KoST – Cost Optimization in Solar Thermal Energy by Means of Standardized Components and Interfaces

Duration: April 2016 - March 2019
Contracting Authority/ Sponsors: Federal Ministry for Economic Affairs and Energy(BMWi), Projektträger Jülich (PtJ)
Project Partners: Fraunhofer IAO, Universität Stuttgart IGTE (Institut für Gebäudeenergetik, Thermotechnik und Energiespeicherung), CitrinSolar GmbH, Emz-Hanauer GmbH & Co. KGaA, Ernst-Schweizer AG Metallbau, GREENoneTEC Solarindustrie GmbH, KBB Kollektorbau GmbH, Ritter Energie- und Umwelttechnik GmbH & Co. KG, Solvis GmbH und Co. KG, Bundesverband für Solarwärme e. V. (BSW), Deutsches Institut für Bautechnik (DIBt), Zentralverband des Deutschen Dachdeckerhandwerks e.V. (ZVDH)

Project Focus:
MechTest - New mechanical load test stand
© Fraunhofer ISE
Belastungsprüfstand am Fraunhofer ISE zur Prüfung der Widerstandsfähigkeit von Kollektoren mit ihren Montagesystemen.
mechanical test facility
© Fraunhofer ISE
A system out of two collectors including mounting system and connection to the supporting structure (rafters) is tested due to thrust loads in the mechanical test facility.
Overview of interfaces used by solar thermal controllers
© Fraunhofer ISE
Overview of interfaces used by solar thermal controllers of different categories (WW: Simple solar controller with mostly one solar control loop; KOMBI: Solar controlers with additional heat support functions; MF: Multi functional controllers)

In order to achieve the climate protection targets set by the Federal Government of Germany, the use of renewable energies for heat generation in general and solar thermal energy in particular is of crucial importance. The aim of the project "KoST" is to reduce costs in solar thermal energy by means of standardized components and interfaces.

In this context, Fraunhofer ISE has particularly analyzed collector mounting and solar controllers and identified possible ways to reduce costs. In addition to the preparation of comprehensive market overviews for collector fastenings and solar controllers, standardization approaches were developed together with the project partners from the analysis of cost reduction potentials.

The results are used in the form of a "ST Mounting Guide". This is used as a guideline for solar thermal mounting systems for cost-optimized design and practical application.

In order to develop solutions for cost reduction in solar thermal energy (ST) in the field of collector mounting, Fraunhofer ISE took the following steps:

  • Market overview of ST and PV mounting systems from the point of view of standardization and ease of installation (see downloads).
  • Execution of exemplary installation procedures of assembly systems according to instructions with time recording and evaluation of results.
  • Empirical load tests along the design specifications on collectors with their mounting system (approx. 5m²) to identify oversizing or insufficiently dimensioned designs (comparison of safety factors from design and test).
  • Derivation of cost reduction potentials and prioritization of possible solutions within the scope of a standardization workshop.
  • Development of a voluntary standard interface for the collector fastening together with the project partners.

The following steps were carried out in the area of solar thermal control:

  • Market overview of solar thermal controllers with a focus on inputs and outputs, interfaces, operating features, remote control options and installation aspects (see downloads).
  • Controller testing in accordance with test standard EN 12977-5 and in relation to individual controller features. The latter in particular with regard to interfaces and their compatibility.
  • Overview of communication interfaces of solar thermal controllers in the market and their classification and interconnectivity.
  • Estimation of cost reduction potentials on the installation side (easy and intuitive installation and commissioning)
  • Design of an approach for standardization regarding minimum control functions, ease of installation, commissioning aids and remote control option for heat assist and multifunction controllers.

The ST Mounting Guide (see downloads) and the developed standards EASY-ST MOUNT and EASY-ST CONTROL (see Links EASY-ST) are the essential results of the project.

The public part of the final report is also available (see Downloads).