to quality, environment, health, and safety requirements. The application of this methodology has permitted to reduce carbon emissions of HVAC systems by 24% in less than 3 years.
This work deals with determining the characteristics of the flow through the penstock of the Three Gorges dam in China. It also allows us to understand the influence of the diameter of the water duct on the modification of the flow structure in the penstock. To achieve our goals, the Eulerian resolution of the Navier-Stokes equations is done by a RANS approach using the FLUENT calculation code. The turbulence model applied is that with two k-ɛ equations. The results show constant velocities upstream of the dam until approaching the water intake at a distance of about 15m upstream, keeping an asymmetric shape in the different sections constituting the penstock. The maximum velocities are observed on the innerside of the various elbow. Layers of positive pressure are also visible in the penstock away from the walls; suggesting substantially coaxial and positive iso-pressures in high velocity zones, with a maximum directed towards the center of the penstock. This phenomenon thus goes against the high velocity-low pressure hypothesis, and may be justified by the geographical arrangement of the penstock, associated with its large diameter.
Crude Distillation Unit often produces gasoline of low Research Octane Number (RON). For efficient engine performance, high RON-gasoline is required. Refiners resort to the use of different chemical compounds called additives to improve the RON of gasoline. One group of these additives is fuel oxygenates, oxygen-containing hydrocarbons. In this study, experimental results of the effect of two fuel oxygenates, Methyl tertiary Butyl Ether (MTBE) and Ethyl tertiary Butyl Ether (ETBE) on the RON, RVP, Distillation, Density, Oxidation Stability (Induction Period), Washed Gum and Copper corrosion were examined and compared. The results showed that ETBE improves the RON of gasoline slightly better than MTBE. The increase in RVP of the gasoline was higher with MTBE than ETBE. Distillation curves were not significantly different from each other and other properties such as oxidation stability and copper corrosion were the same for the blends used.
With the increasing demand for electrical energy worldwide and the proportionate inflation of natural resources, it is important to predict the electrical power output from baseload combined cycle power plants and the factors affecting the yield per hour. Finding reliable factors not only improves the performance of the power plant in terms of production or distribution but also ensures the proper utilization of natural resources (or fuels) with minimal effect on the environment and effective cost management. Though there are sophisticated machine learning models for predicting full load electrical power output, often these deployed models are unable to draw inferences. Thermodynamic models on the other hand are oftentimes too complex, are valid only under a set of assumptions, and are generally non-linear in nature adding to the computation time. Keeping these limitations in mind, the objectives of this study are to find potential predictor variables that affect the power output yield per hour and then use these inferences to construct a simple yet effective model to predict the electrical power output in combined cycle power plants. The dataset used for this study is from a combined cycle power plant over a span of six years (2006-2011), with the power plant operating in a full load. A combined cycle power plant is composed of gas turbines, steam turbines, and heat recovery steam generators. The gas and steam turbines generate the electricity which is combined in one cycle and is transferred from one turbine to another. The input features of the dataset considered for this study consist of average ambient variables: ambient temperature, ambient pressure, relative humidity, and exhaust vacuum which are used to predict the average hourly electrical power output.
In an era saddled by mounting energy dependency and insecurity, some are not only turning to renewable geothermal energy to ensure access, but it is growing in usage in the Western region of the United States of America. Notwithstanding the United States role as a major producer of geothermal resources globally, geothermal energy has over the last several years found ample use in various spheres of daily endeavors within communities. The surging demand is much so that, it now contributes quite significantly in the generation of electricity to power households and farming activities and to sustain domestic supplies essential to segments of the economy for communities from California to Nevada. With much of the production levels, installations and plant capacities of geothermal power fully entrenched in the western region of the country considering the geologic and physical attributes, California stands out as the largest producer of geothermal power compared to its neighbors in the western region. For that, the demand for geothermal resource has been recurrent in quite a few counties over the years on the California side of the US Western region. In the face of widespread demands in the region, geothermal energy infrastructure in the form of new plants has gradually penetrated different states under varying level of production and installed capacities to boost energy security and sustain development of the areas. Even at that, very little has been done in the literature to undertake a regional assessment of the potentials of geothermal energy using a mix scale approach of spatial analysis anchored in Geographic Information Systems (GIS). Accordingly, this study will fill that void in research by utilizing mix scale tools of GIS and descriptive states in analyzing the geothermal energy potentials of states in the Western region of the United States. Emphasizing the issues, trends, impacts, production, factors and future efforts through recommendations, the results point to growing usage and changes in a whole set of energy indicators ranging from production and demands, installed capacity to others over time in the region with much of that in California coupled with an uptick in geothermal portfolio. Additionally, the GIS mapping of the trends highlights gradual dispersion of changing patterns in consumption and presence of infrastructural facilities visibly concentrated in a cluster of areas located in the western region. With all these attributed to a host of socio-economic and physical factors, the paper proposed suggestions ranging from the design of a regional geothermal energy information system, the education of the public and more infrastructural development in the sector.
