Cost Optimization Approach Research Articles

Cost-Optimal Analysis for Nearly Zero Energy Buildings Design and Optimization: A Critical Review

Since the introduction of the recast of the EPBD European Directive 2010/31/EU, many studies on the cost-effective feasibility of nearly zero-energy buildings (NZEBs) were carried out either by academic research bodies and by national bodies. In particular, the introduction of the cost-optimal methodology has given a strong impulse to research in this field. This paper presents a comprehensive and significant review on scientific works based on the application of cost-optimal analysis applications in Europe since the EPBD recast entered into force, pointing out the differences in the analyzed studies and comparing their outcomes before the new recast of EPBD enters into force in 2018. The analysis is conducted with special regard to the methods used for the energy performance assessment, the global cost calculation, and for the selection of the energy efficiency measures leading to design optimization. A critical discussion about the assumptions on which the studies are based and the resulting gaps between the resulting cost-optimal performance and the zero energy target is provided together with a summary of the resulting cost-optimal set of technologies to be used for cost-optimal NZEB design in different contexts. It is shown that the cost-optimal approach results as an effective method for delineating the future of NZEB design throughout Europe while emerging criticalities and open research issues are presented.

2359 - Pareto Optimality for Assessing Multimodal Transportation Accessibility: Balancing Equity and Efficiency When Sitting Interventions

Background Travel time as a proxy for spatial accessibility in health care location-allocation studies can be particularly relevant when spatially concentrated population have a repeating pattern of infections, or a shorter return interval for services. This travel time based accessibility study focuses on a population identified as having repeat sexually transmitted infections. This population has been shown to be strongly associated with low socioeconomic status, which often corresponds to substantive reliance on public transit. Public health intervention studies barely consider transit when quantifying accessibility. Moreover, common frameworks used in these studies mostly focus on efficient allocation of services and usually disregard equity issues. Methods This study proposes a Pareto optimality approach to recommend locations that are multimodal accessible and allow equitable and efficient access to services. A simulated at-risk population, drawn from known core areas of repeat sexually transmitted infections in Kalamazoo County, Michigan, is examined. A raster-based drive time and a transit time model were developed using ArcGIS. Bi-objective optimization models were then developed to balance efficiency (by minimizing average travel time of the cohort) and equity (by minimizing variations of travel time from all simulated households). Results This raster-based cost optimization approach successfully identifies potential locations that are efficiently and equitably accessible using different transportation modes. A range of alternative solutions (Pareto frontiers) spatially and statistically enable decision makers to select from multiple locations and assess acceptable limits to travel for a given population. In our example, choosing a location, T2 over T1 means reducing the average travel time by 2.19 minutes by conceding only 11.94% increase in standard deviation of travel time. Additionally, T2 reduces the average travel time by 8.91 minutes and standard deviation by 3.7 minutes when comparing to existing facility location. In general, the spatial area bounded by the minimum average and minimum standard deviation location for a frontier line would represent the constraints to intervention location. The area then becomes a usable metric to measure transit versus private vehicle accessibility. Conclusions Improving spatial access to health facilities is important in reducing the prevalence of disease. Therefore, multimodal accessibility should be emphasized in future intervention placement research. The analysis of individual's travel time from distinct households to facility locations helps to address the inherent mismatch between current statistical methods that require detection of significant densities and the reality of individuals located on a street network or constrained by a particular transportation modality.

Failure analysis of CPT-based direct methods for axial capacity of driven piles in sand

ABSTRACTDue to variety of current pile bearing capacity methods based on cone penetration test (CPT) measurements, there is always a need for evaluating performance of existing methods to make proper choices of methods as well as safety factors for optimum design. In this regard, geotechnical databases are known as useful tools which facilitate evaluation of existing methods. This paper deals with axial bearing capacity of driven piles in sand using CPT-based methods. A database of seventy-six records is employed to analyze different criteria of interpreting static pile load test results to select the most consistent approach with the CPT-based methods. Then, performance of nine commonly used direct CPT-based methods was evaluated. Finally, via a failure probability and cost optimisation approach, optimum safety factors are presented and discussed. Analysis of different failure criteria shows that the Hansen 80% criterion leads to more consistent results with the CPT-based methods. In addition, almost all of the investigated methods showed promising performance. The attained safety factors range from 1.6 to 3.1 for all records, 1.4 to 3.1 for piles in compression, and 1.4 to 2.2 for the piles in tension. Then, efficiency of methods was evaluated and the methods with higher efficiency are introduced.

Automated layout design of multi-span reinforced concrete beams using charged system search algorithm

PurposeThe preliminary layout design of structures impacts upon the entire design process and, consequently, the total cost. The purpose of this paper is to select the most economical layouts that satisfy structural and architectural requirements, while considering the reciprocal effects of cost factors and layout variables at the preliminary stages of design.Design/methodology/approachThis paper presents an automated method for cost optimization of geometric layout design of multi-span reinforced concrete (RC) beams subjected to dynamic loading by using the charged system search (CSS) algorithm. First, a novel cost optimization approach for geometric layout problems is introduced, in which both cost parameters and dynamic responses are considered in the preliminary layout design of beams. The proposed structural optimization problem with constraints on the static and dynamic equilibrium, architectural dimensions and structural action effects is solved using the CSS algorithm.FindingsThe proposed CSS algorithm for solving the cost optimization problem can be easily used for optimizing the span lengths and is also capable of working with various cost functions. The presented examples show that the proposed algorithm using the new cost optimization function provides satisfactory results and can result in over 7 per cent cost saving.Originality/valueThis is an original paper proposing a novel methodology for preliminary layout design of concrete beams.

University building: Energy diagnosis and refurbishment design with cost-optimal approach. Discussion about the effect of numerical modelling assumptions

The paper discusses a methodological approach for designing energy refurbishment measures basing on a deep energy diagnosis with in-situ measurements that allow the complete characterizations of building /HVAC system and the indoor conditions. Then, the Cost-Optimal approach is applied to compare several retrofit scenarios considering interventions both on the building envelope and on plant systems. The case study is a University building in heating dominated climate of South Italy. According to a macroeconomic perspective, with a discount rate of 3%, the package of energy efficiency measures that combines installation of heat recovery systems, regulation dispositive for HVAC and LED lamps with automatic control induces considerable energy saving and reduction of polluting emissions (−33%) as well as the largest reduction in the overall cost (−35%).Moreover, the importance to use validated models is examined exhaustively by proposing a sensitivity analysis on uncertainties due to modelling assumptions mainly referring to the adoption of stochastic schedules for occupant behaviour and equipment or lighting usage. First of all, this analysis shows that the calibration indexes are always dissatisfied; besides it is demonstrated that refurbishment design can appear more convenient, with wrong assumptions. For instance, one of proposed scenario brings to energy saving of −41% and reduction of global cost of around −36%.

Holistic Design of HTHP Pipeline: PETRONAS’ Experience

When the oil and gas price was declining rapidly in 2016, it is prudent for global oil operator to identify opportunity to reduce the development cost. This is where all form of cost optimisation and holistic design approach have to be conducted, especially when dealing with High Pressure and High Temperature (HPHT) pipeline which normally requires higher CAPEX. Referring to a field case example from one of PETRONAS’s HPHT pipeline project in Malaysia waters, initial analysis had identified that a 24-inch subsea FWS HPHT pipeline with 40mm concrete coating thickness (for its on-bottom stability requirement), requires three numbers of ‘buckle trigger’s in order to manage the pipeline lateral buckling issues. Hence, a holistic design approach had been conducted to re-evaluate such requirement, commenced with detail assessment to look for all possible opportunities to reduce the pipeline temperature, one of it is to have a greater heat transfer from the pipeline. This exercise had landed into detail assessment on the pipeline on-bottom stability requirement which resulted in indication that the 24-inch FWS pipeline, that have a thicker wall thickness at the upstream portion, would be self-stabled - no requirement for concrete weight coating. Thus, benefitting from the results, further detail analysis had been conducted to assess the overall heat transfer from the pipeline as well as the impact towards the pipeline lateral buckling design, which lead to elimination of lateral buckling mitigation requirement. Unfortunately, further analysis had shown that in the absent of concrete weight coating, the pipeline un-concrete weight coated section i.e. hot end area and the field joints, would have rapid condensation and exposed to the intolerable top of line corrosion risk. Also, based on past experience with local installation contractor, there will be possibility of installation issue for the un-concrete coated pipeline with the tapered bracelet anode. Following that, thorough analysis had been performed and successfully mitigated the issue by applying field joint coating material with U-Value of 52 W/m2K to the 3LPP-Coated linepipe. As for the subsea flange connection, it is covered with thermal insulation, whereas the anode at the un-concrete coated section utilized anode sled mechanism. This holistic design approach had successfully reduced the project cost in line with PETRONAS’ aspiration i.e. low cost development project; and most importantly the ‘body of knowledge’ i.e. experiences, lessons learnt and good practices are captured in PETRONAS Technical Standard for future replication

Reliability Based Cost Optimization Approach for Wastewater Treatment Process Design

Reliability Based Cost Optimization Approach for Wastewater Treatment Process Design

Deadline-Constrained Cost Optimization Approaches for Workflow Scheduling in Clouds

Nowadays it is becoming more and more attractive to execute workflow applications in the cloud because it enables workflow applications to use computing resources on demand. Meanwhile, it also challenges traditional workflow scheduling algorithms that only concentrate on optimizing the execution time. This paper investigates how to minimize execution cost of a workflow in clouds under a deadline constraint and proposes a metaheuristic algorithm L-ACO as well as a simple heuristic ProLiS. ProLiS distributes the deadline to each task, proportionally to a novel definition of probabilistic upward rank, and follows a two-step list scheduling methodology: rank tasks and sequentially allocates each task a service which meets the sub-deadline and minimizes the cost. L-ACO employs ant colony optimization to carry out deadline-constrained cost optimization: the ant constructs an ordered task list according to the pheromone trail and probabilistic upward rank, and uses the same deadline distribution and service selection methods as ProLiS to build solutions. Moreover, the deadline is relaxed to guide the search of L-ACO towards constrained optimization. Experimental results show that compared with traditional algorithms, the performance of ProLiS is very competitive and L-ACO performs the best in terms of execution costs and success ratios of meeting deadlines.

On the optimal mix between lead-acid battery and thermal storage tank for PV and heat pump systems in high performance buildings

The coming into force of the European Directive 2009/28/CE [1] increases the role of renewable energy sources to satisfy the energy consumptions of new buildings and major renovations. In this respect, the vapor-compression heat pump coupled with PV panels is a promising solution and, consequently, it is increasingly used for residential heating applications. This HVAC solution is especially advantageous in high performance building when low temperature hydronic systems are adopted. However, in these buildings some issues arise in the HVAC control and the building might be easily subject to poor comfort conditions when approaching the nZEB target while maintaining economical convenience. Besides, the seasonal performance of the heating system is strongly dependent on the HVAC design. Hence, the optimal size of the storage components is a key aspect in order to maximize the renewable coverage factor, overcoming the shift in time between PV production and energy demand. For this reason, different strategies may be adopted such as the thermal storage tank or the electricity storage in lead-acid battery.This paper analyses the mix among the thermal storage tank, the lead-acid battery and the thermal capacitance of the building envelope for the optimal design solutions in three Italian climates. The complex interactions among building, occupants, weather conditions and HVAC systems are considered by means of a dynamic simulation tool. The optimal design solutions were studied, according to the cost optimal approach of the EPBD context, by means of a genetic algorithm developed in Matlab®. The energy performance for heating (EPh) and the net present value (NPV) are considered as competitive goals.

Cost-optimal approach to transform the public buildings into nZEBs: an European cross-country comparison

A cross-country comparison of the RePublic_ZEB project results is presented. The paper reports on the energy efficiency measures and on the options considered for the refurbishment of the public buildings taken as representative of the building stock in the countries involved in the project. The nZEB solutions are compared in terms of adopted energy efficiency measures; moreover, the nZEBs are quantitatively defined through a set of energy, economic and environmental parameters. The paper aims at giving an overview on the meaning of nZEB in the European context, and on its energy and economic feasibility for real public existing buildings.

Impact of Reference Years on the Outcome of Multi-Objective Optimization for Building Energy Refurbishment

There are several methods in the literature for the definition of weather data for building energy simulation and the most popular ones, such as typical meteorological years and European test reference years, are based on Finkelstein–Schafer statistics. However, even starting from the same multi-year weather data series, the developed reference years can present different levels of representativeness, which can affect the simulation outcome. In this work, we investigated to which extent the uncertainty in the determination of typical weather conditions can affect the results of building energy refurbishment when cost-optimal approach is implemented for the selection of energy efficiency measures by means of the NSGA-II genetic algorithm coupled with TRNSYS simulations. Six different reference years were determined for two north Italy climates, Trento and Monza, respectively in the Alpine and in the continental temperate regions. Four types of energy efficiency measures, related to both building envelope and HVAC system, were applied to six existing building typologies. Results showed how the choice of reference year can alter the shape of the Pareto fronts, the number of solutions included and the selection among the alternatives of the energy efficiency measures, for the entire front and, in particular, for energy and economic optima.

Impact of financial assumptions on the cost optimality towards nearly zero energy buildings – A case study

The energy efficiency challenge in Europe is mainly concerned with existing buildings and the investment scenarios to implement deep renovations. The cost-optimal approach imposed on EU-Member states by the European Energy Performance of Buildings Directive aims to identify the investment gap and challenges to transform existing buildings into nearly Zero Energy Buildings (nZEBs). The investment gap is function of several volatile financial parameters including discount rate (r), developing of energy price (e), decline rate of technology price (d), as well as nZEB’s incentives like feed-in-tariff (FiT) and investment grant (iG). In this context, the decision making process of individuals or investment institutions is hindered by complexity and uncertainty.In order to assist the decision making process and improve the visibility of financial energy benefits, a novel optimization-based parametric analysis scheme (OptnZEB-I) is developed. The scheme is designed to investigate a large number of economic scenarios (i.e., combinations of financial assumptions) in a short computational time while a holistic optimization approach is adopting for exploring all possible design options including energy conservation measures (ESMs); renewable energy sources (RETs) and mechanical systems (Sys).For demonstration, the scheme is applied to analyse the impact of several financial parameters on the cost-optimal energy performance level (CO-EPL) of a single family house in Finland. In line with the EU-directive, a large number of possible design options (∼3×109million) are optimized for 4608 cases of economic scenarios. The results of the address case study show that, in average, the CO-EPL ranges from 90 to 160 [kWh/m2]. The range has most frequent value of 145 kWh/m2. The CO-EPL is significantly sensitive to the e, f, then i, respectively. Less sensitivity is found to the other financial parameters.The robustness of the optimization results are verified by solving the addressed design problem by using four different optimization algorithms (i.e., pattern search, interior-point, simulated annealing and genetic algorithms).

Renewable energy technology integration for the island of Cyprus: A cost-optimization approach

In light of the ongoing financial crisis, Cyprus is called to transform its energy sector. The high electricity cost has been recognized as a priority issue and authorities on the island are considering several available options to reduce electricity tariffs. A fuel switch from oil to gas, domestic or imported, an electrical cross-border interconnection and a rapid increase in the share of renewable energy are among the major options being considered. Focusing on the power supply of Cyprus, the present study uses a cost-optimization tool to investigate the impact of different combinations of policy decision, resulting in a series of different scenarios, with some common key findings, with the aim of directly informing future energy policy decisions. Results indicate that renewable energy technologies will play a major role regardless the decisions taken. However, a set of enabling regulatory and market changes on the horizon might prevent least-cost deployment of renewables to take place. This study will review the findings and make some recommendations on the achievement of this optimal pathways for the evolution of Cyprus electricity sector.

A comprehensive cost-optimal approach for energy retrofit of existing multi-family buildings: Application to apartment blocks in Turkey

This research presents a comprehensive cost-optimal approach for existing building retrofits. The approach incorporates energy efficiency measures related to building envelope, building energy systems and renewable energy, all at once. Moreover, the cost-optimal calculation scope is extended through integration of occupant behaviour.The comprehensive approach is implemented for a reference building which represents high-rise apartment blocks in Turkey; these building types accommodate 4500 families corresponding to 23.1% of the national households. Three different climatic regions, that show significant distinction from each other, were selected for the sample application of the approach in order to refer different climates. Cost-optimal calculations were performed for more than 1300 scenarios. Integration of occupant behaviour into this calculation procedure was demonstrated with sensitivity analyses; the present application of the approach was focused on the use of window openings by occupants.Results reveal that cost-effective energy saving potential is higher than 70% in high-rise apartments. Moreover, occupant behaviour related to window openings is able to raise this rate above 80%. The findings indicate the necessity of comprehensive approach and demonstrate that integration of occupant behaviour into cost-optimal calculations is fundamental in order to reach significant and stable results.

Light and Heavy Energy Refurbishments of Mediterranean Offices. Part I: Energy Audit of an Institutional Building on the Naples Coast

The public hand has a demonstrative role in matter of energy efficiency of owned or occupied buildings. Here, the energy audit of a high-rise university building is proposed. The methodology adopts the Cost-Optimal approach, as imposed by the European guidelines (EU Directive 2010/31/EU), based on feasibility studies performed with transient energy simulations. In particular, in situ surveys (infrared thermography and measurements of U-values) have been used for building, as detailed as possible, the building model for the numerical study. The analysis evidenced high-energy demands, mainly for the space heating and cooling. A second study discusses a cost-effective energy retrofit.

Gulf war contamination assessment for optimal monitoring and remediation cost-benefit analysis, Kuwait

Site characterization was performed on an area of 580 km2 around the strategically vital freshwater aquifers of the Al-Rawdhatain and Umm Al-Aish to assess the status of groundwater pollution as the result of Iraq invasion to Kuwait in 1991. Advanced data analysis and visualization software (EVS-Pro) was used for groundwater contamination assessment analytes: total petroleum hydrocarbon (TPH) and total dissolved solids (TDS). This will reduce the number of samples needed (saves time and money) and provide a superior assessment of the analytes distribution. Based on the “minimum–maximum plume technology” analysis, the nominal plume area with a threshold of 0.031 mg/kg TPH is estimated at about 0.47 km2. This is the difference between the maximum and minimum predicted plume sizes. EVS-Pro also computed 3.3775 × 109 and 4.0788 × 106 for the plume volumes and masses (dollars per volume and mass), respectively. Also, new sampling locations were determined for further detailed site assessments based on the confidence and uncertainty analysis, which is more defensible and cost-optimized approach. This will reduce the number of samples needed (saves time and money) and provide a superior assessment of the analytes distribution. These tools prove to be effective in assessing remediation costs of clean-up versus benefits obtained and in developing a cost-effective monitoring programme for insights into processes controlling subsurface contaminant transport that impact water quality.

Technology Focus: Wellbore Tubulars (June 2016)

Technology Focus Today’s economic situation within our industry has been harsh, harder than any downturn I have witnessed during my 44 years in the industry. However, it has provided the environment to influence positively the forging, application, field trialing, and acceptance of innovative technologies within our industry. Recent oil-industry technical publications are filled with a wide variety of applications of models, tools, and techniques being developed and applied to the drilling, completion, intervention, and even wellbore-abandonment arenas, allowing us to be more efficient by driving costly nonproductive time out of our operations. While the development of innovative technologies is critical, their correct and cost-effective application is even more important. No matter how good, technically impressive, or even innovative a technology is, if its application is not operationally practical as well as cost-efficient, then in the end it is just a cute widget. The papers within this Wellbore Tubulars section focus on delivering efficiencies to us, converting nonproductive time into new dollars for the bottom line. These papers span the application of A 1000-m steerable drilling liner directionally drilled in through an unstable shale in the åsgard/ Midgard field in the Norwegian North Sea after multiple attempts to drill and case this same hole section failed. A subsea completion string that would provide efficient hydraulics during fracturing operations while ensuring mechanical and pressure integrity. This high-pressure/high-temperature system was developed to be the answer to extreme completion challenges within multiple deepwater Gulf of Mexico projects within the Jack and St. Malo field reservoirs. A drilling software that delivers operational surveillance in real time, assisting in the avoidance of stuck pipe and with application within a variety of drilling environments. The proposed software was tested with historical data sets from 36 stuck-pipe incidents in the Eagle Ford, Utica, Permian, and Gulf of Mexico. The paper contains discussion of case histories in several shale horizontal unconventional wells. The extended-reading references selected further explore various applications and evaluation techniques spanning tubular-application areas from completion intervention to casing remediation to drilling-challenge mitigation. These include case-history references to assist readers in expanding the applications knowledge within their wellbore-tubulars toolbox. We all strive to deliver quality well construction, production, intervention, and abandonment to our industry. During the evaluation of the writings to be included within these few short pages encapsulating the extensive base of information published that surrounds the application of wellbore tubulars, I was struck by the quality and diversity of information available. Therefore, the reader is encouraged to search further within the industry’s technical-paper and article archives in the OnePetro online library (www. onepetro.org) to explore additional aspects of wellbore tubulars and the tools and techniques that are currently available to responsibly apply and critique their applicability. JPT Recommended additional reading at OnePetro: www.onepetro.org. SPE 175878 Steerable Drilling Liner Matches the Industry’s Common Theme Regarding Cost-Optimization Approaches and Minimizing Geomechanics-Related Challenges—Technology Overview, Applications, and Limitations by Wael El Sherbeny, Baker Hughes, et al. SPE 168271 Tubing-Retrievable Surface- Controlled Subsurface-Safety-Valve Floating-Flapper Remediation by B. Gary, Halliburton, et al. SPE/IADC 178780 Solid-Expandable Solution To Qualify Existing Nonsour- Service Production Casing by Jesus D. Contreras, ConocoPhillips, et al.

Charging, power management, and battery degradation mitigation in plug-in hybrid electric vehicles: A unified cost-optimal approach

Holistic energy management of plug-in hybrid electric vehicles (PHEVs) in smart grid environment constitutes an enormous control challenge. This paper responds to this challenge by investigating the interactions among three important control tasks, i.e., charging, on-road power management, and battery degradation mitigation, in PHEVs. Three notable original contributions distinguish our work from existing endeavors. First, a new convex programming (CP)-based cost-optimal control framework is constructed to minimize the daily operational expense of a PHEV, which seamlessly integrates costs of the three tasks. Second, a straightforward but useful sensitivity assessment of the optimization outcome is executed with respect to price changes of battery and energy carriers. The potential impact of vehicle-to-grid (V2G) power flow on the PHEV economy is eventually analyzed through a multitude of comparative studies.

Cost optimisation approach for cloud-based smart grid data management

The smart grid is an advanced power grid with efficient two-way communication of power and data. Due to the modular nature of network and users, the data storage and processing were required. Cloud computing is one of the efficient technology for storing and managing such data in the real world. To solve such data management issues, we proposed a cloud-based smart grid data management (CSGDM) model and an optimisation algorithm to resolve the challenges of such environment. The proposed algorithm deals with the grid utilisation and power usage cost calculation with an optimisation mechanism for cost function to minimise the data storage prices.

Cost optimization approaches for scientific workflow scheduling in cloud and grid computing: A review, classifications, and open issues

Workflow scheduling in scientific computing systems is one of the most challenging problems that focuses on satisfying user-defined quality of service requirements while minimizing the workflow execution cost. Several cost optimization approaches have been proposed to improve the economic aspect of Scientific Workflow Scheduling (SWFS) in cloud and grid computing. To date, the literature has not yet seen a comprehensive review that focuses on approaches for supporting cost optimization in the context of SWFS in cloud and grid computing. Furthermore, providing valuable guidelines and analysis to understand the cost optimization of SWFS approaches is not well-explored in the current literature. This paper aims to analyze the problem of cost optimization in SWFS by extensively surveying existing SWFS approaches in cloud and grid computing and provide a classification of cost optimization aspects and parameters of SWFS. Moreover, it provides a classification of cost based metrics that are categorized into monetary and temporal cost parameters based on various scheduling stages. We believe that our findings would help researchers and practitioners in selecting the most appropriate cost optimization approach considering identified aspects and parameters. In addition, we highlight potential future research directions in this on-going area of research.