Numerical And Experimental Study Of A Supply Air Wall Based On Integrated Insulation Clay Hollow Blocks

Energy efficient buildings are unimaginable without highly insulating thermal envelopes. Mineral wool among others is a popular material for thermal insulation. Architects and engineers usually use the data given by the manufacturer in the specification of the material for their building physical design. Such data are obtained from laboratory measurements, carried out on non-aged, and dry samples. However, moisture could affect the thermal performance of insulation materials and may affect the durability too. In the research, we examined stone mineral wool hardboard thermal insulations, which were obtained from a flat roof. The samples looked differently: some of them were in good condition and maintained their load bearing capability, but some were spoiled and soft. We measured and compared the used samples’ thermal conductivity, sorption isotherm and deformation under compressive force to new etalon samples. We also investigated the reason behind the lack of load bearing durability of the built-in and spoiled mineral wool boards using scanning electron microscopy and derivatography. In our study, we show how built-in conditions changed the thermal and mechanical properties and thermal performance of the mineral wool insulation layer, which could degrade by up to 40% in terms of thermal resistance under built-in conditions due to certain spoiling and production mistakes of mineral wool.

1.0. INTRODUCTION In the United States, K–12 school buildings spend more than $8 billion each year on energy—more than they spend on computers and textbooks combined [1]. Most occupied older buildings demonstrate poor operational performance—for instance, more than 30 percent of schools were built before 1960, and 53 percent of public schools need to spend money on repairs, renovations, and modernization to ensure that the schools' onsite buildings are in good overall condition. And among public schools with permanent buildings, the environmental factors in the permanent buildings have been rated as unsatisfactory or very unsatisfactory in 5 to 17 percent of them [2]. Indoor environment quality (IEQ) is one of the core issues addressed in the majority of sustainable building certification and design guidelines. Children spend a significant amount of time indoors in a school environment. And poor IEA can lead to sickness and absenteeism from school and eventually cause a decrease in student performance [3]. Different building types and their IEQ characteristics can be partly attributed to building age and construction materials. [4] Improving the energy performance of school buildings could result in the direct benefit of reduced utility costs and improving the indoor quality could improve the students' learning environment. Research also suggests that aging school facilities and inefficient equipment have a detrimental effect on academic performance that can be reversed when schools are upgraded. [5] Several studies have linked better lighting, thermal comfort, and air quality to higher test scores. [6, 7, 8] Another benefit of improving the energy efficiency of education buildings is the potential increase in market value through recognition of green building practice and labeling, such as that of a LEED or net zero energy building. In addition, because of their educational function, high-performance or energy-efficient buildings are particularly valuable for institution clients and local government. More and more high-performance buildings, net zero energy buildings, and positive energy buildings serve as living laboratories for educational purposes. Currently, educational/institutional buildings represent the largest portion of NZE (net zero energy) projects. Educational buildings comprise 36 percent of net zero buildings according to a 2014 National New Building Institute report. Of the 58 net zero energy educational buildings, 32 are used for kindergarten through grade 12 (K–12), 21 for higher education, and 5 for general education. [9] Finally, because educational buildings account for the third largest amount of building floor space in the United States, super energy-efficient educational buildings could provide other societal and economic benefits beyond the direct energy cost savings for three reasons: 1) educational buildings offer high visibility that can influence community members and the next generation of citizens, 2) success stories of the use of public funds that returns lower operating costs and healthier student learning environments provide documentation that can be used by others, and 3) this sector offers national and regional forums and associations to facilitate the transfer of best design and operational practices.

Undoubtedly Europe is facing challenges in the field of economy and energy which are definitely strongly related. The high energy prices, the growing energy demand, the security risks, the climate change parameter, the need for introducing energy upgrade and low carbon measures, form the basic parameters for the energy and environmental policy. Therefore, a list of European Union (EU) directives, standards were adopted specifying the provisions for the energy upgrade as well as energy certification of buildings. The 2010 Energy Performance of Buildings Directive (EPBD), the 2012 Energy Efficiency Directive and the 2018 recast constitute at present the main European legislations concerning the reduction of the energy consumption of the building sector. The nearly Zero or Zero Energy Building (nZEB) was introduced setting the renewable energy sources use a crucial parameter for the upgrade of energy efficiency in buildings. In correspondence to energy, CO2 emission reduction is another quantified goal set in the EU policy. Targeting to compare efficiently the legislation framework of the two countries the crucial parameters concerning the energy performance of residential and commercials buildings were chosen. These parameters are the U values, the energy rating classes, the lighting contribution, as well as the thermal bridges evaluation. Moreover, for Greece was chosen climate zone A, for example, Crete, where the climate is practically identical to the Cypriot conditions aiming to comment successfully on the framework followed by two countries and how the legislation can be successfully implemented.

Economy and parsimony in the consumption of energy resources are becoming a part of common sense in practically all countries, although the effective implementation of energy efficiency policies still has a long way to go. The energy demand for residential buildings is one of the most significant energy sinks. We focus our analysis on one of the most energy-consuming systems of residential buildings located in regions of tropical climate, which are cooling systems. We evaluate to which degree the integration of thermal energy storage (TES) and photovoltaic (PV) systems helps to approach an annual net zero energy building (NZEB) configuration, aiming to find a feasible solution in the direction of energy efficiency in buildings. To conduct the simulations, an Energy Efficiency Analysis Framework (EEAF) is proposed. A literature review unveiled a potential knowledge gap about the optimization of the ASHRAE operational modes (full storage load, load leveled, and demand limiting) for air conditioning/TES sets using PV connected to the grid. A hypothetical building was configured with detailed loads and occupation profiles to simulate different configurations of air conditioning associated with TES and a PV array. Using TRNSYS software, a set of scenarios was simulated, and their outputs are analyzed in a life cycle perspective using life cycle costing (LCC). The modeling and simulation of different scenarios allowed for identifying the most economic configurations from a life cycle perspective, within a safe range of operability considering the energy efficiency and consequently the sustainability aspects of the buildings. The EEAF also supports other profiles, such as those in which the occupancy of residential buildings during the day is increased due to significant changes in people’s habits, when working and studying in home office mode, for example. These changes in habits should bring a growing interest in the adoption of solar energy for real-time use in residential buildings. The results can be used as premises for the initial design or planning retrofits of buildings, aiming at the annual net zero energy balance.

Design a Zero Energy House in Brisbane, Australia

At global scale, the building sector accounts for 40% of total energy end use and almost 35% of greenhouse gas emissions. This makes it one of the most important sectors to focus on for reaching the 1.5–2 °C target of the Paris Agreement, to enhance energy security of supply and to alleviate energy poverty. The European Union (EU) is often seen as a leader in climate governance, which is also true for energy efficiency. The improvement of energy performance of buildings has been part of EU public policy for more than 50 years, making the EU a pioneer in the policy domain. Based on a semi-structured review of the scientific literature (N = 90), this paper is aimed at drawing the lessons from research on governance of energy-efficient and zero-carbon buildings in the EU. As for the findings, there is a multitude of policy instruments developed on different levels of governance, more or less integrated and managed by different actors and no single instrument is sufficient to stimulate energy-efficient and zero-carbon buildings. Five key challenges are identified in the governance literature examining the transition towards energy efficiency and zero-carbon buildings. An ambiguous leadership, heterogeneity of implementation, lack of incentives, limitations of non-regulatory policies and market-based instruments, and limited diffusion between governance levels. We also conclude that most policy instruments focus on new buildings which is problematic since the greatest challenge in the transition is the renovation of the large existing building stock.

Earth-to-air heat exchanger for NZEB in Mediterranean climate

The cavity walls are a widely used construction system. They became popular in traditional masonry construction for their capacity to reduce the passage of moisture and improve the walls’ thermal performance. However, the latter only applied to narrow cavities with restricted internal air movement. Cavities are also present in emerging technologies, such as 3D concrete printed walls. However, the large cavities of the 3D printed concrete walls have high convective heat transfers that affect the envelope’s thermal performance. Therefore, the authors developed a conjugate heat transfer finite element model to study the large cavities in 3D printed concrete walls and determine the effect on the convective heat transfer of subdividing large cavities. The results show it is possible to reduce the heat flux four times, from 40.4 W/m2 to 9.1 W/m2, subdividing a large cavity into sixteen small ones. This reduction might be higher, increasing the number of cavity subdivisions. However, it is infeasible to restrict the air movements in unfilled air cavities over 25 mm wide for the Rayleigh numbers ≥ 105. Therefore, the practicality of minimizing heat transfer by subdividing large air cavities in 3D printed walls is limited.

This paper develops an energy analysis for an existing near Zero Energy (nZEB) and Zero Carbon Emissions building called LUCIA, located at the university campus in Valladolid (Spain). It is designed to supply electricity, cooling and heating needs through solar energy (Photovoltaic Systems, PV), biomass and an Earth–Air Heat Exchanger (EAHE), besides a Combined Heat Power (CHP). It is currently among the top three buildings with the highest LEED certification in the World. The building model is simulated with DesignBuilder version 5. The results of the energy analysis illustrate the heating, cooling and lighting consumptions expected, besides other demands and energy uses. From this data, we carried out an energy balance of the nZEB, which will help to plan preventive actions when compared to the actual energy consumptions, improving the management and control of both the building and its systems. The primary energy indicator obtained is 67 kWh/m2 a year, and 121 kWh/m2 a year for renewable energy generation, with respect to 55 kWh/m2 and 45 kWh/m2 set as reference in Europe. The Renewable Energy Ratio (RER) is 0.66. These indicators become a useful tool for the energy analysis of the nZEB according to the requirements in the European regulations and for its comparison with further nZEB.

<div class="section abstract"><div class="htmlview paragraph">In the quest for reduced cost and shorter development times for fuel cell systems in industrial applications, two major issues arise. First, the electrochemical behavior of fuel cell systems is inherently difficult to predict. Second, testing fuel cell systems is resource intensive. These issues compound: Setting up an accurate model of a fuel cell system incurs long testing periods for model validation. Further, it does not guarantee acceptable results outside the tested range or for other membrane electrode assembly compositions.</div><div class="htmlview paragraph">To mitigate these two major issues an X in the Loop concept is proposed. Essentially, this is the direct integration of the test sample, here a single fuel cell, into the modelling environment of the whole system. In practice, two strategies with different levels of integration are defined.</div><div class="htmlview paragraph">The first strategy consists of initially deducing the operating parameters of the sample cell from the fuel cell system model. Then, setting them to the sample cell in the test bench. The response of the test sample is finally used to validate the designed system or update the parameters of the fuel cell model.</div><div class="htmlview paragraph">The second strategy is a step further towards the integration of the test sample into the model. Here, the core model of the fuel cell inside the fuel cell system model is completely replaced with the test sample, reducing the need for an accurate electrochemical model while improving the prediction of the behavior of the fuel cell system.</div><div class="htmlview paragraph">Compared to previously proposed testing concepts, here the balance of plants is directly integrated through a digital emulator, leading to a closer representation of the complete system. Furthermore, the test bench results are looped back to the model at run-time leading to a closer match between testing conditions and the real world as well a reduced impact of inaccuracies in the modelling of the fuel cell.</div><div class="htmlview paragraph">On the way to realizing this goal, an experimental test bench capable of showcasing working prototypes of the proposed operating strategies has been built.</div></div>

This paper presents a strategy to emulate a reduced scale of sucker rod pump using laboratory test bench. The strategy is based on combination of software and hardware system. Torque reference is generated using the proposed strategy based on real time model of sucker rod pump that runs in LabVIEW. The output of encoder and torque sensor are integrated through NI PCI- 6221 data acquisition card to the real time platform. The performance of the experimental test bench is evaluated using current, voltage, speed, and torque measurements and power calculations. The experimental results are compared to simulation results. The results indicate the capability of this test bench to serve as a platform for conducting experimental studies on sucker rod pump.

Quantitative infrared thermography (QIRT) has emerged as a prominent topic within the field of thermal performance testing of building enclosures. The majority of the previous research has been conducted in Europe and North America, with limited research activity in Asia. Against the backdrop of China’s carbon emission reduction goals, quantitative infrared thermography offers a promising avenue for advancing building energy efficiency testing. This study conducted QIRT testing on three buildings with different insulation capabilities (old buildings, conventional insulated buildings, nearly zero-energy buildings) in Shenyang, China. The objective was to assess the efficacy of the internal QIRT method for walls with varying insulation capabilities and to ascertain the requisite testing environment parameters in the context of China’s climatic conditions and building regulations. The heat flow meter method was employed to verify its accuracy. Furthermore, correlation analysis was conducted on various testing parameters across different building cases and temperature-difference ranges. The results indicate that walls with different insulation capabilities require corresponding indoor–outdoor temperature differentials to establish a stable heat flow environment. For uninsulated buildings, a temperature difference of 10 °C between indoor and outdoor environments is sufficient to meet testing requirements, with a testing error of only 2.28%. For conventionally insulated buildings, a temperature difference greater than 20 °C reduces the relative error to below 10%. For nearly zero-energy buildings, it is recommended to maintain a temperature difference of 25 °C or higher to achieve optimal testing results. Once a stable thermal flow environment has been achieved, the variation in the instantaneous heat transfer coefficient maintains a high correlation with the temperatures recorded at various measurement points. For buildings with high insulation performance, high temperature-difference environments pose higher demands on the testing procedures and data collection using the QIRT method. During the testing process, it is essential to monitor changes in outdoor air temperature, enhance the accuracy of infrared thermography, and avoid interference from indoor radiation sources.

Applied single and hybrid solar energy techniques for building energy consumption and thermal comfort: A comprehensive review

Hierarchical estimation of uncertainties in multi-rotors:A yaw-motion study using test bench

How to evaluate performance of net zero energy building – A literature research