Thesis (M. Tech. (Mech. Eng.)) -- Central University of Technology, Free state, 2010 / The purpose of this research is to minimize the use of active systems in providing thermal comfort in single-family detached, middle to high income residential buildings in Bloemfontein. The typical case study house was selected according to the criteria as reviewed by Mathews et al., (1999). Measurements were taken for seven days (18 – 24 May 2009). The measurements were carried out in the winter period for Bloemfontein, South Africa. Ecolog TH1, humidity and temperature data logger was used in doing the measurements. These measurements included indoor temperatures and indoor relative humidity. Temperature swings of 8.43 ºC and thermal lag of 1 hour were observed. For the period of seven days (168 hours), the house was thermally comfortable for 84 hours. Thermal analysis for the base case house was done using Ecotect™ (building analysis software) and the simulated results were compared with the measured results. A mean bias error (MBE) of between 10.3% ≤≤11.5% was obtained on the initial calibration. The final calibration of the model yielded error between0.364% ≤≤0.365%. The final calibration model which presented a small error was adopted as the base case. Passive strategies were incorporated to the Ecotect™ model (final calibrated model) singly and in combination; then both thermal and space load simulations were obtained and compared to simulations from the original situation (base case) for assessing improvements in terms of thermal comfort and heating, ventilation and air conditioning (HVAC) energy consumption. Annual HVAC electricity savings of up to 55.2 % were obtained from incorporating passive strategies in combination. Incorporating passive strategies resulted in small improvements in thermal comfort.

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning

I detta arbete studeras vilka möjligheter det finns för en av 3D hus kunders hus att klara kraven för passiv- eller minienergihus. Baserat på ett projekterat hus studeras hur olika konstruktioner och produktval påverkar husets möjlighet att uppfylla kraven. Trots att samtliga konstruktionsalternativ påstods vara anpassade för energisnåla hus visar vår undersökning att transmissionsförlusterna varierade mycket mellan de olika lösningarna. Även vilka garantier de olika företagen kunde ge gällande lufttäta konstruktioner varierade stort.De områdena som särskilt studeras i detta arbete är energiförluster genom en bostads klimatskal beroende av olika konstruktioner av väggarna, samt vilka fönster och dörrar som är lämpliga.Vår studie visar att utformningen av huset som studerats kommer kräva mycket höga krav på konstruktionen för att huset ska kunna nå kraven för ett passiv- eller minienergihus. Utformningen gör däremot att förlusterna varierar stort mellan de olika valen och det kan därför vara en god idé att se över vilka produkter som ska väljas inom de olika områdena. / This report considers the possibilities to build a passive house or mini-energy house within reasonable demands on manufacturers and construction firms for one of 3D House’s customers. The client has already been in contact with different manufacturers and construction firms with different demands, but with the same warranty of energy efficient materials. In this study there’s a comparison of these demands and warrants show that, even with the same stated terms of low efficient material, the transmission loss vary considerably. Especially the warrants for airtight constructions vary much.Because of the buildings shape it becomes clear that it would need very high requirement on the products and the work to meet the requirements for passive house. The shape of the house does on the other hand make sure that it's a big difference between the different products which would make it a good idea to look over the different chose.The areas there this report is in first hand how the different companies for walls because of that is an area there it's a big different between different choice and it's a big part of the climate shield. It will also have a look over what kind of windows and doors that exist that meet both the requirements for passive house and the costumer.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The potential benefits from saving energy have driven most industrial processing facilities to pay more attention to reducing energy wastage. Because the industrial sector is the largest user of electricity in South Africa (37.7% of the generated electricity capacity), the application of waste heat recovery and utilisation (WHR&U) systems in this sector could lead to significant energy savings, a reduction in production costs and an increase in the efficiency of industrial processes. Turbines are critical components of WHR&U systems, and the choice of an efficient and low cost turbine is crucial for their successful implementation. The aim of this thesis project is therefore to validate the use of a turbine for application in a low grade energy WHR&U system. An experimental turbine kit (Infinity Turbine ITmini) was acquired, assembled and tested in a specially designed and built air test bench. The test data was used to characterise the turbine for low temperature (less than 120 Celsius) and pressure (less than 10 bar) conditions. A radial inflow turbine rotor was designed, manufactured and then tested with the same test bench, and its performance characteristics determined. In comparison with the ITmini rotor, the as-designed and manufactured rotor achieved a marginally better performance for the same test pressure ratio range. The as-designed turbine rotor performance characteristics for air were then used to scale the turbine for a refrigerant-123 application. Future work should entail integrating the turbine with a WHR&U system, and experimentally determining the system’s performance characteristics. / AFRIKAANSE OPSOMMING: Die potensiële voordele wat gepaard gaan met energiebesparing het die fokus van industrie laat val op die bekamping van energievermorsing. Die industriële sektor is die grootse verbruiker van elektrisiteit in Suid-Afrika (37.7% van die totale gegenereerde kapasiteit). Energiebesparing in die sektor deur die toepassing van afval-energie-herwinning en benutting (AEH&B) sisteme kan lei tot drastiese vermindering van energievermorsing, ‘n afname in produksie koste en ‘n toename in die doeltreffendheid van industriële prosesse. Turbines is kritiese komponente in AEH&B sisteme en die keuse van ‘n doeltreffende lae koste turbine is noodsaaklik in die suksesvolle implementering van dié sisteme. Die doelwit van hierdie tesisprojek is dus om die toepassing van ‘n turbine in ‘n lae graad energie AEH&B sisteem op die proef te stel. ‘n Eksperimentele turbine stel (“Infinity Turbine ITmini”) is aangeskaf, aanmekaargesit en getoets op ‘n pasgemaakte lugtoetsbank. Die toetsdata is gebruik om die turbine te karakteriseer by lae temperatuur (minder as 120 Celsius) en druk (minder as 10 bar) kondisies. ‘n Radiaalinvloeiturbinerotor is ook ontwerp, vervaardig en getoets op die lugtoetsbank om die rotor se karakteristieke te bepaal. In vergelyking met die ITmini-rotor het die radiaalinvloeiturbinerotor effens beter werkverrigting gelewer by diselfde toetsdruk verhoudings. Die werksverrigtingkarakteristieke met lug as vloeimedium van die radiaalinvloeiturbinerotor is gebruik om die rotor te skaleer vir ‘n R123 verkoelmiddel toepassing. Toekomstige werk sluit in om die turbine met ‘n AEH&B sisteem te integreer en die sisteem se werksverrigtingkarakteristieke te bepaal.

Assignment (MPhil)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: Although there are serious hurdles to overcome before green, energy-efficient homes become common; the technological and market-based foundations are already in place to support a shift in standard practice. Many organizations, from the federal government to local non-profits, are driving the transition to more efficient homebuilding practices through research, market-based competition, and tax incentives. However, many builders are resisting the transition, due to the fragmented nature of the building industry and a perceived lack of consumer demand. Because of the nature of the US economy, until American consumers understand green homes and demand builders to build them, green homebuilding will not reach its full potential. If building practices are left unchanged, inefficient homes will continue to cause dire consequences to the world because of their contribution to global climate change. / AFRIKAANSE OPSOMMING: Hoewel daar ernstige struikelblokke bestaan, wat oorkom moet word alvorens groen, energie-doelmatige wonings algemeen raak, is die tegnologiese en markgerigte grondslae reeds gelê om ’n verskuiwing in standaard-praktyk te onderskraag. Verskeie instansies – van die federale regering tot nie-winsgewende organisasies – verleen stukrag deur middel van navorsing, markgerigte mededinging en belastingaansporings aan die oorgang na meer doelmatige gebruike rondom praktyke ten opsigte van die konstruksie van huise. Weens die gefragmenteerde aard van die boubedryf en die waarneembare gebrek aan verbruikersaanvraag staan talle bouers egter die vermelde oorgang teen. Weens die aard van die VSA se ekonomie en totdat Amerikaanse verbruikers groen tuistes kan verkoop en by bouers aandring om hulle op te rig, sal groen woningkonstruksie nie sy volle potensiaal bereik nie. Indien boupraktyke onveranderd gelaat word, sal ondoelmatige wonings as gevolg van hulle bydrae tot globale klimaatsverandering steeds aaklige gevolge vir die wêreld tot gevolg hê.

Thesis (MBA)--University of Stellenbosch, 2011. / The government has stated its intentions to increase the usage of solar water heating (SWH) through its National Solar Water Heater Programme (NSWHP). As described in the report, increased adoption of SWH would have a number of benefits for South Africa. Firstly, replacement of electric geysers by SWHs would contribute to the meeting of energy efficiency targets through the reduction of energy consumption. Secondly, the widespread adoption of SWHs would help SA to meet its renewable energy targets. Thirdly, it would result in growth in the SWH industry, including the manufacturing, installation and related sectors, thereby contributing to an increase in 'green' jobs. It would have the socio-economic benefit of energy security for South Africans. The research report looks at the factors influencing the SWH industry's future growth from the point of view of the suppliers. It considers the interplay between consumers (market demand), government (public policy measures) and suppliers (businesses providing services related to SWH) to determine how government can support industry, how suppliers can grow their business and industry and how government and industry can work together to create the conditions for sustained market demand. As is discussed in the literature review, there are certain barriers to the adoption of SWH technology. As such, government intervention is needed to help overcome these barriers. The literature review recounts the available policy tools and considers how these have been applied in other countries to stimulate demand for SWHs and to support the local industry. The research report takes the form of a survey of SWH suppliers with the following aims: - To describe the industry in terms of its age, maturity and ability to scale up; - To determine the major barriers to the industry's growth; - To specify the appropriate public policy tools to overcome these obstacles to growth; - To establish how confident the industry is in the NSWHP and government efforts to promote the industry; - To provide a list of key success factors that are required for the industry's long-term, sustainable development. The report concludes that there are three criteria that would help the industry to become sustainable: market demand certainty, investment confidence and positive competition. Certainty of future market demand would build confidence in the industry for investors. In turn, increased investment would benefit the forces of positive competition.

A very economical way of reducing the operational energy consumed by large commercial buildings such as an airport terminal is the automatic control of its active energy systems. Such control can adjust the indoor environment systems setpoints to satisfy comfort during occupancy or when unoccupied, initiate energy conservation setpoints and if necessary, shut down part of the building systems. Adjusting energy control setpoints manually in large commercial buildings can be a nightmare for facility managers. Incidentally for such buildings, occupancy based control strategies are not achieved through the use of conventional controllers alone. This research, therefore, investigated the potential of using a high-level control system in airport terminal building. The study presents the evolution of a novel fuzzy rule-based supervisory controller, which intelligently establishes comfort setpoints based on flow of passenger through the airport as well as variable external environmental conditions. The inputs to the supervisory controller include: the time schedule of the arriving and departing passenger planes; the expected number of passengers; zone daylight illuminance levels; and external temperature. The outputs from the supervisory controller are the low-level controllers internal setpoint profile for thermal comfort, visual comfort and indoor air quality. Specifically, this thesis makes contribution to knowledge in the following ways: It utilised artificial intelligence to develop a novel fuzzy rule-based, energy-saving supervisory controller that is able to establish acceptable indoor environmental quality for airport terminals based on occupancy schedules and ambient conditions. It presents a unique methodology of designing a supervisory controller using expert knowledge of an airport s indoor environment systems through MATLAB/Simulink platform with the controller s performance evaluated in both MATLAB and EnergyPlus simulation engine. Using energy conservation strategies (setbacks and switch-offs), the pro-posed supervisory control system was shown to be capable of reducing the energy consumed in the Manchester Airport terminal building by up to 40-50% in winter and by 21-27% in summer. It demonstrates that if a 45 minutes passenger processing time is aimed for instead of the 60 minutes standard time suggested by ICAO, energy consumption is significantly reduced (with less carbon emission) in winter particularly. The potential of the fuzzy rule-based supervisory controller to optimise comfort with minimal energy based on variation in occupancy and external conditions was demonstrated through this research. The systematic approach adopted, including the use of artificial intelligence to design supervisory controllers, can be extended to other large buildings which have variable but predictable occupancy patterns.

This work starts from the proposition that it is beneficial to conserve communication energy in Wireless Sensor Networks (WSNs). For WSNs there is an added incentive for energy-efficient communication. The power supply of a sensor is often finite and small. Replenishing the power may be impractical and is likely to be costly. Wireless Sensor Networks are an important area of research. Data about the physical environment may be collected from hostile or friendly environments. Data is then transmitted to a destination without the need for communication cables. There are power and resource constraints upon WSNs, in addition WSN networks are often application specific. Different applications will often have different requirements. Further, WSNs are a shared medium system. The features of the MAC (Medium Access Control) protocol together with the application behaviour shape the communication states of the node. As each of these states have different power requirements the MAC protocol impacts upon the operation and power consumption efficiency. This work focuses on the development of an energy conservation protocol for WSNs where direct communication between sources and a base station is feasible. Whilst the multi-hop approach has been regarded as the underlying communication paradigm in WSNs, there are some scenarios where direct communication is applicable and a significant amount of communication energy can be saved. The Power & Reliability Aware Protocol has been developed. Its main objectives are to provide efficient data communication by means of energy conservation without sacrificing required reliability. This has been achieved by using direct communication, adaptive power adaptation and intelligent scheduling. The results of simulations illustrate the significance of communication energy and adaptive transmission. The relationship between Received Signal Strength Indicator (RSSI) and Packet Reception Rate (PRR) metrics is established and used to identify when power adaptation is required. The experimental results demonstrate an optimal region where lower power can be used without further reduction in the PRR. Communication delays depend upon the packet size whilst two-way propagation delay is very small. Accurate scheduling is achieved through monitoring the clock drift. A set of experiments were carried out to study benefits of direct vs. multi-hop communication. Significant transmitting current can be conserved if the direct communication is used. PoRAP is compared to Sensor-MAC (S-MAC), Berkeley-MAC (B-MAC) and Carrier Sense Multiple Access (CSMA). Parameter settings used in the Great Duck Island (GDI) a production habitat monitoring WSNs were applied. PoRAP consumes the least amount of energy.

Det globala energibehovet ökar ständigt och i takt med detta ökar även faran för global uppvärmning bortom en hanterbar nivå och därför stramas kraven åt gällande minskade utsläpp av växthusgaser. EU har som följd av detta enats om en uppsättning klimatmål som benämns 20/20/20-målen som syftar till att minska växthusgasutsläppen med 20 procent, jämfört med 1990 års nivåer, sänka energianvändningen med 20 procent, höja andelen förnybar energi samt höja andelen biobränsle i transportsektorn med 10 procent.  Sektorn bostäder och service står enligt energimyndigheten för nära 40 procent av Sveriges totala energianvändning och blir därför ett område som är mycket intressant när det gäller att implementera energieffektiviseringsåtgärder.  Det kommunala företaget AB Gavlegårdarna ska under perioden 2016-2018 renovera ett tiotal punkthus i stadsdelen Östra Sätra i Gävle. Husen är typiska miljonprogramshus och beroende på val av effektiviseringsåtgärder kommer behovet av köpt värme samt el att förändras, dvs deras lastprofiler på det energisystemet. Dessa förändringar kommer i föreliggande arbete att simuleras och studeras i simuleringsprogrammet IDA ICE (IDA Indoor Climate and Energy) version 4.6.2, där resultaten jämförs och valideras med befintlig statistik.  Husen som berörs av upprustningen är av typen punkthus som definieras som friliggande hus med trapphus i mitten med lägenheter runt om.  Punkthusen var vanliga på 1940 talet och byggdes då oftast med 4-5 våningar. Även om huskropparna står fritt är de oftast placerade i grupp för att skapa en områdeskänsla. De aktuella byggnaderna är i stort lika varandra där avsaknad av källarplan hos vissa av husen är den tydligaste skillnaden, i övrigt består konstruktionen av markplan plus 4 våningsplan och ett vindsutrymme. Hus med källarplan rymmer totalt 29 lägenheter medan de övriga rymmer 27. Energisystemmodellen validerades samt modifierades att passa de renoverade husen. Resultatet har sedan använts för att beräkna områdets lastprofil gällande fjärrvärme vilket kan ses i nedanstående figur. Diagrammet visar lastkurvan både före och efter de energieffektiviserande åtgärderna implementerats.  Med hjälp utav de erhållna effektkurvorna kan områdets totala energianvändning jämföras före och efter implementering av energieffektiviseringsåtgärder. Resultatet visar att värmebehovet sjunker med 1,39 GWh. Appliceras detta på kraftvärmeproduktionen resulterar minskningen i 0,55 GWh lägre elproduktion som måste importeras till systemet. Importeras elen från kolkondens kan detta ge upphov till ökade koldioxidutsläpp med 512 ton koldioxidekvivalenter per år jämfört med 2,13 ton CO2 ekvivalenter om elen tas från svensk elmix.

published_or_final_version / Architecture / Doctoral / Doctor of Philosophy