Assessment of indoor environmental quality in existing multi-family buildings in North–East Europe

Sixteen existing multi-family buildings (94 apartments) in Finland and 20 (96 apartments) in Lithuania were investigated prior to their renovation in order to develop and test out a common protocol for the indoor environmental quality (IEQ) assessment, and to assess the potential for improving IEQ along with energy efficiency. Baseline data on buildings, as well as data on temperature (T), relative humidity (RH), carbon dioxide (CO₂), carbon monoxide (CO), particulate matter (PM), nitrogen dioxide (NO₂), formaldehyde, volatile organic compounds (VOCs), radon, and microbial content in settled dust were collected from each apartment. In addition, questionnaire data regarding housing quality and health were collected from the occupants. The results indicated that most measured IEQ parameters were within recommended limits. However, different baselines in each country were observed especially for parameters related to thermal conditions and ventilation. Different baselines were also observed for the respondents' satisfaction with their residence and indoor air quality, as well as their behavior related to indoor environment. In this paper, we present some evidence for the potential in improving IEQ along with energy efficiency in the current building stock, followed by discussion of possible IEQ indicators and development of the assessment protocol.     

Sustainable metal management exemplified by copper in the USA

A sustainable management of non-renewable metals calls for scientific-ecological understanding of the regional material household. The copper household in the USA between 1900 and 2100 was chosen to illustrate mathematical modelling of such systems. Relatively limited and inaccurate sets of data already allow a first approximation of the metal management system. The copper fluxes of the 20th century have contributed to the formation of two new ore deposits of the same order of magnitude as the currently still available reservoir (90 million tons), i.e. copper stock in consumption products (approx. 70 million tons) and in landfills (approx. 40 million tons). The “landfill”, therefore, contains copper whose potential use is lost due to dilution. The long-term copper consumption stock is greater than the short-term stock. Scenarios show that the current economically mineable Cu-stocks will be exhausted in 30 to 50 years if a change in the existing management system does not occur. In case of a reorientation, the use of copper as a “new resource” in the consumption stocks appears to be the most promising strategy. The future waste management processes will have to increase their copper recycling rates. Received: 24 February 1999 · Accepted: 8 June 1999     

Simulation and analysis of a combined cycle heat and power plant process

The regulations of process efficiency and stricter environmental policies require analysis of large-scale thermal energy systems to produce highly efficient, cost effective and low environmental impact energy. For analysis, it is beneficial to simulate an energy system. In this paper, simulation models are developed for the analysis of a combined cycle heat and power plant located in Göteborg, Sweden. With the help of simulation models, characteristics between district heating (DH) water temperature and key parameters such as overall district heat duty, electrical power and electrical efficiency has been developed. The characteristics are useful to estimate and maximize the key parameters during varying DH water temperature. According to a comparison between the full-load simulation models of 2006 and 2013 for the selected power plant, a loss of 2 MW is noticed for gas turbine and a loss of 2.18 MW of heat flow occurs for heat recovery steam generator in the year 2013. The feasibility analysis of modifying the connection between DH economizer and main DH line provides good performance indicators in a winter scenario. The conclusions in this paper are good references to plan and improve the performance of existing large-scale thermal power plants.     

Energy and temperature performance analysis of geothermal (ground source) heat pumps integrated with permeable pavement systems for urban run-off reuse

Geothermal (ground source) heat pumps (GHP) and permeable pavement systems (PPS) have demonstrated their effectiveness in both industry and academic research during recent decades. To meet the rising demand for sustainable, recyclable and energy efficient techniques, research has focused on the combination of techniques to enhance existing or develop new applications.

This paper reports on an experimental programme that combined GHP with PPS for nutrient removal and system energy balancing. Experimental data collected over a 3-year period have provided evidence of highly efficient removal rates of up to 99% for ammonia–nitrate and biochemical oxygen demand; and 96% removal rates were obtained for orthophosphate–phosphorus. This paper also contains energy efficiency ratio (EER) and coefficient of performance (COP) calculations. Cyclic heat removal and heat rejection allowed for stable temperature and pump COP and EER sustainability. The results prove that PPS systems are appropriate for GHP installation, delivering high and stable pollutant removal with EER efficiencies between 1.5 and 5.5.

The combination of GHP with PPS has the potential to provide a new sustainable and eco-friendly practice.     

Filtration efficiencies in electrostatically augmented granular beds

Fine particle filtration efficiencies of electrically enhanced granular beds are computed and compared with available experimental data. Collection efficiencies of a single bed sphere in a gaseous flow are first calculated by numerically solving the equations of particle motion. The collection mechanisms incorporated here are inertial impaction, interception, and charged fine particle-imposed electric field interaction. The approach is based upon a “unit cell” model which enables one to include the effects of surrounding bed particles on the collection process. Stokes' flow and potential flow are used to model the gas flow around the bed particle. Total efficiency is computed by integrating the single-sphere collection efficiency over the bed volume. These calculated total bed efficiencies compare satisfactorily with data obtained from an existing granular bed facility over a range of parameter values. Both theory and experimental data show that the electrical force significantly enhances particulate collection in granular beds.     

Solar-driven technology for freshwater production from atmospheric air by using the composite desiccant material “CaCl<Subscript>2</Subscript>/floral foam”

In this communication, experiments have been performed to check the capability of the newly formed composite desiccant material (CaCl₂/floral) for the extraction of freshwater from atmospheric air. Three numbers of solar glass desiccant box type system (SGDBS) with a captured area of 0.36 m² each, have been used. The design parameters for the water production are height of glass from desiccant bed at 0.22 m, inclination in angle as 30°, the effective thickness of glass as 3 mm and number of glazing as single. The maximum yield by the new composite desiccant material is 0.35 ml/cm³/day. The efficiency of the system SGDBS with 37 % concentration of CaCl₂ is 76.44 %.     

On-chip waste heat-driven absorption cooling system for sustainable data center environment: simulation

Development of waste heat-driven absorption-based cooling system is inspired for the need of removing high heat flux from the sustainable data centre environment. This paper presents a simulation study of single-stage Lithium Bromide–Water (LiBr–H₂O) vapour absorption heat pump for chip cooling. In the present work, a complete thermodynamic analysis of the single-stage LiBr–H₂O vapour absorption-based heat pump for chip cooling without a solution heat exchanger is performed and a user friendly graphical user interface (GUI) package including visual components is developed by using MATlab (2008b). The effect of chip heat flux on COP (Coefficient of Performance), flow rates and conductance is examined using the developed package. The model is verified using the data available in the literature which indicates that there is a greater reduction in the absorber load. The influence of chip heat flux on the performance and thermal loads of individual components are studied, and it is concluded that COP decreases from 0.7121 to 0.68924 with increase in chip heat flux.     

The role of interactions between individual animals in the response to heat stress in the freshwater crustacean <Emphasis Type="Italic">Daphnia magna</Emphasis>

The thermal resistance of Daphnia magna Straus is a trait depending on the interaction between individuals. The group effect is expressed in D. magna as both a decrease in thermal resistance and a marked individual differentiation with respect to thermal resistance. Two types of interactions between individual D. magna have been found: (1) the release of an unidentified factor decreasing thermal resistance (without noticeably changing the phenotypic variability of this trait) into the medium and (2) a decrease in the thermal resistance of individuals poorly adapted to heat stress, with the thermal resistance of well-adapted individuals (determined by the dependence of thermal resistance on interactions between individuals) remaining the same or even slightly increasing.Translated from Ekologiya, No. 2, 2005, pp. 126–131.Original Russian Text Copyright © 2005 by Kalinnikova, Krasnoperova, T. Gainutdinov, Sadykova, M. Gainutdinov.     

Effect of bioethanol and thermal barrier coating on the performance of dual fuel engine operating on Honge oil methyl ester (HOME) and producer gas induction

Alternative fuels have numerous advantages compared to fossil fuels as they are renewable, biodegradable; provide energy security and foreign exchange saving besides addressing environmental concerns and socio-economic issues as well. Renewable fuels can be used predominantly as fuel for both transportation and power generation applications. Improved engine performance with reduced engine exhaust emissions is a major research objective in engine development. Today, the use of biomass derived producer gas is more relevant for addressing rural power generation and is a promising technique for controlling both nitric oxide (NO_x) and soot emission levels. In view of this, exhaustive experiments on the use of Honge oil methyl ester (HOME)–Producer gas in a dual fuel engine have been carried out with an intension of improving its fuel efficiency. This paper mainly presents results on a single cylinder four stroke direct injection diesel engine operated in dual fuel mode using HOME–Producer gas combination with and without bio-ethanol addition and thermal barrier coating (TBC). Further, the results were compared with diesel–producer gas mode of operation. Experimental investigation on dual fuel operation using HOME+5% bioethanol (BE5)–Producer gas operation with TBC showed 12.35% increased brake thermal efficiency with decreased hydrocarbon and carbon monoxide emissions and increased NO_x emission levels compared to HOME–Producer gas mode of operation.     

A Framework for Assessing Carbon Flow in Indian Wood Products

This paper uses a lifecycle analysis to trace the fate of carbon bound in wood products until most of the carbon is released back into the atmosphere. A sensitivity analysis has been carried out to find the effect of change in terminal use (recycling, land filling and burning of discarded products), half-life of wood products and decay rate of carbon in landfills. Of the total carbon harvested from forests in India, about 90% is released into the atmosphere in the first year, due to burning of fuelwood; at the end of 100 years, about 0.8% still remains in the wood products. The sensitivity analysis shows that the length of the lifespan of wood products has only a marginal effect on the amount of carbon sequestered but has significant effect on the amount of carbon in products in use. Thus an important conclusion from this scenario is that by increasing the durability of the wood products, carbon can be locked over a period equal to the time needed to grow the timber for these products. Further, the carbon storage is affected more significantly by the decay rate of carbon in landfills than the proportion of products recycled. The study also shows that wood products can be important stores of carbon, but only if they can substitute for a unit of carbon emitted by burning fossil fuels. Such a lifecycle analysis has the potential to account completely for carbon stock changes in the wood products, where and when they are occurring, and explain how they are occurring.     

Fuel efficiency enhancement of modified diesel engine operated in dual fuel mode using renewable and sustainable fuels

ABSTRACT

Renewable and sustainable fuels for diesel engine applications provide energy protection, overseas exchange saving and address atmospheric and socio-economic concerns. This study presents the investigational work carried out on a single cylinder, four-stroke, direct injection diesel engine operated in dual fuel (DF) mode using renewable and sustainable fuels. In the first phase, a Y-shaped mixing chamber or venture was developed with varied angle facility for gas entry at 30°, 45° and 60°, respectively, to enable homogeneous air and gas mixing. Further effect of different gas and air mixture entry on the DF engine performance was studied. In the next phase of the work, hydrogen flow rate influence on the combustion and emission characteristics of a compression ignition (CI) engine operated in DF mode using diesel, neem oil methyl ester (NeOME) and producer gas has been investigated. During experimentation, hydrogen was mixed in different proportions varied from 3 to 12 l/min (lpm) in step of 3 lpm along with air-producer gas and the mixtures were directly inducted into engine cylinder during suction stroke. Experimental investigation showed that 45° Y-shaped mixing chamber resulted in improved performance with acceptable emission levels. Further, it is observed that investigation showed that at maximum operating conditions and hydrogen flow rate of 9 lpm, Diesel–producer gas and NeOME–producer gas combination showed increased thermal efficiency by 13.2% and 3.8%, respectively, compared to the DF operation without hydrogen addition. Further, it is noticed that hydrogen-enriched producer gas lowers the power derating by 5–10% and increases nitric oxide (NO_x) emissions. However, increased hydrogen addition beyond the 12 lpm leads to sever knocking.

Abbreviations: NeOME: Neem oil methyl ester; BTE: brake thermal efficiency; CI: compression ignition; ITE: indicated thermal efficiency; PG: producer gas; CA: crank angle; K: Kelvin; BP: brake power; IP: indicated power; H₂: hydrogen; HC: unburnt hydrocarbon; CO: carbon dioxide; CO₂: carbon dioxide; NO_x: nitric oxide; HRR: heat release rate; %: percentage; PPM: parts per million; CMFIS: conventional mechanical fuel injection system.     

Redox chemistry of sulphate and uranium in a phosphogypsum tailings dump

The present study aims to assess the effect of redox conditions existing within the tailings dump on the stability of phosphogypsum (e.g. sulphate reduction) and uranium(VI). Phosphogypsum sampling and in-situ measurements were carried out at a coastal tailings dump in Vasiliko Cyprus, pH, E_H and solubility experiments were performed in simulated laboratory systems and thermodynamic calculations using MINTEQA2. Generally, in the open tailings dump oxidizing conditions predominate stabilizing sulphur and uranium in their hexavalent oxidation states. On the other hand, after the application of a soil/vegetative cover and in the presence of natural organic matter, anoxic conditions prevail (E_H < −70 mV) resulting in S(VI) and U(VI) reduction to S(−II) and U(IV), respectively. Although, the sulphide anion can form very insoluble compounds with heavy metal ions (e.g. Cd(II), Pb(II) etc.) and U(IV) oxide has very low solubility, partial reduction of sulphate to sulphide within gypsum may affect the stability of phosphogypsum resulting in enhanced erosion of the material by rain- and seawater and washing out of contaminants in particulate/colloidal form.     

Role of conductive spreader layer in reducing surface temperature of HMA pavements

Rutting is a common type of shear failure-related deformation in asphalt (hot mix asphalt, HMA) pavements. It occurs over time as a result of slow, repeated heavy loads from vehicles moving along the wheel path. This problem is most noticeable when the pavement is at a high temperature and its stiffness is the lowest. Previous investigations have concluded that flowing water in pipes embedded in the pavement leads to a reduction in surface temperature, and consequently rutting. However, the thermophysical properties of HMA limit the cooling effect to a small region immediately around the pipe. It is proposed that the area of cooling be enhanced by adding a highly conductive spreader layer below the pavement in conjunction with the pipe. A theoretical design optimisation has been carried out by exploring different aspects of the spreader layer–pipe spacing (W), depth of the pipe–spreader (D), spreader thickness (t _s), thermal conductivity (k _s) and variation in the boundary conditions. Finite element modelling predicts that a properly designed, highly conductive spreader layer will lead to a significant reduction in surface temperature with a minimal piping network leading to an extended functional life of the HMA pavement.     

贫困山区名牌战略初探：以渝鄂湘黔接壤区为例

渝鄂湘黔接壤区是全国闻名的贫困山区。在这里，开发名牌产品，实行名牌战略，不仅是必要的，而且是可能的。有可能发展成为名牌的产品包括：历史上已有一定知名度的传统产品；山区无污染的绿色产品；拥有较强的科技含量又已有质量优势的工业产品；以天然植物为开发对象的现代生物化工产品；精美的少数民族工艺产品等。推行名牌战略，应提高认识，坚定信心，搞好计划；应巩固和扩大已有的名牌产品；对有潜力的产品应分层次、顺序，先     

Carbon footprint of recycled biogenic products: the challenge of modelling CO2 removal credits

Current carbon footprinting (CF) and life cycle assessment (LCA) methods do not treat recycled biogenic carbon adequately, because the calculation rules for recycled products and biogenic carbon stored in products are defined independently from each other. Therefore, an improved and consistent calculation rule for the CF of product systems containing both recycling processes and carbon stored in products is proposed. The methodological approach consists of the application of the same allocation principles for both greenhouse gas (GHG) releases and GHG removals: (1) explicit accounting of inputs (GHG removals) and outputs (GHG releases) of biogenic carbon flows instead of assuming carbon neutrality per se; (2) consistent application of allocation rules for environmental benefits and environmental burdens. It is shown that the different modelling approaches (e.g. polluter pays, conservative or partitioning) lead to different results in LCA and CF calculations, e.g. the GHG emissions of first life cycle of the product system calculated here range between ? 1.6 units in the polluter pays approach and 4 units in the conservative approach. It is shown that the currently common modelling is an average approach for primary biogenic material, a worst-case approach for recycled biogenic material and a best-case approach for disposed biogenic material. This paper proposes to improve the currently developed standards for CF by adding a requirement to the goal and scope definition phase that ensures the consistent and transparent documentation, how biogenic carbon removal credits are allocated between life cycles.     

Water balance and sustainability of eucalyptus plantations in the Kouilou basin (Congo-Brazzaville)

To appreciate the sustainabilty of these plantations of Eucalyptus, it is necessary to make a comparative study of energy, carbon, mineral and water balances of two ecosystems, i.e. the original savannah ecosystem, and the man-made ecosystem the Eucalyptus plantations that have succeeded it. The aim of this work is to study the water balance of the two ecosystems and more particularly their actual evapo-transpiration. Throughfall, net interception during the rainy seasons (1996–99) were 867. mm and 112 mm for the Eucalyptus plantation and 878 mm and 101 mm for the savannah, respectively. The mean total annual actual evapo-transpiration respectively 1127. mm for a plantation and 821 mm for a savannah. During the year transpiration/potential evapotranspiration ratio (T/E _p ) is related to the soil-water depletion: The T/E _p ratio of 0.79 was not reduced from field capacity until 65% of R _FC , and then it decreased quickly to near zero at wilting point. The drainage out of rooting depths of savannah during the rainy season was of 827. mm, a total over 3 years; while the drainage out of rooting depths of Eucalyptus plantation was of 470 mm, a difference in drainage between two ecosystems of 357. mm a total over these three years. The Eucalyptus plantation is manmade ecosystem which takes up and transpires every day throughout the year and uses all available water. The succession of several rain-deficient years will reduce the wood production of the plantation but, knowing that between 1949 and 1998 four successive rain-deficient years have only occured once while the length of rotation is seven years; this dry episode does not compromise the survival of the plantation, although it reduces its wood production. The savannah has a cycle of vegetation such that at the end of the dry season the water remaining in the rooting depths of savannah is sufficient for three successive rain-deficient years to have no impact on its production.     

Identification of potential applications for recycled polymeric multi-material

Abstract

This research aims to characterise a recycled polymeric multi-material, explore potential areas of application for it and analyse the eventual impacts of the introduction of this new recycled material (NRM) on end-of-life activities. Thus, this research presents a practical study regarding recycled polymeric multi-material from toothbrushes. A preliminary characterisation (via density determination, tensile test and dynamic mechanical thermal analysis – DMTA) and data analysis using the Cambridge Engineering Selector (CES-Edupack 2013) software have been done. The study also presents an analysis of the impacts of introducing the NRM into end-of-life activities. Results shows that, based on the properties considered in this study, NRM may have potential for new applications. The impact on recycling networks indicates that it is a positive solution that would improve process variable efficiencies, maintaining material value as long as possible in industrial closed-loop life cycles. However, an in loco analysis of the treatment of waste containing the NRM is necessary.     

Honge oil methyl ester and producer gas-fuelled dual-fuel engine operated with varying compression ratios

Alternative and renewable fuels have numerous advantages compared with fossil fuels as they are renewable and biodegradable, besides providing food and energy security and foreign exchange savings and addressing environmental and socio-economic issues. Therefore, these renewable fuels can be used predominantly in compression ignition (CI) engines for transportation purposes and power generation applications. Today, the use of biomass-derived producer gas is more relevant for addressing rural power generation and is also a promising technique for controlling both NO_x and soot emission levels. Although a producer gas–biodiesel-operated dual-fuel diesel engine exhibits lower performance, they are independent from the use of fossil fuels. The lower performance of the engine could be due to the slow-burning and lower calorific value of producer gas. For this purpose, exhaustive experiments on the use of Honge oil methyl ester (HOME)–producer gas in a dual-fuel CI engine were carried out for the improvement of its fuel efficiency. This paper presents the effect of the compression ratio (CR) on the performance, combustion and exhaust emission characteristics of a single-cylinder, four-stroke, direct injection stationary diesel engine operated using HOME and producer gas in a dual-fuel mode. The results indicated that the HOME–producer gas combination exhibited lower brake thermal efficiency (BTE) with comparable emission levels with the diesel–producer gas combination at different CRs. Comparative measures of BTE, peak pressure, pressure–crank angle variation, heat release rate, smoke opacity, and hydrocarbon (HC), carbon monoxide (CO) and nitric oxide (NO_x) emission levels are presented and analysed.     

Box models for the CO2 cycle of the earth

Box models for the global CO₂-cycle are described by a system of first order linear differential equations with constant coefficients. Conditions for uniquely existing equilibrium states are given and the reaction to disturbances is analysed. Kalman filtering techniques are applied to uncertainty problems. Some numerical calculations are presented for illustration purposes.