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Installation of a rear-ventilated chilled ceiling with PCM in a seminar room in the physics institute at Universität Würzburg
© ZAE Bayern
PCM in buildings
21.02.2018

PCM chilled ceiling with a high specific surface area in a training room at Landwirtschaftlicher Versicherungsverein Münster. The cooling effect is achieved predominantly passively during the day by the PCM. This is actively regenerated at night.
© Fraunhofer ISE

Monitoring verifies energy savings

Systems with integrated phase change materials (PCMs) offer considerable potential for heating and cooling buildings more efficiently. However, so far there has been very little practical experience that has been underpinned by reliable measurement and monitoring data. In the PCM-Demo II research project, eight partners from research and industry are investigating and assessing PCM systems in various applications in the building sector. The preliminary results are now available.

The scientists are focussing on monitoring reference buildings. They are measuring different PCM systems under realistic conditions: “We're investigating chilled ceilings and wall elements using PCM, as well as PCM storage systems for ventilation and heating systems,” explains Dr Helmut Weinläder, who is coordinating the work of the project partners on behalf of ZAE Bayern. The project partners are recording reliable measurement data and are garnering practical operating experience at seven demonstration buildings. They see a particular focus in developing sensible control strategies for the PCM systems. “Often these are operated with standard control systems that restrict the effectiveness of the PCM or even make it completely useless,” explains Weinläder.

Preliminary results now available

In the demonstration buildings, different PCM systems are being measured during actual use and their energy efficiency evaluated. Preliminary monitoring results are now available for all buildings. These show that PCM systems can achieve very high energy efficiency if they are properly regulated. For example, decentralised ventilation units with PCM storage showed very high EER values (EER = energy efficiency ratio = ratio of generated energy to used energy) in the 7 to 9 range. “With one chilled ceiling system with PCM, however, it showed that the originally implemented control system was inadequate,” says Weinläder. “This actually caused the PCM system to consume additional energy. Here we are now developing optimised control strategies and implementing them.” All in all, the project findings prove that PCM systems can reduce energy consumption in buildings. However, they require appropriate know-how and experience both for their design and implementation as well as for their operation.

It's all about the phase change

Phase change materials buffer temperature fluctuations by melting or solidifying while absorbing or releasing heat. They enable the thermal inertia of components to be increased in a defined temperature range. This increases the room comfort and reduces the air conditioning requirement. PCM storage masses reduce peak loads and, for example, make it possible to shift the cooling to the night time or use waste heat when it is generated.

However, the extraordinary storage capacity of phase change materials is limited to the narrow melting temperature range. This distinguishes them from standard storage materials. The consequences are therefore correspondingly more serious if the operating states deviate from the design data. So far, very little practical experience has been garnered with only a few demonstration buildings. Launched in July 2014, the PCM-Demo II research project provides hands-on experience to accelerate the market introduction.

PCM symposium presents project findings

The scientists will present their project findings at the “Use of PCM in Buildings” symposium. The conference, organised by ZAE Bayern, will take place on 14 and 15 March 2018 in Würzburg. Participants can visit the Energy Efficiency Center at ZAE Bayern with PCM chilled ceilings and PCM wall elements. In addition to PCM systems, the Energy Efficiency Center also includes many other innovative technologies, such as open sorption cooling, passive infrared night-time cooling and an energy-saving lighting concept with state-of-the-art lighting management. Participation in the symposium is free of charge. You can register on the project homepage at www.pcm-demo.info, which also includes the conference programme.

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Addresses

Project coordination and monitoring
ZAE Bayern - Würzburg

Development and optimisation of PCM compact storage devices
Rubitherm Technologies GmbH

Energy storage house with PCM-containing floor slab
Universität Kassel, BPY

Energy storage house with PCM-containing floor slab, modelling
Ingenieurbüro Prof. Dr. Hauser GmbH

Monitoring and model-based evaluation
Fraunhofer ISE

PCM chilled ceiling in the new building belonging to Landwirtschaftlicher Versicherungsverein Münster
Deerns Deutschland GmbH - Niederlassung Köln

Sodium acetate-based PCM storage system, storage optimisation, system integration
H. M. Heizkörper GmbH & Co. KG

PCM parapet module
va-Q-tec AG

Links

ENERGIEWENDEBAUEN
Projects, reports, news and analysis from the research initiative ENERGIEWENDEBAUEN