Thermal and electrical characterization of thin film photovoltaic technologies for building integration

Supervised by:
  1. Antonio Urbina Yeregui Co-director
  2. José Antonio Abad López Co-director

Defence university: Universidad Politécnica de Cartagena

Fecha de defensa: 31 October 2019

  1. Ana Rosa Lagunas Alonso Chair
  2. José Antonio Villarejo Mañas Secretary
  3. Ana María Gracia Amillo Committee member
  1. Electrónica, Tecnología de Computadores y Proyectos

Type: Thesis


Resumen de la tesis This PhD thesis addresses a current and global problem such as mitigating Climate Change. Aware that the provision of energy services will continue to increase in future years, this work focuses on an attractive alternative to reduce greenhouse gas emissions within a sustainable development context in the industry and construction sector. A good penetration of renewable energies, photovoltaics (PV) in particular, involves strengthening their integration, solving the additional systemic costs and improving their functionality in different applications. In the construction sector, the integration of photovoltaic systems, better known as BIPV (Building Integrated Photovoltaics), has numerous advantages since, by generating electricity at the point of consumption, grid power peak demand can be reduced, as well as the losses in the distribution of energy and the infrastructure costs. In addition, the architectural and aesthetic design of the building is taken care of without depriving it of identity and respecting the urban landscape environment. However, there are barriers that do not allow to consolidate these systems, and therefore it is necessary to improve the standardization in the photovoltaic constructive elements such as sizes, shapes, thickness or colours; and at the same time, converting it into a competitive option in terms of economic cost, functionality and design compared to the materials conventionally used in the building sector. Currently, photovoltaic technology based on crystalline silicon still dominates the photovoltaic market. However, some finalist applications, such as building integration, present significant barriers to silicon. The characteristics of silicon PV, such as rigidity, high weight and standard rectangular measurements, cannot be modified on demand, making the architectural integration difficult. In the last decade, new technologies based on thin-film devices have been developed, some have already reached the market (with power conversion efficiencies on module level of ~12%, ~18% and ~19% for amorphous silicon, cadmium telluride and CIGS respectively), but others are still under investigation or demonstration projects (organic PV, hybrid, perovskites and so on). Third generation photovoltaics, such as organic photovoltaics (OPV), stand out by low-cost (fewer material in comparison to silicon PV) and low-weight (solar cell thicknesses up to 200 times lower than silicon PV) having less environmental impact in the manufacturing process (less temperatures in the production and absence of vacuum requirements). These facts make it much easier to integrate on roof or walls as building material. The main objective of the thesis is to assess the use of thin-film photovoltaic technologies in BIPV systems by characterizing its thermal and electrical parameters, which are needed to identify the technical potential of these technologies. For this purpose, an experimental system working in real outdoor conditions has been designed and built to study the thermal and photovoltaic response of four different technologies (crystalline silicon PV technology, two thin-film technologies already at market level: cadmium telluride and amorphous silicon; and a third emerging generation PV with great potential, such as organic PV). The system is a simple experimental model which reproduces real BIPV conditions. The monitoring and recording of electrical, thermal and environmental parameters of the experimental design after a long period of time allows us to have an in-depth knowledge to identify and determine the viability of a range of PV technologies for BIPV applications. This also requires the validation of models used to calculate in-plane irradiation since solar resource at different inclination and orientations (for instance vertical surface in façades) is rarely measured by local meteorological stations being of great utility both for the scientific community and for architects and engineers since, in a context of building integration, the orientation and inclination of the systems are determined by the shape of the building, without adopting the optimal angle as design criterion. This PhD thesis seeks to make an important contribution to the subject of BIPV creating a closer relationship between research and architecture. Each chapter discusses BIPV from different perspectives, together providing knowledge for the further spread of this promising application. The structure of the present dissertation is organised as follows: chapter one presents the energy panorama, the role of photovoltaic technologies in the transition towards low-carbon emission buildings and the key points established for the assessment of the issue, such as the need for reliable solar radiation models and for establishing a global vision of the problem that covers both architectural and construction needs, as well as the photovoltaic response of the system. Chapter two presents the main objective of the thesis and the partial objectives. The methodology and description of the experimental system together with the databases used to examine models are described in chapter three. Solar radiation models to obtain the in-plane irradiance based on horizontal measurements are studied in chapter four. Chapters five and six focus on the thermal and electrical characterization of each PV technology under consideration respectively. Building simulations with PV modules integrated in two different building types are presented and discussed in chapter seven. And finally, conclusions and future work are presented in chapter eight.