scholarly journals Building Retrofitting through Coupling of Building Energy Simulation-Optimization Tool with CFD and Daylight Programs

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2180
Author(s):  
Mehrdad Rabani ◽  
Habtamu Bayera Madessa ◽  
Natasa Nord
Keyword(s):  
Energy Use ◽  
Ventilation System ◽  
Building Energy ◽  
Building Envelope ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
Visual Comfort ◽  
Indoor Climate ◽  
Building Energy Use ◽  
Air System

Simultaneous satisfaction of both thermal and visual comfort in buildings may be a challenging task. Therefore, this paper suggests a comprehensive framework for the building energy optimization process integrating computational fluid dynamics (CFD) daylight simulations. A building energy simulation tool, IDA Indoor Climate and Energy (IDA-ICE), was coupled with three open-source tools including GenOpt, OpenFOAM, and Radiance. In the optimization phase, several design variables i.e., building envelope properties, fenestration parameters, and Heating, Ventilation and Air-Conditioning (HVAC) system set points, were selected to minimize the total building energy use and simultaneously improve thermal and visual comfort. Two different scenarios were investigated for retrofitting of a generic office building located in Oslo, Norway. In the first scenario a constant air volume (CAV) ventilation system with a local radiator in each zone was used, while an all-air system equipped with a demand control ventilation (DCV) was applied in the second scenario. Findings showed that, compared to the reference design, significant reduction of total building energy use, around 77% and 79% in the first and second scenarios, was achieved respectively, and thermal and visual comfort conditions were also improved considerably. However, the overall thermal and visual comfort satisfactions were higher when all-air system was applied.

Energy Impacts of Nonlinear Behavior of PCM When Applied Into Building Envelope

2012 ◽  
Author(s):  
Paulo Cesar Tabares-Velasco
Keyword(s):  
Energy Use ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Peak Load ◽  
Building Energy ◽  
Building Envelope ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
Peak Reduction ◽  
The Impact

Research on phase change materials (PCM) as a potential technology to reduce peak loads and HVAC energy use in buildings has been conducted for several decades, resulting in a great deal of literature on PCM properties, temperature, and peak reduction potential. However, there are few building energy simulation programs that include PCM modeling features, and very few of these have been validated. Additionally, there is no previous research that indicates the level of accuracy when modeling PCMs from a building energy simulation perspective. This study analyzes the effects a nonlinear enthalpy profile has on thermal performance and expected energy benefits for PCM-enhanced insulation. The impact of accurately modeling realistic, nonlinear enthalpy profiles for PCMs versus simpler profiles is analyzed based on peak load reduction and energy savings using the Conduction Finite Difference (CondFD) algorithm in EnergyPlus. The PCM and CondFD models used in this study have been previously validated after intensive verification and validation done at the National Renewable Energy Laboratory. Overall, the results of this study show annual energy savings are not very sensitive to the linearization of enthalpy curve. However, hourly analysis shows that if simpler linear profiles are used, users should try to specify a melting range covering roughly 80% of the latent heat, otherwise, hourly results can differ by up to 20%.

Procedures for Calibrating Hourly Simulation Models to Measured Building Energy and Environmental Data

1998 ◽  
Vol 120 (3) ◽  
pp. 193-204 ◽  
Author(s):  
J. S. Haberl ◽  
T. E. Bou-Saada
Keyword(s):  
Goodness Of Fit ◽  
Building Energy ◽  
Building Envelope ◽  
Energy Simulation ◽  
Environmental Data ◽  
Simulation Program ◽  
Weather Data ◽  
Mean Bias Error ◽  
Building Energy Simulation ◽  
Calibration Methods

This paper discusses procedures for creating calibrated building energy simulation programs. It begins with reviews of the calibration techniques that have been reported in the previous literature and presents new hourly calibration methods including a temperature bin analysis to improve hourly x−y scatter plots, a 24-hour weather-daytype bin analysis to allow for the evaluation of hourly temperature and schedule dependent comparisons, and a 52-week bin analysis to facilitate the evaluation of long-term trends. In addition, architectural rendering is reviewed as a means of verifying the dimensions of the building envelope and external shading placement as seen by the simulation program. Several statistical methods are also presented that provide goodness-of-fit indicators, including percent difference calculations, mean bias error (MBE), and the coefficient of variation of the root mean squared error (CV(RMSE)). The procedures are applied to a case study building located in Washington, D. C. where nine months of hourly whole-building electricity data and sitespecific weather data were measured and used with the DOE-2.1D building energy simulation program to test the new techniques. Simulations that used the new calibration procedures were able to produce an hourly MBE of –0.7% and a CV(RMSE) of 23.1% which compare favorably with the most accurate hourly neural network models (Kreider and Haberl, 1994a, b).

Energy Impacts of Nonlinear Behavior of Phase Change Materials When Applied to Opaque Building Envelopes

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Paulo Cesar Tabares-Velasco
Keyword(s):  
Phase Change ◽  
Energy Use ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Peak Load ◽  
Building Energy ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
Peak Reduction ◽  
The Impact

Research on phase change materials (PCM) as a potential technology to reduce peak loads and heating, ventilation and air conditioning (HVAC) energy use in buildings has been conducted for several decades, resulting in a great deal of literature on PCM properties, temperature, and peak reduction potential. However, there are few building energy simulation programs that include PCM modeling features, and very few of these have been validated. Additionally, there is no previous research that indicates the level of accuracy when modeling PCMs from a building energy simulation perspective. This study analyzes the effects a nonlinear enthalpy profile has on thermal performance and expected energy benefits for PCM-enhanced insulation. The impact of accurately modeling realistic, nonlinear enthalpy profiles for PCMs versus simpler profiles is analyzed based on peak load reduction and energy savings using the conduction finite difference (CondFD) algorithm in EnergyPlus. The PCM and CondFD models used in this study have been previously validated after intensive verification and validation done at the National Renewable Energy Laboratory. Overall, the results of this study show annual energy savings are not very sensitive to the linearization of enthalpy curve. However, hourly analysis shows that if simpler linear profiles are used, users should try to specify a melting range covering roughly 80% of the latent heat; otherwise, hourly results can differ by up to 20%.

scholarly journals Influence of User-Related Parameters on Calculated Energy Use in Low-Energy School Buildings

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2985 ◽  
Author(s):  
Branko Simanic ◽  
Birgitta Nordquist ◽  
Hans Bagge ◽  
Dennis Johansson
Keyword(s):  
Energy Use ◽  
Ventilation System ◽  
Building Energy ◽  
Energy Performance ◽  
Hot Water ◽  
Low Energy ◽  
Building Energy Use ◽  
Low Energy Buildings ◽  
Demand Controlled Ventilation ◽  
The Impact

Literature and experience show that there are large discrepancies between the calculated and measured building energy usages, where user-related parameters are significant factors with regard to energy use in low-energy buildings. Furthermore, the difficulties encountered when quantifying these parameters compound these discrepancies. The main aim of this study was to provide feedback that would help the building industry and research communities to predict more accurately the impact of the user-related parameters on energy performance. The results of the study would, subsequently, contribute to minimizing the discrepancies between calculated and measured energy use. This article analyses simulated building energy use based on randomly chosen combinations of measured user-related parameters in three recently built low-energy schools in Sweden. The results show that energy performance can span from 30 to 160 kWh/(m² y) simply by varying the combination of previously measured user-related parameters in building energy simulations. The study shows that the set points for indoor air temperatures during the heating season and the energy required to run a demand-controlled ventilation system have an extensive influence, while tenant electricity use has a slightly lower influence on building energy use. Variations in occupancy rates and energy for hot water usage have the smallest influences on building energy use.

Energy Saving Opportunities Using Building Energy Simulation for a Typical Mosque in Kuwait

2010 ◽  
Author(s):  
Adnan Al Anzi ◽  
Basma Al-Shammeri
Keyword(s):  
Energy Conservation ◽  
Thermal Behavior ◽  
Life Cycle Cost ◽  
Energy Use ◽  
Simulation Analysis ◽  
Building Energy ◽  
Simulation Software ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
The State Of Kuwait

The weather conditions in Kuwait impose a difficult HVAC building operation due to the hot and arid climate. Most of the time, high ambient temperatures in Kuwait exceed 48° C, which result in difficult indoor comfort condition. Mosques are religious buildings with intermittent occupancy, due to their special cultural and religious requirements. In fact, prayers schedule is scattered throughout five daily times, with a maximum use around noon times on Fridays only. In addition, the number of mosques is increasing, due to population growth, and imposes high electrical load requirements on the public authorities in Kuwait. This paper demonstrates and analyzes thermal behavior of a typical mosque in the state of Kuwait. An energy audit is performed using state of the art building energy simulation software (Visual DOE 4.1). The simulation tool is intended to analyze the thermal behavior of the audited mosques and is used to asses potential energy conservation opportunities for future mosque design in Kuwait. Data collection including drawings, site visits and total daily kWh monitoring are performed to carry out the simulation analysis. It is found that an annual energy use savings up to 72% can be achieved through improvements of buildings envelope designs and operating strategies. In addition, life cycle cost LCC analysis is performed to make economical assessment of the energy conservation measures that are evaluated in this study. It was found that a LCC saving around 40% can be achieved with a simple payback period of less than 4 years.

scholarly journals Modelling Urban Housing Stocks for Building Energy Simulation using CityGML EnergyADE

2019 ◽  
Vol 8 (4) ◽  
pp. 163 ◽  
Author(s):  
Julian F. Rosser ◽  
Gavin Long ◽  
Sameh Zakhary ◽  
Doreen S. Boyd ◽  
Yong Mao ◽  
...  
Keyword(s):  
Computational Complexity ◽  
Energy Demand ◽  
Energy Use ◽  
Housing Stock ◽  
Building Energy ◽  
Urban Housing ◽  
Energy Simulation ◽  
Spatially Explicit ◽  
Building Energy Simulation ◽  
Urban Scenes

Understanding the energy demand of a city’s housing stock is an important focus for local and national administrations to identify strategies for reducing carbon emissions. Building energy simulation offers a promising approach to understand energy use and test plans to improve the efficiency of residential properties. As part of this, models of the urban stock must be created that accurately reflect its size, shape and composition. However, substantial effort is required in order to generate detailed urban scenes with the appropriate level of attribution suitable for spatially explicit simulation of large areas. Furthermore, the computational complexity of microsimulation of building energy necessitates consideration of approaches that reduce this processing overhead. We present a workflow to automatically generate 2.5D urban scenes for residential building energy simulation from UK mapping datasets. We describe modelling the geometry, the assignment of energy characteristics based upon a statistical model and adopt the CityGML EnergyADE schema which forms an important new and open standard for defining energy model information at the city-scale. We then demonstrate use of the resulting urban scenes for estimating heating demand using a spatially explicit building energy microsimulation tool, called CitySim+, and evaluate the effects of an off-the-shelf geometric simplification routine to reduce simulation computational complexity.

IDENTIFYING OPTIMUM GLAZING PROPERTY FOR CONSERVING ENERGY IN HOT SEMI-ARID CLIMATE REGIONS

2021 ◽  
Vol 16 (1) ◽  
pp. 91-101
Author(s):  
Madeeha Altaf ◽  
Frances Hill
Keyword(s):  
Heat Loss ◽  
Energy Use ◽  
Energy Requirement ◽  
Ghg Emissions ◽  
Building Energy ◽  
Building Envelope ◽  
System A ◽  
Building Energy Use ◽  
U Value ◽  
Industry Professionals

ABSTRACT Globally, the building sector is responsible for 40% of energy use and 30% of GHG emissions. The greatest portion of the energy is used during the operational phase (use stage) of buildings. The building envelope, especially the glazed components, plays an important role in determining the energy requirement of buildings. These glazed parts of the building envelope exposed to direct solar radiation are most vulnerable to heat loss and gain. Heat loss and gain through the glazing material depend on glazing properties (U-value, SHGC, VT) and building energy use changes according to the properties of the glazing system. A variety of glazing types has been developed over recent decades that use the properties of the glass as a means of responding to environmental conditions. This study is carried out to identify the optimum glazing property for conserving energy in cooling dominant regions using an early design energy modeling tool. It was found that a low SHGC is the most important glazing property for reducing cooling energy consumption. SHGC of less than 0.3 is found useful. This study would help building industry professionals evaluate the best glazing property while selecting the glazing type.

scholarly journals The ambivalence of personal control over indoor climate – how much personal control is adequate?

2020 ◽  
Vol 172 ◽  
pp. 06010
Author(s):  
Runa T. Hellwig ◽  
Marcel Schweiker ◽  
Atze Boerstra
Keyword(s):  
User Satisfaction ◽  
Perceived Control ◽  
Energy Use ◽  
Sick Building Syndrome ◽  
Personal Control ◽  
Building Energy ◽  
Energy Performance ◽  
Indoor Climate ◽  
Building Energy Use ◽  
Automation Systems

Literature sets personal control over indoor environmental conditions in relation to the gap between predicted and actual energy use, the gap between predicted and observed user satisfaction, and health aspects. A focus on building energy performance often leads to the proposal of more automated and less occupant control of the indoor environment. However, a high degree of personal control is desirable because research shows that a low degree (or no) personal control highly correlates with indoor environmental dissatisfaction and sick building syndrome symptoms. These two tendencies seem contradictory and optimisation almost impossible. Based on current efficiency classes describing the effect of room automation systems on building energy use during operation, fundamental thoughts related to thermophysiology and control, recent laboratory experiments, important lessons learnt from post-occupancy studies, and documented conceptual frameworks on the level of control perceived, we discuss the ambivalence of personal control and how much personal control is adequate. Often-proposed solutions ranging from fully automated controls, over manual controls to dummy controls are discussed according to their effect on a) building energy use during operation and b) occupants perceived control. The discussion points to the importance of adequate personal control. In order to meet the goals for nearly zero energy buildings and for a human-centric design, there is the need to establish design procedures for adequate personal control as part of the design process.

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