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© Patrick Beuchert
Research projects revisited - Printing house in Karlsruhe
10.02.2011

Heat pump rounds off refurbishment

At the beginning of 2009, the BINE "Building Refurbishment – Office and Commercial Construction" Projektinfo brochure presented a printing works in Karlsruhe that has been enlarged and completely refurbished in two stages. The overall evaluation is now available. The optimisation of the building envelope and the building services equipment during the initial refurbishment phase considerably improved the usability and the building comfort. Through intensive monitoring, researchers at the Fraunhofer ISE found out that primary energy savings of around 36% were achieved. At the beginning of 2010, the reversible heat pump was fitted that was originally planned as part of the refurbishment concept but was not initially installed for cost reasons. Compared with the original condition, the primary energy requirement of the enlarged building has now more than halved.

The administrative building for Druck- und Verlagsgesellschaft mbH Engelhardt & Bauer (E&B) in Karlsruhe, which was originally built in the late 1970s, was refurbished and enlarged in 2005. The building was a typical commercial property of this period and was constructed in reinforced concrete. The building had the usual failings that are typical of this class of building: high energy consumption, a poor thermal insulation standard, insufficient daylight provision, unsatisfactory air quality, poor room acoustics and thermal discomfort both in winter and summer.
The package of measures for the first refurbishment phase encompassed fundamental improvements to the building envelope and the building technology. Adding additional floors to the low-rise building created new and attractive workspaces. The heating and cooling system utilises machine waste heat and the ground for direct cooling. Together with a ventilation system, underfloor heating and cooling ceilings ensure a pleasant indoor climate. This has been confirmed by the subjective impressions of the staff. Both the thermal comfort as well as the air quality, light and room acoustics have been very highly rated by the building users.

Refurbishment – Phase two

Following the refurbishment, the heat for space and domestic water heating is still provided by the existing gas boiler. The already installed borehole heat exchanger array was merely used for cooling in summer. Since the beginning of 2010, a ground-coupled heat pump has replaced the fossil-fuelled combustion. A combined heating and cooling system combines the heat and cooling flows in the printing works: direct cooling from the ground in combination with a recooling system that dissipates heat to the exterior air ensures pleasant temperatures in summer. During the heating period, the new ground-source heat pump is supported by three air/water-source heat pumps that use the machine and heat pump waste heat from the printing hall cooling system.

Energy balance

The primary energy requirement for heating, cooling, ventilation and lighting was successfully reduced from 322 kWh/m² p.a. to 205 kWh/m² p.a. in the first refurbishment stage and was then reduced even further to 134 kWh/m² p.a. as a result of the new combined heating and cooling system. The primary energy use thus reduced by 58%. That is considerably below the energy requirement stipulated by German Energy Saving Ordinance (EnEV) 2007, particularly taking into account the special building use with triple-shift operation and the demanding requirements in terms of the workplace lighting.

BINE-Projektinfo brochure

You can read the BINE-Projektinfo brochure on the first refurbishment stage here, download it or order it as a hardcopy version.

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