Search results for: thermal retrofit

Authors: Sang Wook Park, Se Woon Choi, Yousok Kim, Byung Kwan Oh, Hyo Seon Park

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Various retrofit techniques for reinforced concrete frame with infill wall have been steadily developed. Among those techniques, strengthening methodology based on diagonal FRP strips (FRP bracings) has numerous advantages such as feasibility of implementing without interrupting the building under operation, reduction of cost and time, and easy application. Considering the safety of structure and retrofit cost, the most appropriate retrofit solution is needed. Thus, the objective of this study is to suggest pareto-optimal solution for existing building using FRP bracings. To find pareto-optimal solution analysis, NSGA-II is applied. Moreover, the seismic performance of retrofit building is evaluated. The example building is 5-storey, 3-bay RC frames with infill wall. Nonlinear static pushover analyses are performed with FEMA 356. The criterion of performance evaluation is inter-story drift ratio at the performance level IO, LS, CP. Optimal retrofit solutions is obtained for 32 individuals and 200 generations. Through the proposed optimal solutions, we confirm the improvement of seismic performance of the example building.

Keywords: retrofit, FRP bracings, reinforced concrete frame with infill wall, seismic performance evaluation, NSGA-II

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Authors: Ademuyiwa Agbonyin, Stamatis Zoras, Mohammad Zandi

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This paper investigates the extent to which building energy modelling can be informed based on preliminary information provided by infrared thermography using a thermal imaging camera in a walkthrough audit. The case-study building is the Sheffield Cathedral, built in the early 1400s. Based on an informative qualitative report generated from the thermal images taken at the site, the regions showing significant heat loss are input into a computer model of the cathedral within the integrated environmental solution (IES) virtual environment software which performs an energy simulation to determine quantitative heat losses through the building envelope. Building data such as material thermal properties and building plans are provided by the architects, Thomas Ford and Partners Ltd. The results of the modelling revealed the portions of the building with the highest heat loss and these aligned with those suggested by the thermal camera. Retrofit options for the building are also considered, however, may not see implementation due to a desire to conserve the architectural heritage of the building. Results show that thermal imaging in a walk-through audit serves as a useful guide for the energy modelling process. Hand calculations were also performed to serve as a 'control' to estimate losses, providing a second set of data points of comparison.

Keywords: historic buildings, energy retrofit, thermal comfort, software modelling, energy modelling

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Authors: Moses Jenkins

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Much of the focus when improving energy efficiency in buildings fall on the raising of standards within new build dwellings. However, as a significant proportion of the building stock across Europe is of historic or traditional construction, there is also a pressing need to improve the thermal performance of structures of this sort. On average, around twenty percent of buildings across Europe are built of historic masonry construction. In order to meet carbon reduction targets, these buildings will require to be retrofitted with insulation to improve their thermal performance. At the same time, there is also a need to balance this with maintaining the ability of historic masonry construction to allow moisture movement through building fabric to take place. This moisture transfer, often referred to as 'breathable construction', is critical to the success, or otherwise, of retrofit projects. The significance of this paper is to demonstrate that substantial thermal improvements can be made to historic buildings whilst avoiding damage to building fabric through surface or interstitial condensation. The paper will analyze the results of a wide range of retrofit measures installed to twenty buildings as part of Historic Environment Scotland's technical research program. This program has been active for fourteen years and has seen interventions across a wide range of building types, using over thirty different methods and materials to improve the thermal performance of historic buildings. The first part of the paper will present the range of interventions which have been made. This includes insulating mass masonry walls both internally and externally, warm and cold roof insulation and improvements to floors. The second part of the paper will present the results of monitoring work which has taken place to these buildings after being retrofitted. This will be in terms of both thermal improvement, expressed as a U-value as defined in BS EN ISO 7345:1987, and also, crucially, will present the results of moisture monitoring both on the surface of masonry walls the following retrofit and also within the masonry itself. The aim of this moisture monitoring is to establish if there are any problems with interstitial condensation. This monitoring utilizes Interstitial Hygrothermal Gradient Monitoring (IHGM) and similar methods to establish relative humidity on the surface of and within the masonry. The results of the testing are clear and significant for retrofit projects across Europe. Where a building is of historic construction the use of materials for wall, roof and floor insulation which are permeable to moisture vapor provides both significant thermal improvements (achieving a u-value as low as 0.2 Wm²K) whilst avoiding problems of both surface and intestinal condensation. As the evidence which will be presented in the paper comes from monitoring work in buildings rather than theoretical modeling, there are many important lessons which can be learned and which can inform retrofit projects to historic buildings throughout Europe.

Keywords: insulation, condensation, masonry, historic

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Authors: S. A. Anuar, N. H. Hamid, M. H. Hashim, S. M. D. Salleh

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This paper present the experimental work on the seismic performance of double unit tunnel form building (TFB) subjected to in-plane lateral cyclic loading. A one third scale of 3-storey double unit of TFB is tested at ±0.01%, ±0.1%, ±0.25%, ±0.5%, ±0.75% and ±1.0% drifts until the structure achieves its strength degradation. After that, the TFB is repaired and retrofitted using additional shear wall, steel angle and CFRP sheet. A similar testing approach is applied to the specimen after repair and retrofit. The crack patterns, lateral strength, stiffness, ductility and equivalent viscous damping (EVD) were analyzed and compared before and after repair and retrofit. The result indicates that the lateral strength increases by 22 in pushing direction and 27% in pulling direction. Moreover, the stiffness and ductility obtained before and after retrofit increase tremendously by 87.87% and 39.66%, respectively. Meanwhile, the energy absorption measured by equivalent viscous damping obtained after retrofit increase by 12.34% in pulling direction. It can be concluded that the proposed retrofit method is capable to increase the lateral strength capacity, stiffness and energy absorption of double unit TFB.

Keywords: tunnel form building, in-plane lateral cyclic loading, crack pattern, lateral strength, stiffness, ductility, equivalent viscous damping, repair and retrofit

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Authors: Minjung Kim, Hyunkoo Kang, Jinkoo Kim

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In this study, a seismic retrofit scheme for a reinforced concrete shear wall structure using steel slit dampers was presented. The stiffness and the strength of the slit damper used in the retrofit were verified by cyclic loading test. A genetic algorithm was applied to find out the optimum location of the slit dampers. The effects of the slit dampers on the seismic retrofit of the model were compared with those of jacketing shear walls. The seismic performance of the model structure with optimally positioned slit dampers was evaluated by nonlinear static and dynamic analyses. Based on the analysis results, the simple procedure for determining required damping ratio using capacity spectrum method along with the damper distribution pattern proportional to the inter-story drifts was validated. The analysis results showed that the seismic retrofit of the model structure using the slit dampers was more economical than the jacketing of the shear walls and that the capacity spectrum method combined with the simple damper distribution pattern led to satisfactory damper distribution pattern compatible with the solution obtained from the genetic algorithm.

Keywords: seismic retrofit, slit dampers, genetic algorithm, jacketing, capacity spectrum method

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Authors: Jinkoo Kim, Hyungoo Kang, Hyungjun Shin

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In this study, a hybrid energy dissipation device is developed by combining a steel slit plate and friction pads to be used for seismic retrofit of structures, and its effectiveness is investigated by comparing the life cycle costs of the structure before and after the retrofit. The seismic energy dissipation capability of the dampers is confirmed by cyclic loading tests. The probabilities of reaching various damage states are obtained by fragility analysis, and the life cycle costs of the model structures are computed using the PACT (Performance Assessment Calculation Tool) program based on FEMA P-58 methodology. The fragility analysis shows that the probabilities of reaching limit states are minimized by the seismic retrofit with hybrid dampers and increasing column size. The seismic retrofit with increasing column size and hybrid dampers results in the lowest repair cost and shortest repair time.

Keywords: slit dampers, friction dampers, seismic retrofit, life cycle cost, FEMA P-58, PACT

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Authors: Minsung Kim, Hyunkoo Kang, Jinkoo Kim

Abstract:

In this study, a hybrid energy dissipation device is developed by combining a steel slit plate and friction pads to be used for seismic retrofit of structures, and its effectiveness is investigated by comparing the life cycle costs of the structure before and after the retrofit. The seismic energy dissipation capability of the dampers is confirmed by cyclic loading tests. The probabilities of reaching various damage states are obtained by fragility analysis, and the life cycle costs of the model structures are computed using the PACT (Performance Assessment Calculation Tool) program based on FEMA P-58 methodology. The fragility analysis shows that the probabilities of reaching limit states are minimized by the seismic retrofit with hybrid dampers and increasing column size. The seismic retrofit with increasing column size and hybrid dampers results in the lowest repair cost and shortest repair time. This research was supported by a grant (13AUDP-B066083-01) from Architecture & Urban Development Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

Keywords: FEMA P-58, friction dampers, life cycle cost, seismic retrofit

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Authors: Mohamed Noureldin, Jinkoo Kim

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In this study, a genetic algorithm was used to find out the optimum locations of the slit dampers satisfying a target displacement. A seismic retrofit scheme for a building structure was presented using steel plate slit dampers. A cyclic loading test was used to verify the energy dissipation capacity of the slit damper. The seismic retrofit of the model structure using the slit dampers was compared with the retrofit with enlarging shear walls. The capacity spectrum method was used to propose a simple damper distribution scheme proportional to the inter-story drifts. The validity of the simple story-wise damper distribution procedure was verified by comparing the results of the genetic algorithm. It was observed that the proposed simple damper distribution pattern was in a good agreement with the optimum distribution obtained from the genetic algorithm. Acknowledgment: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2017R1D1A1B03032809).

Keywords: slit dampers, seismic retrofit, genetic algorithm, optimum design

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Authors: Foroozan Sadri, Mohammadmehdi Moulaii, Farkhondeh Vahdati

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Smart materials can create a great revolution in our built environment, as living systems do. In this research, the optimal structure of healthcare building envelopes is analyzed in terms of thickness according to the utility of the smart-nano materials as nontoxic substances in the region. The research method in this paper is based on library studies and simulation. Grasshopper program is employed to simulate thermal characteristics to achieve the optimum U-value in Semnan desert climate, according to Iranian national standards. The potential of healthcare envelope layouts in thermal properties development (primarily U-value) of these buildings is discussed due to the high thermal loads of healthcare buildings and also toxicity effects of conventional materials. As a result, envelope thicknesses are calculated, and the performance of the nano-PCM and gypsum wallboards are compared. A solution with comparable performance using smart-nano materials instead of conventional materials would determine a decrease in wall thickness.

Keywords: energy saving, exterior envelope, smart-nano materials, thermal performance, U-value

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Authors: Mutalubi Aremu Akintunde, John Isa

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The negative impact on the atmosphere, of chlorofluorocarbon refrigerants (CFC) radical changes and measures were put in place to replace them. This has led to search for alternative refrigerants over the past decades. This paper presents thermal conductivity, diffusivity and performance of two alternative refrigerants as replacement to R12, which has been a versatile refrigerant which had turned the refrigeration industries around for decades, but one of the offensive refrigerants. The new refrigerants were coded RA1 (50%R600a/50%R134a;) and RA2 (70%R600a/30%R134a). The diffusivities for RA1 and RA2 were estimated to be, 2.76384 X 10-8 m2/s and 2.74386 X 10-8 m2/s respectively, while that of R12 under the same experimental condition is 2.43772 X 10-8 m2/s. The performances of the two refrigerants in a refrigerator initially designed for R12, were very close to that of R12. Other thermodynamic parameters showed that R12 can be replaced with both RA1 and RA2.

Keywords: alternative refrigerants, conductivity, diffusivity, performance, refrigerants

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Authors: Shibei Huang

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In deep energy retrofits, the thermal performance of existing building envelopes is often difficult to determine with a high level of accuracy. For older buildings, the records of existing assemblies are often incomplete or inaccurate. To obtain greater baseline performance accuracy for energy models, in-field measurement tools can be used to obtain data on the thermal performance of the existing assemblies. For a known assembly, these field measurements assist in validating the U-factor estimates. If the field-measured U-factor consistently varies from the calculated prediction, those measurements prompt further study. For an unknown assembly, successful field measurements can provide approximate U-factor evaluation, validate assumptions, or identify anomalies requiring further investigation. Using case studies, this presentation will focus on the non-destructive methods utilizing a set of various field tools to validate the baseline U-factors for a range of existing buildings with various wall assemblies. The lessons learned cover what can be achieved, the limitations of these approaches and tools, and ideas for improving the validity of measurements. Key factors include the weather conditions, the interior conditions, the thermal mass of the measured assemblies, and the thermal profiles of the assemblies in question.

Keywords: existing building, sensor, thermal analysis, retrofit

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Authors: Stefano Sorace, Gloria Terenzi

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The study of a base isolation seismic retrofit solution for a reinforced concrete school building is presented in this paper. The building was assumed as a benchmark structure for a Research Project financed by the Italian Department of Civil Protection, and is representative of several similar public edifices designed with earlier Technical Standards editions, in Italy as well as in other earthquake-prone European countries. The structural characteristics of the building, and a synthesis of the investigation campaigns developed on it, are initially presented. The mechanical parameters, dimensions, locations and installation details of the base isolation system, incorporating double friction pendulum sliding bearings as protective devices, are then illustrated, along with the performance assessment analyses carried out in original and rehabilitated conditions according to a full non-linear dynamic approach. The results of the analyses show a remarkable enhancement of the seismic response capacities of the structure in base-isolated configuration. This allows reaching the high performance levels postulated in the rehabilitation design with notably lower costs and architectural intrusion as compared to traditional retrofit interventions designed for the same objectives.

Keywords: seismic retrofit, seismic assessment, r/c structures, school buildings, base isolation

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Authors: Minsung Kim, Jinkoo Kim

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In order to reduce or eliminate seismic damage in structures, many researchers have investigated various energy dissipation devices. In this study, the seismic capacity and cost of a slit-viscoelastic seismic retrofit system composed of a steel slit plate and viscoelastic dampers connected in parallel are evaluated. The combination of the two different damping mechanisms is expected to produce enhanced seismic performance of the building. The analysis model of the system is first derived using various link elements in the nonlinear dynamic analysis software Perform 3D, and fragility curves of the structure retrofitted with the dampers are obtained using incremental dynamic analyses. The analysis results show that the displacement of the structure equipped with the hybrid dampers is smaller than that of the structure with slit dampers due to the enhanced self-centering capability of the system. It is also observed that the initial cost of hybrid system required for the seismic retrofit is smaller than that of the structure with viscoelastic dampers. Acknowledgement: This research was financially supported by the Ministry of Trade, Industry and Energy(MOTIE) and Korea Institute for Advancement of Technology(KIAT) through the International Cooperative R&D program(N043100016_Development of low-cost high-performance seismic energy dissipation devices using viscoelastic material).

Keywords: damped cable systems, seismic retrofit, viscous dampers, self-centering

Procedia PDF Downloads 217

Authors: S. Sabzchi Asl, N. Tahouni, M. H. Panjeshahi

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Benchmarking of a process with respect to energy consumption, without accomplishing a full retrofit study, can save both engineering time and money. In order to achieve this goal, the first step is to develop a conceptual-mathematical model that can easily be applied to a group of similar processes. In this research, we have aimed to identify a set of key parameters for the model which is supposed to be used for benchmarking of combined cycle power plants. For this purpose, three similar combined cycle power plants were studied. The results showed that ambient temperature, pressure and relative humidity, number of HRSG evaporator pressure levels and relative power in part load operation are the main key parameters. Also, the relationships between these parameters and produced power (by gas/ steam turbine), gas turbine and plant efficiency, temperature and mass flow rate of the stack flue gas were investigated.

Keywords: combined cycle power plant, energy benchmarking, modelling, retrofit

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Authors: A. Flora, A. Di Lascio, D. Cardone, G. Gesualdi, G. Perrone

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This paper considers the seismic assessment and retrofit of a pilotis-type RC frame building, which was designed for gravity loads only, prior to the introduction of seismic design provisions. Pilotis-type RC frame buildings, featuring an uniform infill throughout the height and an open ground floor, were, and still are, quite popular all over the world, as they offer large open areas very suitable for retail space at the ground floor. These architectural advantages, however, are of detriment to the building seismic behavior, as they can determine a soft-storey collapse mechanism. Extensive numerical analyses are carried out to quantify and benchmark the performance of the selected building, both in terms of overall collapse capacity and expected losses. Alternative retrofit strategies are then examined, including: (i) steel jacketing of RC columns and beam-column joints, (ii) steel bracing and (iv) seismic isolation. The Expected Annual Loss (EAL) of the selected case-study building, pre- and post-rehabilitation, is evaluated, following a probabilistic approach. The breakeven time of each solution is computed, comparing the initial cost of the retrofit intervention with expected benefit in terms of EAL reduction.

Keywords: expected annual loss, reinforced concrete buildings, seismic loss assessment, seismic retrofit

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Authors: David Hasurungan

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This paper objective is to assess the power distribution reliability improvement by retrofitting obsolete vacuum contactor. The case study in Badak Liquefied Natural Gas (LNG) plant is presented in this paper. To support plant operational, Badak LNG is equipped with 4.16 kV switchgear for supplying the storage and loading facilities, utilities facilities, and train facilities. However, there is a problem in two switch gears of sixteen switch gears. The problem is the obsolescence issue in its vacuum contactor. Not only that, but the same switchgear also has suffered from electrical fault due to contact fingering misalignment. In order to improve the reliability in switchgear, the vacuum contactor retrofit project is done. The retrofit will introduce new vacuum contactor design. The comparison between existing design and the new design is presented in this paper. Meanwhile, The reliability assessment and calculation are performed using software Reliasoft 7.

Keywords: reliability, obsolescence, retrofit, vacuum contactor

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Authors: Galit Shiff, Yael Gilad

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The need to retrofit old buildings lies in the fact that buildings are responsible for the main energy use and CO₂ emission. Existing old structures are more dominant in their effect than new energy-efficient buildings. Nevertheless not every case of urban renewal that aims to replace old buildings with new neighbourhoods necessarily has a financial or sustainable justification. Façade design plays a vital role in the building's energy performance and the unit's comfort conditions. A retrofit façade residential methodology and feasibility applicative study has been carried out for the past four years, with two projects already fully renovated. The intention of this study is to serve as a case study for limited budget façade retrofit in Mediterranean climate urban areas. The two case study buildings are set in Israel. However, they are set in different local climatic conditions. One is in 'Sderot' in the south of the country, and one is in' Migdal Hahemek' in the north of the country. The building typology is similar. The budget of the projects is around $14,000 per unit and includes interventions at the buildings' envelope while tenants are living in. Extensive research and analysis of the existing conditions have been done. The building's components, materials and envelope sections were mapped, examined and compared to relevant updated standards. Solar radiation simulations for the buildings in their surroundings during winter and summer days were done. The energy rate of each unit, as well as the building as a whole, was calculated according to the Israeli Energy Code. The buildings’ facades were documented with the use of a thermal camera during different hours of the day. This information was superimposed with data about the electricity use and the thermal comfort that was collected from the residential units. Later in the process, similar tools were further used in order to compare the effectiveness of different design options and to evaluate the chosen solutions. Both projects showed that the most problematic units were the ones below the roof and the ones on top of the elevated entrance floor (pilotis). Old buildings tend to have poor insulation on those two horizontal surfaces which require treatment. Different radiation levels and wall sections in the two projects influenced the design strategies: In the southern project, there was an extreme difference in solar radiations levels between the main façade and the back elevation. Eventually, it was decided to invest in insulating the main south-west façade and the side façades, leaving the back north-east façade almost untouched. Lower levels of radiation in the northern project led to a different tactic: a combination of basic insulation on all façades, together with intense treatment on areas with problematic thermal behavior. While poor execution of construction details and bad installation of windows in the northern project required replacing them all, in the southern project it was found that it is more essential to shade the windows than replace them. Although the buildings and the construction typology was chosen for this study are similar, the research shows that there are large differences due to the location in different climatic zones and variation in local conditions. Therefore, in order to reach a systematic and cost-effective method of work, a more extensive catalogue database is needed. Such a catalogue will enable public housing companies in the Mediterranean climate to promote massive projects of renovating existing old buildings, drawing on minimal analysis and planning processes.

Keywords: facade, low budget, residential, retrofit

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Authors: Ga Ye Kim, Hee Sun Kim, Yeong Soo Shin

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Many studies have been done on the repair and strengthening method of concrete structure, so far. The traditional retrofit method was to attach fiber sheet such as CFRP (Carbon Fiber Reinforced Polymer), GFRP (Glass Fiber Reinforced Polymer) and AFRP (Aramid Fiber Reinforced Polymer) on the concrete structure. However, this method had many downsides in that there are a risk of debonding and an increase in displacement by a shortage of structure section. Therefore, it is effective way to enlarge the structural member with polymer mortar or Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) as a means of strengthening concrete structure. This paper intends to investigate structural performance of reinforced concrete (RC) beams enlarged with polymer mortar and compare the experimental results with analytical results. Nonlinear finite element analyses were conducted to compare the experimental results and predict structural behavior of retrofitted RC beams accurately without cost consuming experimental process. In addition, this study aims at comparing differences of retrofit material between commonly used material (polymer mortar) and recently used material (UHPFRC) by conducting nonlinear finite element analyses. In the first part of this paper, the RC beams having different cover type were fabricated for the experiment and the size of RC beams was 250 millimeters in depth, 150 millimeters in width and 2800 millimeters in length. To verify the experiment, nonlinear finite element models were generated using commercial software ABAQUS 6.10-3. From this study, both experimental and analytical results demonstrated good strengthening effect on RC beam and showed similar tendency. For the future, the proposed analytical method can be used to predict the effect of strengthened RC beam. In the second part of the study, the main parameters were type of retrofit materials. The same nonlinear finite element models were generated to compare the polymer mortar with UHPFRCC. Two types of retrofit material were evaluated and retrofit effect was verified by analytical results.

Keywords: retrofit material, polymer mortar, UHPFRC, nonlinear finite element analysis

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Authors: Asad Naeem, Mohamed Nour Eldin, Jinkoo Kim

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In this study, the seismic performance and life cycle cost (LCC) are evaluated of the structure retrofitted with the damped cable system (DCS). The DCS is a seismic retrofit system composed of a high-strength steel cable and pressurized viscous dampers. The analysis model of the system is first derived using various link elements in SAP2000, and fragility curves of the structure retrofitted with the DCS and viscous dampers are obtained using incremental dynamic analyses. The analysis results show that the residual displacements of the structure equipped with the DCS are smaller than those of the structure with retrofitted with only conventional viscous dampers, due to the enhanced stiffness/strength and self-centering capability of the damped cable system. The fragility analysis shows that the structure retrofitted with the DCS has the least probability of reaching the specific limit states compared to the bare structure and the structure with viscous damper. It is also observed that the initial cost of the DCS method required for the seismic retrofit is smaller than that of the structure with viscous dampers and that the LCC of the structure equipped with the DCS is smaller than that of the structure with viscous dampers.

Keywords: damped cable system, fragility curve, life cycle cost, seismic retrofit, self-centering

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Authors: Selin Guleroglu, Ilker Kahraman, E. Selahattin Umdu

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In today’s world, the building sector has a significant impact on primary energy consumption and CO₂ emissions. While new buildings must have high energy performance as indicated by the Energy Performance Directive in Buildings (EPBD), published by the European Union (EU), the energy performance of the existing buildings must also be enhanced with cost-efficient methods. Turkey has a high historical building density similar to south European countries, and the high energy consumption is the main contributor in the energy consumptioın of Turkey, which is rather higher than European counterparts. Historic buildings spread around Turkey for four main climate zones covering very similar climate characteristics to both the north and south European countries. The case study building is determined as the most common building type in Turkey. This study aims to investigate energy retrofit measures covering but not limited to passive and active measures to improve the energy performance of the historical buildings located in different climatic zones within the limits of preservation of the historical value of the building as a crucial constraint. Passive measures include wall, window, and roof construction elements, and active measures HVAC systems in retrofit scenarios. The proposed methodology can help to reach up to 30% energy saving based on primary energy consumption. DesignBuilder, an energy simulation tool, is used to determine the energy performance of buildings with suggested retrofit measures, and the Net Present Value (NPV) method is used for cost analysis of them. Finally, the most efficient energy retrofit measures for all buildings are determined by analyzing primary energy consumption and the cost performance of them. Results show that heat insulation, glazing type, and HVAC system has an important role in energy saving. Also, it found that these parameters have a different positive or negative effect on building energy consumption in different climate zones. For instance, low e glazing has a positive impact on the energy performance of the building in the first zone, while it has a negative effect on the building in the forth zone. Another important result is applying heat insulation has minimum impact on building energy performance compared to other zones.

Keywords: energy performance, climatic zones, historic building, energy retrofit measures, NPV

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Authors: Jin-Uk Park

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Recently, the semiconductor industry is rapidly demanding complicated structures and mass production. From the point of view of mass production, the ETCH industry is concentrating on maintaining the ER (Etch rate) of the wafer edge constant regardless of changes over time. In this study, two major thermal factors affecting process were identified and controlled. First, the filler of the thermal pad was studied. Second, the significant difference of handling the thermal pad during PM was studied.

Keywords: etcher, thermal pad, wet cleaning, thermal conductivity

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Authors: Claire Far, Sara Wilkinson, Deborah Ascher Barnstone

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Energy issues have been a growing concern in current decades. Limited energy resources and increasing energy consumption from one side and environmental pollution and waste of resources from the other side have substantially affected the future of human life. Around 40 percent of total energy consumption of Australian buildings goes to heating and cooling due to the low thermal performance of the buildings. Thermal performance of buildings determines the amount of energy used for heating and cooling of the buildings which profoundly influences energy efficiency. Therefore, employing sustainable design principles and effective use of construction materials for building envelope can play crucial role in the improvement of energy efficiency of existing dwellings and enhancement of thermal comfort of the occupants. The energy consumption for heating and cooling normally is determined by the quality of the building envelope. Building envelope is the part of building which separates the habitable areas from exterior environment. Building envelope consists of external walls, external doors, windows, roof, ground and the internal walls that separate conditioned spaces from non-condition spaces. The energy loss from the building envelope is the key factor. Heat loss through conduction, convection and radiation from building envelope. Thermal performance of the building envelope can be improved by using different methods of retrofitting depending on the climate conditions and construction materials. Based on the available studies, the importance of employing sustainable design principles has been highlighted among the Australian building professionals. However, the residential building sector still suffers from a lack of having the best practice examples and experience for effective use of construction materials for building envelope. As a result, this study investigates the effectiveness of different energy retrofitting techniques and examines the impact of employing those methods on energy consumption of existing dwellings in Sydney, the most populated city in Australia. Based on the research findings, the best thermal retrofitting methods for increasing thermal comfort and energy efficiency of existing residential dwellings as well as reducing their environmental impact and footprint have been identified and proposed.

Keywords: thermal comfort, energy consumption, residential dwellings, sustainable design principles, thermal retrofit

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Authors: Peter Krupa, Svetozár Malinarič

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Transient plane source method has been used to measure the thermal diffusivity and thermal conductivity of a compact isostatic electro-ceramics at room temperature. The samples were fired at temperatures from 100 up to 1320 degrees Celsius in steps of 50. Bulk density and specific heat capacity were also measured with their corresponding standard uncertainties. The results were compared with further thermal analysis (dilatometry and thermogravimetry). Structural processes during firing were discussed.

Keywords: TPS method, thermal conductivity, thermal diffusivity, thermal analysis, electro-ceramics, firing

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Authors: Alok Madan, Arshad K. Hashmi

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The paper presents a plastic analysis procedure based on the energy balance concept for performance based seismic retrofit of multi-story multi-bay masonry infilled reinforced concrete (R/C) frames with a ‘soft’ ground story using passive energy dissipation (PED) devices with the objective of achieving a target performance level of the retrofitted R/C frame for a given seismic hazard level at the building site. The proposed energy based plastic analysis procedure was employed for developing performance based design (PBD) formulations for PED devices for a simulated application in seismic retrofit of existing frame structures designed in compliance with the prevalent standard codes of practice. The PBD formulations developed for PED devices were implemented for simulated seismic retrofit of a representative code-compliant masonry infilled R/C frame with a ‘soft’ ground story using friction dampers as the PED device. Non-linear dynamic analyses of the retrofitted masonry infilled R/C frames is performed to investigate the efficacy and accuracy of the proposed energy based plastic analysis procedure in achieving the target performance level under design level earthquakes. Results of non-linear dynamic analyses demonstrate that the maximum inter-story drifts in the masonry infilled R/C frames with a ‘soft’ ground story that is retrofitted with the friction dampers designed using the proposed PBD formulations are controlled within the target drifts under near-field as well far-field earthquakes.

Keywords: energy methods, masonry infilled frame, near-field earthquakes, seismic protection, supplemental damping devices

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Authors: Daud Mustafa Minhas, Raja Rehan Khalid, Georg Frey

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The next generation power systems are equipped with abundantly available free renewable energy resources (RES). During their low-cost operations, the price of electricity significantly reduces to a lower value, and sometimes it becomes negative. Therefore, it is recommended not to operate the traditional power plants (e.g. coal power plants) and to reduce the losses. In fact, it is not a cost-effective solution, because these power plants exhibit some shutdown and startup costs. Moreover, they require certain time for shutdown and also need enough pause before starting up again, increasing inefficiency in the whole power network. Hence, there is always a trade-off between avoiding negative electricity prices, and the startup costs of power plants. To exploit this trade-off and to increase the profit of a power plant, two main contributions are made: 1) introducing retrofit technology for state of art coal power plant; 2) proposing optimal control strategy for a power plant by exploiting different flexibility features. These flexibility features include: improving ramp rate of power plant, reducing startup time and lowering minimum load. While, the control strategy is solved as mixed integer linear programming (MILP), ensuring optimal solution for the profit maximization problem. Extensive comparisons are made considering pre and post-retrofit coal power plant having the same efficiencies under different electricity price scenarios. It concludes that if the power plant must remain in the market (providing services), more flexibility reflects direct economic advantage to the plant operator.

Keywords: discrete optimization, power plant flexibility, profit maximization, unit commitment model

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Authors: G. A. Florides, E. Theofanous, I. Iosif-Stylianou, P. Christodoulides, S. Kalogirou, V. Messarites, Z. Zomeni, E. Tsiolakis, P. D. Pouloupatis, G. P. Panayiotou

Abstract:

Ground Coupled Heat Pumps (GCHPs) exploit effectively the heat capacity of the ground, with the use of Ground Heat Exchangers (GHE). Depending on the mode of operation of the GCHPs, GHEs dissipate or absorb heat from the ground. For sizing the GHE the thermal properties of the ground need to be known. This paper gives information about the density, thermal conductivity, specific heat and thermal diffusivity of various lithologies encountered in Cyprus with various relations between these properties being examined through comparison and modeling. The results show that the most important correlation is the one encountered between thermal conductivity and thermal diffusivity with both properties showing similar response to the inlet and outlet flow temperature of vertical and horizontal heat exchangers.

Keywords: ground heat exchangers, ground thermal conductivity, ground thermal diffusivity, ground thermal properties

Procedia PDF Downloads 351

Authors: James Katungyi

Abstract:

The Steady State thermal comfort model which dominates thermal comfort practice and which posits the ideal thermal conditions in a narrow range of thermal conditions does not deliver the expected comfort levels among occupants. Furthermore, the buildings where this model is applied consume a lot of energy in conditioning. This paper reviews significant literature about thermal comfort in dynamic indoor conditions including the adaptive thermal comfort model and alliesthesia. A major finding of the paper is that the adaptive thermal comfort model is part of a trend from static to dynamic indoor environments in aspects such as lighting, views, sounds and ventilation. Alliesthesia or thermal delight is consistent with this trend towards dynamic thermal conditions. It is within this trend that the two fold goal of increased thermal comfort and reduced energy consumption lies. At the heart of this trend is a rediscovery of the link between the natural environment and human well-being, a link that was partially severed by over-reliance on mechanically dominated artificial indoor environments. The paper concludes by advocating thermal conditioning solutions that integrate mechanical with natural thermal conditioning in a balanced manner in order to meet occupant thermal needs without endangering the environment.

Keywords: adaptive thermal comfort, alliesthesia, energy, natural environment

Procedia PDF Downloads 183

Authors: Sumit Tiwari, Rohit Tripathi, G. N. Tiwari

Abstract:

Present study focused on the utilization of solar energy by the help of photovoltaic greenhouse solar dryer under forced mode. A single slope photovoltaic greenhouse solar dryer has been proposed and thermal modelling has been developed. Various parameters have been calculated by thermal modelling such as greenhouse room temperature, cell temperature, crop temperature and air temperature at exit of greenhouse. Further cell efficiency, thermal efficiency, and overall thermal efficiency have been calculated for a typical day of May and November. It was found that system can generate equivalent thermal energy up to 7.65 kW and 6.66 kW per day for clear day of May and November respectively.

Keywords: characteristics curve, photovoltaic, thermal modelling, thermal efficiency

Procedia PDF Downloads 416

Authors: Seok Hong Min, Tae Kwon Ha

Abstract:

In this study, thermal fatigue properties of 400 series ferritic stainless steels have been evaluated in the temperature ranges of 200-800oC and 200-900oC. Systematic methods for control of temperatures within the predetermined range and measurement of load applied to specimens as a function of temperature during thermal cycles have been established. Thermal fatigue tests were conducted under fully constrained condition, where both ends of specimens were completely fixed. It has been revealed that load relaxation behavior at the temperatures of thermal cycle was closely related with the thermal fatigue property. Thermal fatigue resistance of 430J1L stainless steel is found to be superior to the other steels.

Keywords: ferritic stainless steel, automotive exhaust, thermal fatigue, microstructure, load relaxation

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Authors: Marco Picco, Mahmood Alam

Abstract:

Improving the energy performance of existing buildings can be challenging, particularly when facades cannot be modified, and the only available option is internal insulation. In such cases, the choice of the most suitable material becomes increasingly complex, as in addition to thermal transmittance and capital cost, the designer needs to account for the impact of the intervention on the internal spaces, and in particular the loss of usable space due to the additional layers of materials installed. This paper explores this issue by analysing a case study of an average office building needing to go through a refurbishment in order to reach the limits imposed by current regulations to achieve energy efficiency in buildings. The building is simulated through dynamic performance simulation under three different climate conditions in order to evaluate its energy needs. The use of Vacuum Insulated Panels as an option for energy refurbishment is compared to traditional insulation materials (XPS, Mineral Wool). For each scenario, energy consumptions are calculated and, in combination with their expected capital costs, used to perform a financial feasibility analysis. A holistic approach is proposed, taking into account the impact of the intervention on internal space by quantifying the value of the lost usable space and used in the financial feasibility analysis. The proposed approach highlights how taking into account different drivers will lead to the choice of different insulation materials, showing how accounting for the economic value of space can make VIPs an attractive solution for energy retrofitting under various climate conditions.

Keywords: vacuum insulated panels, building performance simulation, payback period, building energy retrofit

Procedia PDF Downloads 123