Carlo Maria Bartolini

Assessment of the impact of local energy policies in reducing greenhouse gas emissions.

The present work investigates the potential energy savings coming from a careful and detailed local energy policy. The paper analyzes and assesses from technical, economic and environmental viewpoints different initiatives in the energy sector aimed at increasing energy efficiency in end-uses and reducing overall carbon emissions. The results are based on energy planning for five Italian urban areas sized at about fifty thousand inhabitants. The analysis has been developed with the aim of reaching generally applicable criteria suitable for evaluating the local energy policy contribution to the greenhouse gas (GHG) emissions reduction. Several initiatives for the private and public sectors have been considered, such as: (i) the introduction of combined heat and power generation based on useful thermal demand, suitable for the industry and service sectors (swimming pools, large distribution organizations); (ii) generation of electricity from renewables (solar energy, biomass); (iii) thermal insulation of private and public buildings, such as schools; (iv) introduction of micro-combined heat and power generation in the residential sector. For each solution the primary energy reduction and the consequent reduction in GHG emissions have been evaluated and a feasibility analysis has been developed in order to assess the profitability of the investment. Great attention has been paid to the public sector, which has an important role in providing leadership and driving changes in other sectors; furthermore, a rational use of energy combined with the exploitation of country-based incentives is able to reduce the public administrative expenditure. The results show that local energy policy can give an important contribution to gas emission reduction targets, and underline the fundamental role of public sector initiatives.

Experimental Results From a Two-Stroke Gasoline Direct-Injected Engine Prototype

Recently, research on internal combustion spark-ignited engines has focused increasingly on charge control by means of direct injection. The concepts proposed in this field involve in most cases high-cost systems which do not seem to be widely applicable, especially to small, low-cost engines. In this respect, the challenge is to avoid complicating the existing power systems that make of simplicity and low cost their better qualities. The paper reports on the design and realization of a two-stroke gasoline direct-injection engine prototype which employs a Water-Hammer effect injection system. The experimental data obtained with the prototype are presented showing how the system significantly reduces hydrocarbon emissions and specific fuel consumption.Copyright

Biogas purification and liquefaction by means of a cryogenic upgrading process

Transport sector represents one of the main responsible for greenhouse gas (GHG) emissions and natural gas (NG) could efficiently reduce them, especially in its liquid form (LNG) suitable for heavy-duty vehicles. Nevertheless, in certain regions, LNG is difficult to supply and biogas is actually used as feedstock gas. However, due to its high CO2 content, biogas needs to be purified. At present, several upgrading technologies are existing but since the final scope is the LNG production, cryogenic upgrading technology looks very promising. However, this technology is still in a developing phase. This study proposes a cryogenic upgrading process in which CO2 is removed and biomethane is liquefied (LBG) at the same time. Moreover, specific energy consumption is optimized by means of HYSYS simulation and a rough economical analysis is also performed to evaluate its attractiveness. As a result, cryogenic upgrading technology represents an interesting option for LBG production.

Analysis of Cavitating and Non-Cavitating Transient Flow in Pipelines Connected by Junctions

The paper deals with the development of experimental benches designed with the aim of producing test cases of transients flow through different types of junctions both in non-cavitating and cavitating conditions. The non-cavitating test cases consist in a rapid depressurization of a reservoir to which a pipe network containing the junction is connected while in the cavitating test cases the same pipe network is discharged towards an open-air reservoir by means of an ad hoc very rapid opening valve apparatus. First of all the experimental data allowed for a deeper insight on the subject from a phenomenological point of view. Then the recorded pressure time histories have been used to validate the numerical results of a code which solves the flow by means of a 1D model suitable to describe unsteady friction and cavitating phenomena. In the code the discrete gas-cavity model (DGCM) introduced by Provoost and Wylie is integrated in the method of characteristics and the junctions are modeled using a standard constant pressure approach improved with the gas cavity model.Copyright

A numerical method to evaluate heat exchangers performance of external combustion engine

The results of a computer simulation of the three-dimensional steady-state operation of heat exchangers suitable for the Stirling engine are presented. The temperature, pressure and velocity distribution in the heater have been examined and compared with the experimental data collected by a prototype electrical heater. The results are in good agreement with predicted values. The satisfactory results reached by the simulation code allow its application to other components of Stirling engines and makes it possible to improve the lambda-method simulation model.<<ETX>>