It was intended that the new two-field sports hall in Dresden-Weixdorf should cause the lowest possible operating costs. In spite of the large building volume, it was planned to have a heating demand less than 20 kWh/m² p.a. and a primary energy requirement that was about 50 % lower than that of a passive house (120 kWh/m² p.a.). The operating experience in the first year showed that the targeted energy efficiency goals were not achieved. After an initial evaluation of the measured data, optimisation proposals for the system operation were developed. This enabled the gas consumption to be reduced by about 35 %.

The new Gerhard Grafe Sports Hall is situated in the heart of the Weixdorf district of Dresden. The SG Weixdorf sports association first considered building a new sports hall back in 2005, because they were dissatisfied with their existing training and competition environment. It was also intended that the school sports provided by the neighbouring primary and secondary school should benefit from it. It was therefore decided to construct a new two court sports hall in 2006. In addition to the SG Weixdorf sports association, the Sächsische AufbauBank, the City of Dresden and the District of Weixdorf also participated in the investment costs for the new-build scheme.

Research focus

The research project encompasses the monitoring of the two court sports hall, the analysis of the building operation and the optimisation of the systems. The measurement data derived from the monitoring will undergo model-based data evaluation to enable the measurement data for the sports hall to be compared with similar building types in terms of the energy characteristic values and the overall energy efficiency. This is intended to identify initial potential for optimising the building and system operation. By evaluating the system technology during actual use, the intention is to provide proposals for improving the system operation, identify potential for optimising the general concept and gain information for future designs of system components. In addition, the indoor environment and the comfort conditions in the sports hall will be analysed. The assessment of local comfort criteria will be supported by the use of mobile measurement technology. The optimisation measures will be conceived so as to achieve the intended energy efficiency goals and the desired thermal comfort. The largely automated building operation will be made more resilient to operating errors.

Building concept

A central element of the building concept is provided by the concrete perimeter walls that are designed as thermally activated components. Their considerable thermal mass and associated inertia enable the indoor environment to be kept constant for several hours even with strongly fluctuating outdoor temperatures. In addition, the high thermal mass resulting from the monolithic structure also contributes to energy-saving passive cooling. However, sufficient thermal protection in summer would not be achieved by using just solar shading and night ventilation alone. The transmission heat losses are reduced by using an extremely compact structure with the partial use of double storeys. Rainscreen cladding on the facade ensures that the weather protection, insulation and structural (building mass) functions are separated.

The window surface areas on the south and east elevations were reduced to approximately 20% in comparison with the high proportion on the west and north elevations (40%). The glare-reduced glass has a low solar energy transmittance factor. In order to provide homogeneous and glare-free lighting in the hall, two series of vertically angled ribbon windows were installed around the building. The daylight-dependent lighting control system further reduces the electrical energy consumption for the hall illumination.

Energy concept

The ventilation heat losses were reduced by limiting the number of areas where it was essential to provide air conditioning: the moisture-led ventilation in the sanitary and changing room areas and the CO2-led hygiene ventilation in the hall. The ventilation system was designed so that it works as much as possible without external heat supplies. The energy losses are almost completely balanced out using a highly efficient heat recovery system (93% recovery rate) and a ground-air heat exchanger. The low-temperature heating system is merely intended for covering transmission heat losses. For the heat generation, an absorption heat pump was installed that is operated with natural gas. Boreholes in the ground are used both as a heat source for the heat pumps as well as a heat sink for providing base load cooling using the thermally activated concrete external walls.

The heat is distributed via a collector and distribution centre. This system enables specific temperatures to be defined for various thermal zones. Its unique feature is that neither the supply nor return systems generate any mixed temperatures. This also prevents mutual influencing of the various pumps. The collector and distribution system provides the hydraulic zero point and consists of a steel distributor/collector with 5 thermally separated temperature chambers.

The energy required for domestic water heating is partly provided by a solar thermal system, with the remaining energy requirement provided by the gas heat pump. In the event of damage, a modulated peak-load condensing boiler provides the heat source for the surface heating systems and the ventilation system. Two buffer storage tanks, each with a volume of 1,200 litres, have been provided for temporarily storing surplus solar thermal heat and for balancing out switching differences when operating the heat pump.

Performance and optimisation

After an initial evaluation of the measurement data, optimisation proposals for the operation of the plant technology could be developed. The measures led to a noticeable increase in efficiency compared to the initial period under consideration. Gas consumption was reduced by about 35%.

The planned characteristic values were largely achieved. The building is thus characterised by good thermal comfort as well as a low annual heating and primary energy demand.

After the first measurement data analysis in 2012/13, possibilities for system optimisation were identified:
  

  • In order to achieve a longer running time and a lower cycle time of the heat pump, it must be ensured that the heat provided is taken from the system. This can be achieved by selectively loading the buffer tanks and adjusting the system temperatures.
  • In general, the control of the circulation pumps should be checked. In particular, this concerns the primary and secondary pump of the heat pump and the pump in the secondary circuit "solar heat exchanger", so as not to interfere with the functionality of the Zortström distributor as a hydraulic separator.
  • In the hydraulic circuit of the condensing boiler, only one pump at a time should be operated depending on the changeover valve for charging the hot water tank or for heating support.
  • The WRG unit of the ventilation system should be deactivated in summer (deactivate switching of the accumulator block) in order to be able to effectively use the pre-cooled ambient air through the air-earth register.

    As a result of a cost-benefit consideration by the operators, it was finally decided to modify the system technology and hydraulically decouple the heat pump from the Zortström distributor and connect it to the buffer storage instead. This measure was intended to ensure better acceptance of the heat generated for the heat pump and thus guarantee more stable operation with longer cycle times. After the conversion, some components of the system technology were analysed again.

Last updated:
19.11.2021

At a glance

Short title: EnOB | Modellprojekt Zweifeldsporthalle der SG Weixdorf e. V. in Dresden
Funding number: 0327431S
Topics: Buildings  
Running time: April 2011 till March 2015

Contact

Coordination
TU Dresden, Professur für Gebäudeenergietechnik und Wärmeversorgung
https://tu-dresden.de/ing/maschinenwesen/iet/gewv

+49(0)351-463-32145

Additional links

TIB Hannover
Final report