Contrasting the capabilities of building energy performance simulation programs

For the past 50 years, a wide variety of building energy simulation programs have been developed, enhanced and are in use throughout the building energy community. This paper is an overview of a report, which provides up-to-date comparison of the features and capabilities of twenty major building energy simulation programs. The comparison is based on information provided by the program developers in the following categories: general modeling features; zone loads; building envelope and daylighting and solar; infiltration, ventilation and multizone airflow; renewable energy systems; electrical systems and equipment; HVAC systems; HVAC equipment; environmental emissions; economic evaluation; climate data availability, results reporting; validation; and user interface, links to other programs, and availability

BES with FEM: Building Energy Simulation using Finite Element Methods

An overall objective of energy efficiency in the built environment is to improve building and systems performances in terms of durability, comfort and economics. In order to predict, improve and meet a certain set of performance requirements related to the indoor climate of buildings and the associated energy demand, building energy simulation (BES) tools are indispensable. Due to the rapid development of FEM software and the Multiphysics approaches, it should possible to build and simulate full 3D models of buildings regarding the energy demand. The paper presents a methodology for performing building energy simulation with Comsol. The method was applied to an international test box experiment. The results showed an almost perfect agreement between the used BES model and Comsol. These preliminary results confirm the great opportunities to use FEM related software for building energy performance simulation.Comment: 5 pages, 6 figures, Proceedings of the 2012 COMSOL Conference in Mila

Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation

Accurately computing solar irradiance on external facades is a prerequisite for reliably predicting thermal behavior and cooling loads of buildings. Validation of radiation models and algorithms implemented in building energy simulation codes is an essential endeavor for evaluating solar gain models. Seven solar radiation models implemented in four building energy simulation codes were investigated: (1) isotropic sky, (2) Klucher, (3) Hay-Davies, (4) Reindl, (5) Muneer, (6) 1987 Perez, and (7) 1990 Perez models. The building energy simulation codes included: EnergyPlus, DOE-2.1E, TRNSYS-TUD, and ESP-r. Solar radiation data from two 25 days periods in October and March/April, which included diverse atmospheric conditions and solar altitudes, measured on the EMPA campus in a suburban area in Duebendorf, Switzerland, were used for validation purposes. Two of the three measured components of solar irradiances - global horizontal, diffuse horizontal and direct-normal - were used as inputs for calculating global irradiance on a south-west façade. Numerous statistical parameters were employed to analyze hourly measured and predicted global vertical irradiances. Mean absolute differences for both periods were found to be: (1) 13.7% and 14.9% for the isotropic sky model, (2) 9.1% for the Hay-Davies model, (3) 9.4% for the Reindl model, (4) 7.6% for the Muneer model, (5) 13.2% for the Klucher model, (6) 9.0%, 7.7%, 6.6%, and 7.1% for the 1990 Perez models, and (7) 7.9% for the 1987 Perez model. Detailed sensitivity analyses using Monte Carlo and fitted effects for N-way factorial analyses were applied to assess how uncertainties in input parameters propagated through one of the building energy simulation codes and impacted the output parameter. The implications of deviations in computed solar irradiances on predicted thermal behavior and cooling load of buildings are discussed

Series of experiments for empirical validation of solar gain modelling in building energy simulation codes - experimental setup, test cell characterization, specifications and uncertainty analysis

Empirical validation of building energy simulation codes is an important component in understanding the capacity and limitations of the software. Within the framework of Task 34/Annex 43 of the International Energy Agency (IEA), a series of experiments was performed in an outdoor test cell. The objective of these experiments was to provide a high-quality data set for code developers and modelers to validate their solar gain models for windows with and without shading devices. A description of the necessary specifications for modeling these experiments is provided in this paper, which includes information about the test site location, experimental setup, geometrical and thermophysical cell properties including estimated uncertainties. Computed overall thermal cell properties were confirmed by conducting a steady-state experiment without solar gains. A transient experiment, also without solar gains, and corresponding simulations from four different building energy simulation codes showed that the provided specifications result in accurate thermal cell modeling. A good foundation for the following experiments with solar gains was therefore accomplished

Campus-Wide Integrated Building Energy Simulation

Effective energy management for large campus facilities is becoming increasingly complex as modern heating and cooling systems comprise of several hundred subsystems interconnected to each other. Building energy simulators like EnergyPlus are exceedingly good at modeling a single building equipped with a standalone HVAC equipment. However, the ability to simulate a large campus and to control the dynamics and interactions of the subsystems is limited or missing altogether. In this paper, we use the Matlab-EnergyPlus MLE+ tool we developed, to extend the capability of EnergyPlus to co-simulate a campus with multiple buildings connected to a chilled water distribution to a central chiller plant with control systems in Matlab. We present the details of how this simulation can be set-up and implemented using MLE+\u27s Matlab/Simulink block. We utilize the virtual campus test-bed to evaluate the performance of several demand response strategies. We also describe a coordinated demand response scheme which can lead to load curtailment during a demand response event while minimizing thermal discomfort

Building energy simulation and optimization of industrial halls

Industrial halls are characterized with their rectangular shape and relatively simple construction, as contrasted with office buildings with similar floor area. Industrial halls are usually subject to high energy demand due to the many manufacturing processes, lighting, and the corresponding amount spent on space conditioning. Thermal comfort is seldom a concern for industrial halls. By contrast, saving in energy consumption for lighting and space conditioning is a big issue since even the modest percentage change in energy consumption could be translated into a large monetary sum. With relatively loose requirement in space conditioning, and comparatively high internal heat gain; the approach in industrial hall design is quite different from that of office building. In fact, what poses to be an energy efficient design for office buildings might not be appropriate for high internal heat gain halls. The simplicity in the building geometry and the construction method allow the investigation of energy demand for space conditioning to be limited to a few number of demand side parameters (e.g. insulation value of walls); in which, change in values in some of the parameters presents a significant impact on the overall energy demand. This paper investigates the impact of varying different demand side parameters on the energy demand for space conditioning and lighting for a typical industrial hall. Through building energy simulation, such impact can be investigated; and by applying optimization, the configurations of the most optimal combinations of parameters with the lowest energy demand can be identified. The result indicates that the energy demand of the least efficient configuration can be more than double of that of the optimized design solution. This paper will also explore green building assessment systems such as LEED, in terms of energy performance, with the studied industrial hall as an example. The huge energy saving brought by the optimized design solution over the baseline building of LEED suggests that there might be a potential deficiency of LEED rating system at its current state as it applies to industrial halls

Accented Models: Evaluating their effectiveness in Building Energy Simulation

This report examines the effectiveness of the accented modeling method for building energy simulation. The traditional full-zone modeling method is too time consuming and in some cases unnecessary, so a more efficient building modeling method – accented modeling is introduced. The purpose of this research is to analyze if, and under what conditions, an accented building model is an effective representation of the actual building. By using DesignBuilder and EnergyPlus as software packages for model development and simulation, two building models for the Lofts on the Washington University campus in St. Louis, MO were created for comparison—a full-zone model and an accented model. This report first examines the accuracy of the full-zone model, and then, by comparing the accurate full-zone model to the accented model, shows that the accented modeling method is effective in this case

Simulation and Calibration of Passive Houses in Trondheim

This master thesis has aim to calibrate building energy simulation model of the passive houses by using energy bills, documentation and occupant survey