Task 39

Subtasks

The objectives shall be achieved in the following Subtasks:

Subtask A: Information (Norway, Michaela Meir)
Subtask B: Collectors (France, Philippe Papillon)
Subtask C: Materials (Austria, Gernot Wallner)
Taskforce Certification/Testing/Norms (Germany, Stefan Fischer)
Taskforce Database (Norway, Ingvild Skjelland)

Subtask A: Information

The objective of Subtask A is to collect, create and disseminate information about the application of polymeric materials in solar thermal systems and their figures or merits, especially in terms of cost/performance ratios for an acceptable lifetime, in order to increase the penetration of good applications into the market.

The production of a yearly newsletter, targeted at the solar- and polymer industry, a colored flyer for promotion of the present Task and the preparation of an electronic or printed handbook on polymeric materials in solar thermal applications are main results of this Subtask.

Activities

Provide a state-of-the-art overview of existing applications of polymeric materials in solar thermal systems and other relevant industry sectors.
Investigate standards, regulations and guidelines with regard to the applications of polymeric materials in solar thermal systems and building integration.
Analyze the challenges of polymeric materials in solar thermal applications from a market perspective.
Disseminate information of the work and results in all Subtasks to a wide audience

These activities will be carried out within 4 different projects:

Project A1: State of the art: Polymeric materials in solar thermal applications
Project A2: Standards, regulations and guidelines
Project A3: Challenges of polymeric materials in solar thermal applications from a market perspective
Project A4: Dissemination of information

Fig. 1 Production of polymers and steel in therms of volume
(source: PlasticsEurope)

top >

Subtask B: Collectors

As the full potential of polymeric materials can only be used when several product functions are integrated into a single component in a fundamentally new design (in contrary to the simple substitution of materials), the work in this subtask is based on a review and a detailed definition of technical and economic parameters for collectors and the development of novel designs of collectors.

The concept development and the following verification phase with the demonstration of examples should therewith lead to different, polymeric material oriented, collector designs. The benefits of these could be the replacement of expensive materials (e.g. copper), enhanced freedom of design, realization of cost potentials or the integration of several functions into the collector structure. Considering the prospects of the use of polymeric materials this Subtask will focus on the following areas:

integrated collector structure
collector absorber for new solar
thermal system designs
thermo-syphon and storage collector systems
unglazed collectors

Objectives

The objectives of this Subtask are:

To analyze the state-of-the-art in polymer based solar collectors and to derive and define the requirements to collectors in given applications.
To develop concepts for easy to handle, mass producible polymer based collectors with promising prospects regarding costs.

Activities

The main activities will include a comprehensive state of the art analysis of solar collectors made from plastics and the system requirements. In a second step novel designs are development based on both, new system designs and new materials, for absorbers and entire collectors. Design examples will be produced in order to show the feasibility, performance, durability and cost savings.

These activities will be carried out within 2 different projects:

B1: Integrated Collector Structure
B2: Absorber

Fig. 3 Polymer pyramide
(source: Chevron Philllips Chemicals, 2007)

Fig. 4 Material selection, production and processing
(source: Zörner, 2006)

top >

Subtask C: Materials

Fig. 5 Glazing with thermotropic
coating as overheat protection for
polymeric absorbers
(source: Hartwig, 2003)

Fig. 6 UV/VIS/NIR Spectrometer
(Photo: Resch, 2007)

Polymer engineering and science offers great potential for new products and applications, which simultaneously fulfill technological and environmental objectives as well as social needs. The main components of a solar thermal system are the collector (glazing and absorber), pipes, fittings and pumps, and a storage unit. Polymers are already widely in use for solar thermal systems with an operating temperature range up to 30°C (water preheating and swimming pool heating). For solar thermal domestic hot water systems with intended maximum service temperatures up to 90°C only few polymeric parts and components have been developed and introduced into the market. A main reason is that efficient, spectrally selective glazed flat plate collectors reaches stagnation temperatures up to about 200°C, which are not in agreement with the nominal operating temperature range of solar thermal systems for domestic hot water applications. However, if the nominal operating temperature range is ascertained, nearly any component of a collector system can be realized
by commodity and engineering plastics with material costs ranging from 1 to 10 €/kg.

For a solar thermal system both structural and functional materials are needed. While the main requirement of structural materials is to carry mechanical loads, and thus the mechanical properties are of prime importance, functional materials are defined as solids with special mass and/or energy transfer properties. An important aspect of all research activities in this Subtask will be the strong focus on the performance, functionality and durability of polymer products with respect to the application in solar thermal systems. As with other materials, final product performance,

functionality, durability and costs not only depend on the type of the polymeric material used, but also on many other factors related to product design, processing and production.

Objectives

The objectives of this Subtask are:

Identification of appropriate products for existing commercial and novel polymeric materials with high potential (short-, mid-, and long-term) which fulfill sustainability, durability and performance requirements criteria.
Develop, investigate and establish structure/property-correlation for both, functional polymeric materials and polymer surfaces for solar thermal applications as well as performance defined structural polymeric materials for solar thermal applications.
Evaluation of polymer processing methods for the prototype production and cost-efficient mass production for solar thermal components.

Activities

Providing information like specific property profiles of plastic materials, design approaches and processing routes to Subtasks A and B.
Definition of parts and components of solar thermal systems to develop and investigate polymeric materials for (together with Subtasks A and B).
Screening and evaluation of commercially available functional and structural materials for solar thermal applications.
Formulation and preparation of novel functional and structural polymeric materials for solar thermal applications.
Development and implementation of advanced characterization and test concepts and methods for assessment of the performance and durability that reflect the application and service relevant properties of polymeric materials in solar thermal applications.
Investigation of the behavior of polymeric materials under service relevant loading and environmental conditions.
Establishment of micro-structure/property/performance relationships and systematic further development and optimization of material formulations for solar thermal systems.
Design and layout of polymeric components in solar thermal systems.
Development and manufacturing of prototypes.
Screening and evaluation of processing routes allowing for the mass-production of polymeric components in solar thermal systems.

Subtask C requires input from Subtasks A and B in terms of components to be developed and requirements to be fulfilled. Vice versa input to Subtasks A and B will be given to the specific properties and processing routes of plastics which are due to the macromolecular structure of polymers very different to inorganic materials, such as metal, ceramic or glass (e.g., time/temperature dependent behavior; functional properties; plastics processing).

According to the objectives the work will be carried out in the following three projects:

C1) Functional Polymeric Materials and Polymer Surfaces for Solar Thermal Applications
C2) Performance Defined Structural Polymeric Materials for Solar Thermal Applications
C3) Components and Polymer Processing

Taskforce Certification/Testing/Norms

The existing European Norm EN 12975 does presently not reflect with all test procedures the requirements for testing polymeric collectors or -components. A Taskforce group in Task 39 is working on a proposal for the revision of the existing Norm EN 12975 in order to modify it for the testing of polymeric collectors.

Taskforce Database: "How to make solar heating systems more attractive"

A second Taskforce group in Task 39 compiles an online and open database of solar heating systems. The objective is to show projects where -not only function- but also aesthetics and architectural integration, have been in focus when designing and installing solar thermal systems. The idea is to make solar thermal more desirable by showing visually appealing solar systems.

The fist version of the database is here.

top >