A building integrated solar air heating thermal collector prototype: modelling, validation and case study

In this paper, the thermal performance analysis of a prototype Flat-Plate Solar Thermal Collector (FPC), using air as working medium, is presented. The collector is designed to be integrated in the building envelope (Building Integrated Solar Thermal System - BISTS), Figure 1. With respect to existing commercial collectors, such prototype is characterized by low cost materials and fabrication. In order to predict the thermal performance of the investigated system, a numerical simulation model is developed. The model, written in MatLab environment, is implemented in a suitable computer code for dynamically assessing the system energy, economic and environmental performances. Specifically, the model is capable to predict the collector active effects (e.g. air heating for ventilation purpose, etc.) and the passive ones due to the building integration on the heating and cooling loads. The prototype simulation model was validated by means of experimental data collected in Limassol (Cyprus) during experimental testing. In order to assess the system performances and to show the features of the developed simulation model, several comprehensive case studies are developed. The operation and performances of both the stand-alone and the building integrated collectors are analysed. In particular, the FPC prototype is integrated in the south facing façade of a high-rise building, characterized by diverse uses (dwelling and office buildings), located in different weather conditions (cold and warm climate zones). In addition, for comparison purposes, a building reference system layout is taken into account. With the aim at optimizing some collector design and operating parameters, a suitable parametric analysis is also carried out for the stand-alone collector layout. Simulation results show that interesting energy performances can be achieved, especially for climates with a long heating season.