Tyrimo tikslas – ištirti medienos džiovyklos, kūrenamos biokuru, energijos sąnaudas ir energinį efektyvumą. Tyrimo uždaviniai – išanalizuoti biokuro katilinės technologinį procesą, nustatyti biokuro charakteristikas ir biokuro poreikius medienos džiovinimui, sudaryti džiovinamos medienos elektros ir šiluminės energijos sąnaudų skaičiavimo metodiką. Eksperimentinio tyrimo metu nustatytas biokuro (pjuvenų) šilumingumas (9,3 MJ/kg) ir jo drėgnis (47,0 %). Nustatytos katilinės elektros įrenginių ir medienos džiovyklos suminės energijos sąnaudos, kurios siekia 686 MJ/m3 išdžiūvusios medienos. / The aim – to investigate wood drying, burning biofuels, energy consumption and energy efficiency. Objectives of the study – to analyse the biofuel boiler process that determine the characteristics of biofuels and biofuel needs of timber drying, consist of dried wood of electrical and thermal energy cost calculation methodology. Results of experimental investigation shows that calorific value of biofuel (saw dust) is 9,3 MJ/kg and humidity – 47,0 %. The total energy consumption of electrical installations and wood drying machine has been determined, which shows the total energy input of 686 MJ/m3 dried wood.

Baigiamajame magistro darbe nagrinėjama Daugiabučių namų atnaujinimo programa, atliekama jos įgyvendinimo Lietuvoje analizė, siekiant identifikuoti pagrindines problemas, bei pateikiami pasiūlymus dėl jų sprendimo. Taip pat apžvelgiamas Lietuvos būsto fondas, analizuojama užsienio šalių patirtis daugiabučių namų modernizavimo srityje bei atliekama 2010 m. modernizavimo programoje dalyvavusių atnaujintų daugiabučių namų analizę, apskaičiuojant panaudotų energiją taupančių modernizavimo priemonių investicinį efektyvumą energetiniu požiūriu. Darbą sudaro 4 dalys: įvadas, analitinė dalis, apimanti Lietuvos būsto sektoriaus apžvalgą, Daugiabučių namų modernizavimo programos analizę ir užsienio šalių patirtį daugiabučių namų atnaujinimo srityje, tiriamoji dalis – Lietuvos miestuose renovuotų daugiabučių analizę, išvados ir pasiūlymai, literatūros sąrašas bei priedai. Darbo apimtis – 97 p. teksto be priedų, 23 iliustr., 14 lent., 67 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai. / The master thesis analizes the blocks of flats renovation programme, indentifies the main problems in implementing the programme and lists offers for its solution. Also are carried out the overview of the housing stock in Lithuania and analyzed foreing countries experience in modernization of the blocks of flats. The research of blocks of flats which 2010 participate in the modernization programme are carried out calculating the energy-saving modernization measures in terms of energy efficiency investment. This thesis consist of four parts: an introduction, the analytical part which includes the Lithuanian housing sector review, the blocks of flats modernization programme analysis and foreing countries experience in modernization of the blocks of flats, the research part – the analysis of foreing experience in modernization of the blocks of flats, a conclusion and recommendations, a reference and annexes. Thesis contains 97 pages of text (without annexes). There are 23 figures, 14 tables, 67 bibliographical sources. Appendixes included.

Miljonprogrammet syftar till bostadsbyggandet i Sverige mellan åren 1965 – 1974 där drygten miljon bostäder upprättades, varav majoriteten var flerbostadsfastigheter. Vid upprättandetav miljonprogrammets bostäder prövades nya arbetsmetoder och inga krav ställdes påenergiförbrukning. Idag är dessa flerbostadsfastigheter eftertraktade investeringsobjekt, mende är samtidigt i behov av teknisk upprustning. I samband med detta finns det forskare somhävdar att energieffektiviserande åtgärder bör utföras. Dock påpekar en del fastighetsbolag attde avstår från att utföra energieffektiviserande investeringar då det är svårt att göra dessalönsamma. För att utröna lönsamheten i en investering utförs investeringskalkyler, vilkavanligen utgör en del av ett beslutsunderlag. Energieffektiviserande investeringar innehållerdock osäkerheter vilket gör de svåra att beräkna på ett vis så att kalkylens utfall ligger nära detverkliga utfallet. Denna studie undersöker därför vilken roll investeringskalkylen har förbeslutsfattare vid investering i energieffektiviserande åtgärder av flerbostadsfastigheter frånmiljonprogrammet. För att undersöka detta fenomen har teori gällande investeringskalkylersanvändning som beslutsunderlag tagits fram. Teoretiskt har det även påvisats att andrafaktorer såsom erfarenhet, strategi och intuition påverkar investeringsbeslut, och då det finnsosäkerheter vid investeringsbeslutet kan dessa övriga faktorer användas mer eller mindre. Detbidrar till att investeringskalkylens roll vid beslut påverkas. Empiriskt har vi använt enkvalitativ metod där intervjuer har utförts med fyra fastighetsbolag. Telefonintervjuer ochpersonliga möten har tillämpats. Fastighetsbolagen har valts utifrån ett minimikrav gällandeden andel fastigheter från miljonprogrammet de besitter.I studien har det framkommit att investeringskalkyler alltid finns med som en del av ettbeslutsunderlag vid investering i energieffektiviserande åtgärder. På grund av osäkerheterbehöver kalkylerna dock kompletteras med övriga faktorer såsom erfarenhet, strategi ochkompetens. Dessa övriga faktorer möjliggör en mer precis kalkyl, men visar även påmervärdet av en investering. Teoretiskt har intuition påvisats vara relevant vidinvesteringsbeslut, emellertid har denna faktor inte framkommit som relevant i vår kontext. / Between the years 1965-1974 over a million residences were built in Sweden, this is referredto as the Million Programme. The majority of the buildings that were established during theMillion Programme were so called multidwelling units (MDUs). When establishing thebuildings of the Million Programme new construction methods were tested and there were norequirements regarding energy consumption. Today these MDUs are coveted investmentobjects, but they are still in need of refurbishment. Some researchers point out that energyefficient actions should be implemented in conjunction with this. However, some real estatecompanies argue they refrain from implementing energy efficient investments since they aredifficult to make profitable. Investment calculations are made to determine the profitability ofan investment, these calculations are usually used as a basis of a decision. Energy efficientinvestments, however, contains uncertainties and because of this they are hard to calculateclose to actual outcome. Therefore this study examines the role of the investment calculationfor decision makers while investing in energy efficiency in the Million Programmes MDUs.To examine this phenomenon theory regarding investment calculations as a basis for decisionmaking has been gathered. It has also been shown theoretically that other factors such asstrategy, experience and intuition affect decisions. When an investment contains uncertaintiesthese factors can be used more or less. This affect the investment calculations role in thedecision. Empirically we have been using a qualitative approach. Interviews by telephone andpersonal meetings have been made with four real estate companies. The real estate companiesthat have been examined possess a certain proportion of MDUs from the Million Programmein their property portfolio.The study has shown that the investment calculation always is a part of a decision regardinginvestments in energy efficiency. Due to uncertainties investment calculations however needto be supplemented with other factors such as experience, strategy and competence. Theseother factors enables an investment calculation that is more precise estimated, but they canalso show the added value an investment in energy efficiency may result in. Theoreticallyintuition has been proved to be relevant in investment decisions, however this factor has notbeen emerged as relevant in our empirical context.

Tången 2 is a building situated in Stockholm, Sweden. It´s built in the 1930s and contains both residences and businesses. The property owner, Diligentia AB, wants to lower the energy use in Tången 2. This report consists of an energy audit which clarifies the specific circumstances linked to Tången 2. Collected knowledge is then used, together with the results from the literature study, to decide energy measures to proceed with. Result from the energy audit suggests a high potential to lower the energy use. To calculate the potential energy saving of chosen measures, a model of the building was constructed in IDA ICE. Collected data from the energy audit was used as input in the model. Simulation results suggest that there are several possible measures to implement, both constructional and technical. Results from the economical calculations suggest that there´s a connection between energy saving and investment cost. Even though the energy saving potential of a single measure is significant, it´s not cost effective if it consists of a high investment cost. Results from the study are presented as a program of measures that will lower the energy use and save the owner money in the long run. This study shows that even for a building with big energy saving potential, it´s hard to lower the energy use significantly and maintain a profit. The program of measures suggested in this report has an energy saving potential of 11 % and an IRR of 7, 7 %.

The world of information technology and communications is in a stage of continuous improvement. These new developments are accompanied by a very rapid data traffic growth, particularly for mobile wireless networks. An important effect is the increase of the consumed energy by the network, particularly the radio access section, i.e. the base station systems. This latter issue causes that operational costs associated to energy consumption become more significant for telecommunication operators. In addition to the question of the availability of energy, this problem has an ecological aspect, due to the CO2 emissions associated with the operation of the network but also an issue related to public health given the effects of electromagnetic radiation from wireless transmission. For these reasons, great research efforts in the so-called field of Green Radio are being done in the recent years. The aim of this thesis consisted of finding ways to reduce the energy consumption in wireless and mobile networks respecting the QoS levels assigned to users. After a study of the state of the art analysing the possible approaches, we proposed a set of energy efficient techniques supported on the cell breathing and hybrid cellular networks (macro/femtocells). Our proposed decision making mechanisms include distributed strategies and other features such as the use of a novel multimetric approach. In our work, we also take into account the energy consumption of mobile devices, an issue that to the best of our knowledge was not quite analysed so far. The use of renewable energy sources is also considered into our proposals. Our thesis work includes the study of the consequences of our radio resource management algorithms on the electromagnetic radiation taking into account the acceptable EM exposure thresholds. In the perspectives of future work, we can mention the improvement of our techniques with learning mechanisms and cognitive radio.

Temos aktualumas. Šiuo metu klimato kaitos problemos užima vis didesnę reikšmę ES bei pasaulinėje aplinkosaugos ir energetikos politikoje. Vis akivaizdžiau pasireiškianti klimato kaitos problema, kelia didelį susirūpinimą visame pasaulyje, o jos sprendimui būtinos visuotinės pastangos. Žengiant link tobulesnių technologijų, gamybos plėtros, ekonomikos vystymosi yra susiduriama su vis sudėtingesnėmis problemomis, kurios daro didelį neigiamą poveikį aplinkai ir kelia grėsmę žmonių sveikatai. Energijos gamyba ir jos naudojimas turi ypač didelę įtaką aplinkos kokybei: vietinių energijos išteklių naudojimas ir išeikvojimas, atliekos, miškų iškirtimas, vandens ir oro tarša, rūgštūs krituliai, dirvožemio suardymas, klimato atšilimas – visa tai energijos naudojimo ir jos plėtros padarinių pavyzdžiai. Energetika yra labai svarbi šiuolaikinei ekonomikai, nes energijos tiekimo sutrikimai galėtų visiškai sutrikdyti žmonijos gyvenimą. Tačiau nuo jos priklauso ne tik gamyba, infrastruktūros funkcionavimas, bet ir aplinkos kokybė, nuo kurios priklauso ir mūsų sveikata. Problemos ištyrimo lygis. Nors teršalų išmetimas į aplinką Baltijos šalyse yra sumažėjęs, tačiau taršos problema yra vis dar aktuali ir su ja yra kovojama. Daugelyje pasaulio šalių atsinaujinančiųjų energijos išteklių naudojimas energijos gamyboje duoda puikius rezultatus, kovojant su šia problema. Baltijos šalyse taip pat pastebimi teigiami pokyčiai, tačiau šiose šalyse šių išteklių skatinimo priemonės nėra pakankamai... [toliau žr. visą tekstą] / Today global warming is a worldwide problem that requires global solutions and the main cause of this problem is inefficient usage and making of energy. Sustainable energy means solving all social, economical and environmental problems in ways that support human development over the long term. Current energy system deals with many aspects of unsustainability and energy efficiency and intensity, increasing the share of renewable energy in the energy balance, researches and development of new technologies, energy pricing, reducing Carbon Dioxide emissions, cleaner fuels, subsidization and internalization of externalities and market opening are the main targets of sustainable energy development. Even though all three Baltic States have implemented similar policies and measures helping to reduce GHG emissions but the results are different. And this is mainly because of differences between those three countries: in size, primary energy mix, and in final energy consumption. The object of this work is support mechanisms for climate change mitigation. The main aim is to evaluate the preferences of the potential energy consumers by choosing instruments for the promotion of green energy and by choosing the way energy power is being produced. Research lasted 30 days, from the 3 of April till the 2nd of May. 330 people were questioned in supermarkets: “Mega”, “Savas” and “Akropolis”. There are slightly more respondents who would rather use atomic energy than energy produced by using... [to full text]

A wireless sensor network consists of a number of sensor devices and coordinator(s) or sink(s). A coordinator collects the sensed data from the sensor devices for further processing. In such networks, sensor devices are generally powered by batteries. Since wireless transmission of packets consumes significant amount of energy, it is important for a network to adopt a medium access control (MAC) technology which is energy efficient and satisfies the communication performance requirements. Carrier sense multiple access with collision avoidance (CSMA/CA), which is a popular access technique because of its simplicity, flexibility and robustness, suffers poor throughput and energy inefficiency performance in wireless sensor networks. On the other hand, time division multiple access (TDMA) is a collision free and delay bounded access technique but suffers from the scalability problem. For this reason, this thesis focuses on design and analysis of hybrid channel access schemes which combine the strengths of both the CSMA/CA and TDMA schemes. In a hybrid CSMA/CA-TDMA scheme, the use of the CSMA/CA period and the TDMA period can be optimized to enhance the communication performance in the network. If such a hybrid channel access scheme is not designed properly, high congestion during the CSMA/CA period and wastage of bandwidth during the TDMA period result in poor communication performance in terms of throughput and energy efficiency. To address this issue, distributed and centralized channel access schemes are proposed to regulate the activities (such as transmitting, receiving, idling and going into low power mode) of the sensor devices. This regulation during the CSMA/CA period and allocation of TDMA slots reduce traffic congestion and thus improve the network performance. In this thesis work, time slot allocation methods in hybrid CSMA/CA-TDMA schemes are also proposed and analyzed to improve the network performance. Finally, such hybrid CSMA/CA-TDMA schemes are used in a cellular layout model for the multihop wireless sensor network to mitigate the hidden terminal collision problem.

The Swedish industry uses large volumes of compressed air. The compressed air process isenergy intensive and creates large amounts of excess heat. It is therefore important to utilizethe excess heat, optimize the operation of the compressors and to have a regular maintenanceon the system. This thesis is a pre-study to make a compressed air system energy efficient andis done in collaboration with Ljunghäll AB. Ljunghäll AB is one of Northern Europe's leadingdie casting companies and are located in Södra Vi, Sweden. The purpose is to describe andmap the compressed air system in the old part of the facility in Södra Vi. The thesis will alsogive an explanation of how Ljunghäll AB can improve the compressed air system. Providethem suggestions for energy savings and lower the environmental impact of production. Theobjective of the thesis is to create an understanding of how improvements in the compressedair system can be done by studying the operation, compressor, pipe system and leak detecting.The economic aspects of the solutions together with the effect of noise and engine operationof the compressors have not been taken into consideration. To reach improvement measures avisit to the facility in Södra Vi was made, where measuring and mapping was executed andthen compared with earlier studies and literature. The conclusions of the thesis show thatLjunghäll AB has a good operation and control of the compressors, through the variable speeddrive and steering system. It also showed that the choice of the existing compressors are goodfor their compressed air usage. The study also resulted in the following suggestions for theenergy efficiency and lowering of the environmental impact of production at Ljunghäll AB’scompressed air system: Water heat recovery, replacement of old pipes, cover the leakage,regular maintenance of compressors and fittings, training in compressed air for workers,centralized compressor central and sectioning of the pipe system.

Many rural communities in South Africa do not have running water or electricity. The fetching and heating of water is therefore a time consuming and expensive daily ritual. The use of energy sources such as wood or coal are not readily available and cause environmental pollution. Although solar water heaters are commonly available in South Africa, they are very seldom used in rural areas. Whilst this can mostly be attributed to a high system cost, current designs also do not cater for specific rural problems such as the transporting or purification of water. A prototype model, designed with such an approach in mind, has already been constructed by TEMM International (Pty.) Ltd. The Solar Heat Barrow (SHB) was developed in the 1992 to 2003 period with the intention of combining a number of functions at low cost. Specific requirements were: low cost, a suitable design and materials for manufacture in large volume, sufficiently durable taking into account the harsh conditions of use. suitability for cases where no in-house piped water supply was available, the use of appropriate technology and the improvement of quality of life. The unit combines the absorption of solar radiation, the heating of a relatively small volume of water, the transport of the water from the point of supply and the storage of the hot water until it is used. Untreated water sources such as surface waters (streams, rivers, lakes, etc.) or unprotected open wells are the vehicles for waterborne bacterial diseases such as cholera and typhoid fevers. In the case where water is collected from these sources, the SHB has a build-in Purification Dispenser that purifies the water in the collector against waterborne bacterial diseases. Certain research questions need to be answered. They will be answered by demonstrating the SHB in two communities where no in-house piped water supply is available and by establishing the socio-economic response of the users. The research questions are as follow: What are the responses of the users concerning the SHB, in comparison to those of a control group, regarding its operation, durability, utility and satisfaction of needs? What is the daily use of hot water and the reduction in energy use and cost? To what extent will the target community purchase the SHB at the full or subsidised commercial price? Is there a business case that can be developed for the large scale production, marketing. financing and Small, Medium and Micro Enterprises (SMME) development of the SHB? It was decided to choose a community in the Valley of Thousand Hills in KwaZulu Natal as the demonstration site. The name of the community is Mabedlane. It is a remote rural area 20 km's north of Botha's Hill and is situated along the Umgeni River. The community is dependent on the river for domestic water. Most families are headed by women. The area has low levels of infrastructure, poor roads, a high unemployment rate and poor health facilities. The first survey, which was conducted before the test period started, showed a very positive response from potential users. From 112 questionnaires that were given to the people of Mabedlane, all indicated that they were interested in a product that can transport and heat water for domestic use. The socio-economic study has shown that the price per unit needs to be adapted as 85% of the people who participated in the survey indicated that they would only pay less than R100 for the product. 15% indicated that they would pay between RlOO and R200. From the second and third questionnaires it was clear that the users were satisfied with the heating performances of the SHB. The community was very interested in purchasing a SHB. They have realised that a SHB will improve their standard of living and regard it as a necessity in their day to day activities. It is apparent that people, who will benefit from a SHB most, are those who will not be able to pay the full retail price. Therefore, new business strategies have to be researched when implementing the SHB to the target market in South Africa. The idea of considering ways to sponsorlfund the SHB must also be investigated. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.

The purpose of the study was to investigate the use and losses of energy in an existing older building. Another purpose was also to look through various options for heating systems with renewable energy in the building. The aim was to reduce the use and losses of energy. The first step was to study the related electricity bills of the building and also perform measurements and calculations of the building envelope and ventilation. The next step was to find out the possible actions for energy saving by performing measurements and calculations. To calculate the loss of energy a u-value was used, which describes a materials ability to conduct heat. The results of the energy calculations show what is reasonable to do in the building considering the energy savings versus economy. The study shows that it is important to first analyze and adjust the building envelope and ventilation before a new heating system is installed. That is to reduce the risk of an over-sizing of the heating system. It is not optimal to correct the entire building at energy efficiency because it is not economically feasible. All necessary actions of energy saving should be taken as a package where the most profitable should be picked out and executed. An older building is often of great value and therefore its appearance should be safeguarded at energy efficiency.