The purpose of the thesis is to determine the potential of lessening the high energy cost in the hospitality industry so that the industry could stay alive after a three decades of civil war in Sri Lanka. The hospitality industry is a significant contributor to the country’s economic growth. Tourism industry has much hope of recovering in the year 2010. Improved tourism would also benefit larger part of Sri Lankan population as they are directly and indirectly employed to serve the tourism industry. Sri Lanka has a high electricity production cost as it depends heavily on the imported fossil fuel. Survival of hospitality industry would depend on the manner in which the energy cost - the second highest overhead in hotels is managed. If the industry survives, Sri Lanka would receive more foreign exchange and thereby improve country’s foreign currency reserve which could contribute to high growth rate. As electricity production is mainly depending on thermal, the volatility of world crude oil prices is directly affecting the country’s electricity prices. However, low dependence on the grid would help the hospitality industry to mitigate the energy cost. As the electricity and diesel costs -the highest and the next - are considerable portions in energy cost in hospitality industry, the study aims to discuss the possible ways of mitigating such costs. Measurements done by the presenters found that the usage of electricity for air conditioning system does constitute most of the electricity consumption for a hotel whilst most of the diesel consumption is for thermal applications. If Air Conditioning (AC) can be operated without electricity and thermal applications could be operated using abundantly available alternative energy sources then the overall energy costs of hospitality industry could be reduced thereby making higher profits. This would ensure industry survives and country gets more foreign exchange.  Study and calculations done by the presenters proved that operating of generators only for electricity production is not viable, due to high fossil fuel cost, however if its high exhaust temperature which is wasted otherwise, could be utilized for operation of absorption chillier then the dependence of grid electricity for air conditioning could be minimized. Further studies also revealed that if water cooled generator is used for such purpose instead of air cooled, and then the hot water requirement of hotel also could be fulfilled, thus mitigating the dependence of fossil fuel which is used otherwise for hot water production. Study also revealed that if thermal energy could be fed with biomass- Sri Lanka being a tropical country is blessed with abundantly available biomass - then the dependency on the fossil fuel for thermal applications could be avoided. This would not only mitigate the second highest energy cost for hotels but also create less carbon foot print, more environmental friendly and produce less noxious exhaust gases thereby creating an advertisement to attract tourists who longing to support green hotels

Thesis: M.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980 / Includes bibliographical references. / by Joseph A. Halsch. / M.S. / M.S. Massachusetts Institute of Technology, Department of Mechanical Engineering

One of the great challenges facing society is to convert theglobal energy system to a sustainable process. Currently, 80%of the world´s energy is supplied through the combustionof fossil fuels. Not only are the fossil resources limited, theutilisation also increases the level of greenhouse gases in theatmosphere. The convertion to a sustainable energy system isproblematic since the technology needed to exploit mostnon-fossil energy sources is not yet fully developed, e.g.solar energy. Biofuel is an available renewable energy sourcewhich is already widely used in many countries. If an effectiveswitch-over from fossil fuels to biofuels is to be realised,biofuels must be viewed as a limited resource. Consequently, itis important that the handling, upgrading and utilisationprocesses involving biofuels are efficient so that itspotential can be fully exploited. This thesis considers efficient biofuel utilisation andupgrading within the sawmill industry. The goal has been toanalyse not only the technical opportunities for energy savingsin the sawmill industry, but also to analyse the costeffectiveness and environmental impact of studied measures. Theheat demand of the sawmill industry is almost completelycovered by its own by-products; primarily bark, sawdust andwood chips. The increased demand and improved economic value ofwoody biofuels on the market is thus an incentive for thesawmill industry to place more focus on energy issues. Thesawmill industry also has a more or less constant heat loadover the year, which is a beneficial factor for integrationwith district heating networks, biofuel upgrading plants andcombined heat and power plants. The conclusion of the study is that a variety of energyproducts such as heat, unrefined biofuel, pellets andelectricity can be efficiently produced in the sawmill industryand sold for profit to external customers. The payback periodsfor the proposed investments are moderate and both theemissions of volatile organic compounds and global CO2 aredecreased. Should the proposed measures be fully implemented atSwedish sawmills, about 2.8 TWh of biofuel could be savedannually, 0.5 TWh of waste heat could be sold as districtheating and 0.8 TWh of green electricity could be produced.Language: English Keywords:Sawmill industry, energy efficiency, heatrecovery, integration, biofuel, upgrading, district heating,fuel pellets, CHP, VOC, CO2

This thesis was conducted to analyze and investigate improvement methods for the testing process of steam sterilizers at Getinge AB.Getinge is a leading MedTech multinational company based in Sweden. Steam sterilizer is one of their prominent products. A series of testing must be done before handing over the product to the customer, which mainly requires water and steam as consumable resources. The intention of this project is to find improvement methods or optimization techniques for the testing process and reduce the consumption of resources which would significantly impact the production lead time and cost. Upon the careful examination of the testing process it has been noticed that a significant amount of pure water with heat content has been wasted during the testing process, which could be recirculated/ reused, and the heat could be regenerated for useful purposes. The proposed optimization suggestions through this project are a thermally stratified tank which could handle cold and hot water as the testing process needs the supply of both. Majority of the faults during testing are identified in software implementation and a few in mechanical. A dummy testing is recommended to identify the faults in the implementation of the software without the need of consumable resources. A few methods to tackle mechanical faults are discussed further in this report. When implementing these optimization suggestions, it would drastically improve the testing process by reducing the consumption of resources like water, steam, natural gas, time, and labor.

The objective of this research is to evaluate the potential of thermal energy storage in supermarkets with CO2 refrigeration systems. Suitable energy storage techniques are investigated and the seasonal storage technology of boreholes is chosen to be the focus of the study. The calculations are done for five supermarket refrigeration systems with different combinations of heating systems and borehole thermal energy storage control strategies. The two heating systems analyzed are the ground source heat pump and the heat recovery from the supermarket’s refrigeration system. The simulation results show that the introduction of thermal energy storage in the scenarios with heat pump can reduce the annual total energy by 6.3%. It is also shown that increasing the number of boreholes can decrease the life cycle cost of the system. Moreover, it is established that a supermarket system with heat recovery consumes 8.1% less energy than the one using heat pump and adding thermal energy storage on the heat recovery system further improves the energy consumption by 3.7% but may become costly.

Sweden aims to achieve climate neutrality by 2045. The need to immediately reduce greenhouse gas emissions in order to achieve climate targets affects industry directly. The pulp and paper sector is responsible for more than 50% of industrial energy use in Sweden. Increased energy efficiency is expected to contribute significantly to the reduction of primary energy use. The recovery and utilisation of industrial excess heat (IEH) has been identified as an important potential contribution to energy efficiency in industry. Previous research based on top-down studies has estimated the availability of IEH for entire sectors, and bottom-up results for many case studies are available. While top-down studies lack detailed information on the profile of the excess heat available, bottom-up studies have limited coverage. Detailed information about excess heat amounts and temperature levels is required for the assessment of the potential of the various heat recovery technologies that are available.  The aim of this thesis is to present, in a series of steps, methods to systematically analyse an industrial process to obtain a detailed profile of the excess heat available under various process conditions, to aggregate results that can be generalised to whole industrial sectors, and to obtain IEH recovery potentials using different technologies. The assessment of the utilisation options for IEH recovery is complemented with an analysis of system aspects that could affect profitability and global greenhouse gas (GHG) emissions. An energy-targeting procedure combined with optimisation has been applied to six case studies of kraft pulp and paper mills in Sweden. This method obtained IEH profiles that were used in a regression analysis to estimate the IEH availability and electricity generation potentials from low and medium temperature IEH using organic Rankine cycles (ORC). A comparison of profitability and global GHG emissions between ORC electricity generation using IEH and small-scale combined heat and electricity (CHP) production is presented for three energy markets. The results show that there is a potential to increase electricity generation from low and medium temperature IEH by 7–9% in the kraft mills in Sweden, depending on the level of process integration considered. The utilisation of low and medium temperature IEH for electricity generation has the potential to reduce global GHG emissions in all the energy-market scenarios considered, but if biomass is considered a limited resource, district heating (DH) deliveries can achieve higher global GHG reductions. ORC electricity generation from low and medium temperature IEH is economically viable and showed overall better profitability and GHG emissions reductions than small-scale CHP using ORCs. The economic feasibility of ORC electricity generation is less affected by external conditions and uncertainties than direct DH deliveries. / Sverige siktar på att uppnå klimatneutralitet till 2045. Behovet av att omedelbart minska utsläppen av växthusgaser för att nå klimatmålen påverkar industrin direkt. Massa- och papperssektorn står för mer än 50% av den industriella energianvändningen i Sverige. Ökad energieffektivitet förväntas i hög grad bidra till att minska primärenergianvändningen. Återvinning och utnyttjande av industriell överskottsvärme (IÖV) har identifierats som ett betydande potentiellt bidrag till energieffektivitet i industrin. Tidigare forskning baserad på top-down studier har uppskattat tillgängligheten av IÖV för hela sektorer eller regioner, och bottom-up resultat för många fallstudier finns tillgängliga. Medan top-down studier saknar detaljerad information om profilen för tillgänglig överskottsvärme, har bottom-up studier begränsad täckning och precision. Detaljerad information om överskottsvärmemängder och temperaturnivåer krävs för att bedöma potentialen hos flera värmeåtervinningstekniker. Denna avhandling syftar till att i en serie steg presentera metoder för att systematiskt analysera en industriell process för att erhålla en detaljerad profil av tillgänglig överskottsvärme under olika processförhållanden, för att aggregera resultat som kan generaliseras för hela industrisektorer, och att erhålla återvinningspotentialer för industriell överskottsvärme med hjälp av olika teknologier. Bedömningen av olika möjligheter att använda industriell överskottsvärme kompletteras med en analys av systemaspekter som kan påverka lönsamhet och globala växthusgasutsläpp. Ett energimålsförfarande kombinerat med optimering har tillämpats på sex fallstudier av massa- och pappersbruk i Sverige, med produktion baserat på sulfatmassa. Med denna metod erhålls IÖV-profiler som används i en regressionsanalys för att uppskatta tillgängligheten av IÖV och potentialen för elproduktion från låg- och medeltempererad IÖV med organiska Rankine-cykler (ORC). En jämförelse av lönsamhet och globala växthusgasutsläpp mellan elproduktion med ORC, där IÖV utgör grunden, och småskalig kombinerad värme och el (KVV) produktion presenteras för tre energimarknader. Resultaten visar en potential att öka elproduktionen från låg- och medeltempererad IÖV med 7% till 9% i sulfatmassabruken i Sverige, beroende på graden av processintegration som beaktas. Användningen av låg- och medeltempererad IÖV för elproduktion kan potentiellt minska de globala växthusgasutsläppen i alla övervägda energimarknadsscenarier. Om biomassa betraktas som en begränsad resurs, kan emellertid direkta fjärrvärmeleveranser uppnå högre globala minskningar av växthusgaser. ORC-elproduktion från låg- och medeltempererad IÖV är ekonomiskt lönsam och visade överlag bättre lönsamhet och minskade växthusgasutsläpp än småskalig ORC-kraftvärme. Den ekonomiska genomförbarheten av ORC-elproduktion påverkas mindre av yttre förhållanden och osäkerheter än fjärrvärmeleveranser.

The spray drying process is widely established in the industry worldwide. However, due to its complexity in predicting variables, the technology is often regarded as a "Black box" process. In this study, a model based on energy and mass balances is designed and validated using Matlab/Simulink software and real data from a medium-sized machinery, specifically the Production Minor manufactured by GEA NIRO S/A. Additionally, the simulation incorporates a heat recovery system based on a heat pump, and its economic feasibility is examined.The simulation is validated for a narrow range of variables and demonstrates an accuracy of approximately 95% in most cases.The heat recovery system achieves an average natural gas savings of 0.43 kg/h. However, this saving is accompanied by an additional electrical consumption of 2.1 kW resulting from the operation of the heat pump.The economic feasibility study of the heat recovery system reveals an extra production cost of 0.1€/h in exchange for a 36% average reduction in natural gas dependency.

No description available.

The experiments detailed in this thesis give necessary preliminary information for analyzing the theoretical potential of direct exhaust pulse energy harvesting through expander devices. A detailed review of pertinent literature determined that there has been little specific focus on directly converting exhaust pulse energy into useful power. Crank position resolved exhaust pressure was measured as engine load and speed were varied to quantify their influences. Potential theoretical improvements average a 15.6% increase in overall fuel conversion efficiencies while indicated power can potentially be increased by an average of 14.3% for the operating conditions tested. A potential increase of up to 20% in indicated specific fuel consumption was shown. With increasing regulations on combustion engine efficiencies, emissions, and fuel requirements, the ability to reduce waste energy through improving existing waste energy recovery (WER) technologies and proposing novel WER strategies that maximize WER have the potential to be extremely valuable.

The ever-growing demand for cyber-physical infrastructures has significantly affected worldwide energy consumption and environmental sustainability over the past two decades. Although the average heat load of the computing infrastructures has increased, the supportive capacity of cooling infrastructures requires further improvement. Consequently, energy-efficient cooling architectures, real-time load management, and waste heat utilization strategies have gained attention in the data center (DC) industry. In this dissertation, essential aspects of cooling system modularization, workload management, and waste-heat utilization were addressed. At first, benefits of several legacy and modular DCs were assessed from the viewpoint of the first and second laws of thermodynamics. A computational fluid dynamics simulation-informed thermodynamic energy-exergy formulation captured equipment-level inefficiencies for various cooling architectures and scenarios. Furthermore, underlying reasons and possible strategies to reduce dominant exergy loss components were suggested. Subsequently, strategies to manage cooling parameters and IT workload were developed for the DCs with rack-based and row-based cooling systems. The goal of these management schemes was to fulfill either single or multiple objectives such as energy, exergy, and computing efficiencies. Thermal models coupled to optimization problems revealed the non-trivial tradeoffs across various objective functions and operation parameters. Furthermore, the scalability of the proposed approach for a larger DC was demonstrated. Finally, a waste heat management strategy was developed for new-age infrastructures containing both air- and liquid-cooled servers, one of the critical issues in the DC industry. Exhaust hot water from liquid-cooled servers was used to drive an adsorption chiller, which in turn produced chilled water required for the air-handler units of the air-cooled system. This strategy significantly reduced the energy consumption of existing compression chillers. Furthermore, economic and environmental assessments were performed to discuss the feasibility of this solution for the DC community. The work also investigated the potential tradeoffs between waste heat recovery and computing efficiencies. / Thesis / Doctor of Philosophy (PhD)