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Storing heat and cold in a compact and demand-oriented manner
Themeninfo I/2009
 

© GLASSX, Gaston Wicky

Latent heat storage in buildings

Can heat � or cold � be stored directly in walls and ceilings? Can heat be stored at precisely the temperature level at which it is to be used later on? And can the heat storage effect be used in a controlled manner as regards time and intensity? The answer is a clear �yes� � using materials that store heat �latently�, using a process that occurs at a defined temperature level and delivers high �concentrations�. The term �phase change materials� � or �PCMs� for short � refers to the large number of materials for various temperature ranges that can be used in buildings to achieve heat management that is tailored to meet the specific requirements.

The topic of latent heat storage is in itself nothing new. Water at 0 �C is a standard latent heat storage medium that has been in use for many years in refrigeration technology. As an alternative to traditional hot water storage, latent heat storage devices were introduced into heating technology many years ago in order to significantly increase heat storage capacities. However, the idea of integrating phase change materials into the surfaces of walls and ceilings is new. Heat management and the desired stabilisation of room temperatures operate in a largely passive manner if night ventilation removes heat during the night. PCMs can also be integrated very easily into thermo-active building systems. This results in active systems that can be used to control heat management as desired. Because of the low temperature differences between heating and cooling, low-exergy systems can be implemented that stand out for their particularly efficient use of energy resources.

Bild 1 - themen I09 00:
Copyright: GLASSX, Gaston Wicky
Bild 2 - themen I09 01: Fig. 1: PCMs are used to avoid peak temperatures indoors and thus to save on cooling energy. Conventional night ventilation involves the replacement of warm air in the building with cold night-time air.
Copyright: GLASSX, Gaston Wicky
Bild 3 - themen I09 02 engl: Fig. 2: Temperature profile as a function of the amount of stored heat in the case of storage of sensible heat and latent heat.
Copyright: ZAE Bayern
Bild 4 - themen I09 03 engl: Fig. 3: Material classes that are being investigated and used as PCMs.
Copyright: ZAE Bayern
Bild 5 - themen I09 04a: Fig. 4: Example of macrocapsules
Copyright: ZAE Bayern
Bild 6 - themen I09 04b: Fig. 4: Example of macrocapsules
Copyright: ZAE Bayern
Bild 7 - themen I09 04c: Fig. 4: Example of macrocapsules
Copyright: ZAE Bayern
Bild 8 - themen I09 05a: Fig. 5: Microcapsules.
Copyright: Fraunhofer ISE, BASF
Bild 9 - themen I09 05b: Fig. 5: Microcapsules.
Copyright: Fraunhofer ISE, BASF
Bild 10 - themen I09 06a: Fig. 6: PCM composite materials: mechanically stable, pourable granulate from Rubitherm GmbH
Copyright: ZAE Bayern
Bild 11 - themen I09 06b: Fig. 6: PCM graphite composite with high thermal conductivity.
Copyright: ZAE Bayern
Bild 12 - themen I09 07: Fig. 7: Modern architecture is increasingly characterised by lighter constructions and energy-optimised planning, without compromising on comfort. PCMs integrated into building materials � e.g. in the form of plasterboards � deliver a pleasant indoor atmosphere by balancing temperatures.
Copyright: BASF
Bild 13 - themen I09 08: Fig. 8: Northeast view of the �Living 2015� prototype.
Copyright: TU Darmstadt, Kubina
Bild 14 - themen I09 09: Fig. 9: Internal view: Alongside the cooling ceiling elements, the use of PCM plasterboard also played a crucial role in obtaining the desired constant interior temperature.
Copyright: TU Darmstadt, Christian Stumpf
Bild 15 - themen I09 10: Fig. 10: Frost spraying of apple trees in the Altes Land area near Hamburg
Copyright: Obsthof Axel Schuback, www.apfelpatenhof.de
Bild 16 - themen I09 10b: Fig. 10b: Frost spraying of apple trees in the Altes Land area near Hamburg
Copyright: Obsthof Axel Schuback, www.apfelpatenhof.de
Bild 17 - themen I09 10c: Fig. 10c: Frost spraying of apple trees in the Altes Land area near Hamburg
Copyright: Obsthof Axel Schuback, www.apfelpatenhof.de
Bild 18 - themen I09 11 engl: Fig. 11: Measurements from two test rooms with 15-mm PCM gypsum plaster on all opaque interior surfaces apart from the floor. Under ideal conditions, a temperature reduction of around 3.5 K can be achieved using a PCM.
Copyright: Fraunhofer ISE
Bild 19 - themen I09 12: Fig. 12: PCM plasterboard from Knauf.
Copyright: ZAE Bayern
Bild 20 - themen I09 13: Fig. 13: Interior gypsum plaster with PCM.
Copyright: Maxit Deutschland
Bild 21 - themen I09 14: Fig. 14: PCM board from DuPont Energain.
Copyright: ZAE Bayern
Bild 22 - themen I09 15: Fig. 15: PCM cooling ceiling
Copyright: D�rken
Bild 23 - themen I09 15b: Fig. 15b: PCM sun protection
Copyright: ZAE Bayern
Bild 24 - themen I09 15c: Fig. 15c: GLASSXcrystal facade building element.
Copyright: GLASSX
Bild 25 - themen I09 16: Fig. 16: PCM ceiling cooling panels in an open-plan office.
Copyright: Julia Schmidt/Deutscher Drucker
Bild 26 - themen I09 17 engl: Fig. 17: Schematic representation of active PCM systems for cooling.
Copyright: ZAE Bayern
Bild 27 - themen I09 18a: Fig. 18: Engelhardt & Bauer printing house in Karlsruhe after comprehensive refurbishment measures.
Copyright: Patrick Beuchert
Bild 28 - themen I09 18b: Fig. 18b:Engelhardt & Bauer printing house in Karlsruhe after comprehensive refurbishment measures.
Copyright: Patrick Beuchert
Bild 29 - themen I09 19: Fig. 19: Cooling ceiling system with a PCM (Ilkatherm).
Copyright: Sven Meyer
Bild 30 - themen I09 20: Fig. 20: PCM screed underfloor heating.
Copyright: Maxit Deutschland
Bild 31 - themen I09 21 engl: Fig. 21: DAW cooling ceiling with a cold water system as a heat sink.
Copyright: Fraunhofer ISE
Bild 32 - themen I09 22 engl: Fig. 22: CHCP system implemented at the Fraunhofer ISE for cooling an open-plan office using cooling/heating convectors and for five offices using a PCM cooling ceiling.
Copyright: Fraunhofer ISE
Bild 33 - themen I09 23 engl: Fig. 23: Temperature profiles in a PCM-cooled office.
Copyright: Fraunhofer ISE
Bild 34 - themen I09 24: Fig. 24: Innovative concepts for room cooling create a pleasant atmosphere � especially in workshops and other workplaces.
Copyright: Lichtblau Architekten
Bild 35 - themen I09 25a: Fig. 25a: The Imtech building in Hamburg: Testing ground for 50 PCM ventilation modules.
Copyright: Imtech
Bild 36 - themen I09 25b: Fig. 25: The Imtech building in Hamburg.
Copyright: Imtech
Bild 37 - themen I09 25c:
Copyright:
Bild 38 - themen I09 25d:
Copyright:
Bild 39 - themen I09 26 engl: Fig. 26: Storage concepts for active integration into heating and cooling systems.
Copyright: H. Mehling
Bild 40 - themen I09 27 engl: Fig. 27: Schematic methods for active systems with air as the heat-transfer fluid.
Copyright: ZAE Bayern
Bild 41 - themen I09 28 engl: Fig. 28: Schematic principle of an active PCM cooling ceiling.
Copyright: ZAE Bayern
Bild 42 - themen I09 29: Fig. 29: Screenshot of PCMexpress at www.valentin.de
Copyright:
Bild 43 - themen I09 30 engl: Fig. 30: Schematic representation of the active PCM cooling module from Imtech.
Copyright: Imtech
Bild 44 - themen I09 31: Fig. 31: PCM heating storage device.
Copyright: Alfred Schneider GmbH
Bild 45 - themen I09 32: Fig. 32: Arrangement for a cooling system consisting of a latent heat storage device (1), cooling ceiling with capillary tube mat (2), and facade heat exchanger (3).
Copyright: TU Berlin, Hermann-Rietschel-Institut
Bild 46 - themen I09 33a: Fig. 33a: Phase change fluids (slurries) consist of a carrier fluid and a PCM suspended or emulsified in this fluid. The particle sizes present result in a white liquid.
Copyright: BASF
Bild 47 - themen I09 33b engl: Fig. 33b: Phase change fluids (slurries) consist of a carrier fluid and a PCM suspended or emulsified in this fluid. The particle sizes present result in a white liquid.
Copyright: Fraunhofer ISE
Bild 48 - themen I09 33c: Fig. 33c: Phase change fluids (slurries) consist of a carrier fluid and a PCM suspended or emulsified in this fluid. The particle sizes present result in a white liquid.
Copyright: Fraunhofer ISE
Bild 49 - themen I09 34: Fig. 34: Low-temperature latent heat storage unit for the �SolCool� project.
Copyright: ZAE Bayern
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Copyright:
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Low-exergy systems and technologies are subject of LowEx, a focal point of the German Federal Ministry of Economics and Technology�s EnOB research initiative. As part of this work, systems for buildings, building services technology and energy supply are being developed that work with lowest possible temperature differences for heat generation and refrigeration and for the distribution of heating and cooling in rooms. Renewable energy sources can also be used in this manner, e.g. the natural low temperatures of the ground, or of ground water, can be used for cooling, and solar thermal energy for heating. Latent heat storage media or phase change materials are a key component in LowEx systems.

This Themeninfo will present the current state of the art in PCM technology, alongside current PCM products and their possible applications. Initial pilot projects are also scientifically investigated.