Energy Performance Evaluation Research Articles

BIM-based energy and acoustic analysis through CVE tools

Building information modelling (BIM) is trying to overcome the issue of interoperability by promoting the collaboration between different professions, which enables Building Performance Assessments (BPA) to take place earlier in the design process. Nevertheless, the interoperability is rarely perfect and information is lost during translation from BIM authoring tool to simulation software or the interoperability is limited to the translation of the geometry. The discrepancies in data translations from BIM authoring tool to specific Calculation Virtual Environments (CVE) for energy and acoustic evaluation are considered. For the energy performance evaluation two software tools are tested in the present research paper, namely the Design Builder and IES VE , using IFC and gbXML as data exchange formats. Furthermore, a solution is proposed for overcoming the interoperability issue about acoustic evaluation by adapting programming language in Dynamo Graphical Interface for calculation of acoustic parameters, namely the Reverberation time and Schroeder’s frequency, which allow room quality evaluation to take place earlier in the design process as they are crucial for educational and other facility usage buildings.

Energy and exergy performance evaluation of a novel photovoltaic-thermoelectric system combined with tube and sheet serpentine water collector

ABSTRACT In this paper, a photovoltaic-thermoelectric with serpentine water collector (PV-TE-SWC) is proposed where a serpentine tube and sheet water collector is placed at the rear surface of the combined photovoltaic-thermoelectric system to improve the electrical, thermal, and exergy performance of the hybrid system. The performance of the proposed PV-TE-SW collector is analyzed and compared with the results of a recent state-of-art study on photovoltaic-thermoelectric (PV-TE) air collector. The overall electrical gain and electrical efficiency of the proposed collector are observed 5.2% and 6.2%–7.05% higher than the state-of-art PV-TE air collector. The exergy of thermal energy for the proposed collector is 75.6% higher than the PV-TE air collector due to the serpentine water collector, which is capable to absorb more heat and shows better thermal performance compared to the air channel. Hence, the overall exergy gain of the PV-TE-SW collector is 32.2% higher than that of the PV-TE air collector. The impact of different design parameters over exergy gain has also been examined. The performance of the PV-TE-SW collector is influenced to a great extent by the collector dimensions, mass flow rate, and inlet temperature of the fluid.

Energy Performance Evaluation Method for Machining Systems Towards Energy Saving and Emission Reduction

Energy Performance Evaluation Method for Machining Systems Towards Energy Saving and Emission Reduction

Evaluation of Energy Performance and Comfort: Case-Study of University Buildings with Design Adapted to Local Climate

One of the main strategies to reduce countries’ energy bills is to invest in efficient buildings. To achieve this objective, the European Union Member States have developed different methodologies to evaluate building energy performance, which are often supported by simulation tools. These tools are based on calculation engines that use databases and simplifications to attempt to bring their results close to real building performance and are mostly designed to be used at the end of the process, neglecting their role in project decision-making processes. To compensate for this situation and to obtain the most accurate results, the methodologies recommend previous work during the building design phase to adopt passive design solutions that learn from experience and aim to adapt the building design to the local climate. However, these design solutions are difficult to adopt while working with medium to large public buildings and are often not properly understood by the simulation tools. In addition, new BIM methodologies are being implemented, starting to enable proper interaction between the designer and the results, and opening up the option of introducing other types of calculations, such as building comfort, in the calculation process. Among the group of countries with limited simulation tools that are starting to be substituted is Spain, which recently launched its first BIM-based energy simulation tool. This tool aims to compensate for the limitations of the former simulation tools and opens up the option of performing comfort calculations by sharing information with other programs. The objective of this research is to evaluate, from different perspectives, the performance of this new simulation tool on three buildings at the University of Alicante. These were chosen as university campuses are responsible for large groups of buildings and belong to the group of stakeholders interested in obtaining efficient and comfortable buildings. These case studies are defined by their extreme adaptation to design recommendations for mild-warm weather. At the end of the process, the difference is measured between simulation and real building performance. The results obtained show that simulation still differs greatly from real building performance from the energy performance point of view, while the comfort evaluation shows results that are closer to the reality of the buildings.

A dynamic energy benchmarking methodology on room level for energy performance evaluation

Building energy benchmarking is the basis of energy performance assessment. Most of existing energy benchmarking studies are aimed at building-level or subsystem-level energy performance evaluation, which cannot provide detailed energy performance information inside the building. This study aims to develop a dynamic room-level energy benchmarking method to evaluate energy performance of all rooms in office building. Taking a government office building as a case study, this paper analyses the influence of room types and energy consumption patterns on energy consumption, and proposes a K-shape clustering method to mine five typical energy consumption patterns in this building to describe occupancy behaviors of nearly 1000 rooms. The quartile method is used to establish energy benchmarks for different room types and energy consumption patterns. Finally, this study takes staff room as a case to evaluate the energy performance of rooms. Through the establishment of room-level energy benchmark, it is found that the total energy saving potential accounts for 24.69% of the total energy consumption of all the rooms. This method provides detailed information to help building managers and engineers understand energy consumption status on room level better and help them develop targeted energy-saving measures. Moreover, it should be noted that this energy benchmarking could be periodically updated with energy performance due to the increasing awareness of occupants for energy conservation.

Energy and exergy performance evaluation of a three-stage auto-cascade refrigeration system using low-GWP alternative refrigerants

l Performance of mixtures consisting R1234yf, R170, R41 and R1132a were investigated within a three-stage ACR. l All alternatives presented promising energy results and can be recommended to replace R23. l The isobaric 3D and the isothermal-isobaric ternary VLE diagrams were presented. l R1234yf/R23/R14 (0.59/0.24/0.17) offers the maximum COP and exergy efficiency of 0.614 and 26.15%. l R1234yf/R41/R14 (0.64/0.17/0.19) is suggested as a promising alternative refrigerant at -100 °C. In order to seek promising refrigerants for vapor compression refrigeration system to obtain ultra-low temperatures down to -100 °C, and to determine whether the low-GWP refrigerants, R41, R170 and R1132a, are suitable substitutes for R23, this study conducted a comprehensive comparative analysis on the cycle characteristics of a three-stage auto-cascade refrigeration (ACR) system using R1234yf/R23/R14, R1234yf/R41/R14, R1234yf/R170/R14 and R1234yf/R1132a/R14. The system performances, including cooling capacity, coefficient of performance (COP), evaporation temperature, compressor discharge temperature, exergy destruction and efficiency were investigated with various compositions and vapor qualities. Results show that R41, R170 and R1132a can all be recommended to replace R23, and the alternatives present promising thermodynamic properties in theoretical simulations. Under the same operation conditions, the cooling capacity of the R1234yf/R41/R14 system is the largest, while the maximum COP and exergy efficiency occur in the R1234yf/R23/R14 system. Considering the energy shortage and environmental pollution issues, R1234yf/R41/R14 with the mass fraction of 0.64/0.17/0.19, COP of 0.2713, and exergy efficiency of 13.91% performs better and hence can be suggested as an alternative refrigerant for the three-stage ACR operating at -100 °C. The largest exergy destruction component occurs in the compressor, followed by the air-cooled condenser and expansion valve, on which future optimization work can be carried out. The results provide a basic theoretical analysis of the selection and replacement of refrigerant in three-stage ACR.

Developing an optimization-based simulation approach for building energy performance evaluation (case study: Iran)

Developing an optimization-based simulation approach for building energy performance evaluation (case study: Iran)

Energy, economic, and environmental assessment of the integrated production of palm oil biodiesel and sugarcane ethanol

The key objective of this study was to evaluate and compare, within the concept of integrated biorefining, the potential environmental gains of the life cycle, economic feasibility and energy balance of the production of bioenergetics from palm and sugarcane. In this context, the research model developed in this work involved several assessment techniques; in terms of environmental assessment, the tool used was the Life Cycle Assessment (LCA) from the Well-To-Tank perspective, which is based on the LCA “cradle-to-gate” assignment method. The environmental assessment was performed using SimaPro v.8.0.3 software and the impacts were quantified using the IMPACT 2002+ method. On the other hand, energy performance evaluation was based on the 1st law indicators. Likewise, economic feasibility was based on the evaluation of the fixed capital investment index and the estimate of investment costs for the entire integrated system. Two different scenarios were proposed in order to compare and evaluate traditional systems with the integrated biorefinery. The first conversion scenario (baseline scenario) consisted of a traditional palm oil extraction plant in addition to an ethanol and sugar plant, concerning the use of fossil fuels in all stages of production. The second conversion scenario (improved scenario) explored the substitution of fossil energy sources as well as the energy recovery of residual biomass in more efficient energy conversion systems. The results indicated significant reductions of 29.5% and 29.1% in the global warming impact category when the baseline scenario was compared to the improved scenario. Additionally, the improved scenario achieved a reduction of 2.1 g CO2eq MJ−1 (ethanol) and 2.61 g CO2eq MJ−1 (biodiesel). On the other hand, the improved scenario presented better energy rates since it showed an increase of 3.82% in the global efficiency of the system and produced 106.32 kWh more per ton of processed raw material. Finally, when considering the Life Cycle Energy Efficiency, an increase of 83% was observed and in the case of the Renewability Factor showed an increase of 7.12 energy units. Integration is also economically feasible; however, it could be significantly improved through fiscal incentives founded on the reduction of fossil energy use, enhanced conversion yielding, and improvements in conversion technologies.

Evaluation of energy flow, dissipation and performances for advanced adsorption assisted heat transformation systems: Temperature-entropy frameworks

This article presents the entropy flow and generation of an adsorption assisted heat transformation (A-HT) system. Hence the Gibbs analogy and the thermodynamic property fields of adsorbents + water systems are employed to formulate the entropy balance of adsorption beds. Later, the experimentally confirmed isotherms, kinetics and bed heat exchanger data are applied for computing the energetic performances of adsorption system in terms of entropy flow and generation, from which one can calculate (i) the system-performances with respect to heating and cooling capacities, specific water production and the overall efficiency and (ii) dissipations from each component of A-HT systems. The temperature entropy-flow (T-Sf) maps show close loops for the evaporator, the condenser and the beds indicating the stored energy under batch operating conditions of A-HT cycle. It is observed that the entropy generation (Sg) are mainly contributed by various processes such as mass and heat transfer, de-superheating and flushing of heat transfer fluids. The highest entropy generation occurs in the adsorption bed during desorption period, and the least Si is found in the evaporator. The proposed temperature-entropy maps can be applied to design each component of bed heat exchanger with minimum entropy generation. It is found that the entropy flow and generation depend on the periods of batch operation, the heating source temperature, and the quality of porous adsorbents.

Evaluating the applicability of Typical Meteorological Year under different building designs and climate conditions

Typical year weather files are synthetic files generated from historical weather data used in building energy simulation to evaluate energy performance of buildings. The current work is to illustrate the impact of building types and designs on the deviations between the energy demand predicted using typical year weather files and the average energy demand predicted using 30-year long-term actual year weather data. This study explores design parameters, which have great impact on energy demands, including window-to-wall ratio, window solar heat gain coefficient, floor construction, and solar reflectance of exterior walls and roof. These design parameters are applied to two different building types — small and large office buildings, and two different climatic locations — Montreal and Vancouver, Canada. The results indicate that certain designs exhibit wider deviations between energy demands predicted with a typical year and the long-term average. The maximum deviation is found to be around 4.5%, which suggests that typical year weather file is still a reliable means to predict the long-term average cooling and heating energy performance. However, the study also found that typical year weather files underestimate the peak load in the long run for up to 85% of the time.

Multi-objective optimization of thermochromic glazing based on daylight and energy performance evaluation

Many efforts have been detected to investigate thermochromic (TC) glazing for improving building energy saving, while only a few approaches for daylight performance analysis. In this study, the performance of TC glazing is investigated based on multi-objective optimization for minimizing energy demand while maximizing daylight availability. The effects of five parameters including transition temperature, solar transmittance in clear state, solar transmittance modulation ability, luminous transmittance in clear state, and luminous modulation ability on the building energy consumption and useful daylighting illuminance (UDI300–3000) are examined. Linear Programming Technique for Multi-dimensional Analysis of Preference (LINMAP) is used for the decision-making of Pareto frontier. This research aims to explore the ideal thermochromic glazing by considering the daylight and energy performance of a typical office room, taking the weather condition of Xiamen, China as an example. Although it is impossible to achieve both optimal values of energy consumption and UDI300–3000 simultaneously, the proposed multi-objective optimization method could still provide low energy consumption with sufficient daylight. The non-dominated sorting of Pareto optimal solution (POS) demonstrated that the optimum building energy consumption and UDI300–3000 for single glazed windows are 46.64 kWh/m2 and 70.92%, respectively, while the values for double glazed windows are 44.40 kWh/m2 and 71.88%, respectively. The selected hypothetical TC windows can improve the building energy and daylighting performance simultaneously when compared with traditional clear single and double glazed windows. The presented framework provides a multi-objective optimization method to determine the most suitable TC glazing technologies for designers and architects during the design and retrofit procedure.

Performance Evaluation of RF Energy Harvesting Circuit with DRA and Planar Antennas

In this study, a rectenna (antenna + rectifier) performance is compared with two different types of antennas; planar and DRA. The CST Microwave Studio and Advance Design System (ADS) is used to perform co-simulation. In this, first a .S2P is generated using two similar antennas keeping at a far-field distance in CST, afterward it is imported in ADS and tested with a typical rectifier circuit. Further, two experimental methods are performed in indoor and outdoor environments to validate the simulation results. In the indoor environment, a horn antenna excited with a signal generator is used as an RF power transmitter. In contrast, in the outdoor environment, the horn antenna is replaced with an ambient power source like a mobile base station. In both methods, at receiving side rectenna (antenna + rectifier) is kept in the far-field region. Here, both planar metallic and dielectric resonator antennas are use done after another with the rectifier circuit to test the rectenna system. From the simulation and experiments performed in indoor and outdoor environment method, it is confirmed that the rectenna system tenders the best performance with dielectric resonator antenna.

Evaluation of sustainable energy performance for OECD countries

ABSTRACT This study aims to evaluate the sustainable energy performance of 36 OECD (Organization for Economic Cooperation and Development) countries. The sustainable energy performance evaluation of the countries was made with linear programming-based “DEA (Data Envelopment Analysis)” and multi-criteria decision-making-based “PROMETHEE (The Preference Ranking Organization Method for Enrichment Evaluation)”. Spearman Correlation Coefficients were calculated for the relationships between the rankings obtained from all methods. According to the Spearman’s Rank Correlation Coefficients (R) calculated for the performance rankings of OECD countries, the relations between all rankings of OECD countries were positive moderate (R = +0.6952) and positive high (R = +0.7959; R = +0.8919). The novelty of this article is to verify that DEA models and PROMETHEE technique, which are different from each other in terms of structure, algorithms, and basic purposes, can be used as an alternative performance evaluation tool.

Flow and Heat Transfer Property of Oldroyd-B-Fluid-Based Nanofluids Containing Cylindrical Particles in a Pipe

Flow and heat transfer property of Oldroyd-B-fluid-based nanofluids containing cylindrical particles are studied in a pipe with circular cross-section in the range of Reynolds number (Re) from 100 to 2000, Weissenberg number (We) from 0.1 to 2, particle aspect ratio (β) from 2 to 16 and particle volume concentration (Φ) from 0.1% to 2.5%. The motion equation of Oldroyd-B fluid with particles, the equation for probability density function of particle orientation and convection-diffusion equation for particles are solved numerically. The numerical method used in the simulation is validated by comparing with the available results. The effects of Re, We, β and Φ on the friction factor (f), Nusselt number (Nu) and ratio of energy performance evaluation criterion (PECt/PECf) for Oldroyd-B-fluid-based nanofluids to that for Oldroyd-B fluids are discussed. The results showed that the values of f and Nu of Oldroyd-B-fluid-based nanofluids are larger than that of water-based nanofluids and that of pure Oldroyd-B fluids. The values of f increase with increasing Re, We and Φ, but with decreasing β. The values of Nu and PECt/PECf are enhanced with increasing Re, We, β and Φ. The increase of f is larger than that of Nu at lower Re, but is less than that of Nu at higher Re. It is more effective to use Oldroyd-B-fluid-based nanofluids with cylindrical nanoparticles to improve the heat transfer at the conditions of higher Re, We, β and Φ. Finally, the correlation formula of PECt/PECf as a function of Re, We, β and Φ is derived.

In Situ Evaluation of the U-Value of a Window Using the Infrared Method

The amount of heat lost through the envelope of a building is one of the most important variables that affects the energy performance evaluation of a house. In addition, it is especially important to estimate and accurately diagnose the amount of heat produced by windows. In Korea, windows’ U-values reflect a building’s initial design values and thermal characteristics that determine the thermal performance of an existing building, and is a factor that can overestimate the energy performance of a building. Therefore, there is a need for a field measurement method that can accurately measure the total U-value of windows in an existing house. This study provides a method of quantitatively measuring the total U-value of windows using the infrared (IR) method in ISO 9869-2. As a result of measuring the U-value using the infrared (IR) method, the Korean Standard (KS F 2278) for window performance test result values and the root mean square error (cvRMSE) for the U-value measurements using the IR method showed a high accuracy of about 3.29%. In addition, we confirmed that the IR method is an effective (cvRMSE about 7% improvement) method that can measure the comparison result faster than the heat flow meter (HFM) method, which is a conventional thermal performance measurement method.

Evaluation of Building Energy Performance with Optimal Control of Movable Shading Device Integrated with PV System

Among the envelope components (e.g., walls, roofs, floors, and windows, etc.) affecting the cooling and heating load of buildings, windows are the most thermally vulnerable. Shading devices can minimize the thermal load on windows due to solar radiation and decrease radiation effects. However, the load changes due to convection and conduction should be considered. Therefore, when a shading device is applied to a window, control logic for thermal blocking and heat retention is necessary to prevent the load changes. In addition, by combining the opposite features of photovoltaic (PV) that require solar radiation and the shading device to block solar radiation, energy-saving and production can be achieved simultaneously. Therefore, this study minimized the thermal effects of windows using a movable shading device integrated with PV and evaluated the PV power generation. This study evaluated the effects on window heat transfer by applying artificial intelligence techniques, which have recently attracted attention, to system operation. To achieve this, artificial neural network (ANN)-based control logic was developed, and the control performance of the system was assessed using simulations. In ANN control, the window heat transfer was 86.3% lower in a cooling period and 9.7% lower in a heating period compared with that of a shading device fixed at 45°. Furthermore, the PV system produced 3.0 to 3.1% more electric power under optimal control during the cooling period.

Improved energy performance evaluating and ranking approach for office buildings using Simple-normalization, Entropy-based TOPSIS and K-means method

Reasonable evaluation of building energy performance can provide great benefit for government (policy makers) to put forward effective energy conservation policies, and building regulators to make suitable energy-saving strategies. Traditional approaches employ the annual total energy consumption (or the annual total energy use intensity) to evaluate and rank the energy performance of buildings. However, these approaches ignore the energy consumption fluctuation of buildings in different seasons. As a consequence, this paper proposes an improved data-driven-based building energy performance evaluating and ranking approach for office building in city scale using the Simple-normalization, Entropy-based TOPSIS and K-means method. The proposed approach chooses the monthly energy use intensity in single year of office buildings as evaluation indicators, and consists of three steps: (1) The building energy use intensity are calculated by Simple-normalization method. (2) The Entropy-based TOPSIS method is applied to score and evaluate the building energy performance. (3) Finally, the K-means method is employed to rank the evaluated buildings. To validate the proposed approach, 24 office buildings in Tongling city of China are served as case study to present the evaluating and ranking procedure. Simultaneously, the comparison analysis between the proposed approach and two traditional approaches are conducted considering consistency and rationality synchronously. The comparison results demonstrate the proposed approach can more effectively score the energy performance of office buildings, and achieve the reasonable order and grade. In addition, to demonstrate the application, the proposed approach is also applied on Urban-area Building Energy Consumption Monitoring System of Tongling city in China. As a result, this study provides convenient and effective tool to present the energy efficiency gap and energy-saving potential between different buildings in city scale.

소규모 주택의 그린 리모델링 도입 타당성 분석

Purpose: Recently, various technologies and policies have been introduced in building to reduce the energy demand and to provide a comfort and beneficial residential environment. However, various policies to reduce the heating/cooling load and to improve energy efficiency are mainly applied to new buildings and public institutions. Accordingly, the government is promoting a green-remodeling policy for improving the energy efficiency and performance of aging buildings. In this study, the energy performance evaluation and feasibility analysis on green-remodeling of the small-scale housing was conducted. Method: In this study, in order to quantitatively analyze the energy consumption according to the application of green-remodeling design factors, ECO2 program that used for energy evaluation was utilized. Furthermore, feasibility analysis was conducted based on the green-remodeling technologies and results of the energy consumption. Result: In order to meet the minimum requirements for green remodeling and receive interest support, the insulation performance conditions differed by region. When the renewable system was installed, the results of economic analysis were different depending on the specific period. Considering the support fund of renewable energy provided by the government, the payback period could be shortened from 4 to 8 years.

Integrating GIS-Based Point of Interest and Community Boundary Datasets for Urban Building Energy Modeling

Urban building energy modeling (UBEM) is arousing interest in building energy modeling, which requires a large building dataset as an input. Building use is a critical parameter to infer archetype buildings for UBEM. This paper presented a case study to determine building use for city-scale buildings by integrating the Geographic Information System (GIS) based point-of-interest (POI) and community boundary datasets. A total of 68,966 building footprints, 281,767 POI data, and 3367 community boundaries were collected for Changsha, China. The primary building use was determined when a building was inside a community boundary (i.e., hospital or residential boundary) or the building contained POI data with main attributes (i.e., hotel or office building). Clustering analysis was used to divide buildings into sub-types for better energy performance evaluation. The method successfully identified building uses for 47,428 buildings among 68,966 building footprints, including 34,401 residential buildings, 1039 office buildings, 141 shopping malls, and 932 hotels. A validation process was carried out for 7895 buildings in the downtown area, which showed an overall accuracy rate of 86%. A UBEM case study for 243 office buildings in the downtown area was developed with the information identified from the POI and community boundary datasets. The proposed building use determination method can be easily applied to other cities. We will integrate the historical aerial imagery to determine the year of construction for a large scale of buildings in the future.

An anomaly detection and dynamic energy performance evaluation method for HVAC systems based on data mining

With the wide application of building automation systems (BASs), a large amount of building operation data are usually available, which provide a good basis for the optimal operation of a building’s heating, ventilation and air conditioning (HVAC) systems. In this study, a data mining (DM)-based method is proposed for the anomaly detection and dynamic energy performance evaluation of an HVAC system. In this method, first a DM technology is used to detect the abnormal operation data from historical operation data and identify the possible reasons for abnormalities. Then, the identified abnormal energy consumption data caused by faults are corrected. On this basis, a multilevel dynamic energy performance benchmark and a set of energy performance evaluation rules for the HVAC system are established. Finally, the real-time operation performance of an HVAC system is evaluated, and the causes of abnormal energy consumption are identified at multiple levels. The effectiveness of the proposed method is verified in a case study of a commercial building with a complex cooling system.