Economic optimization of a cogeneration system for apartment houses in Korea

A cogeneration system which can be used as a distributed generation source produces electricity and heat energy simultaneously from a single source of fuel. For industrial and domestic applications, where both kinds of energy are required, the cogeneration system can return fossil fuel energy savings up to 30%, and can reduce CO₂ emissions correspondingly as compared with a conventional system. In this study, eight apartments with residential areas in the range of 57200 m² to 182760 m² were chosen to study how much energy savings can be achieved by adoption of the cogeneration system in those apartments. Based on the energy demand data for heat and electricity, an optimum configuration of the cogeneration system for each apartment was determined by a developed computer program. The economic gain achieved by introducing the cogeneration system in those apartments was estimated and the monitored values compared with the estimated ones. By adoption of the cogeneration system, the natural gas saved was more than 30% and an average economic gain of US$ 3.6 m⁻²/year in the overall energy cost was obtained.     

Emissions from power plants fueled by peat,coal, natural gas and oil

Measurements were carried out to investigate the emissions of SO₂, NO_x, fly ash, heavy metals, radioactive elements and polycyclic aromatic hydrocarbons (PAH) from one oil-fired, two coal-fired, five peat-fired and four natural gas-fired power plants or district heating plants.The emissions of sulphur dioxide depended mainly on the sulphur content of the fuel. In the combustion of oil, practically all the sulphur in the fuel reached the atmosphere as sulphur dioxide. When coal and peat were used as fuel, the amounts of sulphur retained in the ash were about 15 and 20%, of the original sulphur content, respectively. The SO₂ emissions from oil, coal, peat and natural gas were typically 1000, 600, 120, and < 10 mg MJ⁻¹, respectively.The emissions of oxides of nitrogen depended on the nitrogen content of the fuel and also on the combustion temperature. The NO_x emissions from plants burning oil, coal peat and natural gas were typically 100, 300, 160 and 100 mg MJ⁻¹, respectively. The lowest emissions were measured in the small natural gas-fired district heating plants (20–30 mg NO_x MJ⁻¹).The emissions of fly ash and various elements depended mainly on the ash content of the fuel and on the efficiency of the dust collectors, which decreases sharply when the power plant output exceeds its nominal value. When the dust separation efficiency is 99% for coal- and peat-fueled power plants, and when there are no dust collectors in oil-fueled power plants, the typical fly ash emissions are 45, 20 and 25 mg MJ⁻¹, respectively. Characteristic emissions of heavy metals and natural radioactive elements were greatest in the combustion of coal, with the exception of vanadium and nickel, of which the greatest emissions were from oil; the greatest emissions of ²¹⁰Po were from peat.The PAH emissions of the different fuel-fired power plants were, with one exception, similar (2–10 μg MJ⁻¹). Emissions from the circulating fluidized bed combustion of peat were about 10 times (40 μg MJ⁻¹) those of the other methods of combustion.     

家用天然气燃料电池在暖通空调中的应用

介绍了家用天然气燃料电池的概念和基本原理,其最大优点在于高效率和环保性,其能源综合效率达到80%。计算显示,与火力发电比较,一次能源的消费量削减21%,温室气体CO2排放量削减27%,大气污染物质NOx排放量削减66%。分析了家用燃料电池实用化过程中面临的成本、效率、耐久性等问题,提出了发展我国家用燃料电池的构想。     

Polycyclic aromatic hydrocarbons: levels and phase distributions in preschool microenvironment

This work aims to characterize levels and phase distribution of polycyclic aromatic hydrocarbons (PAHs) in indoor air of preschool environment and to assess the impact of outdoor PAH emissions to indoor environment. Gaseous and particulate (PM₁ and PM_2.5) PAHs (16 USEPA priority pollutants, plus dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were concurrently sampled indoors and outdoors in one urban preschool located in north of Portugal for 35 days. The total concentration of 18 PAHs (ΣPAHs) in indoor air ranged from 19.5 to 82.0 ng/m³; gaseous compounds (range of 14.1–66.1 ng/m³) accounted for 85% ΣPAHs. Particulate PAHs (range 0.7–15.9 ng/m³) were predominantly associated with PM₁ (76% particulate ΣPAHs) with 5‐ring PAHs being the most abundant. Mean indoor/outdoor ratios (I/O) of individual PAHs indicated that outdoor emissions significantly contributed to PAH indoors; emissions from motor vehicles and fuel burning were the major sources.     

Variations in vanadium, nickel and lanthanoid element concentrations in urban air

The emission of trace metal pollutants by industry and transport takes place on a scale large enough to alter atmospheric chemistry and results in measurable differences between the urban background of inhalable particulate matter (PM) in different towns. This is particularly well demonstrated by the technogenic release into the atmosphere of V, Ni, and lanthanoid elements. We compare PM concentrations of these metals in large datasets from five industrial towns in Spain variously influenced by emissions from refinery, power station, shipping, stainless steel, ceramic tiles and brick-making. Increased La/Ce values in urban background inhalable PM, due to La-contamination from refineries and their residual products (fuel oils and petcoke), contrast with Ce-rich emissions from the ceramic related industry, and clearly demonstrate the value of this ratio as a sensitive and reliable tracer for many point source emissions. Similarly, anomalously high V/Ni values (> 4) can detect the influence of nearby high-V petcoke and fuel oil combustion, although the use of this ratio in urban background PM is limited by overlapping values in natural and anthropogenic materials. Geochemical characterisation of urban background PM is a valuable compliment to the physical monitoring of aerosols widely employed in urban areas, especially given the relevance of trace metal inhalation to urban health issues.     

Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China, 2007

Over half of coal in China is burned directly by power plants, becoming an important source of hazardous trace element emissions, such as mercury (Hg), arsenic (As), and selenium (Se), etc. Based on coal consumption by each power plant, emission factors classified by different boiler patterns and air pollution control devices configuration, atmospheric emissions of Hg, As, and Se from coal-fired power plants in China are evaluated. The national total emissions of Hg, As, and Se from coal-fired power plants in 2007 are calculated at 132 t, 550 t, and 787 t, respectively. Furthermore, according to the percentage of coal consumed by units equipped with different types of PM devices and FGD systems, speciation of mercury is estimated as follows: 80.48 t of Hg, 49.98 t of Hg²⁺, and 1.89 t of Hg^P, representing 60.81%, 37.76%, and 1.43% of the totals, respectively. The emissions of Hg, As, and Se in China's eastern and central provinces are much higher than those in the west, except for provinces involved in the program of electricity transmission from west to east China, such as Sichuan, Guizhou, Yunnan, Shaanxi, etc.     

The combined effect of multiwalled carbon nanotubes and exhaust gas recirculation on the performance and emission characteristics of a diesel engine

The present experimental investigation focuses on the combined effects of multiwalled carbon nanotubes (MWCNTs) and exhaust gas recirculation (EGR) of a diesel engine fuelled with Calophyllum inophyllum biodiesel blends. The C. inophyllum biodiesel-diesel blend was prepared in a proportion of 20% biodiesel and 80% diesel (B20) by a volumetric basis with a magnetic stirrer. The MWCNTs (in the mass fraction of 40?ppm) were dispersed into the B20 fuel with the help of an ultrasonicator. The results show that brake thermal efficiency increases by 7.6% with the addition of MWCNTs to the B20 fuel, decreases by 2.42% with the EGR to the B20 fuel, and increases by 2.26% with the addition of MWCNTs and EGR to the B20 fuel compared to the B20 fuel. The maximum cylinder pressure and heat release rate was occurred as 67.35 bar and 74.80?kJ/m³ deg for the B20MWCNT40 fuel at full load condition. The CO and HC emissions for the B20MWCNT40+20%EGR fuel sample were lower compared to the B20 fuel. The Smoke emissions were reduced for B20MWCNT40 fuel compared to the B20 fuel. The NO_x emissions were reduced by 25.6%, 29.7% for B20+20%EGR, B20MWCNT40+20%EGR fuel samples compared to the B20 fuel.     

Particle and gaseous emissions from compressed natural gas and ultralow sulphur diesel-fuelled buses at four steady engine loads

Exhaust emissions from thirteen compressed natural gas (CNG) and nine ultralow sulphur diesel in-service transport buses were monitored on a chassis dynamometer. Measurements were carried out at idle and at three steady engine loads of 25%, 50% and 100% of maximum power at a fixed speed of 60 km h^− 1. Emission factors were estimated for particle mass and number, carbon dioxide and oxides of nitrogen for two types of CNG buses (Scania and MAN, compatible with Euro 2 and 3 emission standards, respectively) and two types of diesel buses (Volvo Pre-Euro/Euro1 and Mercedez OC500 Euro3). All emission factors increased with load. The median particle mass emission factor for the CNG buses was less than 1% of that from the diesel buses at all loads. However, the particle number emission factors did not show a statistically significant difference between buses operating on the two types of fuel. In this paper, for the very first time, particle number emission factors are presented at four steady state engine loads for CNG buses. Median values ranged from the order of 10¹² particles min^− 1 at idle to 10¹⁵ particles km^− 1 at full power. Most of the particles observed in the CNG emissions were in the nanoparticle size range and likely to be composed of volatile organic compounds The CO₂ emission factors were about 20% to 30% greater for the diesel buses over the CNG buses, while the oxides of nitrogen emission factors did not show any difference due to the large variation between buses.     

Exergetic modeling and assessment of solar assisted domestic hot water tank integrated ground-source heat pump systems for residences

The present study deals with the exergetic modeling and performance evaluation of solar assisted domestic hot water tank integrated ground-source heat pump (GSHP) systems for residences for the first time to the best of the author's knowledge. The model is applied to a system, which mainly consists of (i) a water-to-water heat pump unit (ii) a ground heat exchanger system having two U-boreholes with an individual depth of 90 m, (iii) a solar collector system composing of rooftop thermal solar collectors with a total surface area of 12 m², (iv) a domestic hot water tank with a electrical supplementary heater, and (v) a floor heating system with a surface of 154 m², and (vi) circulating pumps. Exergy relations for each component of the system and the whole system are derived for performance assessment purposes, while the experimental and assumed values are utilized in the analysis. Exergy efficiency values on a product/fuel basis are found to be 72.33% for the GSHP unit, 14.53% for the solar domestic hot water system and 44.06% for the whole system at dead (reference) state values for 19 °C and 101.325 kPa. Exergetic COP values are obtained to be 0.245 and 0.201 for the GSHP unit and the whole system, respectively. The greatest irreversibility (exergy destruction) on the GSHP unit basis occurs in the condenser, followed by the compressor, expansion valve and evaporator.     

Analysis of feasibility on heating single family houses in rural areas by using sun and wind energy

Households in Lithuania consume about 1/3 of total final consumption of fuel energy. In order to reduce imports of fossil fuel and emissions of dangerous pollutants, solar energy could be used for the above-mentioned needs. That would require large collector areas and volumes for seasonal heat storage. In wintertime the wind speed velocity is much higher than in summertime in Lithuania. Therefore, it is advisable to study meeting the thermal needs of single family houses by combining use of wind and solar energy. To this end analytical research has been made by using deterministic method. The analysis has been carried out for the case when 1 m² of heated room area requires 0.25 m² of solar collector area and 0.5 m² working area of wind turbine rotor. Heat storage is planned for 24 h. By using such a hybrid system during the heating season 42.6–56.2% of heating needs for space and domestic hot water are satisfied. However, for individual days (especially from May to October) a surplus of generated heat is formed and it reaches about 53.6% of space heating needs per year. This relative surplus of energy could be used for transmitting wind power-plant energy to the electric network or in a household and thermal energy can be used for drying agricultural produce, heating greenhouses, open swimming pools and satisfying other needs.     

Emissions in the exhaust of fishing boats after adding viscous agents into fuel oils

In order to avoid the illegal use of fishing boat fuel A (FBFA) by traveling diesel vehicles (TDVs) in Taiwan, alternatives that are easily distinguished from premium diesel fuel (PDF) were prepared to evaluate their suitability. Two new ingredients, pyrolysis fuel oil (PFO) and residue of desulfurization unit (RDS), were added into FBFA and formed PFO0.5 and RDS0.5, respectively. Along with FBFA, these three fuels were analyzed for their chemical and physical properties. Furthermore, they were used by three fishing boats with different sizes, output powers, and weights. The engine performances and pollutant emissions were examined and monitored. Experimental results show that there are significant differences in appearance between PDF and the two new blended fuels (PFO0.5 and RDS0.5), and thus misuse or illegal use of FBFA could be substantially reduced. The fuel consumption, which is negatively related to the heating value of fuels, is in order of FBFA < PFO0.5 = RDS0.5. In contrast with using FBFA in the three fishing boats, using RDS0.5 resulted in a decrease in CO and NO_x emissions, while the PM emission factors (g bhp^− 1 h^− 1 and g L^− 1-fuel) were reduced by approximately 36% and 33%, respectively. Owing to the higher total aromatic content in PFO0.5 and RDS0.5, total-PAH concentrations in the exhausts from the three fishing boats using PFO0.5 and RDS0.5 were slightly (1.2 and 1.1 times, respectively) higher than for those using FBFA. Nevertheless, the estimated total BaP_eq from the three fishing boats using RDS0.5 was 27.5, 19.5, and 8.25% lower than those using FBFA. With using PFO0.5, they were totally different, at 23.5, 2.79, and 2.58% higher. With regard to looking different to PDF, RDS0.5 is superior to PFO0.5, and is thus recommended as a better alternative to FBFA, particularly because it can help lower more emissions of CO, NO_x, PM and BaP_eq.     

Alternative scenarios analysis concerning different types of fuels used for the coverage of the energy requirements of a typical apartment building in Thessaloniki,Greece. Part I: Fuel consumption and emissions

This paper focuses on the analysis (concerning energy and environmental performance) and comparison of different types of fuel intended either for direct use (e.g. domestic boiler combustion) or indirect use (production of electricity that will be consumed) in order to satisfy the energy requirements of a typical apartment building in Thessaloniki, Greece. The energy requirements that are being examined are: space heating, water heating, kitchen and cooking appliances, lighting and other various electrical appliances. For the purposes of this analysis an apartment building model has been designed that simulates combinations of these operations sorted in five scenarios in proportion with the fuel being used and the way electricity is generated. The analysis’ obtained results concern: pollutant emissions per kg, kWh or m³ of the fuel being used, daily total emissions that correspond to the estimated fuel required to satisfy the energy needs of the apartment building and the financial comparison of all scenarios.     

Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province,China

The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) emissions in China. To characterize indoor NO₂ and SO₂ air concentrations in relation to solid fuel use and stove ventilation in the rural counties of Xuanwei and Fuyuan, in Yunnan Province, China, which have among the highest lung cancer rates in the nation, a total of 163 participants in 30 selected villages were enrolled. Indoor 24‐h NO₂ and SO₂ samples were collected in each household over two consecutive days. Compared to smoky coal, smokeless coal use was associated with higher NO₂ concentrations [geometric mean (GM) = 132 μg/m³ for smokeless coal and 111 μg/m³ for smoky coal, P = 0.065] and SO₂ [limit of detection = 24 μg/m³; percentage detected (%Detect) = 86% for smokeless coal and 40% for smoky coal, P < 0.001]. Among smoky coal users, significant variation of NO₂ and SO₂ air concentrations was observed across different stove designs and smoky coal sources in both counties. Model construction indicated that the measurements of both pollutants were influenced by stove design. This exposure assessment study has identified high levels of NO₂ and SO₂ as a result of burning solid fuels for cooking and heating.     

A modelling study for the integration of a PEMFC microCHP in domestic building services design

Fuel cell based micro-combined heat and power( CHP) units used for domestic applications can provide significant cost and environmental benefits for end users and contribute to the UK 's 2050 emissions target by reducing primary energy consumption in dwellings. Lately there has been increased interest in the development of systematic methods for the design of such systems and their smoother integration with domestic building services. Several models in the literature,whether they use a simulation or an optimisation approach,ignore the dwelling side of the system and optimise the efficiency or delivered power of the unit. However the design of the building services is linked to the choice of heating plant and its characteristics. Adding the dwelling's energy demand and temperature constraints in a model canproduce more general results that can optimise the whole system,not only the micro-CHP unit. The fuel cell has various heat streams that can be harvested to satisfy heat demand in a dwelling and the design can vary depending on the proportion of heat needed from each heat stream to serve the energy demand. A mixed integer non-linear programming model( M INLP) that can handle multiple heat sources and demands is presented in this paper.The methodology utilises a process systems engineering approach. The model can provide a design that integrates the temperature and water flowconstraints of a dwelling's heating system with the heat streams within the fuel cell processes while optimising total CO2 emissions. The model is demonstrated through different case studies that attempt to capture the variability of the housing stock. The predicted CO2 emissions reduction compared to a conventionally designed building vary from 27%to 30%and the optimum capacity of the fuel cell ranges between 1. 9 kW and3. 6 kW. This research represents a significant step towards an integrated fuel cell micro-CHP and dwelling design.     

Auxiliary power unit for truck idling reduction

Idling the engine of heavy‐duty truck is the only way a driver can control the temperature in the cab/sleeper and have power for auxiliary devices when the truck is parked. It is an inefficient and noisy process that wastes thousands of litres of fuel per year while standing stationary in a parking lot. Almost all heavy‐duty trucks idle about 20–40% of the time when the engine is running, depending on season, geographic location and trucking operation. This extensive engine idling has many disadvantages, including pollutant emissions, noise pollution, unnecessary fuel and maintenance costs, and driver discomfort. This paper discusses the problems related to truck idling and proposes an auxiliary power generation unit that can significantly reduce the fuel consumption, cut the costs, enhance engine life and reduce pollution. A control methodology is presented to regulate the output voltage of the auxiliary power unit under variable load conditions.     

Efficient recovery of nano-sized iron oxide particles from synthetic acid-mine drainage (AMD) water using fuel cell technologies

Acid mine drainage (AMD) is an important contributor to surface water pollution due to the release of acid and metals. Fe(II) in AMD reacts with dissolved oxygen to produce iron oxide precipitates, resulting in further acidification, discoloration of stream beds, and sludge deposits in receiving waters. It has recently been shown that new fuel cell technologies, based on microbial fuel cells, can be used to treat AMD and generate electricity. Here we show that this approach can also be used as a technique to generate spherical nano-particles of iron oxide that, upon drying, are transformed to goethite (α-FeOOH). This approach therefore provides a relatively straightforward way to generate a product that has commercial value. Particle diameters ranged from 120 to 700 nm, with sizes that could be controlled by varying the conditions in the fuel cell, especially current density (0.04-0.12 mA/cm²), pH (4-7.5), and initial Fe(II) concentration (50-1000 mg/L). The most efficient production of goethite and power occurred with pH = 6.3 and Fe(II) concentrations above 200 mg/L. These results show that fuel cell technologies can not only be used for simultaneous AMD treatment and power generation, but that they can generate useful products such as iron oxide particles having sizes appropriate for used as pigments and other applications.     

CO2, CO, and Hg emissions from the Truman Shepherd and Ruth Mullins coal fires, eastern Kentucky, USA

Carbon dioxide (CO₂), carbon monoxide (CO), and mercury (Hg) emissions were quantified for two eastern Kentucky coal-seam fires, the Truman Shepherd fire in Floyd County and the Ruth Mullins fire in Perry County. This study is one of the first to estimate gas emissions from coal fires using field measurements at gas vents. The Truman Shepherd fire emissions are nearly 1400 t CO₂/yr and 16 kg Hg/yr resulting from a coal combustion rate of 450-550 t/yr. The sum of CO₂ emissions from seven vents at the Ruth Mullins fire is 726 ± 72 t/yr, suggesting that the fire is consuming about 250-280 t coal/yr. Total Ruth Mullins fire CO and Hg emissions are estimated at 21 ± 1.8 t/yr and > 840 ± 170 g/yr, respectively. The CO₂ emissions are environmentally significant, but low compared to coal-fired power plants; for example, 3.9 × 10⁶ t CO₂/yr for a 514-MW boiler in Kentucky. Using simple calculations, CO₂ and Hg emissions from coal-fires in the U.S. are estimated at 1.4 × 10⁷-2.9 × 10⁸ t/yr and 0.58-11.5 t/yr, respectively. This initial work indicates that coal fires may be an important source of CO₂, CO, Hg and other atmospheric constituents.     

Remote sensing of PM, NO, CO and HC emission factors for on-road gasoline and diesel engine vehicles in Las Vegas, NV

A novel light detection and ranging-based remote sensing system was assembled and used to measure mass particulate matter (PM) emissions per unit of fuel burned from in-use on-road vehicles. A commercially available remote sensing system was concurrently used to measure emissions of carbon monoxide (CO), nitrogen oxide (NO) and hydrocarbons (HC). The two systems were used to measure 61,207 gasoline and 1180 diesel powered vehicle emissions in Las Vegas, NV from 4/4/2000 to 5/16/2002. Emission factors were related to vehicle age, weight class and fuel type by matching license IDs to the state registration data. Measurements of vehicle speed and acceleration permitted the analysis of emission factors by vehicle specific power (VSP). Average emission factors were calculated for light-duty (<3863 kg [8500 lbs]) gasoline vehicles (LDGV), light-duty diesel vehicles (LDDV), heavy-duty (>3863 kg [8500 lbs]) gasoline vehicles (HDGV) and heavy-duty diesel vehicles (HDDV). LDDV and HDDV emitted approximately 25 times more PM per mass of fuel than LDGV and HDGV. Sufficient numbers of LDGV were measured to relate VSP with CO, HC and NO emissions. No relationship was observed between PM emissions and VSP. PM emission factors from LDGV increased with vehicle age. Fuel-based emission factors measured by remote sensing were compared with MOBILE6 and PART5 emissions model factors. Good agreement was observed for HC emission factors for vehicles less than 20 years old. MOBILE6 CO emission factors were approximately 2 times greater than measured CO emission factors for vehicles less than 13 years old. Measured NO emission factors were approximately 50% greater than MOBILE6 factors for vehicles 7-15 years old but in good agreement for vehicles less than 7 years old. Measured PM emission factors showed a clear increase with vehicle age, however, PART5 uses only a single PM emission factor for LDGV less than 18 years old. The PM emission factors for the fleet of LDGV, HDGV, LDDV and HDDV were 0.06, 0.05, 1.6 and 1.5 g/kg, respectively.     

Particulate matter chemical component concentrations and sources in settings of household solid fuel use

Particulate matter (PM) air pollution derives from combustion and non‐combustion sources and consists of various chemical species that may differentially impact human health and climate. Previous reviews of PM chemical component concentrations and sources focus on high‐income urban settings, which likely differ from the low‐ and middle‐income settings where solid fuel (ie, coal, biomass) is commonly burned for cooking and heating. We aimed to summarize the concentrations of PM chemical components and their contributing sources in settings where solid fuel is burned. We searched the literature for studies that reported PM component concentrations from homes, personal exposures, and direct stove emissions under uncontrolled, real‐world conditions. We calculated weighted mean daily concentrations for select PM components and compared sources of PM determined by source apportionment. Our search criteria yielded 48 studies conducted in 12 countries. Weighted mean daily cooking area concentrations of elemental carbon, organic carbon, and benzo(a)pyrene were 18.8 μg m^?3, 74.0 μg m^?3, and 155 ng m^?3, respectively. Solid fuel combustion explained 29%‐48% of principal component/factor analysis variance and 41%‐87% of PM mass determined by positive matrix factorization. Multiple indoor and outdoor sources impacted PM concentrations and composition in these settings, including solid fuel burning, mobile emissions, dust, and solid waste burning.     

Retail impact analysis with loosely coupled GIS and a spreadsheet

This paper describes an innovative computer‐based system, GIS‐SHOP, for providing low‐cost decision support for retail impact analysis. The system implements a loosely coupled approach to urban modelling using a widely available, low‐cost desktop geographic information system (GIS) and an electronic spreadsheet to develop a gravity‐model‐based retail shopping model. The paper begins by reviewing the power—and limitations—of the current generation of GIS for planning and the need to extend this technology to develop more powerful planning support systems (PSS). It then describes the GIS‐SHOP model which uses ESRI's ArcView® 2.1 and Microsoft's Excel^® 5.0 together to provide analytic and display capabilities which are available in neither package alone. The paper concludes by considering the advantages and disadvantages of this loosely coupled modelling strategy.