Static Wall Research Articles

Cantilever steel tubular pile wall embedded in soft rock subjected to sequential loadings

A centrifuge model is developed to simulate sequential dynamic and static loadings with clear boundary conditions, aiming to comprehend the mechanical response of a cantilever-type retaining wall embedded into the soft rock. The model wall was made of steel tubular piles with a 2 m diameter and 25 mm thickness in a prototype scale under 50g. Wall retained height (H) and embedment depth (dr) into model soft rock (qu = 1.4 MPa) were 12 and 3 m, respectively. Sequential loadings (dynamic and static) were applied to the wall with dry and saturated backfill sand. It was found that the resilience of the wall created by the confinement of soft rock during the dynamic loading is a critical factor that controls the earth pressure and the dynamic and residual displacements of the wall, both during and after the dynamic loading and the static loading. Due to the resilience effect, an effective earth pressure ratio of more than the design active or even an at-rest pressure coefficient could be expected, especially after dynamic loading. However, a slight wall movement in the static loading and wall creep displacement after dynamic loading could reduce this resilience effect.

Computational Fluid Dynamics-Based Optimisation of High-Speed and High-Performance Bearingless Cross-Flow Fan Designs

To enhance the fluid dynamic performance of bearingless cross-flow fans (CFFs), this paper presents a CFD-based optimisation of both rotor and static casing wall modifications. High-performance CFFs are essential in industrial applications such as highly specialised laser modules in the semiconductor industry. The goal for the investigated rotor modifications is to enhance the CFF’s mechanical stiffness by integrating reinforcing shafts, which is expected to increase the limiting bending resonance frequency, thereby permitting higher rotational speeds. Additionally, the effects of these rotor modifications on the fluid dynamic performance are evaluated. For the casing wall modifications, the goal is to optimise design parameters to reduce losses. Optimised bearingless CFFs benefit semiconductor manufacturing by improving the gas circulation system within the laser module. Higher CFF performance is a key enabler for enhancing laser performance, increasing the scanning speed of lithography machines, and ultimately improving chip throughput. Several numerical simulations are conducted and validated using various commissioned prototypes, each measuring 600mm in length and 60mm in outer diameter. The results reveal that integrating a central shaft increases the rotational speed by up to 42%, from 5000rpm to 7100rpm, due to enhanced CFF stiffness. However, the loss in fluid flow amounts to 61% and outweighs the gain in rotational speed. Optimising the casing walls results in a 22% increase in maximum fluid flow reaching 1800m3/h at 5000rpm. It is demonstrated that the performance of bearingless CFFs can be enhanced by modifying the geometry of the casing walls, without requiring changes to the CFF rotor or bearingless motors.

The effect of including dynamic imaging derived airway wall motion in CFD simulations of respiratory airflow in patients with OSA

Obstructive sleep apnea (OSA) is an airway disease caused by periodic collapse of the airway during sleep. Imaging-based subject-specific computational fluid dynamics (CFD) simulations allow non-invasive assessment of clinically relevant metrics such as total pressure loss (TPL) in patients with OSA. However, most of such studies use static airway geometries, which neglect physiological airway motion. This study aims to quantify how much the airway moves during the respiratory cycle, and to determine how much this motion affects CFD pressure loss predictions. Motion of the airway wall was quantified using cine MRI data captured over a single respiratory cycle in three subjects with OSA. Synchronously-measured respiratory airflow was used as the flow boundary condition for all simulations. Simulations were performed for full respiratory cycles with 5 different wall boundary conditions: (1) a moving airway wall, and static airway walls at (2) peak inhalation, (3) end inhalation, (4) peak exhalation, and (5) end exhalation. Geometric analysis exposed significant local airway cross-sectional area (CSA) variability, with local CSA varying as much as 300%. The comparative CFD simulations revealed the discrepancies between dynamic and static wall simulations are subject-specific, with TPL differing by up to 400% between static and dynamic simulations. There is no consistent pattern to which static wall CFD simulations overestimate or underestimate the airway TPL. This variability underscores the complexity of accurately modeling airway physiology and the importance of considering dynamic anatomical factors to predict realistic respiratory airflow dynamics in patients with OSA.

Seismic performance of sheet pile walls in liquefiable soil using centrifuge tests and an assessment of nonlinear effective stress analysis using PM4Sand

Past earthquakes have revealed that damage to sheet-pile walls under saturated conditions is closely linked to excess pore water pressure buildup in the surrounding soil. Nonlinear effective stress analysis (ESA) is commonly employed to assess the seismic performance of sheet-pile walls in liquefiable soils, incorporating constitutive models for liquefaction simulation. However, ESA results are sensitive to uncertainties in input parameters, model calibration, and modeling techniques. Dynamic centrifuge tests conducted in the Liquefaction Experiments and Analysis Project (LEAP) offer valuable insights into important response mechanisms and validate ESA. Seven centrifuge tests on a cantilevered sheet-pile wall model showed that liquefaction did not occur in the backfill near the wall due to net seaward wall displacement but did occur farther away. In addition, the mechanism of wall displacement was mainly due to the shear deformation of the softened backfill, with the displacement magnitude depending on the relative density of soil, peak ground acceleration of base motion, and wall displacement during gravity loading. Nonlinear ESA was performed for three centrifuge tests using FLAC2D and the PM4Sand constitutive model for soil. Gravity analysis captured static wall displacement and initial stress distribution in the soil. Two calibrations of the PM4Sand model were pursued at the element level: C1 calibration for liquefaction strength and C2 calibration for liquefaction strength and the post-liquefaction shear strain accumulation rate. System-level simulations showed similar liquefaction behavior as observed in the tests for both calibrations. However, the C2 calibration provided closer predictions of wall displacements, while the C1 calibration (default for PM4Sand) resulted in larger and more conservative displacements. Overall, the PM4Sand model performed well with minimal calibration, making it suitable for nonlinear ESA of sheet-pile walls.

Multiple object tracking in the presence of a goal: Attentional anticipation and suppression.

In previous studies, we found that tracking multiple objects involves anticipatory attention, especially in the linear direction, even when a target bounced against a wall. We also showed that active involvement, in which the wall was replaced by a controllable paddle, resulted in increased allocation of attention to the bounce direction. In the current experiments, we wanted to further investigate the potential influence of the valence of the heading of an object. In Experiments 1 and 2, participants were instructed to catch targets with a movable goal. In Experiment 3, participants were instructed to manipulate the permeability of a static wall in order to let targets either approach goals (i.e., green goals) or avoid goals (i.e., red goals). The results of Experiment 1 showed that probe detection ahead of a target that moved in the direction of the goal was higher as compared to probe detection in the direction of a no-goal area. Experiment 2 provided further evidence that the attentional highlighting found in the first experiment depends on the movement direction toward the goal. In Experiment 3, we found that not so much the positive (or neutral) valence (here, the green and no-goal areas) led to increased allocation of attention but rather a negative valence (here the red goals) led to a decreased allocation of attention.

Utility of argon as a static charge and wall fouling suppressant in atmospheric gas-solid fluidized beds

This work aimed to study the usability of argon to mitigate electrostatic charging and fouling of polyethylene resin fluidized in a stainless-steel column. Nitrogen, argon, and their binary mixtures of various concentrations were utilized to fluidize polyethylene. Successive and intermittent fluidizations with argon and nitrogen were also carried out to explore the feasibility of using argon in commercial reactors. Fluidization with pure argon resulted in the lowest specific charge and substantially reduced the fouling by 90% relative to pure nitrogen. The results for the mixture trials showed a decreasing non-linear trend as the concentration of argon increased. Even presence of 10 vol% argon in the mixture reduced the wall fouling by 50%. Successive and intermittent fluidization also yielded fouling and specific charge values comparable to pure argon. The results are attributed to argon's relatively low dielectric strength and subsequent localized gas discharge within the particle-dense section of the bed.

Taylor vortices in yield stress fluids with static wall layers on the outer cylinder

Taylor vortices in yield stress fluids with static wall layers on the outer cylinder

Numerical investigation of the convective heat transfer coefficient for a concentric annulus with rotating inner cylinder with application in the deep geothermal drilling process

We present a numerical analysis of the convective heat transfer coefficient for the turbulent Taylor–Couette–Poiseuille flow in a concentric annular gap. The study utilizes rotational speeds defined by the Taylor number (Ta) ranging from 2×104 to 1×108, each combined with the axial flow defined by Reynolds number Re=4485, resulting in eight distinct simulation cases in addition to one base case where no rotation is involved. The transient k−ω model available with ANSYS FLUENT for computational fluid dynamics is used for turbulence modelling. The hydrodynamic and thermal fields of the model are validated by comparison with experimental and numerical results from the literature, with an overall qualitatively good agreement. Moreover, the resultant velocity fields exhibit an improvement over the LES results from the literature in comparison with the experimental data. The influence of the flow on the thermal fields is investigated by the swirl parameter N, which compares the rotation speed of the inner cylinder and the mean axial speed. There is no noticeable effect on the thermal fields for the magnitudes of N<1.19. Coherent structures are present for N≥1.19, confirming a direct effect of the temperature and the velocity profiles. The convective heat transfer coefficients (CHTC) are examined by their non dimensional form, the Nusselt number Nu, across the inner rotating wall and the outer static wall. The rotation of the inner wall shows a positive effect on the CHTC for both inner and outer walls. The correlation between the Nu and Ta delivers the exponents of 0.334 and 0.266 for the inner and the outer wall, respectively.

CFD modeling and experimental validation of the thermal performance of a novel dynamic PCM Trombe wall: Comparison with the companion static wall with and without PCM

To reduce the heat loss from the PCM Trombe wall and increase its thermal efficiency, an innovative dynamic Trombe wall incorporating a PCM layer on one face and an insulation layer on the opposite face is proposed. During the charging period of the PCM, the face containing the PCM is exposed to solar irradiation, while the face containing the insulation is exposed to the conditioned air. During the discharging period, the two faces exchange position. A large-scale model of a building unit with such a wall is constructed and tested. The model is analyzed using three-dimensional computational fluid dynamics (CFD), with generally good agreement between the two sets of results. Subsequently, CFD models of three building units are analyzed, one having the proposed dynamic wall, the other an analogous static wall, and the last one identical to the static wall but without PCM. Throughout the PCM discharging period, the temperatures of all the surfaces and the air in the conditioned space in the unit with the proposed wall are found to be consistently higher than those in the companion units. Based on energy conservation analysis, compared with the static wall, with and without PCM, the energy saving efficiency of the proposed wall is higher 25.3% and 17.5%, respectively. Similarly, its thermal efficiency is higher 79.8% and 35.4%, respectively. To achieve even higher thermal efficiency, it is shown that the thermal resistance of the glazing in the envelope, and the envelope as a whole, need to be increased by using materials with low density and heat capacity.

Rhinoplasty: Considerations for Patients with Facial Paralysis.

Nasal obstruction is a common sequela of flaccid facial paralysis but one that is often underaddressed surgically. Weakness of nasal musculature on the paralyzed side of the face leads to nasal valve narrowing through loss of static and dynamic nasal side wall tone as well as inferomedial displacement of the alar base. Standard rhinoplasty techniques such as alar batten grafts or flaring sutures may be used to support the nasal side wall in facial paralysis. However, to address the inferomedial alar displacement, suspension techniques are often required. Suture resuspension and fascia lata resuspension techniques are described, with modifications to each to improve longevity of the suspension.

Axion electrodynamics: Green’s functions, zero-point energy and optical activity

Starting from the theory of Axion Electrodynamics, we work out the axionic modifications to the electromagnetic Casimir energy using the Green’s function method, both when the axion field is initially assumed purely time-dependent and when the axion field configuration is a static domain wall, so purely space-dependent. For the first case it means that the oscillating axion background is taken to resemble an axion fluid at rest in a conventional Casimir setup with two infinite parallel conducting plates, while in the second case we evaluate the radiation pressure acting on an axion domain wall. We extend previous theories in order to include finite temperatures. Various applications are discussed. (i) We review the theory of Axion Electrodynamics and particularly the energy–momentum conservation in a linear dielectric and magnetic material. We treat this last aspect by extending former results by Brevik and Chaichian (2022) and Patkos (2022). (ii) Adopting the model of the oscillating axion background we discuss the axion-induced modifications to the Casimir force between two parallel plates by using the Green’s function method. (iii) We calculate the radiation pressure acting on an axion domain wall at finite temperature T. Our results for an oscillating axion field and a domain wall are also useful for condensed matter physics, where some topological materials, “axionic topological insulators”, interact with the electromagnetic field with a Chern–Simons interaction, like the one in Axion Electrodynamics, and there are experimental systems analogous to time-dependent axion fields and domain walls as the ones showed e.g. by Jiang and Wilczek (2019) and Fukushima et al. (2019). (iv) We compare our results, where we assume time-dependent or space-dependent axion configurations, with the discussion of the optical activity of Axion Electrodynamics by Sikivie (2021) and Carrol et al. (1990). We also make comparisons with the properties of known materials, such as optically active, chiral media and the Faraday effect.

Asymptotic Stability of Precessing Domain Walls for the Landau–Lifshitz–Gilbert Equation in a Nanowire with Dzyaloshinskii–Moriya Interaction

We consider a ferromagnetic nanowire and we focus on an asymptotic regime where the Dzyaloshinskii-Moriya interaction is taken into account. First we prove a dimension reduction result via $$\Gamma $$ -convergence that determines a limit functional E defined for maps $$m:\mathbb {R}\rightarrow \mathbb {S}^2$$ in the direction $$e_1$$ of the nanowire. The energy functional E is invariant under translations in $$e_1$$ and rotations about the axis $$e_1$$ . We fully classify the critical points of finite energy E when a transition between $$-e_1$$ and $$e_1$$ is imposed; these transition layers are called (static) domain walls. The evolution of a domain wall by the Landau–Lifshitz–Gilbert equation associated to E under the effect of an applied magnetic field $$h(t)e_1$$ depending on the time variable t gives rise to the so-called precessing domain wall. Our main result proves the asymptotic stability of precessing domain walls for small h in $$L^\infty ([0, +\infty ))$$ and small $$H^1(\mathbb {R})$$ perturbations of the static domain wall, up to a gauge which is intrinsic to invariances of the functional E.

Instability of bubble expansion at zero temperature

In the context of false vacuum decay at zero temperature, it is well known that bubbles expand with uniform proper acceleration. We show that this uniformly accelerating expansion suffers from an instability related to the bubble size. This can be observed in Minkowski spacetime as a tachyonic mode in the spectrum of fluctuations for the energy functional in the reference frame in which the uniformly accelerating bubble wall appears static. In such a frame, arbitrary small perturbations cause an amplifying departure from the static wall solution. This implies that the nucleated bubble is not a critical point of the energy functional in the rest frame of nucleation but becomes one in the accelerating frame. The aforementioned instability for vacuum bubbles can be related to the well-known instability for the nucleated critical static bubbles during finite-temperature phase transitions in the rest frame of the plasma. It is therefore proposed that zero-temperature vacuum decays as seen from accelerating frames have a dual description in terms of finite-temperature phase transitions.

A turbulence modeling study of the precessing vortex core in a pipe flow

The phenomenon of precessing vortex core is observed experimentally when swirl is imparted on an axial flow in a pipe. It manifests as a coherent structure in the form of a helical vortex of regular wavelength whose axis is coincident with the pipe’s axis. The most striking consequence of this pattern of flow is the generation of periodic fluctuations in the streamwise distribution of the wall static pressure and skin friction. While the prediction of the precessing vortex has proved possible with large-eddy simulations, there is no record of this phenomenon being captured in great detail by Reynolds-averaged Navier-Stokes methods utilizing turbulence models to close the time-averaged equations. The purpose of the research reported here was to determine whether the precessing vortex core and its impact on conditions at the wall can be captured using this approach. The turbulence model used was of the Reynolds-stress transport type which involves the solution of a differential transport equation for each of the six non-zero components of the Reynolds stress tensor. Previous studies in which such models were used in the prediction of rotating and swirling flows have shown that their performance is largely determined by the way in which the difficult fluctuating pressure-strain correlations that appear in these equations are modeled. To this end, four very different alternative models for these correlations were assessed by comparisons with experimental data for a swirling pipe flow at relatively high swirl number. It was found that the models do indeed capture the precessing vortex revealing it to be in the form of an exceptionally well-defined double vortex. It was also found that the expected periodic fluctuations in static pressure and wall skin friction, not previously obtained in turbulence model studies, are captured by the present closures.

Generic framework for quantifying the influence of the mitral valve on ventricular blood flow.

Blood flow within the left ventricle provides important information regarding cardiac function in health and disease. The mitral valve strongly influences the formation of flow structures and there exist various approaches for the representation of the valve in numerical models of left ventricular blood flow. However, a systematic comparison of the various mitral valve models is missing, making a priori decisions considering the overall model's context of use impossible. Within this study, a benchmark setup to compare the influence of mitral valve modeling strategies on intraventricular flow features was developed. Then, five mitral valve models of increasing complexity: no modeling, static wall, 2D and 3D porous medium with time-dependent porosity, and one-way fluid-structure interaction (FSI) were compared with each other. The flow features velocity, kinetic energy, transmitral pressure drop, vortex formation, flow asymmetry as well as computational cost and ease-of-implementation were evaluated. The one-way FSI approach provides the highest level of flow detail, which is accompanied by the highest numerical costs and challenges with the implementation. As an alternative, the porous medium approach with the expansion including time-dependent porosity provides good results with up to 10% deviations in the flow features (except the transmitral pressure drop) in comparison to the FSI model and only a fraction (11%) of numerical costs. However, jet propagation speed is highly underestimated by all alternative approaches to the FSI model. Taken together, our benchmark setup allows a quantitative comparison of various mitral valve modeling approaches and is provided to the scientific community for further testing and expansion.

BEHAVIOR OF RETAINING WALLS CONSTRUCTED IN THE SATURATED CLAY AND WATER-SATURATED SAND SOILS UNDER THE DYNAMIC LOADS

Since the main purpose of building retaining walls is to hold up the slopes, the calculations are important during the design process. Although static loads that affect retaining walls are generally taken into consideration, dynamic effects should also be marked in our country located in the earthquake zone. Within the scope of this study, stability checks were performed by taking the effects to the retaining walls subjected to static and dynamic loads and wall designs were also made.&#x0D; In this study, behavior of retaining walls constructed in saturated clay soil and water-saturated sand soil have been determined under static and dynamic loads. Analyses of static and dynamic behavior of gravity and cantilever walls have been done by Plaxis 2D software packet program. The heights of the walls are selected such as 5.0 m, 10.0 m and 15.0 m. Active earth pressures are calculated by using Rankine active earth pressure theory. Factor of safeties such as overturning, sliding and bearing capacity are selected as 2.0, 1.5 and 3.0, respectively. Three different earthquake loads such as Van, Turkey, Petrolia-California, USA and Volcano-Hawaii, USA are chosen to determine the dynamic behavior of walls. Records of earthquake loads were taken from “United States Geological Survey” (USGS) official web site. Format of earthquake records is “strong motion CD” (.smc) due to Plaxis 2D software packet program.&#x0D; The results of analyses done in the saturated clay showed that 5.0 m and 10.0 m heights of retaining walls can be safely constructed in the earthquake zones having the magnitude up to 7.0. 15.0 m height of retaining walls cannot be safely constructed due to the insufficient wall dimensions. The results of analyses done in the water-saturated sand soil showed that 5.0 m height of retaining walls can be safely constructed in the earthquake zones having the magnitude up to 7.0. While the 10.0 m height of retaining walls can be safely constructed in the earthquake zones having magnitude of 6.0, it cannot be constructed in the earthquake zones having magnitude of 5.0 due to the earthquake acceleration. While the 15.0 m height of retaining walls can be safely constructed in the earthquake zones having magnitude of 6.0, it cannot be safely constructed in the earthquake zones having magnitude of 5.0 and 7.0.

Evaluation of computational fluid dynamics models for predicting pediatric upper airway airflow characteristics.

Computational fluid dynamics (CFD) has the potential for use as a clinical tool to predict the aerodynamics and respiratory function in the upper airway (UA) of children; however, careful selection of validated computational models is necessary. This study constructed a 3D model of the pediatric UA based on cone beam computed tomography (CBCT) imaging. The pediatric UA was 3D printed for pressure and velocity experiments, which were used as reference standards to validate the CFD simulation models. Static wall pressure and velocity distribution inside of the UA under inhale airflow rates from 0 to 266.67mL/s were studied by CFD simulations based on the large eddy simulation (LES) model and four Reynolds-averaged Navier-Stokes (RANS) models. Our results showed that the LES performed best for pressure prediction; however, it was much more time-consuming than the four RANS models. Among the RANS models, the Low Reynolds number (LRN) SST k-ω model had the best overall performance at a series of airflow rates. Central flow velocity determined by particle image velocimetry was 3.617m/s, while velocities predicted by the LES, LRN SST k-ω, and k-ω models were 3.681, 3.532, and 3.439m/s, respectively. All models predicted jet flow in the oropharynx. These results suggest that the above CFD models have acceptable accuracy for predicting pediatric UA aerodynamics and that the LRN SST k-ω model has the most potential for clinical application in pediatric respiratory studies.

Numerical analysis of supersonic combustion of hydrogen flow characteristics in scramjet combustor toward the improvement of combustion efficiency

A modification in the ramjet engine, known as the Supersonic Ramjet Combustion, completes the combustion at supersonic speeds. Inside the combustion chamber, the mixing of fuels and the entire combustion procedure completes in milliseconds. So, the combustion chamber's flow physics is highly complicated. Through this study, the target is to improve the combustion efficiency inside the combustion chamber, thereby improving the performance of the scramjet engine. For this study, the performance of a strut-based flame stabilizer was analyzed in various positions, and the impact on energy efficiency and combustion performance is evaluated. SST k-ω model of turbulence is used to work out the Navier-stokes equation. To validate data from the experiment, a single strut configuration was considered for the next step, i.e., the comparison of the available data with a three-strut configuration. While considering the three-strut layout, in the x and y directions, secondary struts are placed, while the position of the primary strut remains constant. Only the flow from the primary strut is considered for the analysis of combustion performance out of three struts. From the obtained results, it is clear that the significant factor in improving energy efficiency is positioning the secondary strut in the present three-strut layout. The experiment results state that the combustion efficiency is boosted by 33.86% compared to a single strut combustor. It was also found that there was a considerable decrease in the level of unburned fuel, which makes the configuration more economical. The placement of struts plays a vital role, as any fault in the configuration makes it less efficient than a single strut layout. Other elements that boost combustion efficiency are expansion fans and shock reflection inside the primary zone of combustion and the secondary strut region. With the inclusion of secondary struts, the static wall pressure also escalated. A discrete flow was also observed on the combustion walls for some particular strut layouts. An increase in combustion efficiency was seen when both primary and secondary struts were placed near each other and also for reacting flow from the primary strut alone. There arises no need to supply fuel to secondary struts. So, overall fuel efficiency is improved, making the whole system energy-efficient.

Reconstruction of flow around a high-rise building from wake measurements using Machine Learning techniques

This paper investigates the unsteady flow around a high-rise building using OpenFoam. A Vortex Method is developed to generate upstream unsteady fluctuations that are validated considering the numerical simulation of a neutral atmospheric boundary layer around a high-rise building. The Vortex Method parameters are tuned to produce an upstream velocity profile whose turbulence characteristics are comparable to experimental data. Comparison between mean and fluctuating velocity profiles of the numerical data measured in the building’s wake with experimental data shows satisfactory results.The resulting database is used to reconstruct the flow from limited velocity measurements inside the wake and static wall pressure measurements on the building surface. Machine learning techniques such as linear regressions (Ridge, Lasso, ElastikNet, MultiTaskLasso regression) and Artificial Neural Network are tested and compared. The flow reconstruction using velocity measurements inside the wake leads to a better result compared to the flow reconstruction from the wall pressure measurements. At the same time, it was noticed that the Artificial Neural Network regression does not lead to more satisfactory results compared to linear regression techniques.

Efficient heating of buildings by passive solar energy utilizing an innovative dynamic building envelope incorporating phase change material

To utilize effectively passive solar energy for heating buildings, an innovative building envelope is proposed, and its superior performance is for the first time experimentally demonstrated by constructing and testing its full-scale model. The proposed envelope comprises a dynamic Trombe wall incorporating phase change material (PCM). Its salient feature and novelty are its innovative multi-panel solar collector-storage wall and the ability of each panel to independently rotate about its vertical axis. One face of each panel is cladded with PCM, and in a typical 24 h cycle, during sunshine hours, this face is turned towards the incident solar irradiation and the rest of the time towards the conditioned space. The thermal performance of the proposed envelope is compared with that of a companion envelope having a traditional static Trombe wall with the same amount of PCM and wall geometry. The results show that compared to the traditional envelope, the new envelope regulates the thermal load more evenly by preventing large temperature swings, it reduces heat loss during the solidification phase of PCM by 29% and is overall 20% thermally more efficient. These benefits can result in energy saving from non-renewable energy sources over the design life of the building.