Elin Markarian

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Predicting energy consumption and thermal comfort in buildings using a hybrid machine learning and building performance simulation approach

Building Simulation Conference proceedings, Sep 4, 2023

This paper develops machine learning surrogate models to emulate a Building Performance Simulatio... more This paper develops machine learning surrogate models to emulate a Building Performance Simulation (BPS) model of an office building at low computational costs. Unlike most previous studies, the surrogate models include design and operational parameters as independent variables, and thermal comfort metrics as dependent variables. The findings indicate that regression-based models achieved high accuracy levels (R2>0.99) when predicting energy consumption metrics, while Extreme Gradient Boosting (XGBoost) outperformed them when predicting thermal comfort metrics. Light Gradient Boosting (LightGBM) also showed competitive predictive results at relatively low computational costs, highlighting the need to further explore algorithms that balance predictive power and model complexity. Highlights • Machine learning algorithms are proposed as surrogates for building performance simulation models. • The models were tested using a model of a mediumsized office building in an extreme hot climate. • Design and operational parameters are used to predict both energy consumption and thermal comfort metrics. • Regression demonstrates high accuracy in predicting energy use and is computationally efficient. • Extreme Gradient Boosting is found to outperform other models in predicting thermal comfort.

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Energy Performance Assessment of PCM Buildings Considering Multiple Factors

2019 International Conference on Power Generation Systems and Renewable Energy Technologies (PGSRET), 2019

Phase change materials (PCM) can be integrated in buildings to stabilize indoor air temperature a... more Phase change materials (PCM) can be integrated in buildings to stabilize indoor air temperature and in turn reduce the energy consumption. However, the energy performance of these materials relies largely on climatic conditions. Therefore, in this study, the energy performance of a PCM integrated building in two cities of Iran namely Tehran and Bandar Abas is analyzed considering different melting temperatures, thermal energy storage capacities and configurations of PCM. The findings indicated that with increase in thermal energy storage capacity, the energy performance of the building improves regardless of the climatic conditions. However, the melting temperature depends highly on climatic condition and in warmer climates, a higher melting temperature has the optimal performance while in cold climates, lower melting temperatures have more promising performance.

DSF Energy Performance Assessment Considering Different Climatic Regions of Iran and Design Parameters

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

Buildings account for over 40% of total energy consumption throughout the world. In recent years,... more Buildings account for over 40% of total energy consumption throughout the world. In recent years, double skin façade (DSF) has gained attention as a solution for energy reduction. However, the performance of DSF varies according to climatic conditions and design parameters such as building orientation, cavity width and glazing type. DSF performance has not yet been fully studied for climatic conditions of Iran. In this regard, a three-story office building with an air-tight DSF is simulated in DesignBuilder software considering three different climatic regions of Iran, namely Tehran, Tabriz and Bandar Abas to assess the impact of orientation, cavity width and glazing types of inner and outer skins. It is found that heating demand of the building correlates strongly with the orientation while the cooling load differs slightly for all the regions under study. With increase in cavity width from 0.4 to 1.2m, heating load is dropped by 0.52 MWh/yr. for Tehran, 0.22 MWh/yr. for Tabriz and 0.2 MWh/yr. for Bandar Abas and the cooling load is reduced by 1.89, 1.48 and 0.08 MWh/yr. for Tehran, Tabriz and Bandar Abas, respectively. Moreover, the study shows that inner skin composition has no significant effect on heating load. Grey double glazing outer skin with the minimum cooling loads of 86.6 MWh/yr. for Tehran, 47.9 MWh/yr. for Tabriz and 154 MWh/yr. for Bandar Abas has the optimal performance.

Optimization of wind farm layout considering wake effect and multiple parameters

Environmental Progress & Sustainable Energy, 2019

The output power of wind farms in real world applications is lower than the theoretical output wh... more The output power of wind farms in real world applications is lower than the theoretical output which is largely due to wake effect. So as to maximize the output power, the wake effect of upstream wind turbines on downstream ones should be attenuated. Thus, arrangement of wind turbines in a wind farm is an essential issue that needs to be tackled. This study pursues the aim of finding an optimal layout. Initially, Jensen wake model is applied to simulate the wake effect. Then, genetic algorithm is employed to optimize the wind farm layout considering multiple factors that include different hub heights, rotor diameters, variable induction factors, power and capacity factor curves. Three cases including constant wind-constant direction, constant wind-variable direction and variable wind-variable direction are studied and compared with previous studies. The results indicate that the efficiency of the wind farm for case 1 is 96.71% which is a high record comparing to the previous literature.

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Impact of building design parameters precision on heating and cooling load calculations

Environmental Progress & Sustainable Energy, 2018

Energy efficiency of buildings is of paramount importance due to limited fossil resources, enviro... more Energy efficiency of buildings is of paramount importance due to limited fossil resources, environmental issues, and increasing energy demand. Thus, in recent years building energy analysis using various programs has experienced a rapid growth. However, these programs are expensive and time consuming. In this study, mechanical engineering building of Tabriz University located in northwest of Iran is analyzed to attain a simplified building model that can reduce the computational time and effort. Therefore, 10 models are considered with distinctive design accuracies. EnergyPlus software has been employed to perform energy analysis of the building. The findings show that building materials, internal walls and zoning of the building are determining factors in thermal loads of the building. However, shadings, number of occupants, and electrical appliances have negligible impact. Thus, it can be concluded that the model in which a detailed envelope design is considered and interior walls, shades, electrical appliances, and duration of occupancy are omitted, has the optimum performance in terms of time saving and accuracy of load calculation. Moreover, to gain more reliable results, it is recommended to consider zones in model No.5. The difference between natural gas and electricity consumption of the first and last models is 20,302 m 3 (2200$) and 1157 kWh (90$) that indicates the significance of proper HAVC sizing. It is worth mentioning that all monetary units are presented in 2018 U.S. dollar.

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Impact of Multiple Parameters on Energy Performance of PV-DSF Buildings

Proceedings, 2018

Double Skin Façade (DSF) has been widely used in buildings to enhance energy efficiency and bring... more Double Skin Façade (DSF) has been widely used in buildings to enhance energy efficiency and bring daylight and aesthetic benefits. Solar photovoltaic (PV) modules can be integrated in DSF to fully or partially meet the electricity demand. Therefore, in this study, the energy performance of a 3-storey PV-DSF building is analyzed for three cities of Iran with distinctive climates namely Tehran, Tabriz and Kish Island considering different orientations, cavity widths and different optical properties for the PV system. The results indicated that the south facing PV-DSF have the maximum electricity generation and the minimum net electricity consumption. With increase in cavity width from 0.4 to 1.2 m, the annual electricity consumption is reduced by 5.88, 5.19 and 7.49 MWh for Tehran, Tabriz and Kish, respectively. The cavity width tends to have negligible impact on electricity generation. The analysis of the outer PV skin showed that the glazing with lower Solar Heat Gain Coefficient (S...

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Wind energy potential and economic assessment of four locations in Sistan and Balouchestan province in Iran

Renewable Energy, 2017

Utilization of wind turbines to produce energy has been increasing in recent years, due to techno... more Utilization of wind turbines to produce energy has been increasing in recent years, due to technology advancement, cost stability and environmental issues. In this paper, the wind resource and economic feasibility have been studied to avoid investment risk in cites of Zabol, Zahak, Zahedan and Mirjaveh in Sistan and Balouchestan province of Iran. The Weibull distribution function has been applied to estimate the wind power and energy density, using meteorological data. Determination of coefficient, root mean square error, mean bias error and mean bias absolute error are also calculated to ensure the accuracy of the statistical analysis of fitted distribution. Windographer software has been employed to investigate the prevailing wind direction. The estimated annual energy densities are 2495.36, 2355.69, 1265.24 and 1214.01 kWh/m 2 /year, and the annual mean power densities are 284.97, 269.02, 144.49 and 138.64 W/ m 2. It is found that Zabol and Zahedan are suitable for large scale power generation. The results indicate that using DW61-900 kW wind turbines are highly beneficial for Zabol and Zahak, while for Zahedan, DW52/54-250 kW wind turbine is more appropriate for generating electricity. However, Mirjaveh is suitable for off-grid applications. It should be noted that in this analysis, monetary units are presented in 2016 U.S. dollar.

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Multi-objective optimization of energy performance of a building considering different configurations and types of PCM

Solar Energy, 2019

Phase change materials (PCM) can be outfitted in building envelopes to not only provide thermal c... more Phase change materials (PCM) can be outfitted in building envelopes to not only provide thermal comfort for occupants but also trim heating, ventilation and air conditioning (HVAC) loads. However, the efficacy of PCMs depends highly on its thermo-physical properties and climatic condition. In this regard, a multi-objective optimization technique is adopted to unearth the optimal type and location of PCM that can minimize heating and cooling loads considering five cities of Iran namely Tehran, Tabriz, Bandar Abas, Shiraz and Yazd with distinctive climates. Then, the optimal PCMs are environmentally and economically assessed. The study showed that the PCM with a melting temperature of 25°C outperforms in terms of cooling load while the PCM with a melting temperature of 21°C favors the heating performance. Moreover, the utilization of PCM results in electricity saving of 4.5-5.5% for all the climates. On average, the annual carbon footprint is reduced by 1297 kg, 1420 kg, 2040 kg, 1027 kg, and 1248 kg for Tehran, Tabriz, Bandar Abas, Shiraz, and Yazd, respectively. The payback period was found to be more than 70 years for all the cities considering current economic conditions. However, the energy subsidies are projected to fall in the near future that may make PCM integration economically feasible.

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