Roberto Fioretti

Numerical study on the thermal performance of a refrigerated container envelope provided by phase change materials (PCMs)

Integration of Phase Change Materials (PCMs) into refrigerated containers envelope is considered a potential way to minimize energy consumption and joined green house gasses emissions (CO2) into the atmosphere. In order to evaluate the thermal effectiveness of this technology and for a broader assessment, the energy behavior of a traditional refrigerated container envelope provided in turn by nine different phase change materials has been numerically analyzed. Furthermore the results have been employed to select the most suitable phase change material on a representative case of study. The numerical results were then compared with the experimental values for validation of the numerical Finite Elements Method (FEM). The results showed that a phase change materials added layer reduces and delays the daily thermal load respect the traditional panel provided by only insulating materials.

Energy saving opportunities in the refrigerated transport sector through Phase Change Materials (PCMs) application

Transportation of food products at controlled temperature is a critical task in the transport sector. In fact, whilst there is a need of ensuring both food quality and safety to the global population, its impact in terms of energy consumption and related CO2 emissions into the atmosphere is becoming increasingly evident. In this regard, Thermal Energy Storage (TES) using Phase Change Materials (PCMs) can be considered as a potential way of reducing the cooling load, energy consumption and related greenhouse gas emissions in refrigerated transport sector. In this paper two different PCM applications are investigated. Specifically, in the first study a PCM (35 °C melting temperature) layer was added to the external side of a refrigerated enclosure wall with the aim of managing the cooling peak (shifting and reducing) and reducing the daily energy rate. Outdoor experimental results showed that the added PCM layer helps to reduce (between 5.55% and 8.57%) and delay (between 4.30 h and 3.30 h) the peak load of incoming heat compared to the reference one. In the second study, the energy performance of a refrigerated chamber with an air heat exchanger containing PCM (5°C melting temperature) was investigated. The study purpose was to reduce the cooling energy consumption during steady state operating conditions and the rate of temperature increase throughout the course of a power failure event. Test results showed that using a PCM air heat exchanger addition, up to 16% of energy can be saved.

Thermal analysis on a phase change material latent heat storage in a cold room in case of power outage

An investigation into the effectiveness of Phase Change Material (PCM) placed near the evaporator of a cold room to maintain stable temperature in case of loss of electrical power was carried out. Specifically, an air heat exchanger consisting of aluminium containers with finned surface was filled with a PCM characterized by 5 °C melting temperature. The aim is to decrease the rate of temperature increase favouring therefore the maintenance of thermal conditions of stored products during power loss. For this purpose, an experimental campaign was carried out and a monitoring system was developed. The experimental results showed that when there is no refrigeration system, both the compartment and refrigerated product temperatures remain at lower values for much longer time when PCM is applied.