24 research outputs found
A comparative evaluation of alternative optimization strategies for a novel heliostat-driven hydrogen production/injection system coupled with a vanadium chlorine cycle
Attenuation of haloperidol induced orofacial dyskinesia by ginkgo biloba extract
 Introduction: Tardive dyskinesia is one of the major side effects of long-term neuroleptic treatment. Increased reactive oxygen species and oxidative stress has been proposed as possible etiopathologic mechanisms. Ginkgo biloba extract (EGB) is a natural antioxidant. We investigated the effects of ginkgo biloba extract on neuroleptic-induced orofacial dyskinesia in rats, a potential animal model for tardive dyskinesia.Methods: Orofacial dyskinesia was induced by chronic administration of haloperidol (1 mg/kg i.p) for a period of 21 days. On 22nd day, animals were assessed for development of oral dyskinesia. Malon di aldehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and catalase levels were evaluated in animal forebrain homogenate.Results: Chronic haloperidol (1 mg/kg) treatment significantly increased the vacuous chewing movementâs frequency, increased MDA and decreased SOD and catalase levels. Co-administration of EGB 25 mg/kg along with haloperidol suppressed the haloperidol induced vacuous chewing movements (Pvalue < 0.05). EGB 100 mg/kg reversed haloperidol induced reduction in SOD level. It also reversed the increment in MDA level observed in haloperidol treated rats.Conclusion: The present study suggested that oxidative stress plays a significant role in neuroleptic-induced orofacial dyskinesia and EGB co-administration reverses these behavioral and biochemical changes.Declaration Interest: None
Advances in Ventilation Heat Recovery : An assessment of peak loads shaving using renewables
The building sector accounts for approximately 40% of total global energy usage.In residential buildings located in cold climate countries, 30-60% of this energy isused for space heating, 20â30% is lost by discarded residential wastewater, and therest is devoted to ventilation heat loss.Sweden experienced a construction boom during the so-called Million Programme(MP) in the 1960s and 1970s. A retrofit requirement of buildings constructed duringthis era shifted from pure exhaust ventilation to mechanical ventilation with heatrecovery (MVHR), which peaked in Swedish dwellings between 1990 and 2000. It isestimated that 43% of Swedish multi-family buildings built during this decade wereequipped with MVHR systems. A common problem with efficient MVHR systemsis frost formation during cold winter hours when cold outdoor air and humid, warmreturn air exchange heat in the air handling unit. Outdoor air preheating usinglocally available renewable heat sources has been an alternative solution to preventfrost formation in the heat exchanger.The main objective of this work was to investigate the solutions for improving theperformance of MVHR systems during the coldest periods of the year. The primaryfocus was frosting, a critical problem in MVHR units that operate duringcold periods. The recovered heat from discarded wastewater and the local geothermalenergy were the two investigated renewable heat sources used to preheat theincoming cold outdoor air to the MVHR in order to prevent frost formation on theheat exchanger surface.The performance of the suggested outdoor air preheating systems and the impactof air preheating on the entire systemâs thermal efficiency were evaluated by TRNSYSdynamic simulations. Temperature control systems were proposed based onthe identified frost thresholds to efficiently use the limited thermal capacity ofwastewater and maintain a high heat recovery of MVHR. Two outdoor air preheatingsystems configurations with temperature-stratified and -unstratified tanks weredesigned and compared. A life cycle cost analysis was applied to further investigatethe cost-effectiveness of the studied systems.Detailed heat transfer simulation of the ventilation heat exchanger revealed thatwhen condensation occurred in the heat exchanger, the heat transfer rate betweenthe return airflow and the plate increased significantly. This was reflected by asharp increase in the plate temperature, increasing the supply air temperature tothe building. Monitoring the relative humidity of the airflow at the inlet of theheat exchanger and using the onset values of frosting/condensation suggested in this work will allow a more precise and proactive prediction of freezing and moreefficient utilization of outdoor air preheating resources.The results obtained from the simulation of building energy usage indicated thatresidential wastewater had sufficient thermal potential to reduce the defrosting needfor MVHR systems (equipped with a plate heat exchanger) in central Swedish citiesto 25%. For colder regions in northern Sweden, the defrosting time was decreased by50%. The suggested temperature control systems ensured high MVHR temperatureefficiencies above 80% for most of the heating season, while the frosting period wasminimized. LCC analysis revealed that outdoor air preheating systems equippedwith temperature stratified wastewater tank and an unstratified storage tank couldpay off their investment costs in 17 and 8 years, respectively.Byggsektorn stĂ„r för cirka 40% av den totala globala energianvĂ€ndningen. I bostadshus belĂ€gna i lĂ€nder med kallt klimat anvĂ€nds 30â60% av denna energi för uppvĂ€rmning av rum, 20â30% gĂ„r förlorat i utgĂ„ende avloppsvatten och resten Ă€r ventilationsvĂ€rmeförluster. Sverige upplevde en byggboom under det sĂ„ kallade miljonprogrammet (MP) pĂ„ 1960- och 1970-talen. Byggnader frĂ„n denna tid har haft behov av renovering frĂ„n ren frĂ„nluftsventilation till mekanisk ventilation med vĂ€rmeĂ„tervinning (FTX). OmstĂ€llningen nĂ„dde sin topp mellan 1990 och 2000. Uppskattningsvis 43% av svenska flerfamiljshus byggda under detta decennium utrustade med FTX-system. Ett vanligt problem med effektiva FTX-system Ă€r frostbildning under kalla vintertimmar nĂ€r kall uteluft och fuktig, varm returluft har vĂ€rmeutbyte i aggregatet. FörvĂ€rmning av uteluft med lokalt tillgĂ€ngliga förnybara vĂ€rmekĂ€llor har varit en lösning för att förhindra frostbildning i vĂ€rmevĂ€xlaren. Huvudsyftet med detta arbete var att undersöka lösningar som förbĂ€ttrar prestandan hos FTX-system under Ă„rets kallaste perioder. Det primĂ€ra fokuset var frostbildning, ett kritiskt problem i MVHR-enheter som Ă€r i drift under kalla perioder. I denna undersökning var Ă„tervunnen vĂ€rme ur utgĂ„ende avloppsvatten och lokal geotermisk energi tvĂ„ förnybara vĂ€rmekĂ€llorna som anvĂ€ndes för att förvĂ€rma den inkommande kalla utomhusluften till FTX-systemet. Detta för att förhindra frostbildning pĂ„ vĂ€rmevĂ€xlarens ytor. Prestandan hos föreslagna förvĂ€rmningssystem för inkommande utomhusluft liksom luftförvĂ€rmningens inverkan pĂ„ hela termiska systemeffektiviteten utvĂ€rderades med dynamiska simuleringar i TRNSYS. Temperaturkontrollsystem, baserade pĂ„ identifierade trösklar för frostbildning, föreslogs för att effektivt kunna nyttja det begrĂ€nsade termiska energiinnehĂ„llet i avloppsvattnet och fĂ„ hög vĂ€rmeĂ„tervinning med FTX. TvĂ„ konfigurationer för förvĂ€rmning av utomhusluft med temperaturskiktade respektive oskiktade tankar skapades och jĂ€mfördes. Livscykelkostnadsanalys anvĂ€ndes för att ytterligare undersöka kostnadseffektiviteten hos de studerade systemen. Detaljerad simulering av vĂ€rmeöverföring i ventilationsvĂ€rmevĂ€xlare visade att nĂ€r kondens uppstod i vĂ€rmevĂ€xlaren ökade vĂ€rmeöverföringen mellan returluftflödet och plattan avsevĂ€rt. Detta resulterade i kraftig ökning av platttemperaturen och ökade tilluftstemperaturen till byggnaden. Ăvervakning av relativa luftfuktigheten i luftflödet vid vĂ€rmevĂ€xlarens inlopp och anvĂ€ndning av i detta arbete föreslagna startvĂ€rdena för frostbildning/kondensering, kommer att möjliggöra en noggrannare proaktiv förutsĂ€gelse av tillfrysningen. Det innebĂ€r ocksĂ„ effektivare utnyttjande av utomhusluftens potential för förvĂ€rmning. Resultaten frĂ„n simuleringar av byggnaders energianvĂ€ndning visade att avloppsvatten frĂ„n bostĂ€der har termisk potential att minska avfrostningsbehovet. Med FTX-system och plattvĂ€rmevĂ€xlare i mellersta Sverige kunde avfrostningsbehovet i vissa fall minska till 25%. För kallare regioner i norra Sverige minskade avfrostningstiden med 50%. De föreslagna temperaturkontrollsystemen sĂ€kerstĂ€llde hög FTX-temperatureffektivitet, dvs. över 80% under större delen av uppvĂ€rmningssĂ€songen, samtidigt som perioden för frostbildning minimerades. LCC-analys visade att förvĂ€rmningssystem för utomhusluft utrustade med temperaturskiktad avloppsvattentank, alternativt oskiktad lagringstank kunde betala av sina investeringskostnader pĂ„ 17 respektive 8 Ă„r.QC 20220422</p
Sustainable building ventilation solutions with heat recovery from waste heat
The energy used by building sector accounts for approximately 40% of the total energy usage. In residential buildings, 30-60% of this energy is used for space heating which is mainly wasted by transmission heat losses. A share of 20-30% is lost by the discarded residential wastewater and the rest is devoted to ventilation heat loss. Â The main objective of this work was to evaluate the thermal potential of residential wastewater for improving the performance of mechanical ventilation with heat recovery (MVHR) systems during the coldest periods of year. The recovered heat from wastewater was used to preheat the incoming cold outdoor air to the MVHR in order to avoid frost formation on the heat exchanger surface. Â Dynamic simulations using TRNSYS were used to evaluate the performance of the suggested air preheating systems as well as the impact of air preheating on the entire system. Temperature control systems were suggested based on the identified frost thresholds in order to optimally use the limited thermal capacity of wastewater and maintain high temperature efficiency of MVHR. Two configurations of air preheating systems with temperature stratified and unstratified tanks were designed and compared. A life cycle cost analysis further investigated the cost effectiveness of the studied systems. Â The results obtained by this research work indicated that residential wastewater had the sufficient thermal potential to reduce the defrosting need of MVHR systems (equipped with a plate heat exchanger) in central Swedish cities to 25%. For colder regions in northern Sweden, the defrosting time was decreased by 50%. The temperature control systems could assure MVHR temperature efficiencies of more than 80% for most of the heating season while frosting period was minimized. LCC analysis revealed that wastewater air preheating systems equipped with temperature stratified and unstratified storage tanks could pay off their costs in 17 and 8 years, respectively.QC 20190830</p
Sustainable building ventilation solutions with heat recovery from waste heat
The energy used by building sector accounts for approximately 40% of the total energy usage. In residential buildings, 30-60% of this energy is used for space heating which is mainly wasted by transmission heat losses. A share of 20-30% is lost by the discarded residential wastewater and the rest is devoted to ventilation heat loss. Â The main objective of this work was to evaluate the thermal potential of residential wastewater for improving the performance of mechanical ventilation with heat recovery (MVHR) systems during the coldest periods of year. The recovered heat from wastewater was used to preheat the incoming cold outdoor air to the MVHR in order to avoid frost formation on the heat exchanger surface. Â Dynamic simulations using TRNSYS were used to evaluate the performance of the suggested air preheating systems as well as the impact of air preheating on the entire system. Temperature control systems were suggested based on the identified frost thresholds in order to optimally use the limited thermal capacity of wastewater and maintain high temperature efficiency of MVHR. Two configurations of air preheating systems with temperature stratified and unstratified tanks were designed and compared. A life cycle cost analysis further investigated the cost effectiveness of the studied systems. Â The results obtained by this research work indicated that residential wastewater had the sufficient thermal potential to reduce the defrosting need of MVHR systems (equipped with a plate heat exchanger) in central Swedish cities to 25%. For colder regions in northern Sweden, the defrosting time was decreased by 50%. The temperature control systems could assure MVHR temperature efficiencies of more than 80% for most of the heating season while frosting period was minimized. LCC analysis revealed that wastewater air preheating systems equipped with temperature stratified and unstratified storage tanks could pay off their costs in 17 and 8 years, respectively.QC 20190830</p
Advances in Ventilation Heat Recovery : An assessment of peak loads shaving using renewables
The building sector accounts for approximately 40% of total global energy usage.In residential buildings located in cold climate countries, 30-60% of this energy isused for space heating, 20â30% is lost by discarded residential wastewater, and therest is devoted to ventilation heat loss.Sweden experienced a construction boom during the so-called Million Programme(MP) in the 1960s and 1970s. A retrofit requirement of buildings constructed duringthis era shifted from pure exhaust ventilation to mechanical ventilation with heatrecovery (MVHR), which peaked in Swedish dwellings between 1990 and 2000. It isestimated that 43% of Swedish multi-family buildings built during this decade wereequipped with MVHR systems. A common problem with efficient MVHR systemsis frost formation during cold winter hours when cold outdoor air and humid, warmreturn air exchange heat in the air handling unit. Outdoor air preheating usinglocally available renewable heat sources has been an alternative solution to preventfrost formation in the heat exchanger.The main objective of this work was to investigate the solutions for improving theperformance of MVHR systems during the coldest periods of the year. The primaryfocus was frosting, a critical problem in MVHR units that operate duringcold periods. The recovered heat from discarded wastewater and the local geothermalenergy were the two investigated renewable heat sources used to preheat theincoming cold outdoor air to the MVHR in order to prevent frost formation on theheat exchanger surface.The performance of the suggested outdoor air preheating systems and the impactof air preheating on the entire systemâs thermal efficiency were evaluated by TRNSYSdynamic simulations. Temperature control systems were proposed based onthe identified frost thresholds to efficiently use the limited thermal capacity ofwastewater and maintain a high heat recovery of MVHR. Two outdoor air preheatingsystems configurations with temperature-stratified and -unstratified tanks weredesigned and compared. A life cycle cost analysis was applied to further investigatethe cost-effectiveness of the studied systems.Detailed heat transfer simulation of the ventilation heat exchanger revealed thatwhen condensation occurred in the heat exchanger, the heat transfer rate betweenthe return airflow and the plate increased significantly. This was reflected by asharp increase in the plate temperature, increasing the supply air temperature tothe building. Monitoring the relative humidity of the airflow at the inlet of theheat exchanger and using the onset values of frosting/condensation suggested in this work will allow a more precise and proactive prediction of freezing and moreefficient utilization of outdoor air preheating resources.The results obtained from the simulation of building energy usage indicated thatresidential wastewater had sufficient thermal potential to reduce the defrosting needfor MVHR systems (equipped with a plate heat exchanger) in central Swedish citiesto 25%. For colder regions in northern Sweden, the defrosting time was decreased by50%. The suggested temperature control systems ensured high MVHR temperatureefficiencies above 80% for most of the heating season, while the frosting period wasminimized. LCC analysis revealed that outdoor air preheating systems equippedwith temperature stratified wastewater tank and an unstratified storage tank couldpay off their investment costs in 17 and 8 years, respectively.Byggsektorn stĂ„r för cirka 40% av den totala globala energianvĂ€ndningen. I bostadshus belĂ€gna i lĂ€nder med kallt klimat anvĂ€nds 30â60% av denna energi för uppvĂ€rmning av rum, 20â30% gĂ„r förlorat i utgĂ„ende avloppsvatten och resten Ă€r ventilationsvĂ€rmeförluster. Sverige upplevde en byggboom under det sĂ„ kallade miljonprogrammet (MP) pĂ„ 1960- och 1970-talen. Byggnader frĂ„n denna tid har haft behov av renovering frĂ„n ren frĂ„nluftsventilation till mekanisk ventilation med vĂ€rmeĂ„tervinning (FTX). OmstĂ€llningen nĂ„dde sin topp mellan 1990 och 2000. Uppskattningsvis 43% av svenska flerfamiljshus byggda under detta decennium utrustade med FTX-system. Ett vanligt problem med effektiva FTX-system Ă€r frostbildning under kalla vintertimmar nĂ€r kall uteluft och fuktig, varm returluft har vĂ€rmeutbyte i aggregatet. FörvĂ€rmning av uteluft med lokalt tillgĂ€ngliga förnybara vĂ€rmekĂ€llor har varit en lösning för att förhindra frostbildning i vĂ€rmevĂ€xlaren. Huvudsyftet med detta arbete var att undersöka lösningar som förbĂ€ttrar prestandan hos FTX-system under Ă„rets kallaste perioder. Det primĂ€ra fokuset var frostbildning, ett kritiskt problem i MVHR-enheter som Ă€r i drift under kalla perioder. I denna undersökning var Ă„tervunnen vĂ€rme ur utgĂ„ende avloppsvatten och lokal geotermisk energi tvĂ„ förnybara vĂ€rmekĂ€llorna som anvĂ€ndes för att förvĂ€rma den inkommande kalla utomhusluften till FTX-systemet. Detta för att förhindra frostbildning pĂ„ vĂ€rmevĂ€xlarens ytor. Prestandan hos föreslagna förvĂ€rmningssystem för inkommande utomhusluft liksom luftförvĂ€rmningens inverkan pĂ„ hela termiska systemeffektiviteten utvĂ€rderades med dynamiska simuleringar i TRNSYS. Temperaturkontrollsystem, baserade pĂ„ identifierade trösklar för frostbildning, föreslogs för att effektivt kunna nyttja det begrĂ€nsade termiska energiinnehĂ„llet i avloppsvattnet och fĂ„ hög vĂ€rmeĂ„tervinning med FTX. TvĂ„ konfigurationer för förvĂ€rmning av utomhusluft med temperaturskiktade respektive oskiktade tankar skapades och jĂ€mfördes. Livscykelkostnadsanalys anvĂ€ndes för att ytterligare undersöka kostnadseffektiviteten hos de studerade systemen. Detaljerad simulering av vĂ€rmeöverföring i ventilationsvĂ€rmevĂ€xlare visade att nĂ€r kondens uppstod i vĂ€rmevĂ€xlaren ökade vĂ€rmeöverföringen mellan returluftflödet och plattan avsevĂ€rt. Detta resulterade i kraftig ökning av platttemperaturen och ökade tilluftstemperaturen till byggnaden. Ăvervakning av relativa luftfuktigheten i luftflödet vid vĂ€rmevĂ€xlarens inlopp och anvĂ€ndning av i detta arbete föreslagna startvĂ€rdena för frostbildning/kondensering, kommer att möjliggöra en noggrannare proaktiv förutsĂ€gelse av tillfrysningen. Det innebĂ€r ocksĂ„ effektivare utnyttjande av utomhusluftens potential för förvĂ€rmning. Resultaten frĂ„n simuleringar av byggnaders energianvĂ€ndning visade att avloppsvatten frĂ„n bostĂ€der har termisk potential att minska avfrostningsbehovet. Med FTX-system och plattvĂ€rmevĂ€xlare i mellersta Sverige kunde avfrostningsbehovet i vissa fall minska till 25%. För kallare regioner i norra Sverige minskade avfrostningstiden med 50%. De föreslagna temperaturkontrollsystemen sĂ€kerstĂ€llde hög FTX-temperatureffektivitet, dvs. över 80% under större delen av uppvĂ€rmningssĂ€songen, samtidigt som perioden för frostbildning minimerades. LCC-analys visade att förvĂ€rmningssystem för utomhusluft utrustade med temperaturskiktad avloppsvattentank, alternativt oskiktad lagringstank kunde betala av sina investeringskostnader pĂ„ 17 respektive 8 Ă„r.QC 20220422</p
Sustainable building ventilation solutions with heat recovery from waste heat
The energy used by building sector accounts for approximately 40% of the total energy usage. In residential buildings, 30-60% of this energy is used for space heating which is mainly wasted by transmission heat losses. A share of 20-30% is lost by the discarded residential wastewater and the rest is devoted to ventilation heat loss. Â The main objective of this work was to evaluate the thermal potential of residential wastewater for improving the performance of mechanical ventilation with heat recovery (MVHR) systems during the coldest periods of year. The recovered heat from wastewater was used to preheat the incoming cold outdoor air to the MVHR in order to avoid frost formation on the heat exchanger surface. Â Dynamic simulations using TRNSYS were used to evaluate the performance of the suggested air preheating systems as well as the impact of air preheating on the entire system. Temperature control systems were suggested based on the identified frost thresholds in order to optimally use the limited thermal capacity of wastewater and maintain high temperature efficiency of MVHR. Two configurations of air preheating systems with temperature stratified and unstratified tanks were designed and compared. A life cycle cost analysis further investigated the cost effectiveness of the studied systems. Â The results obtained by this research work indicated that residential wastewater had the sufficient thermal potential to reduce the defrosting need of MVHR systems (equipped with a plate heat exchanger) in central Swedish cities to 25%. For colder regions in northern Sweden, the defrosting time was decreased by 50%. The temperature control systems could assure MVHR temperature efficiencies of more than 80% for most of the heating season while frosting period was minimized. LCC analysis revealed that wastewater air preheating systems equipped with temperature stratified and unstratified storage tanks could pay off their costs in 17 and 8 years, respectively.QC 20190830</p
Behavioral Analysis of Volvo Cars Instrument Panel During Airbag Deployment
Airbags are a passive safety technology, required to function with zero failure rate. Advances in Computer Aided Engineering have allowed vehicle manufacturers to predict material and system behavior in the event of a crash. The sudden and rapid nature of a vehicle frontal crash, together with strict requirements put on safety make this a sensitive task. This thesis focuses on the front passenger airbag deployment and the instrument panelâs response. Various airbag modelling techniques are studied and presented in this document. This work is part of a larger-scale attempt to model a generic-sled that is physically representative of a real vehicle. Various component tests are to be performed in the sled environment, as opposed to a real vehicle, to save costs. Various modules are added to the sled once their behavior is verified by testing and in simulations. Software are advanced enough to identify location and magnitude of stress concentrations that develop during crash. LS-DYNA is used for explicit finite element simulations of the instrument panel (IP) in question with different airbag models. Verification has been achieved by design of experiment (DOE); with tests conducted to capture both the movements of the airbag housing and IP movements in response. These movements are broken down in various phases, facilitating implementation in the sled environment. Simplifications are made both to the computer models as well as the physical testing environment. The effects of these simplifications are quantified and discussed. Theoretical background is provided where fit while assumptions are justified wherever made. DYNAmore recommendations regarding costeffective calculations as well as result verification are followed. The obtained results show that the FE models replicate the real event with acceptable precision. The findings in this work can, by minor tweaks, be implemented on other IP models in the Volvo Cars range, leading to cost-saving solutions. This thesis provides the necessary information for sled implementations as well as future improvement suggestions.Krockkudde Ă€r en s.k. passiv sĂ€kerhetsteknik som krĂ€vs att fungera felfritt. Framsteg inom Computer Aided Engineering har tillĂ„tit biltillverkare att förutsĂ€ga material och systembeteende i samband med krock. Den plötsliga karaktĂ€ren av krock, tillsammans med höga sĂ€kerhetskrav, gör detta till en kĂ€nslig uppgift. Denna avhandling fokuserar pĂ„ passagerarsidans krockkudde och instrumentbrĂ€dans (IP) respons under uppblĂ„sning. Olika metoder för modellering av krockkuddar har studerats och presenteras i detta dokument. Arbetet Ă€r en del av en större skala försök att modellera en generisk-slĂ€de som Ă€r fysiskt representativ av en riktig bil; dĂ€r olika komponent-tester skall utföras för att minska kostnader. NĂ€r olika modulers beteende verifieras lĂ€ggs de till slĂ€den. Denna verifiering sker genom finita element (FE) simuleringar sĂ„ vĂ€l som fysiska tester. FE mjukvara Ă€r idag tillrĂ€ckligt avancerad för att identifiera samt visualisera spĂ€nningskoncentrationer som uppstĂ„r i en konstruktion vid krock. LS-DYNA anvĂ€nds i detta arbete för explicita FE simuleringar av en Volvo XC90 IP, lastad med olika krockkudde-modeller. Modell verifiering har uppnĂ„tts genom försöksplanering (DOE); med tester utförda för att fĂ„nga rörelser av IP sĂ„ vĂ€l som krockkudde-behĂ„llaren. Dessa rörelser Ă€r sedan uppdelade i olika faser för enklare genomförande i slĂ€de miljön. Förenklingar och antaganden görs bĂ„de till FE modeller och fysiska testmiljön. Effekter av dessa har kvantifierats och relevant teoretisk bakgrund har inkluderats. Dokumentet innehĂ„ller Ă€ven diskussion kring val av mĂ€tutrustning samt förbĂ€ttringsförslag för fortsatt arbete. DYNAmore rekommendationer gĂ€llande kostnadseffektiva berĂ€kningar och verifiering av simulerings-resultat har följts. Under arbetet visade sig att FE modellerna kan Ă„terskapa hĂ€ndelsen med hög noggrannhet; dessa trotts svĂ„righeter i modellering av plast material. Möjligtvis kan man, genom mindre modifieringar, relatera slutsatserna i detta arbete till olika IP modeller i företagets produktkatalog vilket förmodligen leder till ytterligare kostnadsbesparingar. Denna avhandling ger den information som behövs för genomföranden i den generiska miljön
Behavioral Analysis of Volvo Cars Instrument Panel During Airbag Deployment
Airbags are a passive safety technology, required to function with zero failure rate. Advances in Computer Aided Engineering have allowed vehicle manufacturers to predict material and system behavior in the event of a crash. The sudden and rapid nature of a vehicle frontal crash, together with strict requirements put on safety make this a sensitive task. This thesis focuses on the front passenger airbag deployment and the instrument panelâs response. Various airbag modelling techniques are studied and presented in this document. This work is part of a larger-scale attempt to model a generic-sled that is physically representative of a real vehicle. Various component tests are to be performed in the sled environment, as opposed to a real vehicle, to save costs. Various modules are added to the sled once their behavior is verified by testing and in simulations. Software are advanced enough to identify location and magnitude of stress concentrations that develop during crash. LS-DYNA is used for explicit finite element simulations of the instrument panel (IP) in question with different airbag models. Verification has been achieved by design of experiment (DOE); with tests conducted to capture both the movements of the airbag housing and IP movements in response. These movements are broken down in various phases, facilitating implementation in the sled environment. Simplifications are made both to the computer models as well as the physical testing environment. The effects of these simplifications are quantified and discussed. Theoretical background is provided where fit while assumptions are justified wherever made. DYNAmore recommendations regarding costeffective calculations as well as result verification are followed. The obtained results show that the FE models replicate the real event with acceptable precision. The findings in this work can, by minor tweaks, be implemented on other IP models in the Volvo Cars range, leading to cost-saving solutions. This thesis provides the necessary information for sled implementations as well as future improvement suggestions.Krockkudde Ă€r en s.k. passiv sĂ€kerhetsteknik som krĂ€vs att fungera felfritt. Framsteg inom Computer Aided Engineering har tillĂ„tit biltillverkare att förutsĂ€ga material och systembeteende i samband med krock. Den plötsliga karaktĂ€ren av krock, tillsammans med höga sĂ€kerhetskrav, gör detta till en kĂ€nslig uppgift. Denna avhandling fokuserar pĂ„ passagerarsidans krockkudde och instrumentbrĂ€dans (IP) respons under uppblĂ„sning. Olika metoder för modellering av krockkuddar har studerats och presenteras i detta dokument. Arbetet Ă€r en del av en större skala försök att modellera en generisk-slĂ€de som Ă€r fysiskt representativ av en riktig bil; dĂ€r olika komponent-tester skall utföras för att minska kostnader. NĂ€r olika modulers beteende verifieras lĂ€ggs de till slĂ€den. Denna verifiering sker genom finita element (FE) simuleringar sĂ„ vĂ€l som fysiska tester. FE mjukvara Ă€r idag tillrĂ€ckligt avancerad för att identifiera samt visualisera spĂ€nningskoncentrationer som uppstĂ„r i en konstruktion vid krock. LS-DYNA anvĂ€nds i detta arbete för explicita FE simuleringar av en Volvo XC90 IP, lastad med olika krockkudde-modeller. Modell verifiering har uppnĂ„tts genom försöksplanering (DOE); med tester utförda för att fĂ„nga rörelser av IP sĂ„ vĂ€l som krockkudde-behĂ„llaren. Dessa rörelser Ă€r sedan uppdelade i olika faser för enklare genomförande i slĂ€de miljön. Förenklingar och antaganden görs bĂ„de till FE modeller och fysiska testmiljön. Effekter av dessa har kvantifierats och relevant teoretisk bakgrund har inkluderats. Dokumentet innehĂ„ller Ă€ven diskussion kring val av mĂ€tutrustning samt förbĂ€ttringsförslag för fortsatt arbete. DYNAmore rekommendationer gĂ€llande kostnadseffektiva berĂ€kningar och verifiering av simulerings-resultat har följts. Under arbetet visade sig att FE modellerna kan Ă„terskapa hĂ€ndelsen med hög noggrannhet; dessa trotts svĂ„righeter i modellering av plast material. Möjligtvis kan man, genom mindre modifieringar, relatera slutsatserna i detta arbete till olika IP modeller i företagets produktkatalog vilket förmodligen leder till ytterligare kostnadsbesparingar. Denna avhandling ger den information som behövs för genomföranden i den generiska miljön
Life cycle cost analysis of air preheating systems using wastewater and geothermal energy
Frosting is a common problem in air handling units in buildings in cold climates. Tacklingthis problem is so far achieved by using considerable amount of energy while during thisprocess, the indoor air quality is compromised. This article presents the Life Cycle Cost(LCC) assessment of a preventive solution for frosting using two renewable heat sources.QC 20190802</p