Motivation

The Need

Construction is by far one of the most important economic sectors worldwide. It is estimated that the total world annual output of construction is close to 3.000 billion € and constitutes almost one tenth of the global economy. More than 30% of this capital is from Europe, 22% from the United States, 21% from Japan, 23% from developing countries and 4% from the rest of the developed countries. Construction represents more than the 50% of the national capital investment and, with more than 111 million of employees, it accounts for almost 7% of the total employment and 28% of the global industrial employment. Moreover, construction is one of the most prominent European industries, comprising building, civil engineering, demolition and maintenance industries. With an estimated total annual turnover of 910 billion € (EU-15) and 12 million employees, construction undoubtedly constitutes a socioeconomically critical sector for the European Union, also providing the basic infrastructure on which all sectors of the economy depend. Construction, operation and maintenance of facilities acounts for more than 20% of GNP in industrialised countries and construction product life cycle costs are dominated by operation and maintenance while design & construction are less than 25% and even less than 20% in the majority of construction products, those of commercial use. Moreover, commercial construction products remain the largest source of CO2 emissions in the EU, while more than 80% of the total energy consumption comes from their operation.

Construction Products (and especially those of commercial use) constitute energy intensive systems through their whole life cycle, comprising energy demanding assets & facility operations but most importantly, occupants that are the driving operational force, performing everyday business processes and directly affecting overall business performance as well as overall energy consumption.

Energy Efficiency Concerns (and therefore respective solutions) have been presented in the past addressing all phases of construction product life cycle (PLC) from the design phase (early and detailed design and engineering), to the Realisation phase (procurement and development) as well as the Support Phase (mostly focusing on Operation and Renovation).

However, extensive industrial practice throughout the years and respective market studies verify that most crucial decisions concerning construction products happen in the early phases of the design process. And even though more than 80% of total energy consumption occurs during the building operation phase, still this measure is mostly defined by critical decisions made during the early design phase.

This is graphically demonstrated by the diagram in the following figure. It demonstrates that the most efficient choices and modifications happen early in the design process, where change decisions can be realized fast and with the least amount of cost in time and personnel effort, while at the same time having the greatest impact on cost and functional capabilities.

Effort & Reward of Design Decisions according to Phase of Construction Projects

Therefore, to make better, more energy efficient, sustainable buildings, we need to make better strategic decisions early, where the impact of design decisions on the course of the design process, as well as on the performance of the building (design) is biggest.

For an architect, designer and engineer (D&E), and from the Energy Efficiency (and also Sustainability) viewpoint, the need is to have comprehensive (account the many variables at stake) and enhanced (with enriched knowledge) Energy Efficiency analysis and simulation services in order to optimize (e.g. by testing alternate design solutions, changing materials, trialling distinct scenarios, etc.) the overall design towards a more suitable design, that presents the optimal energy efficiency levels while considering the many competing dimensions under concern.

Architects, designers and engineers need tools that will assist them in creating better and more sustainable construction projects. Most specifically, during early design phase the focus on EE should be on realising the best efficient design considering the many variables to be potentially taken into account (health and comfort performance, building costs, whole life costs, etc) also including one of the most important factors, that of occupants’ behavior. However, Architects, Designers and engineers lack the tools that will assist them in the complete evaluation of the energy performance of alternative design decisions towards producing better and more sustainable construction products, taking into account all aspects.

There is a growing trend in construction product design towards a performance-based rather than the conventional prescriptive-based approach. To support this, it is desirable to be able to conduct building performance simulations for “real world” projects based on generic data models accepted by building industries globally. To this end, building simulation has now been established as an integral part of the design process and many simulation tools are available in commercial user and considered a common practice by engineers. Building performance simulation programs should play an important role in the early design process.

Research into engineering firms specifically for information related to their experience with Building Information Modeling (BIM) programs as design and construction tools, shows wider application today. Although the Society has seen companies which fully integrate structural design and analysis programs into those architectural models, only a few companies are able to demonstrate BIM model tie-ins that can fully integrate, dynamically and seamlessly, HVAC-related design programs (such as load calculation programs, pipe and duct sizing programs, building energy modeling/analysis programs such as DOE-2, EnergyPlus, BLAST, IBLAST, TRACE 700, etc.). Furthermore, there are few companies that have totally integrated build¬ing owning, operations and maintenance programs for facili¬ties management. And, even fewer companies have fully integrated natural daylighting design programs (such as Superlite 1.01, LUMEN, or Radiance 3.4, or illumination design programs such as AutoLUX, AG132, ESP Vision, Autodesk Lightscape, Lightcalc+Art or ALADAN™) into BIM models.

However, the industry is much closer to having an interoperable system that can enable fully integrated system design. The great¬est opportunity lies with fully integrated multidisciplinary D&Es practices and where BIM integration is being done as a continuum of the design process, as well as the construction process. BIM is gaining considerable momentum as the technology evolves and greater interoperability occurs between disparate software systems. The rapidly emerging goals of green building/sustainable design, towards net zero-energy buildings, coupled with goals for carbon dioxide emissions reduction, requires whole building, fully integrated design and construction as a dynamic process. BIM constitutes a critical success factor towards fully integrated solutions, nevertheless it lacks one equally important factor, that of occupants.

Within the BIM momentum, Energy efficiency of construction products seems to be an objective measure because it is defined as the ratio of all energy input to that of useful energy output. However, currently available technological solutions fail to adequately capture the underlying relationship between Building Energy efficiency and Business Efficiency (actually translated into productivity). The concept of productivity is studied in present by mental activity, such as attention, vigilance, memory, creativity, mental computation, comprehension, and psychological processes, like motivation, persistence, effort. Workplace conditions were found to have important influence in productivity in office buildings.

Contribution of Workplace to productivity in office buildings

The dominant energy modeling simulation programs in use today have modeling and calculation engines that were primarily developed in the early 1970s, thus presenting a number of important shortcomings with respect to the current available simulation programs and their application. The majority of Building Information Models and respective tools capture 3 main construction aspects, that is a) Thermal load calculation: the calculation of peak building heating and cooling loads, b)Computational fluid dynamics: predicting airflows in building spaces and for analyzing wind flows around buildings and c)Interior lighting and acoustics simulation: analyzing factors influencing the interior lighting and acoustic conditions of buildings towards predicting the interior lighting levels (e.g. daylight level) and acoustics (e.g. reverberation time). All approaches examine in detail the structural behavior of buildings and its relation and response to specific environmental conditions, however they fail to capture the actual relation between the energy performance of the building and the driving factor of energy consumption, that of the occupants.

As far as contemporary research or available technological solutions is concerned there are no modeling & simulation tools which take into account the actual affect that occupants and respective occupancy patterns. The available modeling methods and systems do not deal with activities performed by occupants or with the resulting utilization of space and movement through space. The most used form of input in modeling & simulation systems with regard to occupant presence are so-called diversity profiles. These profiles represent the combined behaviour of all occupants. A diversity profile describes the presence of occupants and (for instance) the corresponding energy loads stemming from utility demands. Diversity profiles however have failed to sufficiently capture dependencies of occupancy patterns with overall environmental conditions or temporal variations.

Due to the complexity of the problem with capturing user preferences and activities engineers and existing simulation and design tools tend to eliminate the influence of active building users as far as possible to optimize building performance, eventually leading to assumptions about average user preferences and behaviors. This does not only result in rough and imprecise architectural designs in terms of energy performance of constructions during future operation, but also in fully automated systems without interaction, poor performance and low end user acceptance.

Uncertainties regarding behavior of building occupants limit the ability of energy models to accurately predict actual building energy performance during operation. Initial results show that predicted energy consumption changes by more than 150% using all high or all low values for what experts believe reasonably represents occupant behavior. Although numerous sources of modeling inaccuracies and over-simplifications exist, contemporary technological solutions have failed to fully evaluate the sensitivity of energy modeling results to variability in occupant behavior.

Another shortcoming of building simulation tools is that most programs were originally not intended to be used by building designers. They were designed to be used by research scientists. Usage of these tools generally requires a steep learning curve and as a consequence these tools are mainly used by domain experts.

The Adapt4EE solution

Building simulation is considered to be common practice in the building industry. It has undergone a substantial growth both in the academic world and the building industry since its emergence three decades ago. Research in this field of building simulation is also abundant, for instance with regard to modeling the behaviour of humans in routine business domain-specific activities or even activities in egress situations. Moreover, much research effort within EU funded projects as well as international research action has been devoted to resolve the shortcomings of the current available building simulation and automation programs and respective Building Information Modeling (BIM) approaches. However, none of these efforts focus on analyzing the overall patterns, semantics and complexity of day-to-day human activity and movement within buildings, as well as the relation of these activities to domain specific enterprise processes governing commercial buildings operation and performance. A system for building simulation, especially in cases of commercial buildings, that produces data about the activity behaviour of occupants as members of an enterprise structure and framework can significantly improve the relevance and performance of building simulation tools. This is relevant for engineering domains, like building physics, as well as for architects to analyse and evaluate the performance of a building design.

Constituents of a Holistic Enterprise Model

Furthermore, in cases of constructions of commercial use, the need to treat and balance energy performance with business performance is still ignored. The benefits of reducing power consumption and respective costs, is usually achieved at the expense of critical business services. Business operations (process organization and management) are an inseparable part of overall business services as well as overall enterprise energy consumption. Ideally, energy consumption should be traced back to spatio-temporal aspects of business operations.

A holistic enterprise modelling and simulation approach should undoubtedly incorporate all levels of business operations, allowing for optimal decisions during early construction design phases. Design decisions on energy performance optimization should be based on sound and realistic estimations of the actual future energy consumption of constructions during operation, taking also into account potential consequences on business operations affected by early design decisions and vice versa.

Our society and economy holds high expectations for the cross-fertilisation of constructions and ICT. Construction products can greatly benefit on all phases of their life-cycle (PLC) from the integration/application of innovative ICT solutions, towards providing more energy efficient, energy positive and energy intelligent constructions.

Energy-intelligent constructions incorporating innovative ICT (self-organized integrated frameworks of sensors, actuators, meters etc) will present the ability to efficiently adapt to occupant needs and preferences, maximize energy performance while at the same time comply to overall business requirements. This will be realized through the fusion of two (currently disjoint) worlds: a) Building Information Modeling (BIM) and b) Business Process Modeling (BPM), having occupants as the main catalyst. This fusion, among other obvious advantages, will also present the ability for enhanced diagnostic and renovation of existing constructions and also generate infrastructures and simulation environments to assess variants of environmental performance of buildings, tools for dynamic building evaluation at run-time, and allowing optimisation based on multi-dimensions / multi-criteria constraints.

Last Update: 08/02/2012 16:07