By means of inter-project and comparative performance and comfort analyses, the large scientific database derived from the many EnOB model projects is being used to develop answers to very specific and practical issues regarding new buildings and renovation projects. This analysis will enable the performance of various new buildings from the "EnBau" research area and several refurbishment projects from the "EnSan" research area to be compared with one another using energy consumption values.

Contents

A)  Actual energy consumption versus the planning data
B)  Monitoring of buildings
C)  Energy consumption for heating, ventilation, cooling and lighting
D)  Energy consumption for use-specific applications
E)  Electricity consumed in different areas
F)  Primary energy balance for new buildings
G)  Energy consumption over time
H)  Buildings included in the evaluation
 

A) Actual energy consumption versus the planning data

For the comparison, the energy characteristic values were based on the net floor area. This approach is also adopted in the current German Energy Saving Ordinance, EnEV 2009. However, in contrast to the method that provides the basis for the Energy Saving Ordinance, the scope of the energy balance relates only to the heated building volume, i.e. it does not include basement garages, etc. The characteristic values relate to the consumption for heating, ventilation, cooling and lighting unless otherwise stated. The measurement data stem from the respective university responsible for each project monitoring. The description ‘not electric’ refers to fossil fuels, biomass and district heating. The reference period is 2009.

The consumption values are relatively widely distributed. This is due to various factors, including the type of use, building concept, energy concept, the quality with which the building services technology is regulated and the specific usage behaviour. 

B) Monitoring of buildings

EnBau refers to the research area "energy-optimised new buildings" (the name EnBau is an abbreviation of the equivalent German term Energieoptimierter Neubau). Here, more than twenty office and administration buildings, as well as public and commercial buildings, are being planned and built with minimal energy requirements. The buildings, which are used in a completely normal manner, are scientifically evaluated over extended occupation periods and optimised while in operation. The possibilities and advantages provided by primary energy-optimised planning are therefore being assessed in actual model projects.

EnSan represents the research area "energy-oriented improvement of the building fabric" (the name EnSan is an abbreviation of the German term Energetische Sanierung or "energy-oriented renovation"). Here, ambitious renovation concepts are being tested in conjunction with innovative technologies. The reliable data derived from the scientific evaluation of the first pilot applications shall provide the basis for the widespread market application of systematic and sustainable refurbishments.

The EnBau and EnSan model projects undergo detailed monitoring over several years in accordance with scientific criteria. In this way, the effectiveness and practical applicability of innovative concepts and technologies are investigated, which enables buildings to be optimised in a targeted manner during operation.

Based on this, the performance of new buildings and refurbishment projects are now compared with one another using energy characteristic values. 

C) Energy consumption for heating, ventilation, cooling and lighting

In Graphic 1, the energy consumption values of several new buildings from the EnBau research area are compared with three refurbishment projects from the EnSan research area. The values are final energy values, which means that they are not yet evaluated in primary energy terms and contain the energy expenditure for heating, ventilation, cooling and lighting (building services equipment). With its more stringent conservation requirements regarding the indoor environment, the “Museum Ritter” building clearly stands out from the rest of the projects. The high consumption requirements in the KfW headquarters building are due to problems with the cooling technology and regulation. The high heat consumption with the “KfW Ostarkade” project is caused by difficulties with the pellet boiler, whereby the atrium is also heated. As a result of heat losses from the ventilation system and leaks in the building envelope, the REB refurbishment project has increased heating requirements.

Graphic 2 shows the same measurement values as in Graphic 1, except here these are weighted in terms of the primary energy. The underlying primary energy factors are based on DIN V 18599. Photovoltaic credits are not taken into account here. This means that buildings where sustainable energy sources are used for the heating and electricity provision show more favourable values, for example those using district heating, local cogeneration and renewable energy sources such as biomass, wood pellet and solar thermal energy. 

D) Energy consumption for use-specific applications

In comparison with Graphic 1, Graphic 3 also includes the consumption values for use-specific electrical loads: these include office equipment, computer and information systems as well as other devices in the buildings. Here it becomes clear that several buildings have a considerably above-average energy requirement for use-specific applications, which can considerably negate the high energy efficiency. That is particularly evident with the "Lamparter" passive office building. Here there is also enormous scope for optimisation and for considerably increasing the energy efficiency.
It can be seen that the use-specific energy consumption in some buildings is very high, particularly for electrical devices, and this negates the high energy efficiency of the buildings. This particularly applies to the Lamparter office building built to passive-house standards and the SurTec factory and laboratory building.

Graphic 4 shows the same measurement values as in Graphic 3, except here these are weighted in terms of the primary energy. The underlying primary energy factors are based on DIN V 18599. This means that buildings where sustainable energy sources are used for the heating and electricity provision also show more favourable values, for example those using district heating, local cogeneration and renewable energy sources such as biomass, wood pellet and solar energy.

E) Electricity consumed in different areas

Graphic 5 shows how much electricity is used for the different building services areas in relation to the different buildings. In addition to the energy concept-related differences, three buildings have a noticeably high electricity requirement. In 2007, the TU Darmstadt’s Solar Decathlon House won the competition of the same name in Washington. However, the small house, which relies solely on electricity as its energy source, has to pay deference to the fact that it has an energy reference area of just 53 m² and therefore an accordingly unfavourable A/V ratio. The increased electricity consumption is also noticeable with the “Museum Ritter” building. This is caused, however, by the use-specific requirements of the museum. The building belonging to the SurTec company is an industrial building with increased energy and use-related requirements. In the building, the production, laboratory, three-part high-bay warehouse and offices are combined under one roof. The first three uses in particular mean that there is a high ventilation requirement.

F) Primary energy balance for new buildings

Graphic 6 shows the balancing of the primary energy consumption for ventilation, cooling, lighting and heating, taking into account electricity generated using photovoltaics and cogeneration. This is incorporated into the energy balance as an electricity credit, whereby the primary energy factors for the cogeneration distinguish between the renewable and non-renewable proportions of the energy sources used. The Solvis solar factory shows a neutral energy balance, which means that the building is a net-zero-energy building. The Solar Decathlon House (SDH 2007) even achieves a positive energy balance, and can therefore justifiably be described as an energy-plus building.

G) Energy consumption over time

Graphic 7 shows the development of the final energy consumption for individual buildings for ventilation, cooling, lighting and heating over the course of two to three years. The projects described undergo a phase of scientific evaluation and optimisation that lasts for at least 2 years. The problems detected by the scientific monitoring make it possible to regulate the systems more precisely and to correct the operation. The projects are therefore further optimised in terms of the energy efficiency and user comfort. With most of the buildings, these optimisation measures enabled a considerable increase in the efficiency to be achieved during the ongoing operation.

H) Buildings included in the evaluation

• EuB: refurbishment of the printing works with pre-press facilities in Karlsruhe
• REB: refurbishment of the administration building for Remscheid waste disposal services with vehicle depot
• KfW headquarters: refurbishment of the office towers of the Kreditanstalt für Wiederaufbau in Frankfurt
• Office refurbishment: building refurbishment to provide offices to the passive house standard (Tübingen)
• SDH 2007: Solar Decathlon House from 2007 (experimental new building)  
• Haus der Region: new building for the ‘Regionshaus’ in Hanover
• PW Haus: new building for the Barnim Service and Administration Centre
• UBA Dessau: new building for the German Federal Environment Agency in Dessau
• SIC: new building for the Solar Info Center in Freiburg
• BOB: new building for the Balanced Office Building in Aachen
• TMZ Erfurt: new building for Technologiezentrum Erfurt
• EnerGon: new offices built to the passive house standard (Ulm)
• KfW Ostarkade: new building for the Kreditanstalt für Wiederaufbau in Frankfurt
• Pollmeier: new administration building for Pollmeier Massivholz GmbH (Creuzburg)
• Lamparter: new offices for the Lamparter company in Weilheim an der Teck
• DB Netz: new building for DB Netz in Hamm
• Ritter: new building for Museum Ritter in Waldenbuch
• Lebenshilfe: new building with barrier-free workshops and an administration block and recreational area in Lindenberg (Allgäu)
• Solvis: new production and administration building for Solvis GmbH in Braunschweig
• SurTec: new multipurpose building with an office, laboratory and production block in Zwingenberg
• GMS: new building for the Gebhard Müller Vocational School in Biberach
• ZUB: New building for the Centre for Environmentally Conscious Construction in Kassel
• NIZ: new institute building with offices and laboratories for the Information Centre at TU Braunschweig