This thesis addresses a critical challenge in the field of renewable energy, focusing on the efficient utilization of Photovoltaic-thermal (PVT) systems. Despite their promising role in sustainable energy production, PVT systems often grapple with excess heat generation, impacting their efficiency and longevity. The primary objective of this research is to explore the synergy between PVT modules and heat storage systems. It aims to develop and implement solutions for effectively storing this surplus heat. This work involves the formulation of new models for heat storage solutions and their assimilation into the PVMD Toolbox, housed within the Photovoltaic Materials and Devices research group at TU Delft. By enhancing the capability of PVT systems to manage excess heat, this thesis contributes to optimizing these systems for broader applications in sustainable energy generation.

This thesis addresses a critical challenge in the field of renewable energy, focusing on the efficient utilization of Photovoltaic-thermal (PVT) systems. Much research has already been done on PVT and there exist many thermal simulation models. However, many of the researches done and existing thermal models are restricted to a specific collector archetype which gives less flexibility in experimentation between multiple archetypes. In addition, many experimental researches require a physical setup for measurements and thermal simulation models would need to be altered for different research approaches and collector archetypes. The primary objective of this thesis project is therefore to create a performance simulation framework model that is suitable for the calculation of the thermal and electrical performance for any PVT archetype. It aims to develop and implement a toolbox application encompassing heat transfer models that can establish a foundation for future research on PVT collector optimization, PVT system integration and PVT performance analysis. This toolbox application will be implemented into the PVMD Toolbox Vogt et al. (2022), housed within the Photovoltaic Materials and Devices research group at TU Delft.

Selected PVT collector: This research has visualized that there is a wide variety of PVT archetypes that can be used for current and future generations of PVT collectors. PVT collectors can be combined with heat pumps, refrigeration pumps, phase change materials and multiple forms of heat collection via fluids or air. These combinations can all contribute to high electrical and thermal efficiencies

Numerical heat transfer model and assumptions: It is possible to calculate heat transfer rates of complex designs when using a Finite Element Method (FEM) approach to calculate the heat transfer within the collector. With the proper convective and radiative equations to the environment, the heat transfer inside the collector and to the environment could be calculated without needing an experimental setup.

Performance calculations: The performance calculations gave insight into the simulated behavior of the PVT collector when operating in real-world conditions. Ranging the inclination angle from 0 to 60 degrees showed that the thermal efficiency became around 55% at an irradiance of 800 W/m2 at 45 degrees. It also showed that differences in dimensions like pipe thicknesses and number of pipes did not affect the thermal performance that much. The daily performance calculations illustrated that the thermal energy lost to the environment can be three times as high as the incoming solar energy due to the low ambient temperatures compared to the inflow temperature. In the summer, PVT can achieve high total efficiencies of around 75% making PVT suitable during those times. The economic analysis showed that a PVT collector can have an LCOE of $0.08/kWh which is lower than the $0.13/kWh of conventional PV.

Photovoltaic-Thermal (PVT) modules, alongside Solar Thermal (ST) and Photovoltaic (PV) technologies, offer solutions to energy demands such as electrical consumption, space heating, and domestic hot water of residential buildings. This research employs a model-based approach to analyze how building insulation, solar collector configurations, and seasonal heating modes impact system design. Enhanced insulation scenarios demonstrate potential space heating demand reductions up to 70\%, highlighting the relevance of proper insulation selection.
The findings identify that using a PVT/PV configuration with one module per string is optimal, reducing roof area usage while achieving balanced thermal and electrical energy exchange. The analysis further reveals that higher indoor temperature settings substantially increase heating demands, suggesting significant energy savings potential through temperature set point adjustments. Operational heat supply strategies are adapted to seasonal variations, optimizing the use of solar energy and effectively incorporating aquifer thermal energy storage (ATES) systems as seasonal storage for winter months. But notably, the integration of PVT modules with heat pumps emerged as the primary driver of heat supply, contributing approximately 67\% of the total heat demand.

Interest in incorporating renewable energy systems into current infrastructure has surged as a result of the growing need for sustainable energy solutions in urban settings. This thesis investigates the optimization of a heating and cooling system designed for residential and commercial buildings, with a focus on Dutch climate conditions. The system consists of photovoltaic thermal (PVT) collectors, aquifer thermal energy storage (ATES), heat exchanger and heat pumps. By using these technologies, buildings will be able to satisfy energy demand sustainably without the need for fossil fuels.

Through dynamic simulations, the research aims to optimize the energy system's performance while taking into account a range of operational scenarios and parameter values. Critical components, including the ATES and PVT collectors, are modeled to evaluate their working and performance with heat pumps to provide heating and with heat exchanger for cooling.

The Photovoltaic Materials and Devices research group at TU Delft uses the PVMD Toolbox, a sophisticated modeling tool. Few models from the toolbox are utilised in developing an integrated model, which is later implemented in the toolbox. Later on, it is optimized to improve its effectiveness through dynamic sizing of collectors and aquifers, and implementation of operational modes, making overall the integrated system more robust and redundant. The performance of the integrated system is then studied for a base scenario with 10 PVT collectors and 27,000 m^3 aquifer volume for the current scenario. It showcases promising results. To assess its applicability, the system is analysed under various scenarios. The first scenario is a season-wise performance assessment, where it is showcased that PVT produce energy during summer months and the rest of the year there is a consistent performance by ATES. On comparing the performance of different insulation levels of the buildings, it is found that the future scenarios require half or one-fourth of the energy as compared to the current scenario and the system performs better for them in terms of power consumption by heat pumps. The system's performance under different flow rates of water from PVT and ST is assessed. It is found that at a higher flow rate, a higher amount of energy is generated by both of the collectors, while ST shows better performance than PVT.

For the case when the system provides underfloor heating, it shows that the heat pumps require almost 25% of the energy required for radiator heating. The integrated system is then compared to that of conventional energy systems, demonstrating similar costs but almost no environmental impact and better energy efficiency.

The research findings present a compelling argument for the implementation of such energy systems in urban environments, as they indicate the possibility of substantial energy savings and a decrease in carbon emissions. The report also offers suggestions for future work, such as the application of advanced software, location feasibility studies, and various ATES to precisely model and scale such systems in various real-world circumstances.

This thesis contributes significant insights into the subject of renewable energy systems and lays the groundwork for further study and development of sustainable heat networks by offering a thorough analysis of an innovative method of sustainable energy management.