Passive Energy Research Articles

Passive energy saving through thermal retrofitting of existing government office building envelopes - Case study for office-research building in Cairo, Egypt

Egypt used several million kilowatts per hour of electrical power in 2023. According to 2022 data, public utilities and agencies used 15% of Egypt's power. Most of Cairo’s government buildings built in the 50th and the 60th of the last century are composed of reinforced concrete structure skeletons, flat concrete roofs, and burnt brick exterior and interior walls. At that time, building energy efficiency was not a priority. Thus, uninsulated building envelopes were built. Nowadays, renovating buildings requires increasing energy efficiency. Previous research showed that lack of thermal insulation in roofs, walls, window solar heat gain, and window frames thermal bridging increases heating and cooling costs. The current research aims to enhance existing buildings energy saving by improving thermal insulation of its envelope components. The existing research building in Cairo was assessed for environmental factors to accomplish the research goal. The research used a three-dimensional (3D) terrestrial laser scanner to assess building facades for creating an environmental study model. The research used the building office top floor construction as a comparative environmental simulation using (Design builder® version6 software) as a base case for yearly energy consumption due to heating and cooling loads, followed by improving the thermal insulation of each building element individually in the base environmental model and comparing its effect on annual energy saving percentage, then applying all of the best annual energy saving building envelope element thermal insulation retrofitting techniques to the improved building model. The research results showed that improving roof thermal insulation saves 33.5% of the yearly top floor total electrical energy, 12% for exterior walls, 0.75% for window glazing, and 1.56 % by retrofitting window frames. Applying all of the best energy-saving thermal insulation retrofit techniques to the whole structure saved 31% of annual energy consumption.

Overall Thermal Transfer Analysis of Glazing Facade Design for Passive Building Energy Efficiency

The global warming incremental impacts such as temperature, precipitation, rise in sea level, and extreme weather events are indeed being observed globally. In recent decades, energy demand and greenhouse gas emissions have increased due to buildings being designed with active cooling and heating solutions, despite global attempts to reduce energy consumption. About 50 percent of all energy use is attributed to buildings. There has been a debate for Decades on building active and passive design, but very limited studies have been carried out to confirm the Overall Thermal Transfer Value (OTTV) during the operation phase of the building. This paper highlights the analysis of OTTV in the Passive Design Strategies using several conditions of glazing facades. The passive design of glazing facade strategies includes the variation in opaque wall Colour with different values of the coefficient of solar absorption, change in glazing type (U-Value and Shading Coefficient), and the decrease in the size of the openings. Building parameters were collected and OTTV was determined using the equation in Malaysian Standard MS 1525 for Energy Efficiency. The OTTV was then compared to the recommended value for Malaysia’s tropical climate. Results showed that different paint Colours improved OTTV by up to 23.05%, changing glazing type reduced OTTV from 76.93 W/m² (Base case) to 64.12 W/m² (Double Low-E, e2=.1 Tint green), and reducing glass area by 10% lowered OTTV to 62.24 W/m².Whereas, by combining the Type of Glazing and White facade Colour the OTTV was reduced to 39.68%. It is concluded that this OTTV analysis enhances building energy efficiency and reduces cooling loads.

Drivers and barriers to the adoption of passive energy consumption optimisation strategies for UK buildings: A fuzzy approach

Drivers and barriers to the adoption of passive energy consumption optimisation strategies for UK buildings: A fuzzy approach

Theoretical and numerical study of the thermo-mechanical coupling effect on the fluid viscous damper

The fluid viscous damper (FVD) is a typical passive energy dissipation device applied to civil engineering structures for vibration control. However, the heat generated during its operation will alter the properties of the fluid, thereby affecting the damping force. This study explores the thermo-mechanical coupling effect on the performance of the FVD. A theoretical model is developed based on fluid dynamics and thermodynamics to reflect the interaction between the real-time damping force and temperature of the FVD. Computational fluid dynamics (CFD) simulations are performed to investigate the impact of the thermo-mechanical coupling effect on the hysteresis performance of the damper and validate the proposed calculation method. The dynamic behavior and vibration mitigation effectiveness of the FVD considering the thermo-mechanical coupling effect are examined based on time history analysis on a single-degree-of-freedom and a multi-degree-of-freedom system. The results indicate that the increased temperature will lead to a reduction in the damping force, while the degraded force will in turn slow the temperature rise. Long-duration and high-intensity excitations can significantly amplify the impact of the thermo-mechanical coupling effect, thus it is essential to be considered in designing dampers for loads in the service stage and major earthquakes. The thermo-mechanical coupling effect on the supplemental damping ratio of the damper is greater than that on structural response control effectiveness, thereby it cannot be neglected when the damping ratio is used as the design criterion for FVDs.

Enhancing thermal performance of phase change materials in building envelopes

AbstractPhase change material in conjunction with a passive latent heat thermal energy storage approach is a potentially effective way to solve the growing concerns about building energy usage. This research examines the thermal performance of building envelopes in Miskolc, Hungary. The factors impacting the thermal performance of phase change material integrated into the building envelope were assessed. The findings indicate that the enthalpy and melting temperature of the phase change material significantly impact the effectiveness of phase change material-based walls. It was determined the optimal location of the phase change material layer is possible. This determination is intricately related to the thermal properties of the phase change material and the prevailing environmental conditions.

Solar Species: Energy Optimization of Urban Form Through an Evolutionary Design Process

This paper proposes design guidelines to enhance energy efficiency and energy generation potential in active solar buildings. Additionally, it presents a variety of optimized urban forms characterized by attributes such as shape, layout, and number of buildings on the plot. These urban configurations are classified into solar species, each associated with a distinct range of high passive and active solar potential. These results were achieved by developing and applying a simulation-driven, multi-objective optimization technique for the early-stage design of a residential building cluster in a temperate climate. This method leverages both passive and active energy indicators, employing a genetic algorithm to identify optimal forms that maximize active solar potential while also minimizing operational energy demand. The approach utilizes a parametric modelling routine that relies on vertical cores and horizontal connections to produce design iterations featuring irregular geometry, while ensuring structural continuity and means of egress. The findings reveal a significant variability in onsite energy generation, with optimized solutions differing by a factor of 2.5 solely based on shape, underscoring the critical role of active solar potential. Taken together, these results hint at the descriptive and predictive capabilities of these solar species, making them a promising heuristic model for characterizing urban form in relation to energy performance.

Renewable Energy-Based Electric Drive with a Novel Control Technique for Smooth Power-Sharing

Energy management between different power sources, which are used to feed Electric vehicles (EVs) is one of the complex scenarios. Normally, power management is done based on the Electric vehicle load requirements. In this work, three different energy sources are considered, in that one is an active energy source and two are passive energy storage elements. The Photo Voltaic (PV) based energy source is considered an active element, on the other hand, the Battery sand supercapacitor (SCap) is treated as a passive type of element. To manage the power flow between two energy sources, a novel control technique is adopted by considering the speed and current of the electric motor as major input parameters known as the Measurement of the parameter-based controller (MPBC). The Measurement of a parameter-based controller is used to control the pulse signals of the Bidirectional converters connected at the battery and supercapacitor ends, and the required pulse signals can be generated by the Conventional Proportional Integral (PI) controller. The main circuit is implemented with a novel hybrid controller which is used to provide controlled pulse signals to the bidirectional converters connected to the battery and supercapacitor. Finally, the MATLAB/Simulink model was developed with the novel hybrid controller and examined the performance at different load conditions of the motor by considering three different states of power delivered by the PV array.

A passive self-excited oscillation AC low-voltage energy harvesting circuit without a bridge

Most current electromagnetic energy harvesters use capacitor voltage multipliers or boost circuits controlled by external signals to step up and store energy. However, for most low-voltage output electromagnetic energy harvesters, generating switching control signals and rectification results in significant energy loss. To reduce these losses, this paper proposes an AC boost circuit without additional power supply or rectifier bridge, designed for low-voltage electromagnetic energy harvesting. Both theoretical analysis and experimental results confirm the effectiveness of the proposed interface. The results show that the circuit can start self-excited boosting at an initial voltage of 0.48V and achieve an AC-DC conversion efficiency of 71.3 % within an input voltage range of 0–2.9V.

A systematic review of hybrid passive energy dissipating devices

Once earthquakes occur, they release a considerable amount of elastic strain energy, which is measured by Peak Ground Acceleration (PGA). To reduce the impact of this energy, buildings can be fitted with dampers. These include passive energy dissipation devices, which are effective in mitigating the effects of both high and low PGA. Hybrid dampers, which combine multiple devices, enhance strengths and minimize weaknesses, significantly improving a building’s seismic resilience by reducing roof displacement, drift, inter-story, floor acceleration, and base shear. These dampers are the focus of extensive research, emphasizing their role in seismic performance enhancement. Despite numerous studies, their application in concrete structures remains underexplored, presenting a vast scope for advancement in the design, development, and implementation of hybrid damping devices. These devices are particularly valued for their superior vibration control capabilities, offering a promising avenue for bolstering structural stability.

LCA comparativo en distintos escenarios del edificio NZEB El Salvador, estimación de CO2 para el desempeño térmico

The recent IPCC 2023 report reiterates that humansare responsible for global warming over the past 200 years, causing a rise temperature of 1.1°C above pre-industrial levels, as well as an increase in energy demand, which can be avoided with mitigation options, reducing its use in all sectors, especially in the building sector. One of the options is the design based on the NZEB concept, as it has been the case of the laboratory built on the UCA campus, using passive and active energy efficiency strategies, studying the interaction between construction systems and energy savings. One of the NZEB El Salvador project research objectives, was to study the thermal performance of different construction scenarios, therefore, the present work presents the results of the Life-cycle assessment(LCA) in three proposals for popular construction systems in El Salvador, regulated by the national regulatory framework, comparing them with the baseline of its current operation, through 3 iterative calculation tools: structural, thermal and carbon footprint estimation, managing to find importantfindings on how vernacular systems meet the NZEB standard. ILIA: Investigaciones Latinoamericanas en Ingeniería y Arquitectura, No. 01, 2024: 160-166.

Optimizing passive energy savings in rural self-built houses: Integrating phase change materials across China's climate zones

The energy consumption of rural residential buildings in China is increasing, and the integration of phase change materials (PCMs) has emerged as an effective strategy to mitigate building energy use and carbon emissions. Given China's diverse climate zones and the varying construction forms of rural self-built houses (RSHs), the efficacy of PCM applications varies significantly across regions. This study presents a comprehensive investigation into passive energy savings using PCMs in RSHs across various climate zones. We investigate the energy saving potential and thermal comfort effects of installing PCMs with varying phase change temperatures and thicknesses at different laying positions in representative buildings from each climate zone. The results indicate that the optimal phase change temperatures in different regions closely align with the outdoor average temperatures during the application season. When the optimal phase change temperatures and appropriate thicknesses of PCM are applied, cost-effective energy savings are consistently achieved in building roofing across regions, with the most significant effects observed in the Severe Cold region, where the uncomfortable degree hours reduction rate (φUDH) exceeds 90 %.

Optimising building performance for a resilient Future: A Multi-Objective approach to Net Zero energy strategies

The escalating impacts of climate change on urban environments underscore the imperative for energy-efficient buildings. As the building sector constitutes approximately 40% of global energy consumption, the implementation of NZE designs is critical for emission reduction. This study utilised Building Performance Optimisation methodologies alongside a multi-stage optimisation framework to evaluate energy consumption, Life cycle cost and carbon emissions under various climate scenarios (RCP 2.6, 4.5, and 8.5) in three Algerian cities—Constantine (semi-arid), Algiers (Mediterranean), and Ghardaïa (arid).The results revealed that the integration of passive, active, and renewable energy strategies significantly curtailed energy consumption and CO2 emissions across different climatic contexts. Specifically, passive measures achieved reductions in energy use ranging from 39% in Ghardaïa to 15% in Constantine. Active systems, including high-efficiency HVAC technologies, resulted in energy savings of 59% in Ghardaïa, 52% in Algiers, and 47% in Constantine. Furthermore, renewable energy sources, with a focus on solar photovoltaics, contributed additional reductions: 44% in Algiers, 26% in Ghardaïa, and 20% in Constantine. The multi-stage optimisation approach also enhanced computational efficiency, significantly reducing simulation time and facilitating the rapid identification of optimal strategies.These findings highlight the efficacy of integrating a range of energy strategies to achieve NZE. Nevertheless, while these systems demonstrate robust performance under current conditions, their effectiveness diminishes under future climate scenarios, underscoring the necessity for adaptive and resilient design approaches. Ongoing optimisation and innovation will be essential to maintaining the efficacy of NZE strategies in the face of extreme future climate conditions.

Experimental and numerical investigation of a novel passive energy dissipation system with viscoelastic damper and angle-reaction controller

Sharp and significant changes in the relative angle between beam and column during earthquakes often lead to failure of structural joints. This study proposed a novel passive Energy Dissipation system (PEDs) consisting of a viscoelastic damper (VED) and an angle-reaction controller (ARC). The ARC provides mutual support to the joint by establishing temporary supports in reinforced concrete or steel frames to allow for free-angle multilevel control in the case of excessive relative angle. This feature distinguishes the novel PEDs from previous systems as it allows the reaction force of the temporary support to compensate for the loss of joint rotational stiffness. The cyclic loading tests were conducted by constructing fundamental components, and then a mechanical model for the novel PEDs was established. Numerical simulations were performed to analyze parameter variations and to provide a comprehensive methodology for evaluating the seismic performance of the novel PEDs. The results demonstrated that two mechanisms were effectively incorporated into the novel PEDs: vibration energy dissipation and protection against excessive angles. The multistage flag hysteresis curve confirmed the reliability of our theoretical model in representing this novel PEDs. Therefore, supplementing rotational stiffness while achieving energy dissipation can be considered a new approach for enhancing seismic performance in frame structures.

Building retrofitting towards net zero energy under climate change

Abstract The challenge in Net-Zero Energy Building (NZEB) retrofitting is to identify the most effective measures to address energy performance issues. This paper presents a machine learning model for optimizing retrofit measures to achieve NZEB under the influence of climate change. Specifically, the non-dominated sorting genetic algorithm (NSGA-III) minimizes energy consumption and the predicted percentage of dissatisfaction (PPD) while achieving a NZE balance, thereby obtaining the Pareto front. The Order of Preference by Similarity to Ideal Solution (TOPSIS) ranking technique is then applied to the Pareto front to obtain an optimal solution. Various passive energy retrofit measures are investigated, and renewable retrofit measures are employed to cover the required energy. This process is repeated for different time frames to consider the impact of climate change on selecting retrofit measures. The results clearly indicate that, for retrofitting a residential NZEB, higher insulation values are needed for future scenarios compared to the present scenario due to the effects of climate change. Using the future scenarios defined by the Shared Socioeconomic Pathways framework, a higher level of envelope insulation and renewable retrofit measures are required to achieve NZEB in the Sustainable Future scenario compared to the Fossil Fuel-dependent Future scenario, with increases of 35% and 50%, respectively.

Rehabilitation of steel structures using innovative brace members equipped with YSPD damper

Earthquakes are serious risks to human life and infrastructure. An earthquake's influence on human life and its socioeconomic consequences highlight the need to investigate and create the most efficient and easily adaptable ways to minimize losses. The basic concept of different control mechanisms used for protecting structures from the destructive impacts of earthquakes is to dissipate the energy efficiently, therefore ensuring that the structure remains undamaged or sustains minimum damage. To achieve this purpose, the passive control mechanism is a particularly suitable and reliable technology as it doesn't rely on external power to actively dissipate energy. The present study proposes using a passive energy dissipation device called the Yielding Shear Panel Device (YSPD) for strengthening the current steel structures. The YSPD consists of a square hollow section (SHS) that houses a diaphragm plate. The fundamental concept of the YSPD involves harnessing the lateral deformation of a steel plate to absorb and disperse the seismic energy. The Bouc-Wen-Baber Noori (BWBN) material has been used for simulating the hysteresis force-deformation relationship of YSPDs by pinching. YSPDs are simulated as spring components that connect between the beam and the V-brace. A nonlinear time history dynamic analysis was performed to assess the alteration in the structural capacity with the setting up of YSPDs. The performance of the tested structure was assessed considering story drift, story displacement, story shear, column shear, and YSPD hysteresis loops. The results indicated that YSPD installation has improved the structure's capacity. However, the use of dampers resulted in significant drift in all stories, a reduction in total floor displacement, and a decrease in the shear force of the stories. However, the results demonstrated that the YSPD dampers effectively absorbed energy and exhibited stable hysteresis loops.

Integration of the passive energy balancing based actuation system into a camber morphing design

A spiral pulley mechanism can be used to passively balance the energy between the morphing structure and actuation system. Applying the energy balancing concept has the potential to improve the performance of the actuation system by reducing the external energy consumption. In the current study, the integration workflow for the passive energy balancing device is established and is adopted in a variable camber morphing wing. The design variables of the passive energy balancing system are optimised and the effects of the different parameters are discussed together with the adaptability of the passive energy balancing device when the load stiffness changes. An integrated demonstrator was also built to validate the mechanism by measuring the currents in the process of morphing actuation.

Innovative passive BLE technology as an alternative to UHF RFID: Preliminary lab performance test results for main use cases

In recent years, an innovative passive Bluetooth Low Energy (BLE) technology, namely Wiliot technology, has emerged as an alternative to passive UHF RFID. This paper proposes an experimental campaign aimed at measuring and evaluating the performance of Wiliot technology, when applied to typical use cases of passive UHF RFID technology. In particular, 9 laboratory tests were conducted to assess read distances, temperature tests, inventory accuracy, and tracking. The results provide interesting feedback, especially regarding reading distances, inventory accuracy, and temperature, suggesting that Wiliot technology could be successfully utilized in these use cases. The tracking tests, however, revealed some limitations, primarily due to the requirement for the tag to remain stationary in front of the bridge for at least 10–15 seconds to obtain consistent results. Although the number of tests conducted is limited, they represent a first experience with the targeted technology, and the results can be useful to both researchers and practitioners. The former can find suggestions for further tests to enhance the technology and its potential use in real operating environments, while the latter can derive suggestions for possible practical implementations.

Thermal-material priming: The influence of building materials on thermal perception and tolerance in immersive virtual environments

The effects of color and lighting on thermal perception and comfort have been studied through a multitude of methods, including virtual reality (VR) simulations as well as in vivo studies. The potential role of surface materials, however, remains poorly understood in this regard, even though materials and surface colors are clearly related factors in the perception of building interiors. In this study, we tested two Virtual Reality (VR) office spaces, one designed with wood and one with concrete. 38 participants (N = 38) were recruited to complete a simple reading task over fifteen minutes while being seated in a controlled temperature thermal booth. During this time, the booth temperature dropped by an average of 0.3 °C (0.5 °F) per minute from 22.2 °C (72 °F) to 17.7 °C (64 °F). Participants had the perceived ability to control the room’s temperature via a virtual reality interface, an action that served as a measure of “thermal tolerance” based on how long it took participants to try and stop the constant temperature drop in the thermal booth during the experimental task. Participants were surveyed after the study to state their perceived starting and ending room temperature. The results confirmed the hypothesis that the wood room was perceived as warmer overall than the concrete room. However, the results for the “thermal tolerance” metric varied based on the current outside temperature as we predict participants expected different interior temperature regimes in warm compared to cool outdoor conditions. The perception of the concrete room as cooler than the wood room showed the greatest correllation with thermal tolerance when outdoor temperatures were warm, increasing thermal comfort in the concrete room. The results of the study validate the hue-heat hypothesis for architectural building materials and support the potential for thermal perception to induce actionable behavior and promote passive energy savings through the choice of interior building materials.

Channel estimation for Massive MIMO systems aided by intelligent reflecting surface using semi-super resolution GAN

Intelligent Reflecting Surfaces (IRSs) coupled with Massive Multiple-Input-Multiple-Output (MIMO) millimeter wave (mmWave) systems hold immense promise for the next generation of wireless communications. However, harnessing their full potential requires accurate channel state information (CSI). Despite the benefits of IRSs, such as passive element integration and energy efficiency, precise channel estimation becomes a formidable challenge due to the absence of active elements. In this paper, we tackle these challenges by employing generative adversarial networks (GANs) to estimate the channel’s cascade matrix between the base station (BS) and mobile users. To leverage the high correlation among adjacent elements in the IRS, we propose turning off a majority of these elements during the estimation phase, effectively creating a low-resolution channel. We then introduce the semi-super resolution GAN (SSRGAN) model, capable of inferring channel values for the deactivated elements based on existing correlations. Our new SSRGAN-based channel estimation method transforms low-resolution channel data into high-resolution channel data. Through a comprehensive comparative analysis, our study showcases the superior performance of our SSRGAN channel estimation method compared to established benchmark schemes.

Experimentally validated passive nonlinear capacitor in piezoelectric vibration applications

Abstract Piezoelectric vibration isolation and energy harvesting applications have been extensively studied in the literature. The studies include linear and nonlinear approaches. Linear methods are simpler but possess inherent limitations. On the other hand, nonlinear ones could perform better over a broader operating frequency range. Nonlinearity can be introduced in the mechanical domain or electrical domain actively or passively. Since electrical components can be on smaller scales compared to mechanical counterparts, inducing nonlinearity on the mechanical system through the electrical domain can be more practical. Moreover, passive structures require no energy supply and controller therefore they are simpler and more reliable than active ones. In this paper, a novel way to attain passive hardening stiffness was suggested by introducing an electrical component in a shunt circuit for passive nonlinear piezoelectric vibration isolation or energy harvesting applications and the induced structural non-linearity is demonstrated experimentally. A passive nonlinear component is suggested to be a hardening capacitor obtained by the P–N junction. An analytic model is derived for parallel connected macro-fiber composite (MFC) piezoelectric material attached bimorph configuration on a cantilever beam and the model is solved numerically. MFC integrated bimorph model, and P–N junction approximate model are presented. The frequency response of the coupled system is obtained by using numerical models and experiments. Both numerical analysis and experiments validated the hardening stiffness effect of the P–N junction. To the best of the authors’ knowledge, this study is the first study to demonstrate that nonlinear capacitance of P–N junctions can be used to attain nonlinearity in a mechanical system.