System to Evaluate the degree of ZEB Ready Achievement in the Early Stages of Design Phase

Highly accurate and quick evaluation using a simplified 3D model to estimate the load on the building skin

Technologies

Obayashi Corporation has developed a system that makes it possible to evaluate the achievement of ZEB Ready (*2) with high accuracy and in a short time in the early design stage by using a simple 3D model to estimate the skin load of buildings (*1).

Background

The need for energy conservation and decarbonization of buildings is increasing, as the revised Act on the Building Energy Conservation Law will be enforced in 2025 in Japan, with the aim of achieving carbon neutrality by 2050. In particular, ZEB Ready certification for office buildings is increasingly required, and there is a growing need to improve energy efficiency and conservation performance during building planning. However, the problem is that the detailed specifications of electrical equipment, air conditioning equipment, and others have not yet been determined at the initial design stage, making it impossible to accurately evaluate the energy efficiency and conservation performance of a building at early design stage.

Configuration and Features of this system

Based on abundant data from office buildings designed by Obayashi, the system formulates calculation logic and simplifies information input, enabling ZEB Ready evaluations in a short period of time in the early design stage, when facility specifications are not yet finalized. The system uses Rhinoceros®, a 3D modeling software used by designers on a daily basis, and ClimateStudio® (*3), an existing environmental performance analysis plug-in (function extension program).

The features of this system are as follows.

Evaluates energy conservation performance with high accuracy using the skin load indicator

The specifications of air conditioning equipment, which determine the energy efficiency of a building, are greatly affected by the skin load. More than 50% of the energy may be used for cooling the skin load during the peak of air conditioning usage in summer. This system utilizes data from offices that have acquired ZEB Ready certification in the past, and evaluates the achievement of ZEB Ready using the skin load as an indicator, enabling highly accurate evaluation of energy conservation performance even in the early design stage.

Skin load calculation screen

Quick evaluation with simple input

In the past, the calculation of the skin load was done by a facility designer with expertise using CAD data over several days. The system formulates the calculation logic in advance and provides a user interface that allows designer to simply input of the necessary information, making it possible for the designer to estimate the skin load in a few dozen seconds.

Calculation is possible with simple input, such as compass bearing, indoor temperature, thermal transmittance of the structure, solar heat gaining rate of glass and others (red frame)

Flexible support for a variety of building design

The system is not just for buildings with rectangular planes but can also be applied to buildings with complex design. In addition, the calculation results can also reflect the sunshade effects of each part of the building, such as eaves, louver materials, and uneven exterior walls on the 3D model. It can assist in the formulation of more effective proposals by comparing proposals and checking the effectiveness of certain environmentally friendly architectural designs in real time.

Future Prospects

In the future, Obayashi plans to expand the scope of this system to include buildings other than office buildings, as well as to cover certification standards other than ZEB Ready. Through these efforts, Obayashi will contribute to the realization of carbon neutrality by providing buildings with superior energy-saving performance.

  • *1 Skin load
    A generic term for the heat load entering a room from the outside through exterior walls and openings of the building.
  • *2 ZEB Ready
    A building enabling reduced energy consumption by 50% or more, which foresees an advanced building with a ZEB (net-zero energy building), which is a building with net-zero or negative annual primary energy consumption.
  • *3 ClimateStudio
    An environmental analysis software developed by Solemma LLC, a U.S. construction systems company, for architectures and construction-field engineers. It operates as a plug-in for the Rhinoceros® 3D modeling software.

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