Adrian Badea

A transient thermal analysis by thermal networks of the Passive House ‘POLITEHNICA’ from Bucharest

This study aims to obtain the information about the thermal characteristics of the Passive House of University POLITEHNICA from Bucharest, Romania. Modelling a house by using the method of thermal networks is a way to find out the specific thermal reaction to the variable outdoor conditions. Heating, ventilation and air conditioning (HVAC) systems including their control have to synchronise with the thermal characteristics of the house expressed by the thermal reaction and heat consumption. The results of this study give the information necessary to define, calibrate and optimise an adequate HVAC system with specific reaction to and good prediction of the changing outer conditions in order to maintain a proposed thermal comfort with minimum energy consumption. Detailed analysis includes two scenarios: Free Running Mode (FRM) and Constrained Running Mode (CRM). The main tool used for this analysis is the software package Matlab-Simulink.

Achieving energy savings and thermal comfort through intermittent heating in very low energy buildings

Energy efficiency and human comfort are key aspects for future owners. Climate conditions plays and important role on choosing the right policy for energy consumption in order to achieve desired interior comfort. Based on these assumptions, current paper is focused on use of various simulated scenarios and measured data in order to evaluate how intermittent heating can reduce energy consumption while mentioning user comfort at desired parameters. The passive house, which is the subject of current article, is a real house and is equipped with an in-house developed automated control solution and serves as a didactic and research platform.

Web service-based monitoring system for smart management of the buildings

Monitoring the energy use and other important parameters together with third party applications for data access can provide a strong tool for comparative analysis. Easy data interpretation and data maneuverability can bring sufficient information to improve the energy performance of the building. Web services for building monitoring can easily represent the underlying mechanism for decision-making entity in automated or intelligent buildings. The developed software solution is composed of three layers. The first layer processes the data retrieved from sensors through various web services which are lunched by a programmed scheduler. The second layer securely stores the collected data from sensors into database and logging files. The third layer is used by authenticated users to review and export the data in most known formats. The current paper presents how wired sensors network can easily be used either as a building monitoring solution or as a part of smart management system.

Experimental Research Regarding the Application of Electro-Flushing Method on Diesel Contaminated Soils

Abstract In 2011, as a result of the inventory conducted at the national level, The Ministry Of Environment concluded that the largest number of contaminated sites with hydrocarbons are due to the petroleum products distribution (nearly 400 sites), followed by the hydrocarbons extraction (about 310 sites). So, soil contamination with liquid petroleum products resulting from many industrial activities became an important issue of environment protection. Unfortunately not all local governments have provided a list of contaminated sites, which means that there is a possibility to have a bigger problem at the national level. All these surfaces are in a continuous growth due to industrial and social development and that is why it is necessary to study and improve decontamination methods of contaminated sites in order to regain one of our most important resources - the soil. In this paper, the main results obtained during a research that aimed to study two different treatment methods of contaminated soil in a combined solution, are presented. The newly developed method is called electro-flushing. Results proved that combining the two nominated methods could be a viable solution for treating diesel polluted soil with better performances comparing with using them separately. Concerning the electrochemical treatment of diesel contaminated soils an efficiency of 35-40 % could be obtained after 28 days; while using the flushing method up to 15-20% efficiency could be reached. On the other hand, if we combine these two methods, we can reach remediation efficiency up to 50%. So, the main interesting results of the present research is given by the fact that combining two known remediation methods, better performances could be achieved.

Decontamination of Petroleum-Contaminated Soils Using The Electrochemical Technique: Remediation Degree and Energy Consumption

Currently, there are different remediation technologies for contaminated soils, but the selection of the best technology must be not only the treatment efficiency but also the energy consumption (costs) during its application. This paper is focused on assessing energy consumption related to the electrochemical treatment of polluted soil with petroleum hydrocarbons. In the framework of a research project, two types of experiments were conducted using soil that was artificially contaminated with diesel fuel at the same level of contamination. The experimental conditions considered for each experiment were: different amounts of contaminated soils (6u2009kg and 18u2009kg, respectively), the same current intensity level (0.25A and 0.5A), three different contamination degrees (1%, 2.5% and 5%) and the same time for application of the electrochemical treatment. The remediation degree concerning the removal of petroleum hydrocarbons from soil increased over time by approximately 20% over 7 days. With regard to energy consumption, the results revealed that with an increase in the quantity of treated soil of approximately three times, the specific energy consumption decreased from 2.94 kWh/kg treated soil to 1.64 kWh/kg treated soil.

The influence of shading in terms of the energy performance of photovoltaic panels in Romanian climate conditions

The performance of the photovoltaic panels (PV) is influenced by the share of the module surface exposed to sunlight. The necessity of shading analysis when designing a photovoltaic system comes from the string construction of the most PV panels and from the number of bypass diode. The most obvious result of a shadow is a decrease in power output from the photovoltaic array. The amount of power loss is a function of the size and shape of the shadow, the geometrical and electrical layout of the cells in the array.

Effect of Nanoparticles Shape on the Efficiency of Hybrid Solar Cells

In recent years, the solar cell research interest has been focused on hybrid solar cells that use the advantage of mixed active layer such as semiconductor nanoparticles and polymeric organic materials. The goal of the solar research groups is to increase the efficiency of solar cells, their lifetime and cost of fabrication. For example, the solar cells based on silicon has long lifetime, good efficiency, but high fabrication costs. Solar market shows a great interest in hybrid solar cells due to their increased yield, extended lifetime compared to organic cells, and ease in fabrication with great potential in reducing the manufacturing costs. In this paper, the effect of various nanostructures on the performance of hybrid solar cells was studied. A relationship between the nanoparticle shapes and solar cell efficiency was developed, which showed that the aspect ratio of nanoparticles was an important factor in designing solar cells with improved efficiency.