International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Application of different retrofitting technologies can play a significant role in reducing energy consumption of existing buildings. This research work analyses a building in Cork (Ireland) where underfloor heating system, and natural ventilation are used to maintain comfort conditions. Underfloor heating system is the main electricity consumer of this building. Different energy efficient technologies were implemented and analyzed in terms of reducing electricity consumption through an energy software. These technologies include replacing illumination with high efficiency light; replacement of electric motos with high efficiency; introducing underfloor heating time scheduling turning on and off based on predicted weather condition; installation of presence sensors to switch ON/OFF lighting. Finally, it was decided to implement underfloor heating time scheduling as energy efficient technology to be analyzed because of limited budget available and high return on investments provided by applying this method. Result analysis shows that electricity saving on bills was about 20% on monthly basis compared to previous consumption.

This research will analyse the utilization of photovoltaic plant in a fruit storage facility to produce electricity for running the refrigerators to keep cool the fruit preservation in the Storage Facility. The building has two sets of refrigerators with a power of 18.2 kW each. Firstly, the work analysis deals with the convenience of installing a Photovoltaic Plant to produce electricity for supplying the refrigerators. Secondly, implementing energy efficiency measures such as adding a new layer of insulation to the walls has been analysed. Result analysis shows that the return of investment by the installation of Photovoltaic plant is less convenient compared to that of a thermal insulation layer on the interior sites. In conclusion, it has been decided to implement only thermal insulation as energy efficiency measures to this facility where the saving is about 15% of electricity consumption per year. Given that the saving in one year is 3069kWh and the cost of electricity is 0.09 EUR/kWh, the savings in monetary value is 276 EUR /year.

New area industry of Albania, in recent years, factories with closed cycle of production and processing of aluminium alloys are being targeted. In Albania about 25,000 tons of aluminum alloys per year are produced and there is a tendency to increase this production. This reality has encouraged us to undertake a number of studies with the primary objective for optimizing the parameters of the basic process of this industry. In this article we focus on the process of artificially aging aluminum alloys. From early and newer studies [2], the importance and delicacy of temperature-time parameters in the evolution of microstructure and in the mechanical properties of the final product are recognized and underlined. We have impost an experimental planning based on the Response Surface Method by choosing Central Composite Design to optimize the temperature and time parameters for the artificial aging with the object ive of maximizing the process indicator – mechanical properties, hardness in our case. The plan includes 13 tests with 5 replicas in the center of the experiment, built with the help of Design-Expert DX7 and DX13 software. The focus of our attention was the assesment of the design, analysis of residuals and diagnostic diagrams and forms of presentation of results: mathematical model, 3D response surface, isocontours and effects of interaction between factors. In the future works we will present the experimental results of the optimization of the artificial aging process for different aluminium alloys produced in Albania.

Eutectic solder alloys are widely used in the microelectronics industry. The phenomenon of creep and its mechanisms are important aspects that influence the performance of solder alloys. During the last two decades, a Pb – solder alloys is fast becoming a reality in lead free electronic products due to harmful caused as toxic material to environment and health, international legislative pressure and marketing. The replacement of Sn – Pb alloys with Sn-Ag-Cu (SAC) alloys needs reliable results for assuring the usage of this solder joints material in electronic industry. In this paper has been studied the creep behaviour of a group of alloy in the system Sn-Ag-Cu (SAC) near the eutectic point. In this research work we have used three different alloy samples which are 95, 5Sn-3, 8Ag-0,7Cu, 96, 5Sn-3, 0Ag-0,5Cu and 95, 46Sn-3, 58Ag-0,96Cu. Indentation technique has been conducted to study the creep behaviour of these three SAC alloys by determining the creep parameters at different temperatures. The temperature used was at room temperature 30oC until 100oC and the stress used was 64MPa-178MPa for the indentation diameter 1 mm and 0.5 mm. The experimental method and results of the creep parameters like activation enthalpy Q, the stress exponent n of the power law model and the parameter of the material A were briefly described in this paper. From the creep curves, constructed for alloys and considered loads, the values of creep stress exponent n were determined for the stud ied alloys.