A new building energy model coupled with an urban canopy parameterization for urban climate simulations—part I. formulation, verification, and sensitivity analysis of the model (original) (raw)
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Theoretical and Applied Climatology, 2010
Recent studies show that the fluxes exchanged between buildings and the atmosphere play an important role in the urban climate. These fluxes are taken into account in mesoscale models considering new and more complex Urban Canopy Parameterizations (UCP). A standard methodology to test an UCP is to use one-dimensional (1D) off-line simulations. In this contribution, an UCP with and without a Building Energy Model (BEM) is run 1D off-line and the results are compared against the experimental data obtained in the BUBBLE measuring campaign over Basel (Switzerland) in 2002. The advantage of BEM is that it computes the evolution of the indoor building temperature as a function of energy production and consumption in the building, the radiation coming through the windows, and the fluxes of heat exchanged through the walls and roofs as well as the impact of the air conditioning system. This evaluation exercise is particularly significant since, for the period simulated, indoor temperatures were recorded. Different statistical parameters have been calculated over the entire simulated episode in order to compare the two versions of the UCP against measurements. In conclusion, with this work, we want to study the effect of BEM on the different turbulent fluxes and exploit the new possibilities that the UCP–BEM offers us, like the impact of the air conditioning systems and the evaluation of their energy consumption.
Combining a Detailed Building Energy Model with a Physically-Based Urban Canopy Model
Boundary-Layer Meteorology, 2011
A scheme that couples a detailed building energy model, EnergyPlus, and an urban canopy model, the Town Energy Balance (TEB), is presented. Both models are well accepted and evaluated within their individual scientific communities. The coupled scheme proposes a more realistic representation of buildings and heating, ventilation and air-conditioning (HVAC) systems, which allows a broader analysis of the two-way interactions between the energy performance of buildings and the urban climate around the buildings. The scheme can be used to evaluate the building energy models that are being developed within the urban climate community. In this study, the coupled scheme is evaluated using measurements conducted over the dense urban centre of Toulouse, France. The comparison includes electricity and natural gas energy consumption of buildings, building façade temperatures, and urban canyon air temperatures. The coupled scheme is then used to analyze the effect of different building and HVAC system configurations on building energy consumption, waste heat released from HVAC systems, and outdoor air temperatures for the case study of Toulouse. Three different energy efficiency strategies are analyzed: shading devices, economizers, and heat recovery.
An approach for coupled simulation of building thermal effects and urban climatology
Energy and Buildings, 2004
The computer software AUSSSM TOOL, originating from the methodology of the revised-architectural-urban-soil-simultaneous simulation model (revised-AUSSSM), was developed by adopting the graphical user interface (GUI) features to support users, who can use the interactive computer display for parameter settings, simulating, visualizing, and reporting the numerical calculation results instead of complicated programming. The purpose of the AUSSSM TOOL is to determine quantitative parameters such as air temperature, exhaustive heat from air conditioning systems, energy heat balance, etc. within the urban canopy structure, which data enables the evaluation of effects of urban heat island (UHI) in concrete terms useful to urban planners, architects, engineers, and so forth in the field of urban climatology involving building scale. In addition to conducting a full numerical simulation, in order to simplify a comparison among complex factors influencing UHI, numerical experiments based on Taguchi design of experiment theory (DOE) were carried out. The results of the numerical experiments were stored in a database and ready to be instantly grasped by any inexperienced user corresponding to their specified conditions. This paper describes the fundamental method of the revised-AUSSSM, the objectives of related software development, and the structures of the AUSSSM TOOL and the techniques comprising its algorithm to present the numerical simulation results in particular.
Development of a numerical model for the evaluation of the urban thermal environment
Journal of Wind Engineering and Industrial Aerodynamics, 1999
A numerical model was developed for the computation of the wind field, air temperature and humidity in the urban canopy layer and in the atmospheric boundary layer above urban areas. The model is of k–ε type. The ensemble-spatial averaged three-dimensional Reynolds equations, equation of continuity, turbulent kinetic energy equation (k-equation), and equation for dissipation rate of turbulent energy (ε-equation) are solved together with equations of heat and moisture transfer in the air. Inside the urban canopy layer, volumes of buildings and other urban structures are accounted for by a spatial averaging procedure. With given average building height and building width for each grid mesh, effects of buildings on the momentum transfer are modelled by introducing a form drag force. Temperatures of the ground surface, building walls or roof are computed by the solution of the heat conduction equation in the ground or walls, roof. Evaporation at the ground surface is evaluated using a Bowen ratio. The exhausted heat by building air conditioning is evaluated by employing a building air conditioning model. This heat together with traffic-induced artificial heat are accounted for in the model as heat sources. A numerical model for the momentum, heat and moisture transfer in the plant canopy is also coupled to the model to investigate the effects of vegetation on the urban climate. Verification of the model against observational data in the Tokyo Metropolitan area, Japan, reveals that the model is capable of simulating the momentum, heat and mass transfer in the urban boundary layer. Especially, the model can compute air temperature, humidity and wind velocity at the street level, which cannot be computed by a general above city atmospheric circulation model.
Boundary-Layer Meteorology, 2005
A multilayer one-dimensional canopy model was developed to analyze the relationship between urban warming and the increase in energy consumption in a big city. The canopy model, which consists of one-dimensional diffusion equations with a drag force, has three major parameters: building width, distance between buildings, and vertical floor density distribution, which is the distribution of a ratio of the number of the buildings that are taller than some level to all the buildings in the area under consideration. In addition, a simplified radiative process in the canopy is introduced. Both the drag force of the buildings and the radiative process depend on the floor density distribution. The thermal characteristics of an urban canopy including the effects of anthropogenic heat are very complicated. Therefore, the focus of this research is mainly on the basic performance of an urban canopy without anthropogenic heat. First, the basic thermal characteristics of the urban canopy alone were investigated. The canopy model was then connected with a three-dimensional mesoscale meteorological model, and on-line calculations were performed for 10 and 11 August, 2002 in Tokyo, Japan. The temperature near the ground surface at the bottom of the canopy was considerably improved by the calculation with the canopy model. However, a small difference remained between the calculation and the observation for minimum temperature. Deceleration of the wind was well reproduced for the velocity at the top of the building by the calculation with the canopy model, in which the floor density distribution was considered.
12 While there have been significant advances in energy modeling of individual buildings and urban canopies, more 13 sophisticated and at the same time more efficient models are needed to understand the thermal interaction 14 between buildings and their surroundings. In particular to evaluate policy alternatives it is of interest how building 15 makeup, canyon geometry, weather conditions, and their combination modify heat transfer in the urban area. The 16 Temperature of Urban Facets Indoor-Outdoor Building Energy Simulator (TUF-IOBES) is a building-to-canopy model 17 that simulates indoor and outdoor building surface temperatures and heat fluxes in an urban area to estimate 18 cooling/heating loads and energy use in buildings. The indoor and outdoor energy balance processes are 19 dynamically coupled taking into account real weather conditions, indoor heat sources, building and urban material 20 properties, composition of the building envelope (e.g. windows, insulation), and HVAC equipment. TUF-IOBES is 21 also capable of simulating effects of the waste heat from air-conditioning systems on urban canopy air 22 temperature. TUF-IOBES transient heat conduction is validated against an analytical solution and multi-model 23 intercomparions for annual and daily cooling and heating loads are conducted. An application of TUF-IOBES to 24 study the impact of different pavements (concrete and asphalt) on building energy use is also presented. 25 26
Applied Energy, 2003
One of the detrimental effects caused by the urban warming phenomena is the increase of energy consumption due to the artificial air-conditioning of buildings in summer. In greater Tokyo, the temperature sensitivity of the peak electricity demand reaches up to 3%/ C in recent years, and about 1.5 GW of new demand is required as the daily maximum temperature increases by 1.0 C. This huge demand for summer electricity is considered to be one of the common characteristics of big cities in Asian countries. In order to simulate this increase in cooling energy demands and to evaluate urban warming countermeasures from the viewpoint of buildings' energy savings, a numerical simulation system was developed adopting a new one-dimensional urban canopy meteorological model coupled with a simple sub-model for the building energy analysis. Then, the system was applied to the Ootemachi area, a central business district in Tokyo. Preliminary verification of the simulation system using observational data on the outdoor and indoor thermal conditions showed good results. Simulations also indicated that the cut-off of the anthropogenic heat from air-conditioning facilities could produce a energy saving up to 6% with the outdoor air-temperature decrease by more than 1 C in the summer urban canopy over Ootemachi area. #
2020 AIA/ACSA Intersections Research Conference: CARBON, 2020
Because of the urban heat island (UHI) effect, an urban agglomeration is typically warmer than its surrounding rural area. Today, UHI effects are a global concern and have been observed in cities regardless of their locations and size. These effects threaten the health and productivity of the urban population, moreover, they alter buildings energy performance. The negative impacts of UHI on human welfare have been confirmed broadly during the past decades by several studies. However, the effects of increased temperatures on the energy consumption of buildings still need a comprehensive investigation. Moreover, considering the UHI effects at the early stages of the design process is still not pervasive due to the lack of straightforward and convenient methodologies to include these effects in the estimation process of buildings' energy consumption. To fill the mentioned gaps, a novel methodology of coupling the Local Climate Zones (LCZs) classification system and the Urban Weather Generator (UWG) model is proposed in this study to evaluate the UHI impacts on the energy consumption of various building typologies positioned in different climate zones. The methodology is applied to the most populated area of city of Philadelphia, Center City, and modified Typical Meteorological Year (mTMY) data comprising the canopy heat islands effect in the scale of an urban block or a neighborhood are produced in the format of .epw. The initial results of this study show an average of 2.7 °C temperature difference between existing local climate zones of Center City and reference TMY3 weather data recorded at Philadelphia International Airport during three sequential summer days. The generated weather data then were incorporated into an Urban Building Energy Model (UBEM) to simulate the spatiotemporal differentiation of energy demand for cooling and heating end-uses at each building typology under two scenarios of weather data i.e. mTMY and TMY3 data.
12 While there have been significant advances in energy modeling of individual buildings and urban canopies, more 13 sophisticated and at the same time more efficient models are needed to understand the thermal interaction 14 between buildings and their surroundings. In particular to evaluate policy alternatives it is of interest how building 15 makeup, canyon geometry, weather conditions, and their combination modify heat transfer in the urban area. The 16 Temperature of Urban Facets Indoor-Outdoor Building Energy Simulator (TUF-IOBES) is a building-to-canopy model 17 that simulates indoor and outdoor building surface temperatures and heat fluxes in an urban area to estimate 18 cooling/heating loads and energy use in buildings. The indoor and outdoor energy balance processes are 19 dynamically coupled taking into account real weather conditions, indoor heat sources, building and urban material 20 properties, composition of the building envelope (e.g. windows, insulation), and HVAC equipment. TUF-IOBES is 21 also capable of simulating effects of the waste heat from air-conditioning systems on urban canopy air 22 temperature. TUF-IOBES transient heat conduction is validated against an analytical solution and multi-model 23 intercomparions for annual and daily cooling and heating loads are conducted. An application of TUF-IOBES to 24 study the impact of different pavements (concrete and asphalt) on building energy use is also presented. 25 26