Scientific Journal of Riga Technical University Environmental and Climate Technologies
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Published By De Gruyter Open Sp. Z O.O.

2255-8845, 1691-5208

Author(s):  
Mohammad Baharvand ◽  
Mohd Hamdan Bin Ahmad ◽  
Tabassom Safikhan ◽  
Sayyed Mohammad Mahdi Mirmomtaz

Abstract Atrium is a popular architectural feature utilized widely by building designers and owners to bring various benefits such as adequate daylight, circulation spaces and surfaces for landscape applications. But atrium problems in tropical climates such as excessive daylight, glare and high temperature, which lead to increase building energy demand, have been reported. To avoid and reduce these unpleasant features, a side-lit atrium has been suggested. Although researchers proposed side-lit atrium to prevent common problems of atria, the lack of precedent research on this issue compels these authors to study atrium performance in hot and humid climate. So the research aims to examine two different atrium roof form types in terms of temperature and ventilation impacts in hot and humid climate of Malaysia using DesignBuilder as a simulation program. The results indicate lower temperature of side-lit model with better airflow pattern in comparison with top-lit model while the top-lit model provides higher air velocity at the air inlet and outlet.


Author(s):  
Christina E. Mediastika ◽  
Floriberta Binarti

Abstract Employees working in cubicles of open-plan offices in Indonesia were studied in regard to their perception on the ability of indoor greenery to reduce noise levels. Sansevieria trifasciata and Scindapsus sp were used. Each was placed in the cubicle and noise levels were measured without plants, with Sansevieria, and with Scindapsus in place. The meters showed very insignificant difference. However, responses to surveys indicated a perception of lower noise in the presence of greenery. This seemed to be supported by prior knowledge and preconception and may be useful in creating a “quieter” indoor environment.


Author(s):  
Radhi Al-Rashidi ◽  
Munir Rusan ◽  
Karem Obaid

Abstract Long-term effects of surface application of secondary treated wastewater on plant nutrients dynamics, the cycling of C and N within the system through the determination of microbial biomass, and associated health hazards were studied in different soil locations. Sites that have been irrigated with wastewater for the last 1, 4, 10, and 17 years were identified and used as sampling locations for this study. Two other sites that have not been irrigated with wastewater were sampled as a control. Soil samples were taken from several sites within each location, and at the following depths: 0-20, 20-40, and 40-60 cm. Results obtained indicated that microbial biomass C and N were increased significantly with increasing application period of treated wastewater. Barley plant tissues analysis showed that plant nutrients content was significantly higher in sites which received wastewater for a long period than other sites. No significances in accumulation of lead (Pb) in barley plant tissues were observed with sites received wastewater for different periods. The bacteriological analysis showed that the total bacterial count of surface soil (0-20 cm) was higher in sites irrigated with wastewater for the last 10 and 17 years. The total coliforms ranged from 0.92x102 cfu/g soil to 3.3x102 cfu/g soil, while fecal coliform were less and detected only in top soils at sites irrigated with wastewater for the last 10 and 17 years.


Author(s):  
Janis Latvels ◽  
Raitis Grzibovskis ◽  
Aivars Vembris ◽  
Dagnija Blumberga

Abstract Organic photovoltaic (OPV) cells are considered as a viable alternative to those energy sources currently in use. In this work three derivatives of original N,N’- dimetilaminobenziliden-1,3-indandione (DMABI) material are presented as potential materials for OPV. The photoconductivity threshold energy was evaluated from the perspective of spectral dependence of photoconductivity quantum efficiency, and the optical energy gap was defined to determine the optical absorption spectra. The absorption spectra of derivatives are blue shifted compared to original DMABI. Use of these derivatives in multilayer solar cells with original DMABI makes it possible to broaden the spectral response range of OPV.


Author(s):  
Gökhan Coşar ◽  
Mirparham Pooyanfar ◽  
Ehsan Amirabedin ◽  
Hüseyin Topal

Abstract Recovering energy from municipal solid waste (MSW) is one of the most important issues of energy management in developed countries. This raises even more interest as world fossil fuel reserves diminish and fuel prices rise. Being one of main processes of waste disposal, anaerobic digestion can be used as a means to reduce fossil fuel and electricity consumption as well as reducing emissions. With growing demand for cooling in Turkey, especially during warm seasons and considering the energy costs, utilizing heat-driven absorption cooling systems coupled with an anaerobic digester for local cooling purposes is a potentially interesting alternative for electricity driven compression cooling. The aim of this article is to study the viability of utilizing biogas obtained from MSW anaerobic digestion as the main fuel for heating facilities of Gazi University, Turkey and also the energy source for an absorption cooling system designed for the central library of the aforementioned campus. The results prove that the suggested system is sustainably and financially appealing and has the potential to replace the conventional electricity driven cooling systems with a reasonable net present worth; moreover, it can notably reduce carbon dioxide emissions.


Author(s):  
Giedrė Lapinskienė ◽  
Manuela Tvaronavičienė ◽  
Pranas Vaitkus

Abstract The paper analyses a traditional Environmental Kuznets Curve (EKC) relationship between greenhouse gases (GHG) and gross domestic product (GDP), extending the research to include some additional factors, such as environmental tax, research and development expenditure, implicit tax rate on energy, primary production of coal and lignite, energy intensity of the economy taken from the Eurostat database. The EKC indicates that, at the early stages of economic growth, pollution increases with the growing use of resources, but when a certain level of income per capita is reached, the trend reverses so that, at a higher development stage, further economic growth leads to the improvement of the environment. In the first part of the research, the validity of the reduced EKC for the Baltic region for the period 1995-2008 is determined. In the second part, the impact of selected factors is statistically tested. In both cases, the standard cubic equation is used because it is believed that this model is the most accurate for the development stage of this region. The research results may be useful for climate change policy design.


Author(s):  
Jurgis Zagorskas ◽  
Gražvydas Mykolas Paliulis ◽  
Marija Burinskienė ◽  
Jūratė Venckauskaitė

Abstract Building standards for energy effectiveness are increasing constantly and the market follows these changes by constructing new buildings in accordance with standards and refurbishment of the existing housing stock. Comprehensive trends in European construction market show tremendous increase in building retrofit works. It can be predicted that after the end of this decade, more than half of the construction works in European cities will be taking place in existing buildings, pushing the construction of new buildings to a less important role. Such a growth in building refurbishment works is creating a demand for suitable materials, retrofitting techniques and research. The differences between refurbishment of new-build projects and historical or valuable buildings are insufficiently recognized - mostly the buildings without further cultural preservation requirements are studied. This article covers the theme of refurbishment measures in historical buildings - the specific measures like inside insulation which are allowed due to the valuable façade or other heritage preservation requirements. An overview of other innovative methods for energy saving in existing buildings and their potential is given.


Author(s):  
Ingo Valgma ◽  
Vivika Väizene ◽  
Margit Kolats ◽  
Martin Saarnak

Abstract In case of stratified deposits like oil shale deposit in Estonia, mining losses depend on mining technologies. Current research focuses on extraction and separation possibilities of mineral resources. Selective mining, selective crushing and separation tests have been performed, showing possibilities of decreasing mining losses. Rock crushing and screening process simulations were used for optimizing rock fractions. In addition mine backfilling, fine separation, and optimized drilling and blasting have been analyzed. All tested methods show potential and depend on mineral usage. Usage in addition depends on the utilization technology. The questions like stability of the material flow and influences of the quality fluctuations to the final yield are raised.


Author(s):  
Karolis Januševičius ◽  
Giedrė Streckienė

Abstract In near zero energy buildings (NZEB) built in Baltic countries, heat production systems meet the challenge of large share domestic hot water demand and high required heating capacity. Due to passive solar design, cooling demand in residential buildings also needs an assessment and solution. Heat pump systems are a widespread solution to reduce energy use. A combination of heat pump and solar thermal collectors helps to meet standard requirements and increases the share of renewable energy use in total energy balance of country. The presented paper describes a simulation study of solar assisted heat pump systems carried out in TRNSYS. The purpose of this simulation was to investigate how the performance of a solar assisted heat pump combination varies in near zero energy building. Results of three systems were compared to autonomous (independent) systems simulated performance. Different solar assisted heat pump design solutions with serial and parallel solar thermal collector connections to the heat pump loop were modelled and a passive cooling possibility was assessed. Simulations were performed for three Baltic countries: Lithuania, Latvia and Estonia.


Author(s):  
Dzintra Slisane ◽  
Dagnija Blumberga

Abstract The improvement of air quality is now an issue for all developed countries. In the European Union transportation is the main source of NOx pollution and the second most significant PM10 and PM2, 5 emission sources. The focus of the research is transportation PM10 emissions. The paper introduces a model of system dynamics for analysis of road transportation PM10 emissions. The developed model is then used to compare PM10 emissions in 4 cases, one of which is the baseline, while in the other 3 a variety of road transport emission reduction methods are implemented. The simulation results have shown that the highest daily PM10 emission reductions can be achieved by combining technological and administrative methods. Administrative methods (rush-hour driving tax and heavy vehicle traffic restrictions) turned out to be the most effective.


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