Search results for "System dynamics"

System dynamics models for decision making in product multiple lifecycles

2015

The main drivers for adopting product multiple lifecycles are to gain ecological and economic advantages. However, in most of the cases it is not straight forward to estimate the potential ecological and economic gain that may result from adopting product multiple lifecycles. Even though many researchers have concluded that product multiple lifecycles result in gain, there are examples which indicate that the gain is often marginal or even none in many cases. The purpose of this research is to develop system dynamics models that can assist decision makers in assessing and analysing the potential gain of product multiple lifecycles considering the dynamics of material scarcity. The foundatio…

Insights from a Simulation Model of Disaster Response: Generalization and Action Points

2016

In a prior paper we presented a system dynamics model that simulates responder behavior in a Norwegian landslide. The model shows how a set of vicious feedback loops caused by following standard organizational procedures that do not fit the disaster situation initially increases errors in response. Eventually learning and sensemaking in an improvisation/experimentation process leads to new emergent dynamics whereby the loops act virtuously. In this paper we aim to generalize this initial study by explaining in more detail how the model can describe large scale disaster responses of different types and how it relates to the wider disaster response literature. We discuss what types of levers,…

Integration of Subject Related ICT in Schools Is Failing; Could Revival of System Dynamics and Simulations Be an Example towards Improvement?

2010

A recent survey of teachers in 172 different Norwegian schools reveals that the integration of new technology into different subjects is far from the goals set by the Ministry. A total of around 1000 teachers responded to extensive questionnaires particularly developed for each one of 8 school subjects. The dominant uses in classrooms are related to standard software and Internet browsers. Very few teachers indicate that they apply software or technology going deeper into their subject teaching, promoting understanding and insight.

Obtaining dynamic Norton parameters of a solar panel from manufacturer data

2016

Photovoltaic arrays have been shown to possess significant influence on the dynamic performance of coupled source-converter-load system while its dynamic resistance is the most important parameter, contributing to the overall system dynamics. In this paper, a method of deriving the parameters of linearized photovoltaic equivalent circuit from manufacturer data is proposed. The approach allows predicting the range of dynamic Norton parameters for the expected irradiation and temperature operation conditions thus defining clear bounds required for robust design of the system controller.

Simulation of stability and dynamics of multistage flash desalination

2011

gPROMS software was used to study the dynamics of a multistage flash desalination brine circulation system (MSF-BR) as a function of major operating parameters. Most of the previous studies focused on MSF-BR dynamic model development however; it gave very little information on dynamic response of the system to the most significant process independent parameters. The present model was first validated against available industrial data of different plants. System dynamics were obtained upon increasing/decreasing several of the operating parameters over a range of ± 15%. Results show that increase/decrease of the cooling seawater flow rate have limited effect on the system dynamics. Increasing/…

Steady State and Dynamic Models of Multistage Flash Desalination: A Review

2010

This article focuses on a review of literature studies on steady state and dynamic modeling of the multistage flash desalination process (MSF). The review shows that both steady state and dynamic models are based on lumped parameter approach. Differences in literature models are found in the assumptions used to model the flashing stage in addition to the correlations used to determine the heat transfer coefficients, thermodynamic losses, thermodynamic and transport properties. Interestingly, literature indicates a rapid progress made in software used for coding and solution of the model equations. The review shows a limited number of literature models for the internals of the flashing stage…

A data-driven methodology to support pump performance analysis and energy efficiency optimization in Waste Water Treatment Plants

2017

Abstract Studies and publications from the past ten years demonstrate that generally the energy efficiency of Waste Water Treatment Plants (WWTPs) is unsatisfactory. In this domain, efficient pump energy management can generate economic and environmental benefits. Although the availability of on-line sensors can provide high-frequency information about pump systems, at best, energy assessment is carried out a few times a year using aggregated data. Consequently, pump inefficiencies are normally detected late and the comprehension of pump system dynamics is often not satisfactory. In this paper, a data-driven methodology to support the daily energy decision-making is presented. This innovati…

Smart grid integrated green data centres as ancillary service providers

2015

In this paper a review of Green Data Centres facilities to support smart grids operation is proposed. The paper describes the ancillary services a Green Data Centre can provide both in terms of spinning reserve provision and different regulation services. In the application section, a real electrical grid hosting a data centre is considered. The infrastructure is owned by Engineering S.p.A. and is installed in northern Italy. The system has been considered as connected to the MV distribution grid in presence of other renewable energy sources. The impact of possible power management operations over the considered data centre has been studied by means of a simulation software and the spinning…

Once t hrough m ultistage fl ash d esalination: gPROMS d ynamic and s teady s tate m odeling

2010

This study focuses on modeling the steady state and dynamic behavior of the multistage flash desalination process (MSF) using gPROMS. This modeling tool allows for simultaneous coding of the system dynamics and steady state performance. In addition, it allows the use of the most efficient solvers for a set of non-linear differential and algebraic equations describing the MSF process. The system model and analysis are based on actual plant data that includes 21 flashing stages and a capacity of 378 kg/s (32,000 m3/d). The simulated unit is part of a massive MSF installation in Doha, Kuwait. System's dynamic behavior is simulated by a step change in the input values of the main operating para…

A CARBON CONSTRAINED SOCIETY: THE ECONOMICS OF CARBON CAPTURE, UTILIZATION AND STORAGE

Traditionally carbon dioxide (CO2) emissions has been viewed and treated as a “bad” rather than a “good”. This mental model is of little surprise due to a well-established consensus on carbon dioxide as a pollutant constraining the sustainability of economic and social development at a global scale. In the world where so many actors are preoccupied with shifting towards a low- carbon economy the very idea of carbon dioxide being a commodity (literally and not in the form of carbon caps or quotas trade, in which case a “commodity” is in fact the right to emit carbon, which is in its essence a very different concept) might be a big of a statement. However, this idea is not a mere perspective …