Lowest Life Cycle Cost Research Articles

Interface shear resistance of clustered shear connectors for precast concrete bridge deck systems

Interface shear resistance of clustered shear connectors for precast concrete bridge deck systems

A Systems Thinking Approach to Managing Sustainment Phase Redesign Planning

This study applies a systems thinking approach to sustainment-phase redesign planning for large-scale, complex, sustainment-dominated systems (SDSs) found in the airline, aerospace and defense, healthcare, and utilities industries. Maintaining the SDS’s effectiveness throughout its long life presents a significant engineering and business challenge. This research contributes to the literature by developing an academically rigorous redesign-planning framework (RPF) through the lens of management and systems theories and the use of the grounded theory, research methodology. With the RPF, engineering managers can now simultaneously consider key issues, improvement opportunities, and risks of SDSs to develop and execute strategic, sustainment redesign plans that improve SDS performance at a lower lifecycle cost.

Implementation of Concurrent Redesign & Manufacture procedure for an automotive component

Implementation of Concurrent Redesign & Manufacture procedure for an automotive component

ANALYZING TAX CREDITS FOR RESIDENTIAL ENERGY EFFICIENCY USING ENERGY MODELING

From roughly 2013 to 2016, ten building product categories related to residential energy efficiency were eligible for United States ENERGY STAR Federal Tax Credits. In general, the objective of residential energy-efficiency tax credits is to encourage individuals to increase residential energy-efficiency investments and invest in properties that generate renewable energy. This research analyses eight of the available tax credit categories for four climatic zones and recommends packages based on low Life Cycle Cost and low First Cost for the eligible ENERGY STAR products. An experiment was conducted using energy modeling software for different tax credits and costs combinations, to explore potential variability in economic impact of the federal program. Analysis used Building America B10 Benchmark as a reference, and the energy computations were completed using Building Energy Optimization (BEopt) software. Results suggest that ENERGY STAR product packages that include PV systems generally have the lowest (best) Life Cycle Costs and packages that include Geothermal Heat Pumps generally have the highest (worst) Life Cycle Costs. However, there are tradeoffs between cost savings and energy source savings, and the particular economics of tax incentives for ENERGY STAR products depend on project specifics as well as owner priorities.

Minimal Solutions

This article discusses aspects of different manufacturing developments where manufacturers are working with researchers to develop ways to make products using less material and energy. Manufacturers looking to make American factories more competitive with foreign-based facilities are finding opportunities through re-engineering long-held wasteful practices. As a part of a multi-pronged approach, Pradeep Rohatgi, professor of materials science and engineering at the University of Wisconsin, Milwaukee, is leading an effort at reducing embodied-energy and decreasing emissions (REMADE) to examine manufacturing processes. REMADE aims to develop technology enablers to accomplish such goals as reducing primary feedstock consumption in manufacturing by 30 percent, reducing energy demand of secondary material processing by 30 percent, and achieving a 25 percent improvement in embodied energy efficiency of materials such as metals, polymers, fibers, and electronic waste. According to an expert, with embedded energy as the measuring stick, it is also possible to find manufacturing processes that produce very low life-cycle energy costs using carbon fiber composites or high-strength steels.

Studies of the constructed rail seat supports

In recent decades, the use of constructed sleepers on the world's railways has been increasing: the United States, the EU countries, Japan and China. Such sleepers, having positive performance qualities of wooden sleepers (good elasticity and dielectric properties, manufacturability during laying and during repair work), do not have negative qualities of wood. The article reviews the US and EU standards for testing sleepers made of constructed materials. The classification of such sleepers is given. Examples of testing of such sleepers by specialists of JSC “VNIIZhT” for the period from 1999 to 2016 are given, including sleepers from modified wood, wooden sleepers with elastomeric coating, composite sleepers from recycled high-density polyethylene with glass-filled polymer. Features of the Russian requirements to the constructed sleepers are considered. Composite rail seat supports are promising in application. Possessing the advantages of wooden sleepers (bars), they have higher wear resistance, lower life cycle costs (recyclable), are more homogeneous and do not rot. Damping properties of composite sleepers contribute to solving the problem of reducing noise and vibration from rolling stock. In addition, their use is one of the ways to reduce the negative impact of rail transport on the environment. With a feasibility study, such sleepers will successfully replace other types of rail seat supports. Spheres of rational application of composite rail seat supports are heaving sections of the railway track, areas with weak soils, turnouts, tracks on bridges, railway tunnels, and underground tracks. Taking into account the tendency to expand the polygon for laying composite sleepers, including railway tracks, metro routes and land transport in the Russian Federation, Kazakhstan and other CIS countries, it is advisable to develop a single interstate standard containing safety requirements and test methods for constructed rail seat supports.

Lifecycle costs and charging requirements of electric buses with different charging methods

Lifecycle costs and charging requirements of electric buses with different charging methods

Multi-period maintenance planning for public buildings: A risk based approach for climate conscious operation

Multi-period maintenance planning for public buildings: A risk based approach for climate conscious operation

CRACK HEALING UTILISING BACTERIAL SPORES IN CONCRETE

This self repair system is based upon harmless ground borne bacteria as the self-healing agent. The bacteria are activated after the concrete is cracked and the bacterial spores are exposed to moisture and air. The bacterial reproduction process creates a calcite by-product which fills the cracks in the concrete. By sealing the cracks in concrete, an effective barrier to air or liquid borne deleterious materials are formed and as a consequence of this, enhanced durability is achieved in the structure, resulting in lower life cycle costs. The concrete/mortar prisms were cracked and tested for water flow. They were then left for 56 days to heal and were subject to a test for water tightness. Healing was observed and a reduced water flow (74% and 32% healed) measured with the healed samples when compared to the specimens that were cracked and subjected to a water flow test without any healing agent. The number of samples were limited and a larger scale test is recommended for further work; however, this is a proof of concept of the process of healing and testing.

Feasibility of Magnesium Phosphate Cement (MPC) as a repair material for ballastless track slab

Feasibility of Magnesium Phosphate Cement (MPC) as a repair material for ballastless track slab

Development of a very light rail vehicle

The collaborative very light rail project involves the development of a novel railcar designed to revolutionise the rail industry: a self-powered, very light rail vehicle. Each of the two bogies contains a complete diesel–electric series-hybrid drive system, while the whole vehicle has undergone significant lightweighting activity to realise a target weight of less than 18 t, or 1 t per linear metre. The target cost is £500 000, which is to be achieved through the use of standardised, modular components, and appropriate materials and structural design methodologies. The research covers several aspects of the GB Rail Technical Strategy chapter relating to rolling stock. Lightweighting leads to a reduction in the propulsion requirements and reduces the infrastructure installation and maintenance costs. The use of higher-efficiency drive systems achieved through on-board energy systems enables a reduction in carbon dioxide emissions. These hybridisation activities improve the passenger experience through quieter operation, decreased vibration and the possible elimination of exhaust emissions in stations. Combining new drive systems with modular lightweight structures will lead to lower life-cycle costs and thus could enable the economical reopening of lines.

Quantification of concrete railway sleeper bending moments using surface strain gauges

Quantification of concrete railway sleeper bending moments using surface strain gauges

Determination of optimal volume of temporary storage tanks in a ship-based carbon capture and storage (CCS) chain using life cycle cost (LCC) including unavailability cost

Determination of optimal volume of temporary storage tanks in a ship-based carbon capture and storage (CCS) chain using life cycle cost (LCC) including unavailability cost

Evaluation of energy retrofit in buildings under conditions of uncertainty: The prominence of the discount rate

Evaluation of energy retrofit in buildings under conditions of uncertainty: The prominence of the discount rate

Parametric Analysis of Design Parameter Effects on the Performance of a Solar Desiccant Evaporative Cooling System in Brisbane, Australia

Solar desiccant cooling is widely considered as an attractive replacement for conventional vapor compression air conditioning systems because of its environmental friendliness and energy efficiency advantages. The system performance of solar desiccant cooling strongly depends on the input parameters associated with the system components, such as the solar collector, storage tank and backup heater, etc. In order to understand the implications of different design parameters on the system performance, this study has conducted a parametric analysis on the solar collector area, storage tank volume, and backup heater capacity of a solid solar desiccant cooling system for an office building in Brisbane, Australia climate. In addition, a parametric analysis on the outdoor air humidity ratio control set-point which triggers the operation of the desiccant wheel has also been investigated. The simulation results have shown that either increasing the storage tank volume or increasing solar collector area would result in both increased solar fraction (SF) and system coefficient of performance (COP), while at the same time reduce the backup heater energy consumption. However, the storage tank volume is more sensitive to the system performance than the collector area. From the economic aspect, a storage capacity of 30 m3/576 m2 has the lowest life cycle cost (LCC) of $405,954 for the solar subsystem. In addition, 100 kW backup heater capacity is preferable for the satisfaction of the design regeneration heating coil hot water inlet temperature set-point with relatively low backup heater energy consumption. Moreover, an outdoor air humidity ratio control set-point of 0.008 kgWater/kgDryAir is more reasonable, as it could both guarantee the indoor design conditions and achieve low backup heater energy consumption.

Characterisation of rigid polyurethane foam-reinforced ballast through cyclic loading box tests

As train speeds and heavy haul axle loads constantly increase due to market demands, so do the stresses and strains experienced by track structures. This is especially true for track transitions that generate high dynamic forces on both the track and vehicles because of poor vertical track geometry and/or differing track stiffness values on either side of the track transition. Reducing differential settlement between the two track structures at a track transition is one method of improving the life of the track, and increasing maintenance intervals. In this study, rigid polyurethane foam was used to reinforce ballast. Tests were conducted using a dynamic hydraulic load frame and a single sleeper in a large ballast box subjected to heavy haul axle loads. Unreinforced, reinforced and 50% reinforced ballast layers of 300 mm depth were tested to approximately 5 000 000 load cycles. The results showed that rigid polyurethane foam-reinforced ballast exhibited in the order of 60% less settlement for a fully reinforced layer, and 42% less settlement for a half reinforced layer. The use of rigid polyurethane foam (RPF) to reinforce ballast has a number of benefits that could result in better track geometry and longer maintenance cycles, in turn resulting in lower life cycle costs.

Comparative Life Cycle Cost Analysis of Si and SiC PV Converter Systems Based on Advanced $\eta$- $\rho$-$\sigma$ Multiobjective Optimization Techniques

This paper presents a novel virtual prototyping routine for power electronic converter systems. The approach facilitates a comprehensive and systematic benchmarking of different converter concepts based on a multiobjective optimization regarding the efficiency, power density, and costs. The underlying modeling framework is based on detailed and experimentally verified models. In particular, novel cost data as well as unpublished switching loss and core loss measurements are incorporated. The proposed virtual prototyping routine is employed to carry out a comparative study of the potential of Si and SiC semiconductors in a 10-kW residential three-phase photovoltaic inverter application. For this purpose, a state-of-the-art hard-switched three-level Si insulated-gate bipolar transistor (IGBT) system is compared to a hard-switched and to a soft-switched two-level SiC MOSFET system. The candidate systems for each concept are selected among the $\boldsymbol {\eta}$ - $\boldsymbol {\rho}$ - $\boldsymbol {\sigma}$ Pareto-optimized designs based on the life cycle costs. The hard-switched two-level SiC candidate system is found to be the most attractive solution featuring the lowest life cycle costs. When compared to the Si-based candidate system, not only a better power density and efficiency result. At the same time, besides the lower life cycle costs ( $-$ 22%), lower component costs ( $-$ 5%) can also be attained. The attractiveness of the found SiC solution is underlined by the simple control and the lowest component count among all concepts.

Lifetime reliability-based optimization of post-tensioned box-girder bridges

Lifetime reliability-based optimization of post-tensioned box-girder bridges

The First Polish Road Bridge Made of FRP Composites

Fibre reinforced polymer (FRP) composites have become an integral part of the construction industry because of their versatility, high strength-to-weight ratio, enhanced durability, resistance to fatigue and corrosion, accelerated construction and lower maintenance and life-cycle costs. However, all-composite structural bridge systems have specific shortcomings such as high initial costs, low stiffness and existence of brittle failure modes. To make the best use of materials and overcoming the above shortcomings, combinations of FRP and conventional materials have recently been investigated. The innovative hybrid idea of a “FRP composite–concrete” structural system for bridges has been proposed. The objective of the paper is the description of the bridge itself and the presentation of research results on its development. The finite element model (FEM) analysis, vacuum assisted resin transfer moulding (VARTM) manufacturing technique used for FRP girder production, some research results on the bridge system and demonstrative bridge construction are briefly presented.

Using a VSC Based HVDC Application to Energize Offshore Platforms from Onshore – a Life-cycle Economic Appraisal

Using a VSC Based HVDC Application to Energize Offshore Platforms from Onshore – a Life-cycle Economic Appraisal