Paolo Principi

Five Years of Laboratory and In Situ Test Experiences to Verify Therms Comfort Conditions in an Innovative Hybrid Ventilated Building

Abstract Climatisation and natural ventilation concepts are today, in most countries, considered to be an essential aspect of the building project. In fact they are utilised to guarantee summer thermal comfort and indoor air quality control. Also there are many other advantages including low energy use, reduction of noise levels and easy plant maintenance. In recent years the use of hybrid ventilation systems in office buildings has been developed. The achievement of thermal comfort conditions in buildings is an important aim in order to satisfy occupants. To achieve a high level of life quality a study of climatic parameters of the ambient air is needed. International Standard ISO 7726 and ASHRAE Standard 55-81 define the values of parameters affecting thermal comfort in offices. The aim of the present work is to evaluate the fluid dynamic phenomena connected to the running of the air conditioning and natural ventilation systems in an innovative office building, constructed in central Italy, aimed at achieving energy optimisation with good thermal comfort. This building has been monitored and the main fluid dynamic data of the air have been recorded. In addition the recorded values have been related to external parameters including solar radiation, wind speed and wind direction, to verify the indoor conditions in relation to the energy use of the building and to outdoor conditions. This research has been accomplished using automated monitoring for indoor data acquisition, a microclimatic station and a meteorological station equipped with the probes needed to measure the external environmental parameters. The experimental data corresponding to a monitoring period are reported. Results verified the performance of the measuring system developed for this project. They also provided information about the ventilation behaviour and thermal comfort conditions in the building under various sets of climatic conditions.

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.

Results of an Experimental Investigate of Natural Ventilated Building

Climatization and natural ventilation concepts are today in most countries considered as an essential aspect of the building project. In fact they are utilised to guarantee the summer thermal comfort and the indoor air quality control. Besides there are many others vantages as the low use of the energy, the reduction of noise levels and an easy plant maintenance. In the last years the use of the hybrid ventilation systems in the office buildings has been developed. The aim of the present work is to value the fluidodynamic phenomena connected to the running of the air conditioning and natural ventilation system in a innovative building, constructed in central Italy, to realise the energetic optimisation and to reach the thermal comfort conditions.

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.