Maintaining IAQ (Internal Air Quality) and thermal comfort of occupants in buildings have been a challenge to overcome satisfying the two ends: criteria for sustainability and cost effectiveness. Although there was a movement for mechanical ventilation systems in the recent past, in addition to the cost involved, they are found to not deliver the desired air quality, lead to social consequences such as sick building syndrome, contribute to environmental consequences related to ozone-depleting substances with increasing energy consumption, generate noise and having difficulties in cleaning and maintaining. These consequences compelled research on natural ventilation systems, which were used in ancient buildings. Although it has been found that natural ventilation of buildings can become a substantial architectural design tool that leads to “breathing architecture,” fluctuations in indoor temperature and air quality makes depending entirely on natural ventilation less effective. The combination of natural and mechanical ventilation, the hybrid ventilation or mixed-mode ventilation, systems utilizes advantages and eliminates drawbacks from both mechanical and entirely dependent natural ventilation systems. Hybrid ventilation systems, which have been utilized in historical buildings, with less investment cost and reduction of energy usage have been found to be a solution to provide acceptable standards of IAQ and thermal comfort through natural air circulation in buildings. This research study was carried out to verify the effectiveness of a hybrid ventilation system in an auditorium built around 60 years back for its effectiveness as a provider of thermal comfort to its occupants. Computational Fluid Dynamic (CFD) modeling was carried out on a Finite Element (FE) model owing to its capability of offering a wide range of flexible analytical solutions, lower realization time and comparative cost effectiveness to experimental methods of modeling. This verification of the system has revealed that hybrid ventilation systems could provide effective thermal comfort in buildings designed specifically to allow circulation of air through the system. The results of the study were in agreement with measured data and the expected flow of air through the building when the thermal load due to metabolism of occupants was not included in the analysis. In addition, the expected results complied with similar studies on natural/hybrid ventilation systems. With the addition of the thermal load, as a uniform heat flux from the flow of the auditorium, it was observed that the conditioning of the air throughout the space was better than the without thermal load scenario. In the case modeling people as cylinders, with a convective heat flux, it was observed that the air flow direction changes and the seating level of the auditorium do not get sufficient air flow to maintain a comfortable air quality.  Ineffective simulation of the inlet louver was assumed to be the primary reason for this scenario and other reasons such as the seating arrangement modeling too could have effects on the result. As conclusions of the study it was found that the whole building system properties have to be selected, as the control component to produce operating commands, to circulate air through the building in accordance with the air flow: both velocity and patterns, required to maintain thermal comfort of all occupants. Air inflow could be through windows as acquisition components to collect indoor and outdoor climatic parameters and air outflow could be mechanically controlled through exhausted fans turning on or off as the operating component in the system. The result of the study ensures the method of solutions through CFD to be utilized to provide effective and less costly path to verify systems such as natural or hybrid air flow systems through buildings.  The whole system studied could be applied with suitable contextual modifications to any new location, with similar cost effective modeling, to produce less fuel consuming building systems leading to sustainability of built environment.

De nombreux procédés industriels utilisent ou génèrent des sources chaudes : fours, traitement de surface, soudage…Les dégagements de chaleur s’accompagnent généralement d’une dispersion de polluants dans l’atelier. Ainsi, la caractérisation des panaches de convection naturelle des sources thermiques est nécessaire au dimensionnement des installations de ventilation (hotte ou ventilation générale par déplacement d’air) pour l’assainissement des ambiances de travail. L’I.N.R.S a mis au point une méthode expérimentale pour caractériser en vraie grandeur le panache de sources thermiques de géométrie simple. Un banc d’essais a été réalisé et instrumenté à cet effet. Il est constitué d’une cellule aéraulique dont les dimensions sont 4,2 m x 4,8 m x 5,6 m équipé d’une centrale de traitement d’air et d’un système de ventilation permettant un déplacement vertical des flux d’air. La cellule est équipée d’un robot de déplacement tridimensionnel permettant le positionnement de sondes de température et de vitesses en tout point du volume. Les expérimentations menées étudient l’influence de la géométrie de la source sur les lois de développement de panache à partir de mesures de champs de température et de vitesse. Pour une même puissance thermique convectée, la géométrie des sources sera variée pour identifier son affluence sur le développement du panache. Une source cylindrique composée de cinq éléments d’aires identiques (4 cylindres identiques superposés et un disque supérieur) régulés indépendamment en température permettra de mener des études paramétriques sur des sources tridimensionnelles. De manière similaire une source rectangulaire modulable sera utilisée. / Many industrial processes use or generate hot sources: furnaces, surface treatment, welding... the releases of heat are generally accompanied by a dispersion of pollutants in the workshop. Thus, the characterization of the plumes of natural convection of the thermal sources is necessary to the dimensioning of the installations of ventilation (exhaust system localised or general ventilation by air volume displacement) for the cleansing of environments of work. I.N.R.S developed an experimental method to characterize in real-scale the plume of thermal sources of simple geometry. A test bench was realised and instrumented for this purpose. It consists of an aeraulic cell whose dimensions are 4,2 m x 4,8 m x 5,6 m equipped with a power station of treatment of air and with a system of ventilation allowing a vertical displacement of flows of air. The cell is equipped with a robot of three-dimensional displacement allowing the positioning of speed and temperature sensors in any point of volume. The carried out experiments study the influence of the geometry of the source on the laws of development of plume starting from measurements of fields of temperature and speed. For the same convective thermal power, the geometry of the sources will be varied to identify its multitude on the development of the plume. A cylindrical source made up of five elements of identical surfaces (4 superimposed identical cylinders and a higher disc) controlled independently in temperature will make it possible to undertake parametric studies on three-dimensional sources. In a similar way a flexible rectangular source will be used.

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MSc(Med), Physiotherapy, Faculty of Health Sciences, University of the Witwatersrand / Introduction Many patients that have suffered traumatic injuries require admission to Intensive Care Unit (ICU). Mechanical ventilation (MV) is deemed to be the defining event marking many ICU admissions. As many as 30% of admissions, and 90% of all critically ill patients will require at least a short period of MV. There are many risks and complications associated with prolonged MV, such as rate of pneumonia, morbidity and mortality, increased cost, hospital LOS, emotional distress and decreased bed availability. To minimize these risks and complications it is important that patients be weaned and extubated from MV at the earliest possible time. However, just as delayed weaning and extubation carries the risk of complications, premature extubation and subsequent re-intubation should be avoided where possible, as extubation failure leads to an eight-fold higher risk of infection and a twelve-fold increase in mortality. Weaning is the transition from ventilatory support to spontaneous breathing and can often be achieved easily, but may be difficult in up to 25% of patients. Numerous studies have shown the benefit of allied health care worker (nurses and physiotherapists) driven weaning protocols in decreasing MV days and costs. Purpose To determine if the use of a nurse and therapist-driven weaning protocol to wean and extubate long-term patients with trauma from MV in an open ICU results in decreased total MV days and ICU length of stay (LOS), and to determine time to spontaneous breathing trial (SBT) failure. Methods A weaning protocol was developed by the researcher using clinical guidelines compiled for the American Association for Respiratory Care, American College of Chest Physicians and American College of Critical Care Medicine. A total of 56 mechanically ventilated trauma patients were enrolled in two phases of the study. A prospective cohort of 28 patients (Phase I), weaned according to the protocol, was matched retrospectively with a historical cohort of 28 patients (Phase II), weaned according to physician preference. Pairs in the two groups were matched to be similar for gender, age, type and severity of injury. Data analyzed for both groups were number of MV days, number of ICU days, self-extubation and need for re-intubation. For Phase I patients, time to SBT failure and reason for failure was recorded. v Results and Discussion With respect to the mean MV days it was found that the two protocol groups did not differ significantly (p = 0.3 ; Phase I = 14.4 days vs Phase II = 16.3 days), although the two day reduction in MV was considered clinically significant in view of the complications associated with additional MV days. The difference of 0.25 days for length of ICU stay between the groups was not statistically significant (p = 0.9; Phase I = 20.8 days vs Phase II = 21 days), and demonstrates that a reduction in MV days may not necessarily result in a reduction of ICU LOS. Rate of re-intubation was similar in the two groups (Phase I = 3/28 vs Phase II = 4/28). Eleven patients (39%) in Phase I failed at least one SBT and four of these patients (36%) failed two SBTs prior to successful extubation. Failure of the first SBT occurred an average of 18 hours after onset of SBT. Injury severity scores for these patients were higher than the average for Phase I (16.1 vs 14.5). Mean MV time in this group was 20.5 days as opposed to 14.4 days in the total Phase I group. This indicates that these patients were more critically ill and that they may require longer SBTs than advocated in many studies. All patients failed SBT due to increased RR. Conclusion In this study of longer-term ventilated patients who had traumatic injury as reason for admission to ICU and mechanical ventilation, the use of a standardized protocol to assist with weaning and extubation from MV demonstrated a clinically significant reduction in total MV time, even though this did not reach statistical significance. The reduction in MV time did not lead to a reduction in ICU LOS, however it reduces the risks of ventilator-associated complications such as VAP. The use of a weaning and extubation protocol did not lead to a higher rate of re-intubation, demonstrating its safety for use in this patient population. This protocol was driven by nurses and physiotherapists, and the role of physiotherapists and nursing staff in weaning and extubation of patients from MV could be greatly expanded in the majority of ICUs in South Africa.

Energy use in buildings accounts for more than a third of global energy demand, with humans seeking to create comfortable internal environments year-round. In the UK, air or water active thermal mass systems have demonstrated viability at delivering energy efficient comfort to office spaces. Whilst an attractive proposition, there are limitations to the cooling capacity and dynamic thermal response, giving rise to overheating in poorly designed buildings. The thesis work presented documents the investigation into active thermal mass enhancement to a prototype ventilated hollow core sample. Through engineering modelling (CFD, Excel VBA and IES) and laboratory (DSC, component and thermal chamber) testing two solutions were tested (an active-PCM module suitable for retrofit and embedded cool water pipes), with results conveying a 1 to 3°C temperature reduction and 0.1 to 0.2 kWh/m2/day AC savings during summer conditions. COP figures up to 10.6 were achieved through temperature set-point controlled water and air activated thermal mass. Economic analysis was conducted with positive results with the active-PCM module becoming viable for the UK’s non-domestic ‘Green Deal’ at a price point of approximately £300 per module. Following the laboratory led, and simulation supported work it was possible to conclude that active thermal mass enhancements can provide financially-viable energy-efficient, thermal-comfort for non-domestic UK properties. However the extent of the benefit depends heavily on the building thermal demands, available technology and optimised system control. Further work should be conducted to; develop additional modelling tools, underpinned by the laboratory data generated, and optimise the novel active-PCM technology, suitable for lucrative target markets.

In order to replace a conventional air-conditioner (AC) based on vapour compression technology that directly has high global warming potential and also currently consumes the most fossil fuel primary energy in building sector of tropical countries for generating thermal comfort on sleeping purpose, other alternative green space cooling technologies, as thermoelectric cooling (TEC), has to be improved to have same performance with AC. This research aims to develop and investigate a performance of Solar-powered Thermoelectric Radiant Cooling (STRC) system, as the combination of TEC and radiant cooling (RC) that is well known in its low energy consumption advantage. The studies were conducted through calculations, CFD simulations, system performance simulations and experiments. The results of optimum STRC system design was proved to provide better thermal and air quality performances, while the result in energy performance was depended on the TEC’s COP and vapour condensation prevention. After novel developing of TEC’s cooling channel with combined helical and an oblique fin to induce effective secondary flows that highly reduced the TEC’s hot side temperature in this research, the COP was able to increase up to 175%. Meanwhile, a novel bio-inspired combined superhydrophobic and hydrophobic coating on RC panel were able to competently repel most condensed water droplets, leaving just tiny droplets that was hard to be seen by naked eye. Finally, the COP of STRC system from house model experiment in 1:100 scales under hot and high humid climate was as high as 2.1 that helped STRC to consume electricity 34% less than AC system. Along with other benefits, as no working fluid, noise-free and low maintenance needs, the return of investment (ROI) was studied to be only 5-6 years when being operated with grid electricity and 17-18 years with PV panel generated electricity.

Pappers- och massaindustrin stod år 2010 för 52 procent av den svenska industrins energianvändning, vilket motsvarade 76 TWh. Detta gör branschen intressant ur ett energieffektiviseringsperspektiv då små åtgärder kan leda till stora besparingar. Fiskeby Board AB är ett företag som tillverkar kartong baserad på returfiber. Då torkning- samt bestrykningsprocessen står för 2/3 av företagets energibehov föreligger intresse att använda energin på ett bättre sätt för att minska energibehovet och därav minska sina kostnader. Syftet med denna rapport var således att genomföra en energikartläggning av tork- samt bestrykningspartiet och utifrån resultaten presentera åtgärder för att minska energibehovet. Arbetet utfördes genom mätningar av lufttemperaturer och flöden, beräkningar, litteraturstudier samt intervjuer. De ytvikter som undersöktes var för vinterdrift 300 g/m2, 350 g/m2 samt 450 g/m2 och för sommardrift 450 g/m2. Resultaten visade att inläckaget till torkkåpan, som rekommenderas till 25 procent av totalt inflöde, var mellan 48 och 59 procent. Vidare påvisades även hypotesen om att det i regel används större mängd luft för att transportera bort vattnet från kartongen än vad som krävs. Detta på grund av att det inte finns någon reglering av värmeåtervinningsaggregatens fläktar, vilket medför att frånluften får ett lågt vatteninnehåll vid viss produktion. Ett annat viktigt resultat behandlar hetluftsystemet. Här bör ett visst undertryck föreligga i hetluftskåporna, men genomförda mätningar visade på att enbart en av tre hetluftskåpor erhöll detta undertryck. Åtgärdsförslagen som presenteras i rapporten behandlar bland annat de påträffade bristerna ovan. Ett förslag är att minska det våta frånluftsflödet samtidigt som den inläckande luften bör ersättas med redan uppvärmd luft från andra delar av anläggningen. Enligt förslaget kan detta göras genom att nyttja frekvensstyrda till- och frånluftsfläktar vilka styrs av frånluftens daggpunktstemperatur och nollnivån i torkkåpan. Denna lösning har potential att minska den årliga energianvändningen med 17,9 GWh vilket kan ge en kostnadsbesparing av 2,25 miljoner SEK per år. Ett annat åtgärdsförslag är att ta bort förbigångsventilerna till värmeåtervinningsaggregaten och låta ångtillförseln styras med enbart reglerventiler. Detta ger en potential att minska energibehovet med 0,47-0,64 GWh per år vilket skulle ge en kostnadsbesparing av 55 000-77 000 SEK per år. För hetluftsystemet finns potential att spara 0,64 GWh vilket skulle ge en kostnadsbesparing på 77 000 SEK per år. Det som behövs är ett manuellt reglerspjäll i kanalen från hetluftskåpa 1 alternativt hetluftskåpa 2, för att styra luftflödet och därav erhålla ett undertryck i systemet. Genom att sammanställa de tre mest rekommenderade åtgärdsförslagen skapas en möjlighet att spara 5,7 procent av Fiskeby Board ABs energibehov vilket skulle resultera i en årlig kostnadsreduktion av 2,41 miljoner SEK. Om en generalisering att även den övriga pappers- och massaindustrin besitter liknande potential finns möjlighet för denna bransch att årligen minska energianvändningen med 4,4 TWh.

Sweden is a country that has made some progress in developing energy efficient solutions. The problem in Sweden is that many houses and apartment buildings are old and have inefficient ventilation- and heating systems. This energy is lost when systems are inefficient, which then results in huge economic costs. Luckily, more and more people are becoming aware of this, which means that Sweden is on track to become even better within energy efficiency.Energy use for the housing- and service sector amounts to 166 TWh of total use at 616 TWh. Without distribution and conversion losses, these figures show that the housing- and service sector accounts for almost 40 % of the country's total energy consumption. As a part of this sector, there is in downtown Umeå a building complex named Thor that is contributing significantly to the energy consumption of the area. Thor is a building complex whose first phase of construction began in 1963 and has since then been built on over the years. The complex has several inefficient parts that waste energy and thus gives rise to substantial economic costs. In the Thor-building there are numerous venues in place with a large variety of stores. On the groundfloor there are some business premises. The rest of the houses consist of either offices- or apartment spaces. This gives rise to large air handling units and heating systems that must be able to deliver suffiecient power when required.This work is an investigation of the building complex Thor and its purpose is to find parts that are inefficient energy-wise and be able to provide suggestions for various improvements that would reduce costs and create profit with a short payback time.The investigated parts are the following: • Roof insulation • Exhaust fan to the loading bay • Supply and exhaust fans, "Tower" • Supply and exhaust fans, Kungsgatan 58 • Comfort Cooling • Heating coils • Main fuses The energy consumption for the different areas have been divided into two different parts, electricity- and heat consumption. Electricity consumption is roughly 500 MWh per year and the heat consumption is around 1020 MWh per year. This is only the consumption of the areas that have been investigated. After the energy efficient actions will be made, the heat use will instead decrease to 213 MWh, which is a considerable improvement. Electricity consumption after the actions will increase, but because of the economical electricity agreement Thor possesses, it will ultimately pay off. Straight pay off for heat exchangers in the "Tower" and the supply- and exhaust fans at Kungsgatan 58 is 2,09 year and 2,11 years respectively.This proves that large amounts of energy are lost to the surroundings, and that there is a big need of change.   A future project is to improve energy efficiency throughout the majority in large parts of Thor, so that one saves money rather than "blowing" it away. Riksbyggen was unsure if there were ventilation aggregates large enough to clear off the necessary volume flows at Kungsgatan 58. This report proved that they did in fact exist. The result of this report bodes well for future efforts to improve energy efficiency at Thor. This report can serve as a basis for future work. / Sverige är ett land som har kommit en bit i utvecklingen gällande energieffektiva lösningar. Problemet i Sverige är att många villor och flerbostadshus är gamla och har ineffektiva ventilation- och värmesystem. Denna energi går förlorad när systemen är ineffektiva vilket sedan resulterar i stora ekonomiska kostnader. Som tur är har fler och fler fått upp ögonen för detta vilket gör att Sverige är på god väg att bli ännu mer energieffektiva.   Energianvändningen för bostads- och servicedelen uppgår till 166 TWh av landets totala användning på 616 TWh. Dessa siffror visar att bostads- och servicedelen står för nästan 40 % av landets totala energianvändning. Inom denna faktor har ett område i Umeå stad ”dragit sitt strå i stacken” av användingen och detta område heter Thor. Thor är en bostadsrättsförening och började byggas 1963 och sedan byggts på under årens lopp. Området har flera ineffektiva delar som slösar energi och detta ger upphov till stora ekonomiska kostnader. De hus som finns på plats idag har olika typer av lokaler. På bottenvåningarna finns affärslokaler och resten av husen består av antingen kontorslokaler eller lägenheter. Detta ger upphov till stora ventilationsaggregat och värmesystem som ska klara att leverera rätt effekt när det behövs.   Detta arbete är en utredning av området för att hitta delar som är ineffektiva och för att sedan kunna ge förslag på olika förbättringar som skulle minska framförallt energi, kostnader och skapa vinst inom kort. De delar som har undersökts är: Takisolering Frånluftsfläkt till lastbrygga Till- och frånluftsfläktar, ”Tornet” Till- och frånluftsfläktar, Kungsgatan 58 Komfortkyla Värmeslingor Huvudsäkringar     Energiförbrukningen för de olika områdena har delats in i två olika delar, Elförbrukning och Värmeförbrukning. Elförbrukning hamnar på 529 MWh per år och värmeförbrukningen hamnar på 1020 MWh per år. Detta är då enbart för de områden som har utretts. Efter energieffektivisering av dessa så hamnar värmeanvändningen istället på 213 MWh vilket är betydligt mindre. Elförbrukningen kommer att höjas efter installation av aggregaten, men på grund av elpriserna som bostadsrättsföreningen har så kommer det löna sig relativt fort. Rak payofftid för värmeväxlare på ”Tornet” och till- och frånluftsfläktarna på Kungsgatan 58 ligger på vardera område på cirka 2 år. Detta är då ett bevis på att stora mängder energi går förlorad på detta område och därmed är det i stort behov av förändring   Ett framtida arbete är att energieffektivisera på stora delar av Thor så man sparar pengar och energi istället för att ”blåsa” bort dem. Riksbyggen var osäkra om det fanns aggregat som klarade flödena på Kungsgatan 58, vilket denna rapport bevisade. Resultaten från denna rapport bådar gott för framtida arbete för att energieffektivisera Thor. Denna rapport kan då ligga som grund till arbetet.

Syftet med detta examensarbete är att konkretisera och visa på de grundläggande problemen med inomhusklimatet i Brogårdsfabriken i Vetlanda, för att utifrån detta komma fram med åtgärdsförslag för att minska dem. Detta samt att utreda möjligheterna att ta till vara den i fabriken internt genererade överskottsvärmen och minska energianvändningen. Arbetet har skett i ett top-down-perspektiv, vilket betyder att fabriken ses som ett slutet system där tillförd energi in i systemet ställs mot bortförd energi ut ur systemet. Stor del av arbetet har bedrivits i simuleringsprogrammet IDA – Indoor Climate and Energy till vilket data samlats in genom fysiska mätningar i fabriken och genom intern dokumentation på företaget. Problemen med inomhusklimatet för de anställda ute i produktionen är av olika karaktär i olika delar av fabriken och varierar även i intensitet beroende på vilken tid på året som studeras. Dock är de bakomliggande orsakerna till problemen alltid desamma. Det handlar bland annat om bristfällig processventilation, stora öppna lokaler som är svårkontrollerade, problem med infiltration genom portar och andra öppningar i klimatskalet. Förslag att återskapa en tidigare befintlig vägg rekommenderas för att lösa problemet med kalldrag i packhallen. Väggen skulle förhindra luftrörelser i områden där problemen upplevs och nästintill eliminera dem. Fokus på att minska energianvändningen har skett genom att titta på en optimering av ventilationsdriften vilket har resulterat i en kostnadsbesparing på cirka 370 tkr/år vid reducering av driften under enbart helger. Det finns ytterligare potential till kostnadsbesparingar för ventilationsdriften under andra tillfälliga driftstopp eller semesterstängningar av fabriken, om ventilationsdriften anpassas efter detta.

Den traditionella båsladugården har idag utvecklats till lösdriftstallar där korna har fri tillgång till foder och liggplatser. Korna mjölkas i antingen mjölkgrop, karusell eller av en robot. För att uppnå bra termisk komfort i lösdriftsstallen så använder man sig av naturlig eller mekanisk ventilation. I detta arbete så undersöks några olika ventilationssystem som använder sig av naturlig ventilation på fem utvalda kostall för att se hur de fungerar i praktiken. Detta görs med fukt- och temperaturmätare och med rökpatroner för att se hur luften rör sig i stallet. Resultatet analyseras för att se om det är något ventilationssystem som sticker ut jämför med de andra. Beskrivning kring hur man skulle kunna gå tillväga vid en vidare utveckling av detta arbete diskuteras.