Showing papers in "Energy Engineering in 2012"

The Prospects of Alternatives to Vapor Compression Technology for Space Cooling and Food Refrigeration Applications

Abstract: This article identifies and describes five alternative cooling technologies (magnetic, thermionic, thermoacoustic, thermoelectric, and thermotunnel) and qualitatively assesses the prospects of each technology relative to vapor compression for space cooling and food refrigeration applications. Assessment of the alternatives was based on the theoretical maximum percent of Carnot efficiency, the current state of development, the best percent of Carnot efficiency currently achieved, developmental barriers, and the extent of development activity. The prospect for each alternative was assigned an overall qualitative rating based on the subjective, composite view of the five characteristics.

HVAC Equipment Right-sizing: Occupant Comfort and Energy Savings Potential

Abstract: HVAC equipment uses a significant amount of electricity and affects occupant comfort. In recent years, ventilation code requirements have often driven the size of the equipment upward, resulting in mismatched cooling capacities. Oversized cooling equipment will experience shorter run cycles, which reduces the ability to dehumidify air and reduces the life span of the equipment. Increased humidity levels can lead to mold conditions, resulting in building damage and occupant health issues. It is important to correctly match cooling capacities with the real load requirements of a facility, as this will reduce costs and increase comfort. Facilities undergoing capital renewal HVAC renovations were evaluated for energy saving opportunities. For facilities that had been experiencing combined high humidity and energy usage, revised load calculations were performed to correctly size the equipment. (Load calculations need to be performed twice: once to size the air handling units for code required ventilat...

Building Simulation Tools for Retrofitting Residential Structures

Abstract: This article evaluates the energy performance of a single family home using three widely used industry standard simulation packages in the United States—REM Design, Energy Gauge, and Treat. It disc...

Establishing Baseline Electrical Energy Consumption in Wood Processing Sawmills for Lean Energy Initiatives: A Model Based on Energy Analysis and Diagnostics

Abstract: This research focuses on the benchmarking of electrical energy use at sawmills. Lean energy (a programmatic concept similar to lean manufacturing) is facilitated by this research, which furthers the understanding of energy intensity at sawmills, leading to reductions in operating costs and increases in profitability. A user-friendly interactive model, Baseline Electrical Energy Consumption in Wood Processing Sawmills (BEECWPS), was developed to enable the user to create an energy profile based on sawmill process dynamics and to provide information about product, process, and system parameters. These parameters were gathered by visiting six sawmill facilities in West Virginia. A detailed methodology was developed to collect the field data and determine an energy intensity. The proposed model has the capability of developing the energy benchmark for a facility under consideration, upon successful submission of required data, and will aid lean energy initiatives within the organization. Manufacturin...

Optimization of Single-unit Compressed Air Systems

Abstract: Commercial and industrial customers are switching from reciprocating to rotary screw compressors for small, single-compressor systems (under 50 hp). Systems of this size represent a majority of the compressed air market in terms of numbers. Rotary screw compressors do not have the same energy profile as reciprocating compressors, making them significantly less efficient at part loads if installed in a standard manner. Because most compressed air systems operate at partial loads most of the time, significant savings of 50–80% can be gained if energy efficiency optimization measures are applied. Although the full-load efficiency of a rotary screw compressor is normally higher than a two-stage reciprocating compressor, contrary to popular belief the rotary screw is much less efficient at part load if running in modulation or load/unload operating mode. Four modes of compressor operation are possible for small rotary screw compressors, with modulation mode and load/unload mode shown to be much less e...

Do Older Schools Use Less Energy? Results of Calibrated Simulations and Post-occupancy Evaluations

Abstract: There is a considerable body of evidence, both nationally and locally, that older school buildings use less energy than newer ones. This article explores the issue with four elementary schools, two old (1960s construction) and two new (2000s construction) in the Albuquerque Public Schools school district. Computer modeling is done on the four schools for the most recent full year, calendar year (CY) 2010, then calibrated to actual energy consumption, to provide a calibrated simulation. This determines the breakdown of actual energy use into the major end uses. These are evaluated to determine which end uses are higher or lower for each school, each decade of construction, and each HVAC system type. The four energy use indexes (EUIs) are evaluated: Electricity, Natural Gas, Site Btu, and Source Btu EUIs. Post-occupancy evaluations are conducted to determine occupant satisfaction, perceived comfort, perceived lighting conditions, and zone control of HVAC and lighting. Also considered in the study a...

Financing Renewable Energy Projects In Difficult Economic Times

Abstract: Successful renewable energy developers are able to obtain and retain project financing Their projects are typically funded through a combination of equity provided by the developer and investors, as well as short- and long-term debt provided by lenders Despite the political appeal of renewable energy projects and the popular perception that massive amounts of funding are readily available at the turn of a tap, developers face increased difficulty in the current economic environment in obtaining both equity and debt financing for projects Equity participants, lenders, and other project participants are applying more stringent evaluations of the operations, finances, and credit of the developer Additionally, because the cooling of the economy has slowed energy demand, utilities not subject to mandatory standards are less eager to pay a premium for green power It is more important than ever for developers to explore every avenue of project funding to ensure a successful, viable project This ar

Energy Conservation Also Yields: Capital, Operations, Recognition, and Environmental Benefits

Abstract: Previous research indicates there are additional (often unreported) benefits from saving energy.

Managing Energy Productivity with a Sustainable Energy Index (ENDX)

Abstract: Business managers have few tools with which to determine whether their firm's energy productivity is getting better or worse. We propose a sustainable energy index (ENDX) that • tracks the energy productivity of a business • characterizes the description of energy risk on business operations • supports the continuous improvement of energy productivity • disassociates energy investments from cognitive bias A positive change of this index means that a business is improving its relative cost position and reducing its energy risk. A negative trend implies the opposite.

Hydraulic design and numerical simulation of super low specific speed francis turbine runner

Abstract: In oder to recover the surplus energy from cooling tower,a new type of super low specific speed turbine was developed to match fan directlyUsing binary theory,new Francis turbine was designed,by the relative height of guide vanes(H / D),runner channerl,blade circulation,and leaf numberBased on N-S equation and κ-e turbulence model,FLUENT was applied to simulate the new model of Francis turbine runnerThe flow,cavitation and energy characteristic were analyzedNumerical simulation results showed that the super low speed turbine had good flowing property,and the efficiency of turbine in a large range of angle was more than 80%

A Tale of Two Biomass Boilers

Abstract: What could be better than using energy grown locally to heat your facility? This article discusses two biomass boiler installations at two typical public school facilities in Pennsylvania. These systems were installed at the Benton Area School District in 2009 and at the East Lycoming School District in 2010. This article provides an overview of biomass energy and biomass boiler technology. Important aspects of the design, costs, and savings of these two projects are analyzed. Discussion of design includes heating multiple buildings versus a single building. Typical biomass boiler system design elements such as fuel storage requirements, fuel handling, boiler sizing, and backup heating equipment are investigated. Costs of both projects are evaluated, and clarification of key cost areas are highlighted. An explanation of the biomass boiler system savings is presented, along with information regarding project funding and air quality permitting. Unique to these two schools is that one school is usin...

Findings of an ASHRAE Level II Energy Audit of a Senior Living Facility

Abstract: An ASHRAE level II energy audit was conducted at a mid-atlantic, 340-bed senior living facility of approximately 225,000 square feet. The audit reviewed energy use and conducted detailed surveys of installed mechanical and electrical building systems. The audit developed multiple energy conservation measures (ECMs) with savings potential classified as immediate, short-term, and long-term. The listed ECMs are reviewed by classification: Immediate Tighten occupancy schedules to reduce energy demand. Reprogram rooftop units for proper operation of economizer and heat pumps and to minimize electrical resistance heating. Correct inaccurate labeling and control of heating and cooling coils and control valves in one energy recovery unit to improve effectiveness. Short-term Install high efficiency lighting to reduce direct energy use and reduce air conditioning loads. Install a new heat exchanger to utilize an existing cooling tower for low-cost chilled water in the heating season, reducing the need for ...

A research on the regeneration of deactivated SCR catalyst used in coal-fired plant

Abstract: Using the deactivated SCR catalyst used in coal-fired plant as material,a cheap and effective regeneration process was developed by washing with de-ionized water,soaking in dilute sulfuric acid,reloading active substance.Through the characterization such as ICP-OES,SEM and XRD,the influences of every processing method on structure and catalytic performance were investigated.The results showed that the catalyst regenerated had a 30% increase of SCR efficiency compared to the deactivated sample from 300 to 400 centigrade.Most sulfur and calcium were removed by washing with water,and the active sites on the surface of catalyst were increased and strengthened due to dilute sulfuric acid,while XRD patterns proved that V2O5/WO3 kept amorphous or disperse on the supporter after regeneration.

Experimental study on combustion characteristics of lignite blends

Abstract: Two kinds of lignite(XLT-A and XF-B) and its blends were studied by TGA.Combustion characteristics between single and blended coal were analyzed.A general combustion parameter S,which can well indicate the combustion characteristics,was proposed.Then,the chemical kinetics parameters,including activation energy and frequency factor were calculated.

Effect of microwave on drying and slurryability of lignite

Abstract: Microwave was employed to improve the slurryability of lignite with high external and inherent moistureThe maximum solid concentration was 5165% for the irradiated lignite slurry(700 W for 10 min),comparing to 4567% for the initial lignite slurryAmong the six different thin layer drying mathematical models,Page model was found the most appropriate model to describe the drying process of ligniteThe dehydration energy consumption decreased with the increasing of microwave powerMoreover,bigger reactor and more samples resulted in lower energy consumption,comparing with the smaller reactor and fewer samplesMoisture was reabsorbed to the level of the dry air base for lignite irradiated by microwave when placed in air for a periodThe negative effect of secondary bibulous was significantly inhibited by microwave

Sustainability in Multi-tenant Office Buildings: Anatomy of a LEED EBOM Program

Abstract: Multi-tenant commercial office buildings are host to unique relationships between ownership, management, and tenants. A typical owner-occupied corporate facility benefits from a streamlined process...

Comparison of maximum power point tracking techniques for the distributed photovoltaic power generation system

Abstract: Based on the current photovoltaic arrays maximum power point tracking technology research,a variety of commonly used control methods of maximum power point tracking for the distributed photovoltaic power generation system were introducedThe technical principles of each control method were described,the characteristics of these methods were analyzed and compared,and the advantages and disadvantages of each were summarizedFinally,the problem of method selection of maximum power point tracking for the distributed photovoltaic power generation system was discused,and the various factors that should be considered were given when the specific method was selected

Energy Management at Albuquerque Schools: Lessons Learned

Abstract: Energy consumption data analysis is arguably the most important tool in an energy management program. The Albuquerque Public Schools (APS) district has 139 schools, 89,500 students, 14 million square feet, and an annual energy bill of $14 million. The present analysis reviewed several energy-use indexes and compared them among all APS schools. Facilities with high and low energy consumption were identified, and benchmarks were established. Schools with high energy use were targeted for energy efficiency retrofits and evaluated to determine the likely reasons for the higher usage. One finding was that older schools typically use less electricity per square foot. Facilities that had energy efficiency modifications were monitored for savings. Variables in the analysis included building age, HVAC system type, type of energy efficiency modification, and time of use. HVAC equipment time controls yielded reductions in off-peak electricity usage, whereas lighting retrofits yielded reductions in on-peak u...

Research on the portfolio prediction methods of China energy consumption based on Shapley value

Abstract: Using exponential smoothing model,system dynamics model and gray prediction model,the energy consumption of China was forecasted,the Shapley value method of cooperative game was applied to determine the weight of each forecast model in the combined forecast model by distributing the total combined error,and then the energy consumption of China was forecasted through the combined modelThe result showed that the prediction accuracy of the combined model was higher than that of the model selected,and the prediction of energy consumption was feasible and effective

A method of human reliability analysis in substation

Abstract: First of all,the analysis method of power equipment reliability in substation was summarized together with the history of human reliability analysis in industry except power system.The operation in the substation and operation ticket system were analyzed.The effects which come up with the development trend of digital unattended substation and the dissemination of sequential operation and telecontrol devices were sketched.Combined with the characteristics of the power operation,the basic CREAM was modified to meet the actual power system.A method of human reliability analysis in substation based on cognitive reliability and error analysis method(CREAM) was proposed.Through a case study of electric switching operation in a substation,the accuracy of proposed model was proved,and the application of the model direction was ponted out.

Effect of Climate Change on Outside Air Design Temperature for Air Conditioning Cooling Load Calculations For Ikeja and Ilorin, Nigeria

Abstract: Hourly dry-bulb temperatures for Ikeja and Ilorin were obtained from the Nigerian Metrological Services Agency, Oshodi, Lagos, for the years 1995-2008. Statistical analyses were carried out on the data to obtain the average hourly temperatures for each month, the average temperature for each month, and the average temperature for the four warmest months (along with the standard deviations for each case). The average hourly temperatures were compared with those obtained by Ariyo for the two locations for the year 1978-1992. The 1%, 2½%, and 5% design temperatures obtained from the average temperature for the four warmest months, assuming the temperature distribution follows a normal distribution pattern, were also compared with those obtained by Ariyo for 1978-1992, as well as with those obtained by Shoboyejo and Shonubi for 1951-1965. It was observed that the average hourly temperatures were higher in the Shoboyejo-Shonubi work than those obtained by Ariyo for all the months for both locations. T...

Recycling system for vacuum pumping steam-heat in tobacco vacuum pre-conditioner

Abstract: The value of steam-heat recycling in steam-jet type vacuum pre-conditioner was analyzed,and it's difficulties were briefly discussed.The structure and working principle of the equipment for vacuum pumping steam-heat recycling were introduced.After application of the system,about 250,000 m3 natural gas can be reduced per year in Zhengzhou Cigarette Factory.In the meanwhile,pollution of the hot steam and it's noise to the surrounding environment was decreased,and the efficiency of the equipment was increased by 16.2%.

Study on the improvement of the outlet temperature of roller ring mills in the 600MW supercritical unit

Abstract: According to the structural features of the roller ring mills,experiments of improving the outlet temperature were conducted to reduce the exhaust gas temperature and improve the unit's economy.First,the feasibility of the improvement of the outlet temperature was studied by the entrusted unit,then the debugging was conducted in the power plant.The rusults showed,the outlet temperature raised to 100℃ had certain safety margin,and no CO generation.When the outlet temperature raised from 80℃ to 100℃,the exhaust gas temperature reduced 6.1℃,the boiler efficiency raised 0.31%,and the coal consumption reduced 1g/kWh.It can save the standard coal more than 7500 t/a and $6 million,and with no cost input,it can save $6 million.

Experimental study on emission characteristics of pollutants during Zhuyuan sludge combustion

Abstract: Shanghai Zhuyuan sludge was selected and sorted for three kinds: absolute dried sludge,uniformed dried sludge(the moisture content: 10%) and the mixture of dried sludge and wet sludge(the moisture content: 20%).Then they were sent into a lab-scale fluidized bed incinerator for combustion.The characteristics of pollutants emission from absoluted dried sludge combustion was studied at temperature of 750℃,850℃ and 950℃.Also the characteristics of pollutants emission from uniformed sludge combustion and the sludge mixture combustion was studied at the temperature of 850℃.It was indicated that the major pollutants included CO,SO2,NOx,HCl,dioxins and some heavy metals like Cd,Hg and Pb during Zhuyuan sludge combustion in the lab-scale fluidized bed incinerator.Different combustion temperatures and moisture contents have impact on pollutants emission.Raising the combustion temperature will reduce the emission of CO,SO2,NOx and HCl,while the emission of Pb in flue gas will increase with the temperature increasing.At the same combustion temperature raising the moisture content will reduce the total amount of dioxins emission and the heavy metals in fly ash while it will increase in the bottom slag.

Experimental investigation on the coal ignition characteristics for a W-shaped flame boiler

Abstract: To obtain the ignition characteristics of a 300 MW unit W-shaped flame boiler,experiments were performed with measurements taken of gas temperatures in the burner region at different secondary air damper openings on arches and at different vent air damper openings for cyclone concentrators,respectively.Results showed that both the secondary air and vent air damper openings impacted the coal/air mixture ignition in the furnace but with different extent.The effect of the vent air damper opening was far lower than that of the secondary air damper opening,despite the air distribution between the primary air and vent air changing with the vent air damper opening.This was because that the secondary air was prematurely mixed with the primary air at the early stage of ignition due to the respective nozzles and ports being arranged in closely alternating positions.After leaving the port outlet,secondary air with velocities much higher than that of the primary air mixed rapidly with the slower flow resulting in the coal ignition delaying a lot.

Application of solar mid-high temperature steam and economical analysis

Abstract: A kind of application system of solar mid-high temperature steam was designedAnd economical benefits of this system were analyzedAccording to cost of parabolic trough electricity system,total investment cost and payback period of this system were calculated and analyzedThe results showed that construction and total investment costs could reach to 650MYM/kW and 750MYM/kWFor areas with sunshine more than 2000 hours,payback period would be 56~125 years according to system scaleResults indicated that application of solar mid-high temperature steam had good economy

Research progress of optimization for distributed energy system in domestic

Abstract: Distributed energy system is a complex system with multi-energy output.The application of distributed energy system is still at initial stage in domestic,and there is no intergrated optimization method and evaluation system.Research progress of optimization for distributed energy system was summarized from thermodynamic factors,ecnomic factors and environmental factors.For its multi-factor complex characteristic,the optimization research of distributed system should include hermodynamic factors,ecnomic factors and environmental factors.These analysis may provide usful reference for subsequent studies.

Analysis on influencing factors of low-temperature pyrolysis technology of municipal sludge

Abstract: According to the environmental problems cansed by municipal municipal sludge treatment,sludge pyrolysis technology was introduced.Low-temperature pyrolysis technology of sludge was discussed.The influence of reaction temperature,reaction time,reaction rate and catalyst on sludge pyrolysis products were analyzed.Advices on how to treat sludge better were put forward.

Research and application of power system state estimation debugger based on the D5000 model and the cross-section

Abstract: In order to solve the artificial verification measurement inaccuracies and die data,using power system state estimation algorithm based on the block Givens rotating and successive type estimate identification method for bad data identification,the power system state estimation debugger was developed based on the D5000 model and section,which had multidimensional measurement problem organization way and valve value punch tool.Practice showed that the debugger effectively solved Zhejiang power grid artificial check grid measuring various existing problems,provided an effective technical tool machines for power grid measuring problemes.

Analysis for gypsum rain of wet flue gas desulfurization system

Abstract: After the uninstalling of gas-gas heater(GGH) from wet flue gas desulfurization system,the liquid drips of gypsum rain was carried by flue gas at the outlet of stack.The cause and solution of gypsum rain from WFGD were analyzed.