Task 54
Task 54
SHC Task 54

Price Reduction of Solar Thermal Systems

Publications

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The following are publications developed under Task 54:

General Task Publications

IEA SHC Task 54 Investigating Cost Factors Along the Value Chain - Posted: 2017-07-14
By: B. Epp
Publisher: Solarthermalworld.org
Researchers have worked intensively for one-and-a-half years across national borders to find ways of reducing the costs of solar thermal systems and making them more attractive to end users. The members of Task 54 of the IEA Solar Heating and Cooling Programme, Price Reduction of Solar Thermal Systems, have discussed the effects of standardised product designs or changes in product offerings on cost structures. They have also analysed the entire value chain from component manufacture to system assembly and installation to help identify cost-cutting potential. This is the first time that methods of Process Cost Analysis are being adapted for the solar thermal business.

Subtasks

Subtask A: Market success factors and cost analysis

Neue Ansätze zur Kostenreduzierung von Solarthermischen Systemen
Tandemvortrag Teil 1: Projekt TEWIsol
May 2017 - Posted: 2017-07-18
By: Wolfgang Kramer, Frederic Diels, Axel Oliva
Publisher: 27. Symposium Thermische Solarenergie, Kloster Banz, 10.-12. Mai 2017
A total cost perspective on use of polymeric materials in solar collectors
Importance of environmental performance on suitability
July 2014 - Posted: 2017-07-14
By: Bo Carlsson, Helena Persson, Michaela Meir, John Rekstad
Publisher: Elsevier
To assess the suitability of solar collector systems in which polymeric materials are used versus those in which more traditional materials are used, a case study was undertaken. In this case study a solar heating system with polymeric solar collectors was compared with two equivalent but more traditional solar heating systems: one with flat plate solar collectors and one with evacuated tube solar collectors. To make the comparison, a total cost accounting approach was adopted. The life cycle assessment (LCA) results clearly indicated that the polymeric solar collector system is the best as regards climatic and environmental performance when they are expressed in terms of the IPPC 100 a indicator and the Ecoindicator 99, H/A indicator, respectively. In terms of climatic and environmental costs per amount of solar heat collected, the differences between the three kinds of collector systems were small when compared with existing energy prices. With the present tax rates, it seems unlikely that the differences in environmental and climatic costs will have any significant influence on which system is the most favoured, from a total cost point of view. In the choice between a renewable heat source and a heat source based on the use of a fossil fuel, the conclusion was that for climatic performance to be an important economic factor, the tax or trade rate of carbon dioxide emissions must be increased significantly, given the initial EU carbon dioxide emission trade rate. The rate would need to be at least of the same order of magnitude as the general carbon dioxide emission tax rate used in Sweden. If environmental costs took into account not only the greenhouse effect but also other mechanisms for damaging the environment as, for example, the environmental impact factor Ecoindicator 99 does, the viability of solar heating versus that of a natural gas heating system would be much higher.
Document Number: https://doi.org/10.1016/j.apenergy.2014.03.027

Subtask B: System design, installation, operation and maintenance

Polymer Collectors with Temperature Control - Potentials for System integration
October 2016 - PDF 2.05MB - Posted: 2016-10-03
By: Alexander Thür, Katarina Maslikova
Within the Austrian research project SolPol-4/5 it is the goal to find solutions for solar thermal systems based on cheap polymer materials but with low temperature limits in order to realize significant cost reduction potentials. Therefore one major point is to keep the temperature of the solar collector (and the complete system) below the material limits which means below 100°C for cheap polymer materials. For this, several possibilities are under investigation in many research projects. One solution is to design the collector in such a way, that the performance does not allow stagnation temperatures above 100°C (temperature limited collector – TLC). Other solutions try to keep the collector performance highest possible during operation and reduce the performance during stagnation by different technical solutions (overheat controlled – OHC) like reduction of absorption characteristic at high temperatures (Föste, 2015), reduction of transmission of the transparent cover or increasing the heat losses by activating cooling processes like internal ventilation of the collector (Harrison, 2004) or using a thermosyphon driven backcooler (Thür, 2014). This simulation study based on different parameter variations estimates how different operating conditions can influence design parameters for a solar domestic hot water system (SDHW) with different collector types. For different possible market conditions, which can potentially be situated world-wide, the goal of these investigations is to find out dependencies of different design parameters depending on specific operating conditions for solar domestic hot water systems (SDHW).

Subtask C: Cost-efficient materials, production processes and components

Replacing traditional materials with polymeric materials in solar thermosiphon systems
Case study on pros and cons based on a total cost accounting approach
February 2016 - Posted: 2017-07-14
By: Bo Carlsson, Michaela Meir, John Rekstad, Dieter Preiss, Thomas Ramschak
Publisher: Elsevier Solar Energy
The pros and cons of replacing traditional materials with polymeric materials in solar thermosiphon systems were analysed by adopting a total cost accounting approach. In terms of climatic and environmental performance, polymeric materials reveal better key figures than traditional ones like metals. In terms of present value total cost of energy, taking into account functional capability, end user investment cost, O&M cost, reliability and climatic cost, the results suggest that this may also be true when comparing a polymeric based thermosiphon system with a high efficient thermosiphon system of conventional materials for DHW production in the southern Europe regions.

When present values for total energy cost are assessed for the total DHW systems including both the solar heating system and the auxiliary electric heating system, the difference in energy cost between the polymeric and the traditional systems is markedly reduced. The main reason for the difference in results can be related to the difference in thermal performance between the two systems. It can be concluded that the choice of auxiliary heating source is of utmost importance for the economical competiveness of systems and that electric heating may not be the best choice.
Document Number: https://doi.org/10.1016/j.solener.2015.12.005

Other

Info Sheets

LCOH for Solar Thermal Applications
INFO Sheet A.2
March 2017 - PDF 0.48MB - Posted: 2017-04-18
By: Yoann Louvet, University of Kassel; Stephan Fischer, ITW Stuttgart; Simon Furbo, Technical University of Denmark; Federico Giovanetti, ISFH; Franz Mauthner, AEE Intec; Daniel Mugnier, Tecsol; Daniel Philippen, SPF
In the framework of the IEA-SHC Task 54 appeared the need of assessing the costs of the heat produced by solar thermal systems over their life time in order to compare different designs and technological solutions with one another. The levelized cost of heat (LCOH), a measure based on the concept of levelized cost of energy, widespread in the electrical power sector, was chosen. This info sheet builds on the work of the FRoNT project [1] who laid the foundations for the application of the method to any heating technology. It aims at detailing the methodology to calculate the levelized cost of the heat substituted by solar thermal energy. Furthermore, an extension of the concept is suggested in order to estimate the cost of the heat generated by the entire solar assisted heating system, or the conventional sources of heat supply.
Cost Drivers and Saving Potentials
INFO Sheet C1.2
October 2016 - PDF 0.46MB - Posted: 2016-11-28
By: Karl Schnetzinger, Advanced Polymer Compounds (APC), Austria / Gernot M. Wallner, University of Linz (JKU), Austria
Due to the specific characteristics of polymeric materials (e.g., variety of property profiles, ease of processing, mass production capability, freedom of design) this material class has been used to replace metal parts and components in various industrial sectors. In this case study the cost reduction achieved by material substitution is described and discussed exemplarily for industrial pumps.
Cost Drivers and Saving Potentials
INFO Sheet C1.1
September 2016 - PDF 0.29MB - Posted: 2016-11-28
By: Alexander Thür, University of Innsbruck (UIBK-EEB), Austria
A main challenge of the solar thermal market is the reduction of the production and installation cost finally following by the reduction of the market price of solar thermal systems. Installation costs are a major share of the total costs for solar thermal systems. Good ideas for cost reduction are needed. This sheet will give input for the discussion of this topic.

Articles

Industry and Research Join Forces on Reliability Testing of Collectors and Materials
December 2016 - PDF 0.13MB - Posted: 2016-12-08
Editor: Pamela Murphy
Solar thermal collectors and their components are commonly exposed to a wide range of climatic influences. Next to UV radiation, factors like humidity, wind, extremely high or low temperatures, salt, sand and other particles in the atmosphere affect the surfaces and performance of these products. Although these influences are decisive factors for the lifetime and long-term efficiency of solar thermal collectors, there are no validated or binding test procedures for reliability assessment over time or models that allow a location-specific service life prediction.
Novel solar thermal collector systems in polymer design – Part 5: Fatigue characterization of engineering PA grades for pressurized integrated storage collectors
2016 - PDF 0.94MB - Posted: 2016-10-21
By: Joerg Fischer*, Patrick R. Bradler, Mathias Schlaeger, Gernot M. Wallner, Reinhold W. Lang
Publisher: Energy Procedia, Elsevier
A novel aging test method considering the superimposed mechanical and environmental (temperature and environmental medium) loads representative for pressurized integrated storage collectors (ICS) is described. Engineering polyamide (PA) grades with short glass fiber (GF) reinforcement, which are of high relevance for endcaps of steel-pipe ICS absorbers or all-polymeric absorber/storage-tanks, are characterized on a specimen level. Therefore, specific test devices and test arrangements for fracture mechanics specimens with or without weld-line are implemented on an electro-dynamic test machine. Fatigue crack growth kinetics data are obtained by conducting cyclic mechanical loads under various environmental testing conditions. The experimental results of two glass-fiber reinforced PA grades, using compact type specimens, performed at two different temperatures (23 °C and 80 °C) and in two environmental media (air and water), are compared in terms of crack growth kinetics. Moreover, the influence of welding on the crack growth kinetics for one PA grade is shown. For all specimens (unwelded and welded) the fatigue crack growth rates are enhanced in water compared to air. In welded specimens the fatigue crack growth resistance is significantly reduced compared to unwelded specimens.
Novel solar thermal collector systems in polymer design – Part 3: aging behavior of PP absorber materials
2016 - PDF 0.43MB - Posted: 2016-10-21
By: Markus Povacz, Gernot M. Wallner, Michael K. Grabmann*, Susanne Beißmann, Klemens Grabmayer, Wolfgang Buchberger, Reinhold W. Lang
Publisher: Energy Procedia, Elsevier
A novel, accelerated aging test method was used to characterize the long-term stability of commercial black-pigmented polypropylene (PP) model materials for solar thermal absorbers at elevated temperatures. The PP model materials investigated, PP-B1 and PP-B2, are based on carbon black pigmented PP block copolymer grades. Using an automatized planning technique, sliced 100 µm thick specimens were prepared, aged in hot air and heat carrier fluid (mixture of 60 vol.-% deionized water and 40 vol.-% commercial propylene glycol) at 95°C, 115°C and 135°C for up to 15,000 hours, and characterized in terms of various aging indicators (i.e., remaining primary stabilizer content, oxidation temperature, carbonyl index and ultimate mechanical properties). In general two major trends were discerned. First, the aging processes of the PP compounds depend on the stabilizer system, but even more heavily on the interaction of the stabilizers with the carbon black pigments and the structure and morphology of the polymer. Although the compound PP-B2 exhibited much faster stabilizer loss and an associated drop in oxidation temperature than PP-B1, mechanical investigations proved a better long-term stability for PP-B2. Second, it was shown for the compounds investigated that exposure to hot air causes harsher aging than exposure to hot heat carrier fluid. This is, presumably related to the reduced quantity of dissolved oxygen and triazole-based corrosion inhibitors used in the heat carrier fluid. While PP-B1 is use for absorbers in unglazed collectors and overheating-protected glazed collectors, the investigations clearly revealed that PP-B2 is a promising alternative.
Polymeric materials in solar-thermal systems - performance requirements and loads
2016 - PDF 1.91MB - Posted: 2016-10-21
By: Thomas Ramschak, Robert Hausner, Christian Fink
Publisher: Energy Procedia, Elsevier
A major basic problem in selecting appropriate polymeric materials and processing technology routes is related to the lack of well-defined functional and performance requirements on the component level and to material property requirements on the specimen level. Hence, in a first step several reference climate regions were defined for pumped systems (continental (Graz/Austria), moderate climate (Beijing/China)) and non-pumped systems (Mediterranean (Athens/Greece), hot and dry (Pretoria/South Africa), hot and humid (Fortaleza/Brazil)), respectively. For each of these reference regions various solar-thermal plant types (e.g., domestic hotwater systems for single family houses (pumped and thermosiphon); domestic hot-water systems for multi-family houses; solar combi-systems for domestic hot-water and space heating (pumped) were pre-defined and evaluated and optimized virtually by modelling and simulation. To determine performance requirements on the component level and to derive material property requirements on the specimen level all-purpose modelling and design tools for collectors were implemented and used which allow for the description of temperature profiles, stagnation conditions, efficiency curves, pressure losses, distribution of fluid and heat flow and the thermal and hydraulic optimisation of the whole collector.
Lifetime modeling of polypropylene absorber materials for overheating protected hot water collectors
January 2016 - Posted: 2016-10-21
By: G.M. Wallner, M. Povacz, R. Hausner, R.W. Lang
Publisher: Solar Energy, Elsevier
For the utilization of polymeric materials in high-demanding applications like solar thermal systems it is of utmost importance to define the performance requirements and to investigate the applicability of components for defined systems under service relevant conditions. This paper deals with the lifetime estimation of black-pigmented polypropylene (PP) absorber grades for overheating protected solar thermal collector systems for hot water preparation in five representative climate zones. Based on experimental aging data in hot air and heat carrier fluid at elevated temperatures (95 °C, 115 °C and 135 °C) and climatic input data, as well as deduced loading conditions and absorber temperature distributions, the lifetime was calculated using a theoretical and an empirical extrapolation approach and assuming cumulating damages in service relevant temperature intervals. Depending on the PP grade, the extrapolation method and the location, endurance limits ranging from 8 to 50 years were obtained. The PP grade with ß-spherulithic structures and less carbon black exhibited a superior performance (factor 2) compared to a well-established grade which is currently widely used for swimming pool absorbers.
Task 54: Price Reduction of Solar Thermal Systems
November 2015 - PDF 0.11MB - Posted: 2015-11-17
By: Michael Köhl, ISE Fraunhofer
Publisher: IEA SHC
Driving down the costs of solar thermal systems is not just about cheaper collector production. In fact, post-production processes, such as sales, installation and maintenance account for up to 50% of the price that end consumers pay. This new IEA SHC Task, Price Reduction of Solar Thermal Systems, will investigate these other factors and find ways to reduce systems costs. The Task’s kick-off meeting was hosted by Fraunhofer ISE in Freiburg, Germany the end of October. Researchers and industry representatives from all over the world participated.
Simulation of a solar collector array consisting of two types of solar collectors, with and without convection barrier
2014 - PDF 0.54MB - Posted: 2017-02-15
By: Federico Bava*, Simon Furbo, Bengt Perers
Publisher: Energy Procedia, Elsevier
The installed area of solar collectors in solar heating fields is rapidly increasing in Denmark. In this scenario even relatively small performance improvements may lead to a large increase in the overall energy production. Both collectors with and without polymer foil, functioning as convection barrier, can be found on the Danish market. Depending on the temperature level at which the two types of collectors operate, one can perform better than the other. This project aimed to study the behavior of a 14 solar collector row made of these two different kinds of collectors, in order to optimize the composition of the row. Actual solar collectors available on the Danish market (models HT-SA and HT-A 35-10 manufactured by ARCON Solar A/S) were used for this analysis. To perform the study, a simulation model in TRNSYS was developed based on the Danish solar collector field in Braedstrup. A parametric analysis was carried out by modifying the composition of the row, in order to find both the energy and economy optimum.
© 2015 The Authors. Published by Elsevier Ltd.
Peer-review by the scientific conference committee of SHC 2014 under responsibility of PSE AG.

Highlights

Task 54 Highlights 2016
April 2017 - PDF 0.73MB - Posted: 2017-04-17
By: Task 54
SHC Task 54 aims to reduce the purchase price for end-users of installed solar thermal systems by evaluating and developing sustainable means to reduce the production and/or installation costs of materials, sub-components and system components. Special emphasis is being placed on the identification and reduction of post-production cost drivers (e.g., channels of distribution). An extensive market research, the definition of reference systems, cost analyses and the study of socio-political boundary conditions for solar thermal prices in selected regions will provide the basis for the evaluation of cost structures and cost reduction potential. Additionally, ways to make solar thermal more attractive by improving marketing and consumer-oriented designs are being explored.
Task 54 Highlights 2015
April 2016 - PDF 0.72MB - Posted: 2016-04-08
One of the greatest challenges of the 21st century is to secure a sustainable energy supply and to considerably reduce CO2 emissions and the potential serious consequences of climate change. The challenging goals with regard to the contributions of renewable energy cannot be obtained without considerable growth of the solar thermal markets worldwide. Therefore, cost-competitive, efficient and reliable solar thermal systems are required. The first of these attributes is particularly hard to achieve as the prices for the production of solar thermal systems are still far from being equalled by the prices end-users have to pay. A great number of complex, costly and oftentimes non-transparent work steps are needed in order to bring solar thermal from the factory to the actual users. Task 54 is looking for ways to optimize each of these steps and is also looking into the social political contexts in which solar thermal installations are embedded. The ultimate goal is to strengthen the solar thermal industry by finding solutions for the cost-efficient production and installation of solar thermal systems and their marketing at a competitive price.