Francesco Goia

Numerical Model of a Slurry PCM-Based Solar Thermal Collector

Flat-plate solar thermal collector is the most common device to convert solar energy into heat. This technology, which mostly adopts water-based fluids, has been widely investigated and improved since it was introduced, yet the exploitation of solar energy is limited by innate technological constraints. An interesting approach to overcome the limitations of these systems is based on the exploitation of the latent heat of fusion/solidification of the fluid—e.g., using a microencapsulated PCM suspended in a water fluid phase, also called slurry PCM. In this chapter, the numerical model of a PCM-based flat-plate solar thermal collector is presented and discussed. Starting from the well-known Hottel–Whillier equation, the physical–mathematical model of a water-based flat-plate solar is suitably modified to incorporate the phase change equations and to account for the different thermophysical properties of a non-Newtonian fluid, such as the slurry PCM. Examples of applications are also given, developing the simulation of the solar collector for different boundary conditions and showing the improved performance of the PCM-based technology in comparison with a conventional solar thermal collector.

Energy Performance Assessment of Advanced Integrated Façades by Means of Synthetic Metrics

Facades play an important role in architecture, with deep implications in both the quality of the indoor environment and the appearance of the building. R&D in the field of energy conservation is moving toward advanced integrated facades (AIFs): these are innovative and dynamic facades deeply connected with the building equipment. Their dynamic features allow the energy performance of the facade to be optimized, adapting its behavior to different boundary conditions. The substantial lack of synthetic performance parameters to assess and to characterize the energy performance of AIFs is one of the main limitations to the widespread of these technologies. This inconvenience is due to the fact that conventional synthetic metrics (such as U-value and g-value) cannot be fully applied with these technologies. The research activity presented in the paper is an attempt to investigate new synthetic metrics able to characterize the thermal behavior of an AIF. A multiple linear regression (MLR) approach is adopted to identify synthetic parameters able to replicate the energy performance of the facade as a function of the main boundary conditions, e.g., solar irradiance and thermal gradients.

Laboratory Approaches to Studying Occupants

Laboratories offer the possibility to study occupant behavior in a very detailed manner. A wide range of indoor environmental scenarios can be simulated under precisely controlled conditions, and human subjects can be selected based on pre-defined criteria. The degree of control over experiments is high and a large number of physical, physiological, and psychological quantities can be monitored. This chapter gives an overview of various types of test facilities in the world and their main features in terms of experimental opportunities. It then presents typical technical equipment and sensor technologies used in laboratory environments. Finally, questions on appropriate laboratory design and experimental set-ups are discussed. One conclusion is that, in spite of many advantages, there are limits to investigating occupant behavior in a laboratory’s “artificial” environment, in part due to the fact that subjects always feel observed to some extent. However, valuable results can be achieved if the specific opportunities of laboratories are utilized both by appropriate design and precise experiments during operation.