Energy Spotlight

Decentralized heat pump systems for apartment buildings

Small, compact and inexpensive

If a house containing multiple apartments is built to high standards, almost the same amount of heat is needed to supply hot water or heat the building. Almost one quarter of all heat is lost in the distribution and circulation system used to heat hot water. As part of a collaboration project with Geothermiekontor GmbH, the Steinbeis Transfer Center for Energy, Building and Solar Engineering has developed a decentralized, module-based geothermal heating system for apartment buildings.

Heat is supplied by small, decentralized heat pumps which are set up in each apartment. The building features a cold geothermal network filled with brine and this takes the source heat from the geothermal probes and distributes it. The heat is generated where it is needed almost without loss. Operation of the heat pumps is also more efficient as the supply temperature of recirculating water in the drinking water system is only 55°C instead of 65°C, mainly because of different hygiene requirements. Compared to centrally supplied heat, this approach saves over 20% of the electricity needed for the heat pump. Thanks to the new system, the individual temperature of recirculating water can be regulated for each apartment – a first for such systems.

With only an electricity and cold water bill, there is now much less administration as the heating costs disappear. The new compact heat pump has an integrated system for domestic hot water storage and it is no bigger than a refrigerator (60 x 60 x 210 cm). Since it is extremely quiet at less than 30 decibels, it can also be placed in a family room. By using inverter technology, the heating output can be regulated freely between 2 and 5 kW.

The two-year project is part of program dubbed the “Central Innovation Program in Medium-Sized Enterprise” (German: ZIM), which is sponsored by the Federal Ministry of Economics and Technology.

Monitoring energy in clean room systems

Steinbeis researchers pinpoint potential cost savings

A special energy monitoring system makes it possible to capture rapid, quick-repetition measurements and usage data in indoor climate control systems (HVAC systems). The insights this data gives into potential improvements can result in significant energy and cost savings. This has been proven by experts at the Steinbeis Transfer Center for Energy, Environment and Clean Room Technology – quantitatively and adjusted for weather variations.

The owner of a clean room (used in sterile production) was planning to optimize the regulation of a mixed air flap to save the energy required to operate its HVAC system. This would have involved retrofitting an enthalpy-controlled mixed air flap regulator onto all eight of its existing HVAC systems, which used defined minimum levels of outside air. The idea was to use “free cooling.” Beforehand, a simulation was needed to assess the efficiency of the planned change, based on a reference HVAC system. The results (in terms of the amount of energy saved) would be used as decision-making support for implementing the planned changeover.

Based on the experts’ analysis, the mixed air flaps will be switched to enthalpy-controlled operation on all eight systems and errors identified by monitoring energy levels will be eradicated. Optimizing dampness targets within the system is also planned. Compared to operation with a fixed minimum proportion of external air, the new system is expected to save 36 % of the energy. With the reference system used, this equates to a cost saving of approx. Euro 28,000 p. a., or Euro 174,000 p. a. for eight systems. Energy monitoring will be extended by one year to verify the predicted savings.

Combined with the system simulations carried out, the energy monitoring used for the project showed that the energy efficiency of the HVAC systems is strongly influenced by the method used to regulate the system. Using energy monitoring not only makes it possible to establish how much energy an HVAC system requires, it can also pinpoint a variety of errors in the control system, such as overlapping heating and cooling cycles. As a result, there’s no need for special investments for troubleshooting which contributes to significant energy savings in the HVAC system.

Micro-CHP systems meet energy efficiency criteria

Steinbeis experts provide advice to the Ministry of the Environment in Baden-Württemberg

The state of Baden-Württemberg is currently drafting a new legislation for the Renewable Heat Act (EWarmeG). The plan is to make it compulsory to use renewable energy to heat buildings. The Baden-Württemberg ministry of the environment asked a Steinbeis research center based at Reutlingen University – Heat and Energy Engineering, Stirling Machines – to conduct a study to evaluate micro-combined heat and power systems (micro-CHPs).

The key question to be answered was whether conventionally operated micro-CHPs that use natural gas would also be sufficient to fulfill statutory requirements based on their levels of energy efficiency. To find out, the scientists went back to the primary energy savings and carbon footprint savings made by the systems. This was because both factors cannot only be observed by using renewable energy, but also because they can be calculated and defined for the operation of micro-CHP systems. The approach has already been used in other studies, for example, when assessing and confirming the efficiency of micro-CHPs in order to meet funding criteria. While using this approach to provide evidence, it was also possible to join forces with Reutlingen University and use their test rig to check and even certify the output of a micro- CHP system, in keeping with DIN standard 4709 or approval guidelines used by the “Blue Angel” environmental endorsement program.

The study also showed that in terms of primary energy savings, highly efficient micro-CHP systems intended for the lower end of the scale – in single-family homes or apartment buildings – can also meet the tighter requirements being looked at for the new law. The study thus concluded with a proposal to consider formulating provisions for micro-CHPs within the Renewable Heat Act as means of alternative fulfillment of the statutory requirement.


Prof. Dr.-Ing. Bernd Thomas
Steinbeis Research Center Heat and Energy Engineering, Stirling Machines (Reutlingen)

Ingenious technology mix of different renewable energy sources

Award for an augmented reality app called Smart Cities

An augmented reality app called “Smart Cities – Ready to go!” which has been developed by Steinbeis-Europa-Zentrum and the Stuttgart company Solid White as part of the EU initiative CONCERTO, is one of the winners of the 2014 Silver Award of Distinction. The app was developed on behalf of the European Commission DG Energy.

The app, which is freely available for iOS and Android systems, uses a brochure as an “image marker” to create 3D environments in augmented reality. The app operates on three levels, revolving around individual buildings, urban districts and cities of Europe. In addition to presenting different types of technologies, examples of implemented projects are shown. An edutainment approach is used to introduce users to the topic with links to videos and Internet content which provides more detailed scientific information. The app is targeted at city mayors, energy managers, architects, city planners, scientists, and anyone else interested in energyefficient construction and renovations. It is also great for showing how to achieve a clever mix of renewable energy in urban districts. Using simple 3D animations, it shows how schools, offices, residential buildings, and even entire communities can become more energy-efficient and find smart ways to mix different types of renewable energy.


Prof. Dr. Norbert Höptner, Valerie Bahr, Anette Mack
Steinbeis-Europa-Zentrum (Stuttgart/Karlsruhe) |

Balance between research, innovation and education – the approach favored by KIC InnoEnergy

A sustainable energy model for Europe

KIC InnoEnergy is a European company working in the fields of innovation, startups, business development and education, with a focus on energy markets. It is currently fostering the interests of a sustainable energy system for Europe. Steinbeis-Europa-Zentrum (SEZ) is also working as a partner on the project with a view to helping medium-sized enterprises gain support with funding, technology transfer and access to new markets.

The objective of KIC InnoEnergy is to back market-ready technologies for the provision of sustainable energy in Europe. Since its foundation in 2010, it has sponsored 52 business concepts, 458 students are currently enrolled on apprenticeship programs, and 40 patents have been drafted as part of innovation programs. KIC InnoEnergy carries out its work through a network of offices in the Benelux countries, France, Germany, the Iberian peninsula, Poland and Sweden. The German limited company (KIC InnoEnergy Germany GmbH) was established in 2012 and looks at “Energy from Chemical Sources.” Its shareholders include the Karlsruhe Institute of Technology (KIT), Stuttgart University, the energy company EnBW and Steinbeis-Europa-Zentrum (SEZ). SEZ ensures that technology transfer measures are successful, especially among SMEs. It also provides support with the validation of possible projects, the forming of consortia, and submission of proposals. SEZ’s work on innovation projects involves tasks relating to project management, market analysis and feasibility studies. It also fosters more involvement of women in science, education and business.


Prof. Dr. Norbert Höptner, Dr. Annette C. Hurst, Charlotte Schlicke
Steinbeis-Europa-Zentrum (Stuttgart/Karlsruhe) |

Share this page