Integrating Building Energy Simulation in the design process

To significantly increase building energy performance, the use of building simulation software at the earliest has been emphasized. Inherent complexity in data representation, I/O (Input and Output) and Visualization of available software requires specialist knowledge to leverage the potentials offered. Early stages of design are characterized by unstructured and incomplete data which is insufficient as inputs to software based on detailed representations of the systems in the building. Existing simulation software, developed in research organizations are targeted to be used by building services engineers at detailed stages and does not suit the purposes of design community. This article attempts at identifying the reasons behind unpopularity of simulation software in the early stages of design and also argues that a new breed of decision support systems is needed for energy efficient building design. Introduction: Building regulations, energy labelling, and tax exemption for low-energy buildings all are contributing towards the increased use of building energy simulation programs in the design process. Based on algorithms evolved and matured over time, these tools simulate physical properties and behaviour of buildings; provide designers with an indication of performance and help to make informed decisions. To take it a step further, integrated simulation approach considering interactions among all of the building’s components and systems are incorporated in the current generation of simulation programs. Benefits offered by these concepts include but not limited to increased energy savings, occupant comfort, and ROI (Return On Investment). Apart from some exemplary projects, these holistic concepts and advanced simulation programs are of little use in the design community. Developed mostly in research organizations, building energy simulation programs focus on modelling and simulation than on the integration with the design process. Enormous amount of input processing is required even to simulate of a small subset of the domain. Complicated process to accomplish tasks made their use limited to occasional validation of the proposed idea than to assist in the design development. Extension of the capabilities of simulation software/ UI (User Interface, some simulation software clearly separates engines from interfaces) can play a vital role in early stages of design, in which most of the decisions affecting energy-efficiency of the building are made. Design process and building simulation Building design is a sequential decision making process, in which decisions taken at an early stage dictate the properties and behaviour of the building at later stages. Composition of the design team, fragmentation of the process and activities make it unique from other mass-manufactured product design. Although the concept of integrated design and construction has been emphasized, it merely imitates what has been done in the manufacturing industry and focuses more on the product than on the process. Increased complexity due to the technological advancements in materials, construction, and management calls for whole and integrated building simulation at the earliest to guide the decision making process. Early stages of design are characterized by unstructured data, incomplete building information and horizontal data-flow from one stage to another. Figure 1 shows that vertical data-flow increases as design progresses with increased level of collaboration among design professionals. Decision support systems leveraging capabilities of building simulation software can offer help in integrating expertise of different domains in the design process particularly in early stages. Figure 1: Data flow among design professionals in different stages A B