Seasonal Power-to-Heat Storage based on Ca(OH)2 - Development of Pilot Plant

Until today the space heat demand of residential buildings in northern and middle European countries is still mainly supplied by the combustion of fossil fuels. The sector thus contributes a major share of the yearly energy related CO2 emissions of these countries. One main reason for this is that in winter the availability of renewable energy sources is generally low, while heat demand is at its highest. Simultaneously, renewable production often exceeds the energy demand in buildings during the summertime. To compensate the seasonal discrepancy, a novel seasonal power-to-heat storage for buildings is being developed. Its function principle is based on the thermochemical, exothermal reaction between calcium oxide (obtained from limestone) and water, resulting in calcium hydroxide. The reaction can be repeated as often as desired as long as renewable electricity is available. This presentation will outline our storage system’s development as well as our latest experimental data

Kalkstein - Saisonaler Strom-Wärme-Speicher für Gebäude

In Deutschland machen Heizen und Warmwasser über 80 % des Energiebedarfs eines durchschnittlichen Haushalts aus. Aktuell deckt sich dieser Bedarf vor allem aus fossilen Energieträgern. Bisher gibt es kaum Möglichkeiten, im Winter effektiv mit erneuerbaren Energien zu heizen. Denn große Mengen erneuerbarer Energien lassen sich vor allem im Sommer gewinnen, der Wärmebedarf ist jedoch im Winter besonders hoch. Um diese saisonale Diskrepanz auszugleichen, entwickelt das DLR einen grundsätzlich neuartigen Ansatz. Überschüssiger, erneuerbarer Strom wird in den Sommermonaten genutzt, um gelöschten Kalk zu brennen. Der gebrannte Kalk kann die chemisch gebundene Energie über Monate ohne Energieverluste speichern. Um im Winter Wärme zu erzeugen, wird der gebrannte Kalk mit Wasser in Verbindung gebracht und findet die exotherme Rückreaktion statt. Steht wieder erneuerbare Energie zur Verfügung, kann der Vorgang beliebig oft wiederholt werden. Das Innovative am Konzept ist es, die besonders nachhaltigen Eigenschaften des Material Kalks für die Energiespeicherung zu nutzen: Kalk ist weltweit in großen Mengen und zu geringen Kosten verfügbar. Die an der Reaktion beteiligten Stoffe, Steine und Wasser, sind ökologisch vollkommen umweltverträglich. Die chemische Reaktion bietet gegenüber bekannten Wärmespeichertechnologien eine vielfach höhere Energiedichte, welche die Bevorratung von genügend thermischer Energie für eine ganze Heizperiode bei vertretbarem Raumbedarf im Gebäude erstmalig ermöglicht

The program of his foreign policy

Title: Tó πpóypaμμa τῆς ἐξωτεp ῆς αủτoũ πoλιτιĸῆς (The program of his foreign policy) Originally published: Appendix to the newspaper Πατpíς (Motherland), Athens, 1915 Language: GreekThe excerpts used are from the original. About the author Eleftherios Venizelos: [1864, Mournies (the island of Crete) – 1936, Paris]: the most prominent Greek politician of the twentieth century. He was born to a well-off merchant family. He completed his secondary education in Chania (Tur. Hanya) in Crete. His ..

The program of his foreign policy

Title: Tó πpóypaμμa τῆς ἐξωτεp ῆς αủτoũ πoλιτιĸῆς (The program of his foreign policy) Originally published: Appendix to the newspaper Πατpíς (Motherland), Athens, 1915 Language: GreekThe excerpts used are from the original. About the author Eleftherios Venizelos: [1864, Mournies (the island of Crete) – 1936, Paris]: the most prominent Greek politician of the twentieth century. He was born to a well-off merchant family. He completed his secondary education in Chania (Tur. Hanya) in Crete. His ..

Entwicklung und Charakterisierung eines Metallhydrid-basierten Vorheizers für luftgekühlte Brennstoffzellen

Diese Masterarbeit beschäftigt sich mit dem Einsatz eines Metallhydrid-Reaktors als Vorheizer für den Froststart in einer fluidgekühlten Brennstoffzelle, die ein Lastenfahrrad antreibt. Zwei Metalllegierungen

Long-term Power-to-Heat Storage based on Ca(OH)2 - Experimental Development of Pilot Plant

Natural limestone is an abundant and inexpensive material in Europe. Therefore, using the reversible thermochemical reaction of Ca(OH)2 (calcium hydroxide), which is obtained from limestone, to CaO (calcium oxide) and water vapor for energy storage is a promising approach. After the energy charging process, CaO can be stored in solid form at ambient temperature for an indefinite amount of time free of thermal energy losses. Hence, such a storage principle has a particular advantage compared to latent or sensible storage methods, in case a longer storage duration (several weeks to months) is required. Consequently, an application that is of particular interest is, charging Ca(OH)2 during summer using excess renewable electricity, storing the CaO for several months and discharging it during winter supplying heat for the building sector. Based on this concept, a storage system including a novel reactor has been developed at the DLR. This publication presents its experimental data during operation including its performance and the challenges for the application of the storage system