تجزیه و تحلیل عملکرد تجاری ساختمان های؛ نتایج و تجربیات از برنامه تظاهراتی آلمان" انرژی بهینه ساختمان" (ENOB)

With the objective of monitoring and building performance analysis the German research initiative ‘Research for Energy Optimized Building (EnOB)’ has funded more than 70 buildings so far. The buildings comprise a large variety of new as well as refurbished examples of building types in the residential and commercial sectors. An important feature of all buildings was the integration of energy efficiency technologies into the architectural concept. The focus of this paper is on performance evaluation of non-residential buildings, mostly office buildings, which are characterized by passive cooling strategies. The monitoring revealed very low total site energy consumptions outperforming the reference values in the German building code by far. First approaches for net zero energy concepts were investigated as well. A thorough analysis showed that the investment costs of energy-efficient buildings were in the same range as the costs of conventional buildings. Surveys in the buildings discovered that high energy efficiency does not necessarily coincide with higher occupant satisfaction. A significant correlation was found between indoor temperature and air quality and the occupants’ possibilities to control them individually

Within the program ‘Research for Energy Optimized Building (EnOB1)’, the German Federal Ministry of Economics and Technology (BMWi) has been supporting the planning, construction and monitoring of demonstration buildings since 1995 as part of Germany's energy research program. Main objectives are an accelerated implementation of innovative, energy-efficient building technologies in practice and their scientific investigation in a real-life context. Different funding areas for demonstration projects range from single buildings (EnOB, EnEff:Schule) to urban districts (EnEff:Stadt) considering new buildings (EnBau) as well as refurbishments (EnSan) through a variety of building types; further lines focus on energy performance optimization (EnBop) and heat infrastructures (EnEff:Wärme). The continuity of the funding program over a period of more than 15 years emphasizes the importance which is associated with the building sector within the national German energy concept and energy research program [1]. To date, 53 individual buildings have been monitored and evaluated in EnOB for at least two years while a further 23 buildings are presently being planned, built or monitored. Three of them received the highest rating of the German certificate for sustainable buildings (golden DGNB certificate). The majority of new buildings investigated are used as offices or administration buildings, whereas renovations can be predominantly found in the residential sector. The spectrum is currently widened in order to encourage the application of new concepts and technologies. Museums, swimming pools, supermarkets and hospitals represent new categories. Detailed information on each project is provided on the project website http://www.enob.info/ together with cross-sectional analyses on various topics. This paper focuses on the performance evaluation of non-residential buildings, mostly office buildings, which are characterized by passive cooling strategies.

As EnOB is a major component of the new energy research program defined by the German federal government, demonstration projects and accompanying research in the addressed fields above will be developed further. Besides research and development of new buildings technologies their integration into a whole building concept has to be improved. This includes, e.g. smart system engineering to minimize auxiliary energy consumption for mass transport and energy performance optimization by better adapted control strategies. Appropriate monitoring has proved to be a substantial part of continuous commissioning. Its potential for improving building operation and energy performance is huge; it can be made accessible by new tools offering data processing and visualization, automated fault detection and model based optimization. Against the background of ambitious energy-saving goals for the building sector, more attention has to be paid to high-quality refurbishment of the existing building stock in the future. One of the major challenges in Germany is the increase of the renovation rate of buildings which is currently only 1%. Besides technological progress, particularly in the field of highly efficient insulation materials, multi-disciplinary efforts are necessary to accelerate the renovation process. These include also combinations of measures on different scales linking EnOB with the corresponding research programs EnEff:Stadt and EnEff:Wärme. High occupant acceptance and economic benefits in terms of lower building life cycle costs, in addition to energy performance itself, will become important marketing criteria in the real-estate sector. The demand for energy-optimized buildings can already be seen to increase due to correspondingly defined real-estate funds. The German public sector has already taken a leading role by implementing high benchmarks on energy efficiency and sustainability in its purchasing criteria. The passive-house standard has proved to be a good base for proceeding toward “zero-energy or plus-energy buildings”. In addition to photovoltaic systems, combined heat and power generation (gas engines, fuel cells, micro-turbines) presents another option for obtaining energy credits, particularly for larger buildings. Not only the energy-related evaluation but also the funding policy concerning the two approaches is very disparate at present, which makes comparison of concepts for “zero-energy buildings” more difficult. The need for action in this respect is evident. As distributed and fluctuating energy supply will increase during the transition of the electricity grid toward 100% renewable energies, the demand for “flexibility” at the consumption end is also growing. This has to be accompanied by the introduction of new criteria beyond energy efficiency alone for building energy concepts. Buildings will be regarded more intensively than previously from the perspective of grid infrastructure. Favorable interaction between measures taken in the building itself – like energy storage (electrical and thermal), load shifting and load management – and those of the infrastructure will become important, e.g. to minimize negative effects from load mismatch. Therefore, a distinct focus will be put on demonstration projects with regard to energy concepts for urban districts and campuses.