The European Union has adopted a plan to decrease 20 % of total energy consumption through improved energy efficiency by 2020. One way of achieving this challenging goal may be to use efficient water-based heating systems supplied by heat pumps or othersustainable systems. The goal of this research was to analyze and improve the thermalperformance of water-based baseboard heaters at low-temperature water supply. Both numerical (CFD) and analytical simulations were used to investigate the heat efficiency of the system. An additional objective of this work was to ensure that the indoor thermal comfort was satisfied in spaces served by such a low-temperature heating system. Analyses showed that it was fully possible to cover both transmission and ventilation heatl osses using baseboard heaters supplied by 45 °C water flow. The conventional baseboards, however, showed problems in suppressing the cold air down-flow created by 2.0 m high glazing and an outdoor temperature of – 12 °C. The draught discomfort at ankle level was slightly above the upper limit recommended by international and national standards. On the other hand, thermal baseboards with integrated ventilation air supply showed better ability to neutralize cold downdraught at the same height and conditions. Calculations also showed that the heat output from the integrated system with one ventilation inlet was approximately twiceas high as that of the conventional one. The general conclusion from this work was that low-temperature baseboards, especially with integrated ventilation air supply, are an efficient heating system and able to be combined with devices that utilize the low-quality sustainable energy sources such as heat pumps. / <p>QC 20101029</p>

The European Union is planning to greatly decrease energy consumption during the coming decades. The ultimate goal is to create sustainable communities that are energy neutral. One way of achieving this challenging goal may be to use efficient hydronic (water-based) heating systems supported by heat pumps. The main objective of the research reported in this work was to improve the thermal performance of wall-mounted hydronic space heaters (radiators). By improving the thermal efficiency of the radiators, their operating temperatures can be lowered without decreasing their thermal outputs. This would significantly improve efficiency of the heat pumps, and thereby most probably also reduce the emissions of greenhouse gases. Thus, by improving the efficiency of radiators, energy sustainability of our society would also increase. The objective was also to investigate how much the temperature of the supply water to the radiators could be lowered without decreasing human thermal comfort. Both numerical and analytical modeling was used to map and improve the thermal efficiency of the analyzed radiator system. Analyses have shown that it is possible to cover space heat losses at low outdoor temperatures with the proposed heating-ventilation systems using low-temperature supplies. The proposed systems were able to give the same heat output as conventional radiator systems but at considerably lower supply water temperature. Accordingly, the heat pump efficiency in the proposed systems was in the same proportion higher than in conventional radiator systems. The human thermal comfort could also be maintained at acceptable level at low-temperature supplies with the proposed systems. In order to avoid possible draught discomfort in spaces served by these systems, it was suggested to direct the pre-heated ventilation air towards cold glazed areas. By doing so the draught discomfort could be efficiently neutralized.     Results presented in this work clearly highlight the advantage of forced convection and high temperature gradients inside and alongside radiators - especially for low-temperature supplies. Thus by a proper combination of incoming air supply and existing radiators a significant decrease in supply water temperature could be achieved without decreasing the thermal output from the system. This was confirmed in several studies in this work. It was also shown that existing radiator systems could successfully be combined with efficient air heaters. This also allowed a considerable reduction in supply water temperature without lowering the heat output of the systems. Thus, by employing the proposed methods, a significant improvement of thermal efficiency of existing radiator systems could be accomplished. A wider use of such combined systems in our society would reduce the distribution heat losses from district heating networks, improve heat pump efficiency and thereby most probably also lower carbon dioxide emissions. / <p>QC 20131029</p>

This thesis has been carried out on behalf of the department of Digital Services - SDI at Ericsson. Ericsson Software Defined Infrastructure (SDI) is a telco grade hardware management solution for cloud infrastructure. In datacenter deployments, the extra management equipment needed by the solution becomes insignificant due to the amount of equipment it manages. But the closer to the cloudedge you get, the smaller in size the deployments become, thus making the management equipment an ever-increasing share of the total deployment seize leading to inefficient resource utilization, so called overhead. Especially with Distributed Radio Access Networks (RAN) many small deployments, often only consisting of a single compute-server used to process radio, will be deployed at radio sites and/or in buildings around cities to deliver cell service. In this type of usage, the overhead of equipment management builds up cumulatively due to the numerous amounts of deployments. This overhead leads to excessive maintenance, power usage, space needs for equipment, costs, and electronic waste. The goal of this thesis was to evaluate how to reduce the overhead of equipment management in a scenario involving numerous small-capacity widely-distributed sites which are common in the 5G telco cloud. The idea was to determine if the overhead could be reduced by exploiting Baseboard Management Controllers (BMC), this was tested by designing a low-footprint and lightweight proof of concept equipment management solution and implementing a prototype of it. By testing, verifying, and analyzing the proof-of-concept solution, it was concluded that by exploiting the BMC to run a custom software service that phoned home to a centralized management server it was possible to drastically reduce the overhead in such scenarios. It also became clear that BMCs could have even more usage areas and provide even greater value if support to run third partyapplications existed among them. / Detta examensarbete har utförts på uppdrag av avdelningen Digital Services - SDI på Ericsson. Ericsson Software Defined Infrastructure (SDI) är en hårdvaruhanteringslösning av telekomkvalitetför molnifrastruktur. I datacenterinstallationer blir den extra hanteringsutrustning som behövs av lösningen obetydlig på grund av mängden utrustning den hanterar. Men ju längre ut till molnkanten du kommer, desto mindre blir storleken på installationerna, vilket gör att hanteringsutrustning blir en ständigt ökande andel av den totala installationsstorleken som leder till ineffektivt resursutnyttjande, så kallat overhead. Speciellt med Distribuerade Radio Access Nätverk (RAN) så kommer många små installationer, ofta endast bestående av en enda server som utför radiolänksberäkningar, att vara fysiskt utplacerade vidbasstationer och/eller i byggnader runt städer för att leverera och tillhandage mobiltjänster. Vid denna typ av användning ökar overheadet för utrustningshanteringen kumulativt på grund av antalet installationer. Detta overhead leder till mer underhåll och elektroniskt avfall, större utrymmesbehov för utrustning samt högre strömförbrukning och kostnader. Målet med detta examensarbete var att utvärdera hur man kan minska overheadet hosutrustningshantering när det tillämpas på ett stort antal, små decentraliserade distribuerade installationer, vilket är förekommande i telekommoln. Idén var att undersöka om overheadet kunde minskas genom att utnyttja Baseboard Management Controllers (BMC), detta testades genom att designa en liten och lättviktigt konceptlösning för utrustningshantering samt implementera en prototyp av den. Genom att testa, verifiera och analysera konceptlösningen drogs slutsatsen att det var möjligt att drastiskt minska overheaden i sådana scenarion genom att utnyttja BMC att köra en egen mjukvarutjänst, som automatiskt anslöt till en central hanteringsserver. Genom arbetet blev det också tydligt att BMC:er skulle kunna ha ännu fler användningsområden och ge ännu större värde om stödet för att köra tredjepartsapplikationer på dem var mer utbrett