PVT (Combined photovoltaic - solar thermal - modules)


"Photovoltaic systems are still operated mainly for very limited purposes. Regardless of whether a standalone system or a grid connected system is realized, there are neither interconnections with other systems in the building and the building and room automation. The important synergy effects remain unused. "(Prof. Fraaß)

The field of research "synergies of photovoltaic" which was initiated by Prof. Fraaß, followed the aim of an integral and coupled optimization of existing concepts and technologies. The interaction between photovoltaic, solar thermal energy, building automation and weather forecast is of great importance. In this part of the project the focus lies on the investigation and optimization of hybrid modules (PVT).



Synergistic effect of photovoltaics: the way in energy efficiency

Currently, the laboratory EMR (electrical, measurement and control engineering) of the Department IV builts a PVT system for testing. Besides the structure of the modules and the control of the system, the distribution of heat in the building plays a crucial role. To illustrate the efficient use of solar energy, a room model is developed.
In addition to the laboratory-built PVT system, data is extracted and evaluated from the system, the weather station as well as the German Weather service by an optimized BMS-concept. With the IP-based WAGO 750-830 BACnet controller, the data can be evaluated location-independent.

PVT systems in connection with thermally activated components

As the temperature increases, the efficiency of the module decreases. This behavior is different depending on the production technique. Therefore, different types of PV-modules are used for the project.
To increase the efficiency, the PVT modules are cooled with BEKA capillary tube. Simultaneously, the heat absorbed by the mat is to be routed to and stored in the house.

State of the art

The PVT technology makes it possible to use electrical and thermal solar energy at once. The integration of capillary tubes on the back of the water cooled PVT modules, which are currently developed by the laboratory EMR of the Beuth University of Applied Sciences Berlin, improves the efficiency in the use of solar energy.
Hybrid modules are implemented in various ways. A variant is to laminate fine oval capillary tubes in the form of mats on the back of the panel. In another variant, a trough-shaped sheet metal profile is attached to the laminate, which formes a space for water circulation. The structure is sealed using a special machine that seals everything but the glass front with a two-component plastic.
In recent years, several module manufacturers have addressed the problem of the cooling module. However, there is no clear implementable and robust concept that is reproducible and has been tested. This also explains why there are still no commercially available models. Also the lack of DIN standard is a barrier for the connection between the developed concept and the industry respectively the consumers. The Beuth University of Applied Sciences Berlin is among the pioneers in the field of research and development of PVT modules.