In this study, a novel counter-cross-flow run-around membrane energy exchanger (RAMEE) system was designed and tested in the laboratory. The RAMEE system consists of two (2) counter-cross-flow Liquid-to-Air Membrane Energy Exchangers (LAMEEs) to be located in the supply and exhaust air streams in the building Heating Ventilation and Air-Conditioning (HVAC) system. Inside each exchanger, a micro-porous membrane separates the air and liquid streams and allows transfer of the sensible and latent energy from the air stream to the liquid stream or vice-versa. The system exchanges sensible and latent energy between supply and exhaust air streams using a desiccant solution loop. The supply and exhaust air streams in the RAMEE can be located far apart from each other or adjacent to each other. The flexibility of non-adjacent ducting makes the RAMEE system a better alternative compared to available energy recovery systems for the retrofit of HVAC systems.<p> Two counter-cross-flow exchangers for the RAMEE system were designed based on an industry recommended standard which is to obtain a target overall system effectiveness of 65% for the RAMEE system at a face velocity of 2 m/s. The exchanger design was based on heat exchanger theory and counter-cross-flow design approach. An exchanger membrane surface aspect ratio (ratio of exchanger membrane surface height to exchanger length) of 1/9 and the desiccant solution entrance ratio (ratio of desiccant solution entrance length to exchanger length) of 1/24 were employed. Based on different heat transfer case studies, the energy transfer size of each exchanger was determined as 1800 mm x 200 mm x 86 mm. ProporeTM was used as the membrane material and Magnesium-Chloride solution was employed as the desiccant solution.<p> The RAMEE performance (sensible, latent and total effectiveness) was evaluated by testing the system in a run-around membrane energy exchanger test apparatus by varying the air stream and liquid solution-flow rates at standard summer and winter operating conditions. From the test data, the RAMEE effectiveness values were found to be sensitive to the air and solution flow rates. Maximum total effectiveness of 45% (summer condition) and 50% (winter condition) were measured at a face velocity ¡Ö 2 m/s. A comparison between the experimental and numerical results from the literature showed an average absolute discrepancy of 3% to 8% for the overall total system effectiveness. At a low number of heat transfer units, i.e. NTU = 4, the numerical and experimental results show agreement within 3% and at NTU = 12 the experimental data were 8% lower than the simulations. The counter-cross-flow RAMEE total system effectiveness were found to be 10% to 20% higher than those reported for a cross-flow RAMEE system by another researcher.<p> It is thought that discrepancies between experimental and predicted results (design and numerical effectiveness) may be due to the mal-distributed desiccant solution-flow, desiccant solution leakage, lower than expected water vapor permeability of the membrane, uncertainties in membrane properties (thickness and water vapor permeability) and heat loss/gain effects. Future research is needed to determine the exact cause of the discrepancies.

In this study, a novel counter-cross-flow run-around membrane energy exchanger (RAMEE) system was designed and tested in the laboratory. The RAMEE system consists of two (2) counter-cross-flow Liquid-to-Air Membrane Energy Exchangers (LAMEEs) to be located in the supply and exhaust air streams in the building Heating Ventilation and Air-Conditioning (HVAC) system. Inside each exchanger, a micro-porous membrane separates the air and liquid streams and allows transfer of the sensible and latent energy from the air stream to the liquid stream or vice-versa. The system exchanges sensible and latent energy between supply and exhaust air streams using a desiccant solution loop. The supply and exhaust air streams in the RAMEE can be located far apart from each other or adjacent to each other. The flexibility of non-adjacent ducting makes the RAMEE system a better alternative compared to available energy recovery systems for the retrofit of HVAC systems.<p> Two counter-cross-flow exchangers for the RAMEE system were designed based on an industry recommended standard which is to obtain a target overall system effectiveness of 65% for the RAMEE system at a face velocity of 2 m/s. The exchanger design was based on heat exchanger theory and counter-cross-flow design approach. An exchanger membrane surface aspect ratio (ratio of exchanger membrane surface height to exchanger length) of 1/9 and the desiccant solution entrance ratio (ratio of desiccant solution entrance length to exchanger length) of 1/24 were employed. Based on different heat transfer case studies, the energy transfer size of each exchanger was determined as 1800 mm x 200 mm x 86 mm. ProporeTM was used as the membrane material and Magnesium-Chloride solution was employed as the desiccant solution.<p> The RAMEE performance (sensible, latent and total effectiveness) was evaluated by testing the system in a run-around membrane energy exchanger test apparatus by varying the air stream and liquid solution-flow rates at standard summer and winter operating conditions. From the test data, the RAMEE effectiveness values were found to be sensitive to the air and solution flow rates. Maximum total effectiveness of 45% (summer condition) and 50% (winter condition) were measured at a face velocity ¡Ö 2 m/s. A comparison between the experimental and numerical results from the literature showed an average absolute discrepancy of 3% to 8% for the overall total system effectiveness. At a low number of heat transfer units, i.e. NTU = 4, the numerical and experimental results show agreement within 3% and at NTU = 12 the experimental data were 8% lower than the simulations. The counter-cross-flow RAMEE total system effectiveness were found to be 10% to 20% higher than those reported for a cross-flow RAMEE system by another researcher.<p> It is thought that discrepancies between experimental and predicted results (design and numerical effectiveness) may be due to the mal-distributed desiccant solution-flow, desiccant solution leakage, lower than expected water vapor permeability of the membrane, uncertainties in membrane properties (thickness and water vapor permeability) and heat loss/gain effects. Future research is needed to determine the exact cause of the discrepancies.

A CO2 emission analysis and system investigation of a direct fuel cell waste energy recovery and power generation system (DFC-ERG) for pressure letdown stations was undertaken. The hybrid system developed by FuelCell Energy Inc. is an integrated turboexpander and a direct internal reforming molten carbonate fuel cell system in a combined circle. At pressure letdown stations, popularly called city gates, the pressure of natural gas transported on long pipelines is reduced by traditional pressure regulating systems. Energy is lost as a result of pressure reduction. Pressure reduction also results in severe cooling of the gas due to the Joule Thompson effect, thus, requiring preheating of the natural gas using traditional gas fired-burners. The thermal energy generated results in the emission of green house gases. The DFC-ERG system is a novel waste energy recovery and green house gas mitigation system that can replace traditional pressure regulating systems on city gates. A DFC-ERG system has been simulated using UniSim Design process simulation software. A case study using data from Utilities Kingston’s city gate at Glenburnie was analysed. The waste energy recovery system was modelled using the design specifications of the FuelCell Energy Inc’s DFC 300 system and turboexpander design characteristics of Cryostar TG120. The Fuel Cell system sizing was based on the required thermal output, electrical power output, available configuration and cost. The predicted performance of the fuel cell system was simulated at a current density of 140mA/cm2, steam to carbon ratio of 3, fuel utilization of 75% and oxygen utilization of 30%. The power output of the turboexpander was found to strongly depend on the high pressure natural gas flowrate, temperature and pressure. The simulated DFC-ERG system was found to reduce CO2 emissions when the electrical power generated by the DFC-ERG system replaced electrical power generated by a coal fired plant. / Thesis (Master, Chemical Engineering) -- Queen's University, 2010-08-31 02:02:11.392

Limitations in energy recovery technology require extended research for development of existing and alternative solutions. This thesis project has treated valuing pneumatic drivetrain independent energy recovery system as a potential solution. The prototype built during this project uses a piston compressor to transform kinetic energy into compressed air. The compressed air was then stored in two air tanks and transformed into kinetic energy with an air motor on demand. The prototype was built on a rig using a high power electrical engine to simulate energy input from the wheels during braking. The air motor was then used to rotate a Volvo S40 engine simulating energy output to the wheels. To further illustrate how the technology can be implemented in vehicles and to emphasize the variety of pneumatic energy recovery solutions a 3D CAD model was designed and other components was reflected. Such as using a screw compressor instead of piston and also using the compressor as a motor reducing the number of components optimizing the system. The system storing the kinetic energy does not mean that the vehicle can manage without an ordinary brake system. The regenerative braking effect rapidly reduces at lower speeds; therefore friction brake is still required in order to bring the vehicle to a complete halt.Analyses of strength of strained components acknowledge that limited energy recovery is possible without redimensioning the driveshaft´s. The limitation is regulated by the original dimension for engine load, with subject to the CV joint. Optimum positioning of the compressor due to the limited space in a modern vehicle is behind the gearbox in conjunction with the gearbox outgoing pinion for short energy transportation.Electrical energy recovery system is the solution with the highest potential on the market today but electrical vehicles covers just a fraction of the vehicle industry doe to technical and infrastructural limitations. Drivetrain independent pneumatic, hydraulic or mechanical energy recovery systems lay the foundation of a common ground for all vehicles and other waste energy machinery to use one energy recovery technology. The market research indicates that this type of technology is up-to-the-minute. / <p>Validerat; 20110106 (anonymous)</p>

The office environment is an important part of the workers’ performance and need therefore to be designed in a pleasant and functional way. The problem is not that today’s offices do not function but rather that these need to be improved to achieve better work results. Lighting and ventilation are big parts of the office environment. In this project will three offices be examined, and these are Archus, WSP and Sweco. Purpose: This study is done to find improvement measures for these three offices based on the examination of the light and ventilation conditions. The improvements that will be suggested are mainly based on a survey but also a study on how these two factors affect the employees’ performances. Method: To perform this project was a literature study, a case study and measurement of illuminance used. A survey om how the employees experience the office environment were also conducted. Drawings provided by the office managers were used to perform calculations of the airflow. Results: The survey shows that 73.5 percent of the 68 people who answered the survey feel comfortable in the current design of the offices. The rest feel that they lack privacy and a quiet environment. In addition, 82.4 percent are happy with the lighting situation and 69.1 percent with the air quality. Archus, WSP and Sweco all meet the required guidelines set for illuminance in an office with certain deficiency. For ventilation do Archus and Sweco meet the minimum requirements for airflow, but there are small differences between the dimensioned airflow and the minimum requirement for WSP. Conclusions: The conclusion of this study is that the three studied offices lack seclusion which affects the office workers’ ability to work. The current lighting, and the ventilation in smaller rooms also contribute worsened working conditions. Good lighting conditions is required to achieve good work results. The same applies to ventilation where the air flow is deficient in certain rooms and should be regulated. / Kontorsmiljön är en viktig del i arbetarnas prestation och ska därför utformas på ett trivsamt och funktionellt sätt. Problematiken är inte att dagens kontor inte fungerar utan att dessa kan förbättras för att uppnå goda arbetsresultat. Belysning och ventilation är stora delar inom ämnet och kontoren som undersöks i detta arbete är Archus, WSP och Sweco.  Syftet med studien är att ta fram förbättringsåtgärder för tre kontorslokaler utifrån en undersökning avseende belysnings- och ventilationsförhållanden. Förbättringsförslaget bygger främst på en enkät men även en studie om hur de två faktorer spelar in i medarbetarnas presterande.  För att utföra studien tillämpades ett antal olika metoder däribland en litteraturstudie för att sätta grund till arbetet, en fallstudie där ett studiebesök till de undersökta kontoren och mätningar utfördes. Även en enkät om hur medarbetarna upplever sina kontorsmiljöer gjordes. Ritningar som tillhandahölls av ansvariga på kontoren tillämpades för att utföra beräkningar av luftflödet.  I resultat visar enkäten att 73,5% av de 68 personer som besvarade enkäten känner sig bekväma i den nuvarande utformningen men att resterande att de saknar avskildhet och tystare miljö. Utöver det trivs 82,4% med belysningen och 69,1% med luftkvalitén i dagsläget.  Archus, WSP och Sweco uppfyller de riktvärden som ställs för belysningsstyrka i kontorslokaler med vissa avvikelser. För ventilation uppfyller Archus och Sweco minimikraven för luftflödet men för WSP förekommer det skillnader mellan minimikravet och det dimensionerade luftflödet.  Diskussionen visar att vid utförandet av mätningar var det svårt att anpassa omgivningen efter önskemål vilket medförde att vissa mätvärden avviker från verkligheten. Även för beräkning av ventilation uppstod oförväntade svårigheter som att tillgång till egna instrument för luftflödesmätning saknades samt brister i ritningar.  Slutsatserna som dras för arbetet är att de tre kontoren saknar avskildhet vilket påverkar kontorsarbetarnas arbetsförmåga. Även den nuvarande belysningen samt ventilationen i mindre rum bidrar med försämrade arbetsförhållanden. För att uppnå ett gott arbetsresultat krävs god belysning i verksamheten. Samma gäller för ventilation där luftflödet brister i vissa rum och bör regleras.