Collector Overheating Protection with Backcooler
IEA-SHC Task 39 INFO Sheet B5
May 2015 - PDF 0.54MB
Within the Austrian project SolPol-2 (www.solpol.at) the concept of a flat plate collector, which can be completely produced with cheap plastic (max. temperature 90°C) with integrated overheating protection was investigated and functional models were developed, constructed and tested.

Overheating protection
IEA-SHC Task 39 INFO Sheet B4
May 2015 - PDF 0.34MB
In order to enable the usage of cost-effective polymeric materials in flat-plate collectors, approaches to control and reduce the maximum absorber temperature are necessary.

Performance requirements (general)
IEA-SHC Task 39 INFO Sheet B1
May 2015 - PDF 0.43MB
A crucial aspect of using polymeric materials in solar thermal systems is the exact knowledge about the occurring loads especially for temperature and pressure changes. The limited thermal property in various polymers in comparison to the present primarily used materials (copper, aluminum or glass) in reference systems makes it inevitable to determine load profiles. In the framework of the national project SolPol investigations were made to create temperature and pressure load matrices for the main components of solar thermal systems. To achieve a broad knowledge-base, different applications (domestic hot water in single and multifamily houses, combi-systems) and systems concepts for the main climate zones of the world have been investigated. Furthermore, modified polymeric solar thermal systems with overheat protection (backcooling, ventilation, thermotropic layer) and without overheat protection (drain-back, thermosiphon) have been examined. Extended simulations form the basis to deliver load profiles for solar thermal systems based on polymeric materials. Building on the results (system efficiency) derived from reference systems, the accompanying INFO Sheets B2: “Thermal stress” and B3: “Pressure stress” give an overview about the performance requirements for the materials which will be investigated.

Performance requirements (pressure stress)
IEA-SHC Task 39 INFO Sheet B3
May 2015 - PDF 0.54MB
Conventional system behavior during stagnation is well understood and measures to handle this state are known. Nevertheless for economically priced polymer collectors stagnation will be a considerable challenge caused by the high temperature and pressure stress during standstill times of the solar system. In closed systems the pressure development is directly related to the temperature development. Therefore measures to overcome this disadvantage have already been mentioned in the accompanying INFO Sheet B2: “Temperature stress”. Open drain-back systems offer the ability to reduce the pressure stress.

Performance requirements (thermal stress)
IEA-SHC Task 39 INFO Sheet B2
May 2015 - PDF 0.6MB
Solar thermal systems that reach the stagnation state will overheat, resulting in high temperature and pressure loads for the collector and the surrounding components. Depending on how well these loads can be limited without reducing the efficiency in normal operation, determines whether high performance polymers or low-cost engineering or commodity plastics can be used.

Thermal limitation of glazed collector for DHW
IEA-SHC Task 39 INFO Sheet B6
May 2015 - PDF 0.62MB
A plastic collector using a Polyolefin absorber, a Nylon glass reinforced casing and a double wall Polycarbonate glazing were designed. In order to limit the dry stagnation temperature to an acceptable level (120 °C) it was necessary to invent a venting system which would function without external intervention.

Task 39 Subtask B Report
Presentation at SHC 2014 in Beijing China
October 2014 - PDF 1.97MB
Task 39 Subtask B Final Report

Performance Optimisation of Polymeric Collectors by Means of Dynamic Simulation and Sensitivity Analysis
Energy Procedia, Volume 48, 2014, Pages 181–191
March 2014
Editor: Andreas Häberle
Publisher: Elsevier Ltd.
--- A dynamic flat-plate collector model for parametric sensitivity studies on polymer-based collector designs was developed. Validation using experimental results of conventional flat-plate collectors showed satisfying results especially regarding the calculation of individual part temperatures of a collector. The model was used to predict system efficiency as well as individual part temperatures in order to analyse a polymeric collector approach in comparison to a conventional collector. The simulation results showed that the fractional energy savings of systems with conventional flat-plate collectors cannot be reached with the analysed polymeric collector approach. Also the stagnation temperatures of more efficient approaches are too high for low-cost polymeric materials. The exemplary analysis of annual temperature loads of the backside insulation for different approaches proved the necessity of careful collector design aiming at temperature reduction for all individual collector parts.

Kunststoffe in solarthermischen Kollektoren – Ein Weg zur Kostensenkung
ee-erneuerbare energie 2013-01
January 2013
Publisher: AEE - Arbeitsgemeinschaft ERNEUERBARE ENERGIE - Dachverband
--- Polymerwerkstoffe in solarthermischen Kollektoren versprechen aufgrund von geringen Materialkosten und effizienten Fertigungsmöglichkeiten eine Verringerung der Herstellkosten. Das Kompetenzfeld Erneuerbare Energien der Hochschule Ingolstadt untersucht hierbei im Rahmen eines Kooperationsprojektes mit einem Industriepartner die dafür notwendige Fertigungstechnik und Kollektorkonstruktionen.

Solarthermische Systeme aus Polymerwerkstoffen: Das Großforschungsvorhaben SolPol
ee-erneuerbare energie 2013-01
January 2013
Publisher: AEE - Arbeitsgemeinschaft ERNEUERBARE ENERGIE - Dachverband
--- Das Ende 2009 gestartete Großforschungsvorhaben SolPol-1/2 ist eine Forschungsinitiative des Instituts für Polymerwerkstoffe und Prüfung der Johannes Kepler Universität Linz [...]. Hauptzielsetzung von SolPol-1/2 ist die Entwicklung neuartiger, gepumpter thermischer Kollektoren in Kunststoffbauweise, die auf optimierten Polymerwerkstoffen und kunststoffgerechten Fertigungstechnologien basieren.

Status Quo der Entwicklungen eines überhitzungsgeschützten Kunststoffkollektors
ee-erneuerbare energie 2013-01
January 2013
Publisher: AEE - Arbeitsgemeinschaft ERNEUERBARE ENERGIE - Dachverband
--- Moderne thermische Solarkollektoren sind Hightech-Produkte und bestehen aufgrund unterschiedlicher Anforderungen an die Komponenten, aus einer Vielzahl an Materialien. Dadurch ergeben sich für die Produktion dementsprechend höhere Kosten. Kunststoff bietet hier eine Vielzahl von neuen Möglichkeiten im Hinblick auf Fertigungsmethoden und Design. Der vorliegende Artikel bezieht sich auf im Rahmen des vom Klima- und Energiefonds geförderten Forschungsvorhabens „Solarthermische Systeme aus Polymerwerkstoffen: SolPol-2“ durchgeführte Arbeiten ...

Kunststoffe in solarthermischen Kollektoren - Anforderungsdefinition, Konzeptentwicklung und Machbarkeitsbewertung
Abschlussbericht im Forschungsvorhaben Solarthermie2000plus; THi Ingolstadt, 30.04.2011
April 2011
--- Die Hersteller von Solarwärmeanlagen bemühen sich stetig um die Senkung der Herstellkosten, vor allem des Solarkollektors, des weithin sichtbaren „Herzstücks“ jeder Solarwärmeanlage. Mas- siv steigende Weltmarktpreise für die hauptsächlich eingesetzten Werkstoffe Aluminium und Kup- fer laufen den Bemühungen nach weiteren Kostensenkungen in der Kollektorfertigung aber leider entgegen. Der Einsatz von alternativen Werkstoffen, wie etwa Kunststoffen, für Solarkollektoren wird daher als vielversprechend angesehen ...