Project description
Building, overall energy concept
The STRABAG HOUSE was constructed as a multifunctional office property (Photo 1). The 21.000 m2 area of the 50 meters high building is divided in thirteen floors with about 18.000 m2 office area and 3.000 m2 for shops and commerce. The building is heated by floor convectors and cooled through micro perforated sheet-metal cooling ceilings.
The system was designed in a way that the office and retail space require no additional power supply - apart from the electric power needed for the operation of the energy supply system.
Heat pump system
Energy supply needed for heating and cooling is effected through a ground source heat pump system with an installed cooling capacity of 3*693 kW. The three heat pumps are linked to a closed loop heat exchanger comprising of cast-in-situ driven piles integrated into the foundation. In total 68.000 meters of PE-pipes were furnished partly in the foundation of the building and partly in 250 cast-in-situ driven piles, each of them 17 meters long (Photo 2). The thermal energy is distributed via 800 circuits (Photo 3).
The main objectiv of the project was to collect and analyse real data dealing with the operation of the energy supply system. The monitoring data were analysed for the following operation modes:
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Figure 1: Heating mode
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Figure 2: Heating and free cooling mode
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Figure 3: Cooling and free cooling mode
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Figure 4: Cooling mode
Operation experiences
The monitoring results can be summarized as follows:
- Heating demand: 3.000 MWh
- Cooling demand: 1.600 MWh
- Electricity consumption: 1.750 MWh
- Seasonal Performance Factor: 2,6
The monitoring of the STRABAG HOUSE during its second year of operation in the period from 27 December 2004 to 1 January 2006 has shown that the installed system can accomplish the requirements with respect to the heating and cooling demand of the building. Less than 0,1 percent of the heating demand was supplied by the electric flow water heater. 2,5 percent of the heating and cooling demand was provided in the free cooling mode. In comparison to the results of the year 2004 the utilisation of free cooling could be doubled due to control optimisation.
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Diagramme 1: Comparison of measured SPF values for the years 2004 and 2005.
For future implementation of such a energy supply system it is recommended to decrease the supply temperature of the heating system to improve its performance.
From an ecological point of view the installed system shows a favourable CO2 balance compared to conventional heating and cooling systems based on natural gas, fuel oil or the usage of district heating.
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Diagramme 2: Comparison of the TEWI value for different heating/cooling systems
For more detailed information have a look at the presentation listed below.
Costs, economic efficiency, incentives
• Conventional system (district heating + chiller): 10,10 €/m² year
• Ground coupled Heating and cooling system: 6,26 €/m² year
• Additional costs: 273.700 €
• Payback time: 3,4 years
Regulations, guidelines, benchmarking
Not available
References
1 Monitoring of the system during two years (2004 + 2005)
2 Heat pump type: TRANE RTWB 222
3 Heat pump type: TRANE RTWB 222
4 SPF of the system for operation mode heating. Operation mode free cooling + heating: 6,55
5 SEER of the system for operation mode cooling. Operation mode free cooling + cooling: 7,81
Contacts, Links
| Institution/Company | arsenal research |
| Responsibility/Function | Monitoring |
| Street/PoBox | Giefinggasse 2 |
| ZIP | 1210 |
| City | Vienna |
| Country | Austria |
| Contact Person | DI (FH) Andreas Zottl |
| Phone/Fax | +43 (50) 550-6303 / +43 (50) 550-6390 |
| Email | andreas.zottl@arsenal.ac.at |
| Website (URL) | http://www.arsenal.ac.at |
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