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  Numarul 2/2022

Volumul 13 (2022), Nr. 2

Modelarea sistemelor de drenaj urban durabil
Modelling Sustainable Urban Drainage Systems
Alexandra Georgiana Ioan, Iulian Iancu, Anton Anton

In the recent years natural phenomena such as flood have cost billions of euros and numerous losses of human life. In this context, accurate modelling of storm runoff from urban catchments is very important, but it is difficult to achieve because of the complexity of modelling green areas. Depending on the local practice, the available software, the data availability, the possibility of data processing, computation time, and even the experience of the modeller, storm runoff from urban catchments can be analysed using different modelling approaches. Choosing the modelling approach, the rainfall loads to the model and the model parameters are very important steps that must be made with caution, and there is thus a need to establish more precise guidelines to help modellers in choosing the most suitable modelling approach. The overall objective of the research project is to investigate the possibilities of managing the storm water to cope with climate change in a sustainable way. The storm water can be used as a resource, as an element in urban recreational activities. This initiative is supported by the key principles of sustainability: water recycling, minimizing pollutants in storm water and urban environmental protection against flood events

Keywords: 1D modelling, Climate Change, Sustainability, SUDS

Conditii specifice pentru o functionare optima a pompelor de caldura aer-apa
Specific conditions for an optimal operation of air-water heat pumps
George Dragomir, Ioan Boian

The paper presents conditions required for an optimal operation of air-water heat pumps used for space heating and cooling. Designing such an installation able to reduce the greenhouse gas, GHG emission involve a prerequisite envelope improvement: its thermal performance is in a correlation with the seasonal performance factor, SPF resulting from the climatic conditions and from the heat pump setting having the primary energy factor, PEF together with the specific emission index for electricity generation, Ie as influencing factors. At the same time, the type of the fuel, (gas, coal, etc.) i.e., its GHG emission intensity, If and the efficiency, ηc of the original boiler that is to be replaced with the heat pump are important when analyzing the performance that can be achieved after this replacing. For air-water heat pumps an operation under the air temperature of +7 oC seems to be not advisable from the efficiency and from the power consumption point of view.

Keywords: air-water heat pumps

Material usor pe baza de gips fabricat printr-un proces de expandare cu pulbere de aluminiu
Light weight gypsum-based material manufactured by expanding process with aluminum powder
Lucian Paunescu, Sorin Mircea Axinte, Bogdan Valentin Paunescu

Lucrarea prezinta metoda de preparare a unui material usor pe baza de gips. Principiul spumarii materiei prime este aplicat la fabricarea betonului aerat autoclavizat prin eliberarea in masa materialului a hidrogenului prin reacția de coroziune a pulberii de aluminiu in soluție apoasa de Ca(OH)2. Originalitatea lucrării este metoda de generare a aluminiului pulbere prin topirea cu microunde a deseurilor metalice si atomizarea topiturii cu jeturi concentrate de azot. Produsul are densitatea intre 530-600 kg/m3 si rezistenta la compresiune intre 1,2-2,2 MPa, fiind similar cu betonul aerat autoclavizat, cu domenii de aplicare identice, insa costuri energetice reduse

Cuvinte cheie: material usor, gips, aluminiu, soluție apoasa, microunde, spumare

The paper presents the preparing method of a light weight gypsum-based material. The raw material foaming principle is applied to the manufacture of aerated autoclavized concrete by hydrogen release in the material mass by the corrosion reaction of aluminum powder in aqueous solution of Ca(OH)2. The work originality is the generation method of powder aluminum by microwave melting of metal waste and melt atomization by concentrated nitrogen jets. The product has density between 530-600 kg/m3 and compressive strength between 1.2-2.2 MPa, being similar to aerated autoclaved concrete, with identical application fields, but low energy costs.

Keywords: light weight material, gypsum, aluminum, aqueous solution, microwave, foaming.

Eficienta biofiltrelor in eliminarea amoniului din apa destinată consumului uman
Biofilters efficiency in removing ammonium from water intended for human consumption
G Radu, G Racoviteanu, E Vulpasu

Nitrogen is the most abundant element of Earth atmosphere and is a component part of all living organism, being found in DNA and RNA. In most ecosystems, ammonium is the main source of nitrogen for plants. In natural water sources, ammonium concentrations are usually low, but due to industrial, agricultural and other human activities, its concentration is quite high. In water supply systems it leads to degradation of water quality and to formation of other by-products with effects on human health. Existing technologies used to reduce the ammonium concentration in water are ion exchangers, biological filtration, air stripping, breakpoint chlorination and reverse osmosis. This article is based on experimental tests aimed to determine the efficiency of biofilters in reducing the ammonium concentrations in water, depending on the carrier/filtration media used in the biofilters, depending on the ammonium concentration in raw water and depending the contact time between water and the attached biomass, but also the impact of the sudden change of ammonium concentration in the raw water on the biofilters efficiency.

Keywords: nitrogen, biofilters

Evaluarea performantelor energetice a sistemului hibrid compus din pompa de caldura cu compresie de vapori utilizata in incalzirea cladirilor si apa zilnica
Hibrid system energetic performances evaluation composed by vapor compression heat pump used in building heating and dailly hot water
Florin Iordache, Mugurel Talpiga, Alexandru Draghici

This paper addresses the topic of wide interest, regarding the positive impact to environment by using renewable energy resources, in terms of building heatinf thermal agent and daily hot water preparation. Thus, a hydraulic scheme is proposed which consists of an air-water heat pump and a gas boiler that takes over the additional load in the conditions of external temperatures for which the heat pump cannot satisfy the entire needs of the consumer. In the first part of the analysis, the calculation procedure is structured with the necessary equations for the energy evaluations specific to each type of system, thus being possible to calculate the thermal input brought by each equipment. The method also summarizes the procedure for establishing Meteo data for the heating season, respectively for the entire year in terms of daily hot water consumption. The data thus structured are used to construct BINs that contain a number of hours characterized by an average temperature over the entire subinterval. After establishing the working procedure and the BIN database, in the last part of the material two examples were proposed, for both situations in which an air-to-water heat pump of known dimensions is evaluated for establishing the energy coverage of a known consumer. The two examples address both heating and hot water consumption.

Keywords: hibrid system, heat pump

Proiectarea unui sistem adaptiv de umbrire solară bazat pe cuboctaedru
Design of adaptive solar shading system based on the Cuboctahedron
Ana-Maria Graur

This paper will develop the design of an interactive, kinetic facade that has the ability to adapt to the intensity of natural light to filter hierarchically, in real time, and prevent visual and thermal discomfort generated by light inside spaces. The purpose of the study is to provide an overview of the main parameters that determine the geometry and design of the system, the kinematic character of the shading system, and also the impact that the kinetic shading system will have on the design of the building facade.

Keywords: shading envelope, adaptability, kinetic façades, cuboctahedron, hyperbolic paraboloid

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