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An innovative very low-cost thermo-electric technology for large-scale renewable solar energy applications

Final Report Summary - INNOVTEG (An innovative very low-cost thermo-electric technology for large-scale renewable solar energy applications.)

Executive Summary:
The aim of the INNOVTEG project was to create nano-structured thermo-electric materials based on (low cost and abundant) sulphur with carefully controlled structure and properties. Further by doing this create a step-change in the application of thermo-electric technologies for large-scale solar renewable applications in the EU by developing thermo-electric materials at massively reduced cost (€5.20/kg). The technologies developed would be particularly suited to building integrated renewable systems. This would enable the creation of a very low-cost thermo-electric system suitable for building integration that can achieve an output of ~30Wp/sq.m and a power generation cost of €533/kWp (significantly less than the corresponding cost of ~€3,000/kWp for PV systems) across a range of European climatic conditions. In so doing offer greatly improved environmental performance due to improved reduced dependence on fossil fuels, reduced emissions (CO2, nitrogen oxides, hydrocarbons, carbon monoxide and particulates) at a cost that is affordable to the end-user.
The work on the thermoelectric materials centred on obtaining an improvement in the Figure of Merit (ZT) performance beyond that achieved in the literature and aiming at the target value of 0.6. Optimisation of the thermoelectric properties of the preferred n- and p-type families of materials was carried out. Within the target temperature range of ≤ 100 °C the best performing materials delivered were: n-type - a nanocomposite of TiS2 with 0.5 vol% nanoparticulate TiO2 (ZT = 0.38 at 100 °C) and p-type - a nickel substituted tetrahedrite, Cu10.4Ni1.6Sb4S13 (ZT = 0.30 at 100 °C). These materials currently represent the best performing sulphur based thermo-electric materials at the temperatures of interest. Although this performance is below the target of ZT=0.6 the materials development work provides a very strong basis for further development activities.

Development work on the scale-up of the thermo-electric material powders has shown that direct reaction of the elements in high boiling point solvents provides a scalable route to n-type materials. While for p-type material a mechanical alloying route and scalable liquid phase route under solvothermal conditions were developed.

The design of a thermo-electric system suitable for building integration was generated and subjected to thermodynamic modelling. The solar panels for the prototype were designed taking into account the specific requirements for building applications and for the thermo-electric power generation system. Modelling and simulation software was used to optimize and validate the panel design. The prototype was tested and technological and economic validations carried out.

The ambitious project target was a very low cost thermo-electric system suitable for building integration that can achieve an output of ~30Wp/sq.m across a range of European climatic conditions. The figure achieved in the project was 10Wp/sq.m and although this remains short of commercial viability, the development work carried out provides a very strong basis for further development activities.


Project Context and Objectives:
The aim of the INNOVTEG project is to create nano-structured thermo-electric materials based on (low cost and abundant) sulphur with carefully controlled structure and properties. By doing this our consortium will create a step-change in the application of thermo-electric technologies for
large-scale solar renewable applications in the EU by developing thermo-electric at massively reduced cost (€5.20/kg). The technologies developed will be particularly suited to building integrated renewable systems. This will enable us to create a very low-cost thermo-electric system suitable for building integration that can achieve an output of ~30Wp/sq.m and a power generation cost of €533/kWp (significantly less than the corresponding cost of ~€3,000/kWp for PV systems) across a range of European climatic conditions. In so doing, the InnovTEG technology will offer greatly improved environmental performance due to improved reduced dependence on fossil fuels, reduced emissions (CO2, nitrogen oxides, hydrocarbons, carbon monoxide and particulates) at a cost that is affordable to the end-user. It is expected that the InnovTEG project will generate ~€200m million business growth for its SMEs within a 5 year period creating more than 171 jobs. The project results are expected to benefit other SMEs in the renewable energy, materials processing and electronics industry sectors. In addition, the technology has the capability to reduce CO2 emissions by 208,000 tonnes of CO2 per year 5-years post-project.



Project Results:
The work on the thermoelectric materials centred on obtaining an improvement in the Figure of Merit (ZT) performance beyond that achieved in the literature and aiming at the target value of 0.6. Optimisation of the thermoelectric properties of the preferred n- and p-type families of materials, MoxTi1-xS2 and Cu12-xNixSb4S13 respectively, was carried out with respect to composition and synthesis, processing and nanostructuring conditions.

Within the target temperature range of ≤ 100 °C the best performing materials delivered were: n-type - a nanocomposite of TiS2 with 0.5 vol% nanoparticulate TiO2 (ZT = 0.38 at 100 °C) and p-type - a nickel substituted tetrahedrite, Cu10.4Ni1.6Sb4S13 (ZT = 0.30 at 100 °C). These represent more than a factor of two improvement in performance of n-type and an order of magnitude improvement in p-type transition-metal sulphides at these temperatures. These materials currently represent the best performing sulphur based thermo-electric materials at the temperatures of interest.

Initial laboratory scale-up of the n-type material TiS2 was successfully completed, however, recognition of the limitations of this method in scaling up to industrial size quantities led to the investigation and creation of a range of alternative methods. Direct reaction of the elements in high boiling point solvents provides a scalable route to n-type materials.

Laboratory synthesis of p-type tetrahedrite was demonstrated. Subsequently a mechanical alloying (MA) route was developed. The thermo-electric performance of materials prepared by MA was shown to be comparable with the conventionally synthesised phase. These successful trials opened the way to a scalable preparation route which was subsequently used for the large-scale synthesis by the SME partner Euro Support. A scalable liquid phase route under solvothermal conditions was also created.

Although this performance is below the target of ZT=0.6 at this temperature, the materials development work provides a very strong basis for further development activities. In relation to improved thermo-electrical performance and scaled-up commercial production of the powders and their consolidation not only in respect of building applications but also in relation to other energy harvesting applications with higher working temperatures than targeted in this project e.g. automotive, marine and industrial which are applicable across Europe. In addition the technological benefits obtained by the SME partners can be further enhanced.

The design of a thermo-electric system suitable for building integration was generated and subjected to thermodynamic modelling. The solar panels for the prototype were designed taking into account the specific requirements for the use in building applications and for the thermo-electric power generation system. Modelling and simulation software was used to optimize and validate the panel design. The prototype was tested and technological and economic validations carried out.

The ambitious project target was a very low cost thermo-electric system suitable for building integration that can achieve an output of ~30Wp/sq.m across a range of European climatic conditions. The figure achieved in the project was 10Wp/sq.m and although this remains short of commercial viability, the development work carried out provides a very strong basis for further development activities.

No Intellectual Property Rights (IPR) in terms of patent applications have been identified, however, the know-how generated during the project will be invaluable for any follow up project.

Potential Impact:
The InnovTEG technology will need to be further developed to allow for future commercialisation. From an economic perspective implementation and commercialisation of this technology will help the SME participants to achieve sustainable and profitable business growth. This will be achieved from (1) their specific activities within the supply chain which will lead to increased sales and profits; (2) their IPR ownership which will enable each SME to expand its company product portfolio and/or license (or sub-contract) the technology including for other applications; (3) the specific knowledge acquired as a result of their participation in the project will allow them to gain deeper integration within the supply chain R&D activities. In addition the technology has potential for other energy recovery from waste heat applications. Potential end-user sectors could include: heavy duty vehicles, rail, marine and large scale solar heat plants.

In terms of the environment implementation and commercialisation of this technology in the identified end-users sectors will have a positive impact through reduced power consumption and thereby reduced CO2 emissions.
A dissemination plan was created and updated regularly with new opportunities identified by the partners. News of the project was promoted through the project website, which has enhanced search engine links optimisation of the site, and partner websites. Relevant trade magazines/websites have also been identified with the aim of obtaining editorial exposure for the project. Awareness raising with clients and customers has been undertaken by networking at events and through conversation with contacts. CNRS presented an award winning poster on 'Thermoelectric Properties and non-stoichiometry in TiS2 based compounds' together with a presentation entitled 'Structure and thermoelectric properties of Ag intercalated TiS2 compounds' at the ICT 2013 international conference held in Kobe, Japan. Also CNRS and The University of Reading co-wrote a paper called Ordered-Defect Sulphides as Thermoelectric Materials in the international Journal of Electronic Materials (JEM).

In total there have been 13 events attended with presentations given or posters presented, 5 peer-reviewed publications accepted into international journals and eighteen news articles published on websites. In addition a project video, including all partners, has been produced and uploaded to the Co-ordinator YouTube channel. It is also available for partners to upload to their own media channels.

No Intellectual Property Rights (IPR) in terms of patent applications have been identified, however, the know-how generated during the project will be invaluable for any follow up project. This project will generate IPR in its own right.


List of Websites:
www.innovteg.com

To contact the INNOVTEG Project Manager then please use the online form on the project website or directly using the numbers below:

Telephone: +44 (0)116 279 6899

Fax: +44 (0)116 279 3490