DYNAMIC BUILDING SIMULATIONS FOR THE ESTABLISHMENT OF A MOROCCAN THERMAL REGULATION FOR BUILDINGS

Comprehensive dynamic building simulations are used in order to conduct sensitivity analyses on the influence of building shell parameters to the heating and cooling demands of a variety of building types in Morocco. In a first step, five climatic zones are defined covering the range of specific heating and cooling demand combinations of a reference building located in eleven locations throughout Morocco. Afterwards, 22 single parameter variations for each building type and each climate zone are performed and analyzed in such a way, that suitable promising combinations can be defined as well. This procedure is faster and easier to analyze than a multidimensional regression. The results show indeed that the selected combinations may reduce energy demands substantially. This paper explains the procedure and results in detail for one residential type of building and for one typical non-residential building. The major overall results are discussed.

CUBATURES FOR MEDIUM-SIZED PLUS ENERGY BUILDINGS

INTRODUCTION On the basis of dynamic building simulations within a maximal realistic framework,it may be useful with respect to the overall energy balance to dispense with pursuing a minimal surface/volume ratio of buildings-thus minimizing heat losses across the building shell-in favor of solar energy use.The specific use of the building(here:office or residential)plays a crucial role.Balancing the energy demand for heating and cooling and a possible photovoltaic yield,a surplus is possible in all cases under investigation.Long,low unobstructed buildings perform best due to large portions of roof area suitable for solar energy use.For tall buildings with less roof area,parts of the facades may be used for solar applications which makes them also perform better than compact designs.If the total energy demand including auxiliary energy for HVAC and especially electricity for the office and residential usages,respectively,is considered,compact cubatures of the size considered here(about 3500 m2)are not capable of providing positive energy balances.Residential usage performs worse than office use.Investigations are performed for the climatic conditions of Berlin,Germany.

A performance comparison of multi-objective optimization algorithms for solving nearly-zero-energy-building design problems

Integrated building design is inherently a multi-objective optimization problem where two or more conflicting objectives must be minimized and/or maximized concurrently.Many multi-objective optimization algorithms have been developed;however few of them are tested in solving building design problems.This paper compares performance of seven commonly-used multi-objective evolutionary optimization algorithms in solving the design problem of a nearly zero energy building(n ZEB) where more than 1.610 solutions would be possible.The compared algorithms include a controlled non-dominated sorting genetic algorithm witha passive archive(p NSGA-II),a multi-objective particle swarm optimization(MOPSO),a two-phase optimization using the genetic algorithm(PR_GA),an elitist non-dominated sorting evolution strategy(ENSES),a multi-objective evolutionary algorithm based on the concept of epsilon dominance(ev MOGA),a multi-objective differential evolution algorithm(sp MODE-II),and a multi-objective dragonfly algorithm(MODA).Several criteria was used to compare performance of these algorithms.In most cases,the quality of the obtained solutions was improved when the number of generations was increased.The optimization results of running each algorithm20 times with gradually increasing number of evaluations indicated that the PR_GA algorithm had a high repeatability to explore a large area of the solution-space and achieved close-to-optimal solutions with a good diversity,followed by the p NSGA-II,ev MOGA and sp MODE-II.Uncompetitive results were achieved by the ENSES,MOPSO and MODA in most running cases.The study also found that 1400-1800 were minimum required number of evaluations to stabilize optimization results of the building energy model.

Building dynamic thermal simulation of low-order multi-dimensional heat transfer

Multi-dimensional heat transfers modeling is crucial for building simulations of insulated buildings,which are widely used and have multi-dimensional heat transfers characteristics.For this work,state-model-reduction techniques were used to develop a reduced low-order model of multi-dimensional heat transfers.With hot box experiment of hollow block wall,heat flow relative errors between experiment and low-order model predication were less than 8% and the largest errors were less than 3%.Also,frequency responses of five typical walls,each with different thermal masses or insulation modes,the low-order model and the complete model showed that the low-order model results agree very well in the lower excitation frequency band with deviations appearing only at high frequency.Furthermore,low-order model was used on intersection thermal bridge of a floor slab and exterior wall.Results show that errors between the two models are very small.This low-order model could be coupled with most existing simulation software for different thermal mass envelope analyses to make up for differences between the multi-dimensional and one-dimensional models,simultaneously simplifying simulation calculations.

Influence of soil——structure interaction on seismic collapse resistance of super-tall buildings

Numerous field tests indicate that the soilestructure interaction （SSI） has a significant impact on thedynamic characteristics of super-tall buildings, which may lead to unexpected structural seismic responsesand/or failure. Taking the Shanghai Tower with a total height of 632 m as the research object, thesubstructure approach is used to simulate the SSI effect on the seismic responses of Shanghai Tower. Therefined finite element （FE） model of the superstructure of Shanghai Tower and the simplified analyticalmodel of the foundation and adjacent soil are established. Subsequently, the collapse process of ShanghaiTower taking into account the SSI is predicted, as well as its final collapse mechanism. The influences ofthe SSI on the collapse resistance capacity and failure sequences are discussed. The results indicate that,when considering the SSI, the fundamental period of Shanghai Tower has been extended significantly,and the collapse margin ratio has been improved, with a corresponding decrease of the seismic demand.In addition, the SSI has some impact on the failure sequences of Shanghai Tower subjected to extremeearthquakes, but a negligible impact on the final failure modes. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

BUILDING PERFORMANCE SIMULATION AS AN EARLY INTERVENTION OR LATE VERIFICATION IN ARCHITECTURAL DESIGN:SAME PERFORMANCE OUTCOME BUT DIFFERENT DESIGN SOLUTIONS

INTRODUCTIONA Current green building practice has been largely advanced by an integrated design process.This integrated design process involves multiple disciplines,such as archi-tecture,civil,mechanical,and electrical engineering.The design method heavily relies on utilizing building performance simulation to illustrate how design param-eters affect the energy consumption and quality of the indoor environment before actual design decisions are made(Anderson,2014).The architectural design tools in the integrated design process supersede traditional geometrical exploration instruments,such as Sketchup,Revit,ArchiCad,and Rhino(Negendahl,2015).More building performance simulating tools,such as Ecotect,Computational Fluid Dynamics(CFD),Radiance,and EnergyPlus,have been developed to help architects measure building performance(e.g.,natural ventilation,daylighting,solar radiation,and energy uses)in the design process and attain green building standards such as Leadership in Energy and Environmental Design(LEED).The information presented by these tools guide architects at a certain level in achieving green building goals.

Plus Energy Buildings:A Numerical Case Study

The feasibility of Plus Energy Building for a sample relevant case is investigated.After a literature review aimed to identify key aspects of this type of buildings,a preliminary evaluation of the thermal performance of a building constructed using conventional material is presented together with a parametric analysis of the impact of typical influential parameters.Solar domestic hot water(SDHW)and photovoltaic systems(PV)are considered in the study.Numerical simulations indicate that for the examined sample case(Beirut in Lebanon)the total annual energy need of conventional building is 87.1 kWh/y.m^(2).About 49%of energy savings can be achieved by improving the building envelope and installing energy efficient technologies.Moreover,about 90%of energy savings in domestic hot water production can be achieved by installing a SDHW system composed of two solar collectors connected in series.Finally,the addition of a grid connected PV array system can significantly mitigate the energy needs of the building leading to an annual excess of energy.

Development and Application of Decision Support Model for the Performance Optimization of Office Buildings Based on Grasshopper

With the expansion of the office building area,the energy consumption of office buildings is growing.High⁃performance building design contributes to energy saving and the development of green buildings.However,there is a lack of high⁃performance building tools and the workflow is often time⁃consuming.The building performance simulation,multiple objective optimizations,and the decision support model are the new approaches of high⁃performance building design.This paper proposes a newly developed decision support model,a high⁃performance building decision model named HPBuildingDSM,which integrates the building performance simulation,building performance multiple objective optimizations,building performance sampling,and parameter sensitivity analysis to design high⁃performance office buildings.In this research,the HPBuildingDSM was operated to search for the desirable office building design results with low⁃energy and high⁃quality daylighting performances.The simulated results had better daylighting performance and lower energy consumption,whose UDI100-2000 was 37.94%and annual energy consumption performance was 76.28 kWh/(m2·a),indicating a better building performance than the optimized results in the previous case study.

GPPre:A Python⁃Based Tool in Grasshopper for Office Building Performance Optimization

With the development of the economic and low⁃carbon society,high⁃performance building(HPB)design plays an increasingly important role in the architectural area.The performance of buildings usually includes the building energy consumption,building interior natural daylighting,building surface solar radiation,and so on.Building performance simulation(BPS)and multiple objective optimizations(MOO)are becoming the main methods for obtaining a high performance building in the design process.Correspondingly,the BPS and MOO are based on the parametric tools,like Grasshopper and Dynamo.However,these tools are lacking the data analysis module for designers to select the high⁃performance building more conveniently.This paper proposes a toolkit“GPPre”developed based on the Grasshopper platform and Python language.At the end of this paper,a case study was conducted to verify the function of GPPre,which shows that the combination of the sensitivity analysis(SA)and MOO module in the GPPre could aid architects to design the buildings with better performance.

Optimisation of Climate Robust Buildings under Summer Conditions with ＂Primero-Comfort＂ Simulation Software Including Detailed User Behaviour and Comfort Expectance

In this paper the possibilities for avoiding active air conditioning by all means of the room itself （window size, glazing, shading system, natural ventilation, and furniture）, artificial light and control strategy of these systems are investigated. A very important component of the system is the user with his ability to adapt to changing conditions in his surrounding and with his possibilities to manipulate the window, the shading system, the light switch etc. All these aspects interact together. It is necessary to optimize them simultaneously. But real planning often separates them into single sections. Simulation tools also handle normally only one or a few aspects, we know for example the thermal simulation or the daylight simulation. Primero-Comfort （2009） is a simulation tool based on energy＋, what is able to consider thermal simulation as well as daylight simulation as well as user behaviour in regard to the probability of window openings. The resulting thermal comfort is rated by an adaptive comfort model, the Dutch ISSO 74 （2004）. This allows designing office rooms more realistic. And it shows that an optimized solution has to include the interactions of aU mentioned aspects. Investigations with Primero-Comfort for a moderate European climate （Hamburg） show that a very good comfort can be reached only by passive means of building design also for hot summer weather just like the summer in the year 2003. The keys for such hot-summer-robust-buildings are night ventilation with height difference, heat protection glazing and good shading system, reduced internal heat gains for artificial light by accepting a threshold of 300 lx of daylight as comfortable and a reduced window size oriented on daylighting and the view out of the window.

VARIABILITY OF BUILDING SIMULATION RESULTS DEP ENDING ON SELECTED WEATHER FILES AND CONDITIONING SET POINTS-A CASE STUDY FOR A RESIDENTIAL BUILDING IN VICTORIA,AUSTRALIA

Building simulation is a powerful way to evaluate the performance of a building.The quality of simulation results however strongly depends on the accuracy of simulation input data.Especially for weather data files and occupant behaviour it is difficult to obtain accurate data.This paper evaluates the variability of building simulation results with regards to different weather data sets as well as different heating and cooling set points for a residential building in Victoria,Australia.Thermal comfort accord-ing to ASHRAE Standard 55,final energy consumption and peak cooling and heating loads are assessed.Simulations have been performed with Energy-Plus,and weather data for a multi-year approach have been generated with the software Meteonorm.The results show that different weather files for the same location as well as different conditioning set points can influence the results by approximately a factor of 2.

Zero-Energy-Buildings in Different Climates： Design Strategies, Simulation and Prognosis METHOD for Energy Demand

The European Directive 2010/31 claims that by 2020 only （nearly-） ZEB （zero-energy-buildings） may be built. To reach this goal, it is pertinent for buildings to be energetically optimized first. The remaining energy demand must then be covered by on-site renewable energies （PV, geothermal, etc.）. With the area of use （energy demand） and the size of the building envelope/estate （renewable energy supply） in competition with each other, the maximum number of building stories will be most likely limited. For 15 different climatic locations worldwide, the energy demand of optimised office rooms has been simulated and compared with the possible renewable energy production on site. For every location, a good correlation has been found between the simulated energy demand and data like heating and cooling degree hours. Correspondent linear equations are given here. As another result, the maximum numbers of possible stories for ZEBS have been derived, being between 3 and 10 depending on the location.

THERMAL ENVIRONMENTS OF AN OFFICE BUILDING WITH DOUBLE SKIN FACADE

As a symbol of green architecture,double skin facade(DSF)represents a design which possesses many energy saving features,but due to the complexity of the system,the real performances and benefits have been difficult to predict.The objective of this study was to inform the applicability of DSFs,and contribute to the positive impacts of DSF designs.This study compared and contrasted energy savings in a temperate climate,where heating was the dominant energy strategy,and in a subtropical climate,where cooling spaces was the dominant issue.This paper focused on a university office building with a west facing shaft box window facade.The research method was a paired analysis of simulation studies which compared the energy performance of a set of buildings in two different climates.Simulation results showed a good agreement with measurements undertaken in the exiting building during a two-week period.The results specified that DSFs are capable of almost 50%energy savings in temperate and 16%in subtropical climates.Although these indicated DSFs are more suitable for temperate climates than warmer regions,the amount of energy savings in subtropical climates were also considerable.However,due to the costs of DSFs and potential loss of leasable floor area,investigations into other feasible ventilation options are necessary before final building design decisions are made.

APPLYING THE PASSIVE HOUSE STANDARD TO OFFICE BUILDINGS—HOW MUCH GLASS IS ADMISSIBLE?

Enjoying a pleasant interior temperature in both summer and winter without the necessity for additional heating or cooling—a level of comfort already offered by private homes built with an eye to energy effi ciency.What has become known as the passive house standard is now increasingly demanded in tenders and competitions revolving around offi ce buildings.Below,Dr Friedrich Sick,professor at the HTW Berlin,and Stefan Schade,a graduate in Environmental Engineering/Renewable Energies who explored this particular fi eld in his thesis[1],examine the conditions necessary for the implementation of this standard.

A Predictive Nighttime Ventilation Algorithm to Reduce Energy Use and Peak Demand in an Office Building

The effect of two nighttime ventilation strategies on cooling and heating energy use is investigated for a prototype office building in several northern America climates, using hourly building energy simulation software （DOE2.1E）. The strategies include： scheduled-driven nighttime ventilation and a predictive method for nighttime ventilation. The maximum possible energy savings and peak demand reduction in each climate is analyzed as a function of ventilation rate, indoor-outdoor temperature difference, and building thermal mass. The results show that nighttime ventilation could save up to 32% cooling energy in an office building, while the total energy and peak demand savings for the fan and cooling is about 13% and 10%, respectively. Consequently, finding the optimal control parameters for the nighttime ventilation strategies is very important. The performance of the two strategies varies in different climates. The predictive nighttime ventilation worked better in weather conditions with fairly smooth transition from heating to cooling season.

A STRATEGY FOR ENERGY PERFORMANCE ANALYSIS AT THE EARLY DESIGN STAGE:PREDICTED VS.ACTUAL BUILDING ENERGY PERFORMANCE

Developments in information technology are providing methods to improve current design practices,where uncertainties about various design elements can be simulated and studied from the design inception.Energy and thermal simulations,improved design representations and enhanced collaboration using digital media are increasingly being used.With the expanding interest in energy-efficient build-ing design,whole building energy simulation programs are increasingly employed in the design process to help architects and engineers determine which design strat-egies save energy and improve building performance.The purpose of this research was to investigate the potential of these programs to perform whole building energy analysis during the early stages of architectural design,and compare the results with the actual building energy performance.The research was conducted by simulating energy usage of a fully functional research laboratory building using two different simulation tools that are aimed for early schematic design.The results were compared with utility data of the building to identify the degree of close-ness with which simulation results match the actual energy usage of the build-ing.Results indicate that modeled energy data from one of the software programs was significantly higher than the measured,actual energy usage data,while the results from the second application were comparable,but did not correctly predict monthly energy loads for the building.This suggests that significant deviations may exist between modeled and actual energy consumption for buildings,and more importantly between different simulation software programs.Understanding the limitations and suitability of specific simulation programs is crucial for successful integration of performance simulations with the design process.

Energy consumption simulations of rural residential buildings considering differences in energy use behavior among family members

The“average occupant”methodology is widely used in energy consumption simulations of residential buildings;however,it fails to consider the differences in energy use behavior among family members.Based on a field survey on the Central Shaanxi Plain,to identify the energy use behavior patterns of typical families,a stochastic energy use behavior model considering differences in energy use behavior among family members was proposed,to improve the accuracy of energy consumption simulations of residential buildings.The results indicated that the surveyed rural families could be classified into the following four types depending on specific energy use behavior patterns:families of one elderly couple,families of one middle-aged couple,families of one elderly couple and one child,and families of one couple and one child.Moreover,on typical summer days,the results of daily building energy consumption simulation obtained by the“average occupant”methodology were 25.39%and 28%lower than the simulation results obtained by the model proposed in this study for families of one elderly couple and families of one middle-aged couple,and 13.05%and 23.05%higher for families of one elderly couple and one child,and families of one couple and one child.On typical winter days,for the four types of families,the results of daily building energy consumption simulation obtained by the“average occupant”methodology were 21.69%,10.84%,1.21%,and 8.39%lower than the simulation results obtained by the model proposed in this study,respectively.

Coupled simulation of BES-CFD and performance assessment of energy recovery ventilation system for office model

Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recovery ventilator and to investigate the effect of the air supply arrangement. Three types of mixing ventilation are chosen for the analysis of coupling ANSYS/FLUENT （a computational fluid dynamics （CFD） program） with TRNSYS （a building energy simulation （BES） software）. The adoption of mutual complementary boundary conditions for CFD and BES provides more accurate and complete information of indoor air distribution and thermal performance in buildings. A typical office-space situated in a middle storey is chosen for the analysis. The office-space is equipped with air-conditioners on the ceiling. A heat recovery ventilation system directly supplies flesh air to the office space. Its thermal performance and indoor air distribution predicted by the coupled method are compared under three types of ventilation system. When the supply and return openings for ventilation are arranged on the ceiling, there is no critical difference between the predictions of the coupled method and BES on the energy consumption of HVAC because PID control is adopted for the supply air temperature of the occupied zone. On the other hand, approximately 21% discrepancy for the heat recovery estimation in the maximum between the simulated results of coupled method and BES-only can be obviously found in the floor air supply ventilation case. The discrepancy emphasizes the necessity of coupling CFD with BES when vertical air temperature gradient exists. Our future target is to estimate the optimum design of heat recovery ventilation system to control CO2 concentration by adjusting flow rate of flesh air.

Energy Performance and Condensation Risk of DCDV System in Subtropical Hong Kong

The combined use of dry cooling(DC) system and dedicated ventilation(DV) system to decouple cooling and dehumidification process for energy efficiency was proposed for subtropical climates like Hong Kong. In this study, the energy performance and condensation risk of the use of DCDV system were examined by analyzing its application in a typical office building in Hong Kong. Through hour-by-hour simulation using actual equipment performance data and realistic building and system characteristics, it was found that with the use of DCDV system, the annual energy consumption could be reduced by 54% in comparison with the conventional system(constant air volume with reheat system). In respect of condensation risk, it was found that the annual frequency of occurrence of condensation on DC coil was 35 h. Additional simulations were conducted to examine the influence of different parameters on the condensation risk of DCDV system. Measures to ensure condensate-free on DC coil were also discussed.

Groundwater Utilisation for Energy Production in the Nordic Environment: An Energy Simulation and Hydrogeological Modelling Approach

Groundwater provides one option to utilise renewable energy sources. The long-term groundwater energy potential for three building complexes, situated at latitude of 64°, was investigated by combining an energy demand simulation for the buildings with hydrogeological modelling. First, a reference year for the building energy demand was created. Secondly, groundwater flow requirements were calculated. The results of the previous stages were utilised in groundwater heat transport modelling in an environment where the natural temperature of groundwater was 4.9°C. Finally, the long-term (50 years) groundwater energy potential was calculated. The groundwater maintained its heating potential during 50 years of operation. When both heating and cooling power were demanded, the long-term pumping rate of groundwater decreased by 60,000 m3/a. Energy utilisation created a cold groundwater plume downstream, in which the temperature decreased by 1 to 2.5°C within a distance of 300 m from the site. Groundwater can provide a long-term energy source for large building complexes in the Nordic climate. Results indicate that groundwater could effectively be utilised until the temperature reaches approximately 4°C. Accurate information on the building energy demand and hydrogeology is essential for successful operation.