Energy Simulation Tools Research Articles

Implementation of BIM Modelling and Simulation Tools in Reducing Annual Energy Consumption of Multifamily Dwellings

In current research, building modelling and energy simulation tools were used to analyse and estimate the energy use of dwellings in order to reduce the annual energy use in multifamily dwellings. A three-story residential building located in Kabul city was modelled in Revit and all required parameters for running energy simulation were set. A Total of 126 experiments were conducted to estimate annual energy loads of the building. Different combinations from various components such as walls, roofs, floors, doors, and windows were created and simulated. Ultimately, the most energy efficient option in the context of Afghan dwellings was figured out. The building components consist of different locally available construction materials currently used in buildings in Afghanistan. Furthermore, the best energy efficient option was simulated by varying, building orientation in 15-degree increments and glazing area from 10% to 60% to find the most energy efficient combination. It was found that combination No. 48 was best option from energy conservation point of view and 120-degree rotational angle from north to east, of the existing building was the most energy-efficient option. Also, it was observed that 60% glazing area model consumed 24549 kWh more electricity compared to the one with 10% glazing area.

Managing climate-change-induced overheating in non-residential buildings

Large and rapid climatic changes can be uncomfortable and sometimes hazardous to humans. Buildings protect people from external climatic conditions, and also mitigate the impacts of external climate extremes through their design and construction, as well as with the help of dedicated building service and other technical systems. Active space conditioning accounts for more than 30 per cent of the overall final energy use in Germany. In the life cycle of a building, the construction phase (planning and construction) is the phase with the shortest duration. However, the quality applied during this phase has a significant impact on the resources required, as well as the overall building performance during the much longer operational phase. Once built, buildings are often unable to adapt to boundary conditions that were not considered in the original building design. Consequently, changing outdoor climate conditions can result in an uncomfortable indoor climate over the lifetime of a building. The aim of this study was to determine the effectiveness of flexible solutions for reducing winter heating loads and to reducing/avoiding summer cooling loads in nonresidential buildings in Germany. Various external shading scenarios for non-residential buildings were analysed using the IDA ICE indoor climate and energy simulation tool. Key simulation parameters included the orientation and location of the building, as well as the envelope structure. We investigated the impacts of solar shading on heat storage in the building mass and indoor climate and how different types of envelopes affect overall energy use. The result shows that the use of an adaptive building envelope allows a higher reduction of the total energy demand by 7 % to 15 % compared to an increase in insulation thickness only.

Three-dimensional unsteady energy simulation of building envelopes composed of hollow concrete blocks

Building Energy Simulation (BES) tools commonly use 1-D formulation for computing conductions loads through building envelopes. As this assumption may cause significant errors on the prediction of building energy and thermal performance, this work proposes a methodology for taking into account the 3-D heat transfer phenomenon nature and compare the results for three case studies. The different approach is also used to investigate the effects of considering brick’s cavity detailing with convection and radiation phenomena on the results of transient simulations at the building scale. The present method has the potential to increase precision in the energy analysis of buildings and analyse more precisely the performance of elements of complex geometry. The results demonstrate that traditional simulation methods may not ensure good precision. The magnitude of relative errors varies significantly in each case study.

Evaluation of measurement techniques for modelling buildings in energy simulation and labelling tool

The dwellings built between 1945 and 1980 have the largest energy demand in the EU, which by 2009 represented 70% of the final energy use in buildings. A great portion of these dwellings have not been retrofitted and most of them were not built with any energy efficiency measures, since most of the energy regulations were implemented after the oil crisis in the 1970s. The current renovation rate of residential buildings has not reached targeted goals, due to the numerous barriers that arise in the renovation process. The evaluation and labelling of existing residential buildings represent a big challenge, and the lack of geometric information on buildings is one of the main issues hindering an assessment through simulations. Currently, there is no scientific literature that focuses on improving this task. However, the emergence of new technologies from different fields may streamline the geometric data gathering with the modelling task and greatly improve both accuracy and workload. This study focuses on the revision of geometry measurement techniques, based on the application and quantification of the benefits and barriers that these techniques represent for their use in the building simulation and labelling. The techniques tested were Hololens, handheld laser scanner and handheld laser distance measurer. The evaluation considers time, cost and accuracy as well the tasks related to the post process of the data in BIM, which is not mandatory for building simulation, but it provided multiple benefits.

Energy Audit and Management of a Tannery Company: A Case Study of Kano State

Energy audit is considered as one of the comprehensive methods in checking the energy usage and wastage in facilities/buildings. This paper presents the results of the energy audit conducted to investigate the energy consumption pattern of tannery company from its record of fuel expenditure and electricity bills for a period of 5 years (2012 - 2016). Also, the use of energy models system, Energy Quick Energy Simulation Tool (eQUEST) to evaluate the consumption of the energy end users and performance of the company. Results shows peak electricity demand during the hot months from April to August due to high cooling or significant Air condition requirement. 2.37% of electricity consumed was contributed by the burning of AGO in the diesel power generators showing very less contribution over that of National grid 97.63%. The annual average consumption demand of electricity and diesel (kWh equivalent) of the company were 118960.72 kWh and 2881.17 kWh respectively. The energy modeling and simulation results shows that the sum total of the total monthly energy consumption by the end users is 138164 kWh representing the total average value of the annual energy use in air-conditioning (space cooling) was 27%, ventilation fan 2%, factory machineries 39%, heat rejection is 4%, pump and auxiliary is 2% and area lighting 26%. Also, the total monthly peak demand by space cooling was 22372.2 kWh, ventilation fan 1376 kWh, factory machineries 14294kWh heat rejection is 4461 kWh, pump and auxiliary is 1343 kWh and area light 11023 kWh respectively having a sum total monthly peak demand by the end users to be 44969.2 kWh. This represent energy use in air-conditioning (space cooling) was 41%, ventilation fan 3%, 26% factory machineries, heat rejection is 8%, pump and auxiliary is 2% and 20% area light of the annual peak demand. The Energy Used Index (average annual electricity use per tones of leather) was found to be 717.38kWh/tones of leather/Annum.

Energy in Dwellings

Energy simulation models for buildings are widely used by policymakers, researchers and consultants as a tool to advice on the reduction of residential energy consumption. Previous studies have shown that there is a gap between theoretical building energy simulation results and actual energy use. The discrepancy between theory and practice is problematic, as for instance expected energy savings are often not achieved. This thesis shows that analysing specific household types and building characteristics can contribute to a better understanding of amongst others the influence of the occupant on actual energy consumption. The effectiveness of thermal renovations is dependent on both occupants and building characteristics, which means tailored advice on renovation measures is necessary. We also found that occupants and building characteristics are equally responsible for variances in actual residential energy consumption. To reduce the gap between theory and practice on a single building level, simulation models are improved using calibration methods. In the final part of this thesis, a method is developed to calibrate simulations on a building stock level, making building energy simulation tools more reliable for policymakers.

Modification of building energy simulation tool TRNSYS for modelling nonlinear heat and moisture transfer phenomena by TRNSYS/MATLAB integration

Software for numerical simulation of various types of energy used in buildings, i.e. building energy simulation (BES), have become an essential tool for recent research pertaining to building physics. TRNSYS is a well-known BES used in both academia and the construction industry for a wide range of simulations, such as the design and performance evaluation of buildings and related facilities for heating, cooling, and ventilation. TRNSYS has a modular structure comprising various components, and each component is interconnected and compiled through a common interface using a FORTRAN compiler. Its modular structure enables interactions with various external numerical simulation tools, such as MATLAB, Python, and ESP-r. For ordinary simulations of building energy load using TRNSYS, the generic module Type 56 is usually recommended, which provides detailed physics modelling of building thermal behaviours based on unsteady energy conservation equations and Fourier’s law for each building material. However, Type 56 explicitly depends on the transfer function method to discretise the original differential equations; therefore, it cannot model nonlinear phenomena, such as latent heat and moisture transfer between a building surface and ambient air. In other words, the current TRNSYS cannot be used to estimate the effectiveness of evaporation during cooling, which is a typical passive design method. Hence, the authors developed a MATLAB/TRNSYS integration scheme, in which TRNSYS was modified to model simultaneous heat and moisture transfer from the wet roof surface of a building. This scheme enabled TRNSYS to calculate the rate of evaporative heat and moisture transfer dynamically from the roof surface, assuming a control volume approximation of the roof surface. Finally, the effect of evaporative cooling on the thermal performance of an Indian building was estimated using the modified model.

Techno-economic and environmental appraisal of a hybrid distributed generation system for a hospital building

In this paper, the techno-economic, energy efficiency, and environmental parameters of three different types of distributed generation systems, including high-temperature fuel cells, micro-turbines and photovoltaic (PV) systems were performed for a hospital building in Tehran, Iran using the eQUEST energy simulation tool and HOMER international optimisation model. The demand of electricity and natural gas of the hospital was calculated by the eQUEST software. Based on that, economic parameters, energy efficiency and environmental issues for three distributed generation systems have been evaluated by the HOMER international optimisation model and results are proposed for decision making. The results show that emissions produced by the fuel cell system including F and nitrogen oxides (NOx) are far less than other distributed generation systems. Therefore, the high-temperature fuel cell is more sustainable and affordable from economic and environmental aspects.

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発（その246） BEST省エネ基準対応ツールの認定と運用

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発（その246） BEST省エネ基準対応ツールの認定と運用

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発 （その241）設計用気象データを用いた連成計算による空調機器容量の自動調整

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発 （その241）設計用気象データを用いた連成計算による空調機器容量の自動調整

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発 （その244）実験計画法を用いた自然換気システムの効果推定

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発 （その244）実験計画法を用いた自然換気システムの効果推定

Influence of Materials in Life Cycle Energy Assessment of a Six Storey Building

Life Cycle Energy Assessment (LCEA) is one of the evaluating tools for assessing environmental impact of various types of materials used in the buildings components. The LCEA is based on reduction of total amount of energy consumed during the life cycle of building. Operational phase has been taken and the energy consumed for the phase has been evaluated in this study for three cases with respect to change in materials. This mainly focuses on the change in the energy consumption due to the usage of RCC and Wood materials in various building component such as roofs and infill walls etc. under Indian conditions. A six storey building with a plan dimension of 48m x 24m is considered. The ‘eQuest’ is the quick energy simulation tool which is widely used to calculate the whole building’s energy performance. This tool is used to estimate the energy consumption in month wise on various aspects.

에너지 프로슈머 제도를 고려한 태양광 주택의 전력거래 유형별 수익성 비교에 관한 연구

In line with the government’s policy to expand renewable energy and vitalize the energy new business, the importance of expanding the private sector’s supply of solar energy for housing is also growing. This paper provides basic data in terms of securing economic benefits to lead to the activation of the policy in designing all the rules of the energy prosumer policy. First, the standard housing model was selected and the energy simulation tool was used to derive the annual energy demand and the generation of 5 kW solar power. The economy was then analyzed according to the type of energy prosumer transaction. Three types of models were derived: current energy offset transaction model, optimal selling model through the transaction platform, and best-selling model of surplus power. Among these, the return on the best-selling model of surplus power was found to be the most advantageous. The types of transactions presented in this study will be flexible as the energy market changes in the future, but will be useful in an advance study in designing the rules for rapid institutionalization of energy prosumers.

Energy savings approaches for high-tech manufacturing factories

This study integrates a fab energy simulation (FES) tool and energy conversion factors to analyze energy consumption and identify energy savings opportunities of high-tech manufacturing factories. The data used is the 169,124 MW h annual energy consumption of a Taiwanese semiconductor manufacturing fab. We proposed a compressed/clean dry air (CDA) system as a two-pressure system using a heated-type dryer. The proposed method achieved 3050 MW h as the highest energy savings in the CDA system compared to the original fab data. The results also indicate that lowering the make-up air unit (MAU) operating temperature caused significant energy savings for the high-temperature water chiller system. When the outlet air temperature of the MAU system was 14 °C, the maximum energy savings were 3532 MW h. In addition, the process cooling water (PCW) system could potentially save energy by reducing the pumping head of water in its open system. Therefore, we suggested a closed PCW system that reached a maximum energy saving of 1541 MW h.

Methodology to assess business models of dynamic pricing tariffs in all-electric houses

There is a need for methodologies that integrate energy simulation and cost calculation to assess grid rent business models as incentive for demand-side management (DSM) in buildings. Despite the proliferation of energy simulation and cost calculation tools, there are no tool (e.g., software program) with appropriate methodology that caters specifically for the assessment of business models based on aggregation of dynamic pricing tariffs. Furthermore, the majority of existing methodologies focus on evaluating the supply-side management (SSM) of energy grids, and largely overlook the issue of influencing the customer to make good choices when it comes to DSM and/or design/renovation actions. This paper introduces energy and cost oriented methodology that provides informative support for utility companies and electric-grid customers including households’ occupants to assess the economic incentives of different energy and power dynamic pricing tariffs. A physical model-based building simulation tool (IDA-ICE) is used to assess the energy performance of a representative residential benchmark including 96 all-electric houses in Norway with and without renewable energy technology. A business model-based cost calculator is developed and linked with the energy simulation's outputs to assess the effectiveness of three dynamic pricing tariffs, suggested recently by the Norwegian Water Resources and Energy Directorate (NVE). The effectiveness of the three pricing tariffs is compared (improving building's energy efficiency vs enhancing grid's demand side load shifting). Overall, results indicate that the Tiered Rate tariff is the most effective business strategy for customers to reduce the electric-based heating load during high demand periods. However, the methodology generated a comprehensive suite of scenarios analysis that allow customers, utility companies and policy makers to accurately address several building renovation variations and demand side management strategies to make the right decision upfront.

Embodied versus operational energy in residential and commercial buildings: where should we focus?

We analyze 100 case studies, which were conducted in 23 countries, and contrast their data on embodied and operational energy in residential and commercial buildings. The case studies include conventional, retrofit, low-energy, passive, and net-zero energy buildings. The buildings have different lifetimes varying from 25 to 100 years. We calculate the estimated total Life Cycle Energy (LCE) as the sum of Embodied Energy (EE) and Operational Energy (OE). The LCE in the 100 case studies ranges from 50.8 to 1840 MJ/m2 per year. Our results show that operational energy significantly dominates the life cycle energy of the buildings by an average of 419 MJ/m2 per year and an average share of 72%. The share of embodied energy increases with decreasing operational energy. However, the overall LCE decreases significantly when the operational energy decreases. Naturally, the assumptions on the lifetime of the buildings have a great impact on the LCE. We conclude that operational energy should be primarily reduced in order to decrease greenhouse gas emissions from the existing building stock because most of the buildings are already built and changes in the embodied energy are often obtained only through new construction or deep retrofit strategies. Depending on the strategy to decrease OE, the share of EE was found to show wide fluctuations within the case studies, ranging from 4% up to 100%. In addition, most of the operational energy consumption has been reported by using energy simulation tools. Only about 14% of the case studies had metered operational energy data. In order to create more accurate data, metering of buildings should be considered in future case studies.

Development and dissemination of deep-energy retrofit strategies through a mandatory municipal building tune-up ordinance in Seattle, Washington, USA

This paper describes initial implementation of a municipal-scale building-owner engagement and technical assistance process aimed at accelerating voluntary deep energy retrofits as part of a new mandatory building tune-up requirement. Leveraging building energy consumption disclosure data, a municipal ordinance mandating building tune-ups at five-year intervals, and a suite of freely-available energy simulation tools, the university-based research and deployment team seeks to develop a scalable pathway for creating custom technical and financial roadmaps for deep-energy retrofits that drive carbon-neutral operations in existing medium-sized buildings.

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発 （その207）BEST誘導基準対応ツールによる事務所ビルのZEB評価

外皮・躯体と設備・機器の総合エネルギーシミュレーションツール「BEST」の開発 （その207）BEST誘導基準対応ツールによる事務所ビルのZEB評価

FEASIBILITY OF NEARLY-ZERO ENERGY BUILDING RETROFITS BY USING RENEWABLE ENERGY SOURCES IN AN EDUCATIONAL BUILDING

Dissemination of education is vital especially in developing countries like Turkey. Besides, proper use of energy resources is required while dissemination of education is ensured. Considering the regions where energy is limited, renewable energy sources should be used to achieve the goal of a zero-energy building. Moreover, an increase of smart technologies has potantial in order to decrease energy consumption in educational buildings. This paper aims to investigate renewable energy sources to decrease energy consumption to achieve nearly-zero energy building goal by implementing different energy efficient retrofitting scenarios. The retroffitting scenarios are based on renewable energy sources and are presented for an educational building located in Ankara-Turkey, through a Building Energy Simulation Tool, Design Builder Software. In order to develop an accurate model, educational building is monitored and the model is calibrated. Then, various energy efficient retrofitting scenarios are defined such as implementing PV panels, solar collectors and adding wind turbines for electricity generation.

Thermal comfort and energy performance of a dedicated outdoor air system with ceiling fans in hot and humid climate

The performance of a Dedicated Outdoor Air System integrated with ceiling fans (DOAS-CF) to enhance thermal comfort, perceived air quality (PAQ) and energy-saving potential was examined. 26 subjects were exposed to the combinations of temperatures (24, 27 and 30 °C) and air velocities in the range of 0.07 to 1.87 m/s at relative humidity (RH) of 60% for 3.5 h. The results showed that subjects felt thermally neutral and comfortable at 24 °C with air velocity of 0.07 m/s, 27 °C with air velocity of 0.94 m/s and 30 °C with air velocity of 1.87 m/s. Thermal comfort (87%), thermal preference (72%), thermal acceptability (100%) and indoor air quality acceptability (98%) were highest at 27 °C at 0.94 m/s. The mean thermal sensation was highly correlated to the average SET* as a linear function. An energy simulation tool (IES-VE) was used to simulate the energy consumption and quantify the energy savings of the DOAS-CF. Relative to a typical room design condition of 24 °C with a conventional air-conditioning system, DOAS-CF achieved a 25.8% reduction in annual energy consumption when the room temperature was raised by 3 °C but compensated by increased air movement.