Electricity usage by a household dishwasher can be reduced by using a heat pump system to heat the dishwasher cabinet, dishware and washing water. The evaporator obtains the energy from an energy storage unit which consists of a container filled with water which freezes to ice. The majority of the heat transfer from the energy storage to the evaporator occurs when ice is created in the energy storage unit. A transient simulation model of a dishwasher with a heat pump system was developed and compared to an experimental setup with good agreement. A simulation study of the compressor cylinder volume and the compressor operating time was performed. The results showed a 24% reduction in total electricity use compared to a dishwasher cycle using a traditional electric element.

In the interests of competitiveness, manufactures of tumble dryers are seeking to reduce both their electricity use and the drying time. This study examines how the cylinder volume of the compressor and the total heat transfer of the condenser influence the drying time and electricity use in a heat pump tumble dryer. A transient simulation model was developed and compared to an experimental set-up with good similarity. The simulations show that increasing the cylinder volume of the compressor by 50% decreases the drying time by 14% without using more electricity.

Sverige är inte längre världsledande som pelletsproducent. USA producerar allra mest pellets i världen. Kanada och Ryssland producerar också allt mer pellets. Ingen av dessa länder har någon omfattande inhemsk konsumtion. I stort sett all pellets exporteras och det sker huvudsakligen till Europa. Sannolikt kommer det att leda till att priset på pellets i Europa sjunker, med följd att lönsamheten för svenska pelletsproducenter minskar.

In 2011, the total consumption of pellets in Sweden amounted to 1.9 million tons, which represents an energy value of 9 TWh. The pellets are used in large-scale as well as in small-scale applications, and increased demands on pellet quality are likely to force pellet producers to improve on the pellet properties. One way of increasing pellet quality is by using additives. The purpose of this article, therefore, is to examine kraft lignin as an additive. Pelletswere produced in a small industrial pellet press located at KarlstadUniversity, Karlstad, Sweden, and 1–4% of kraft lignin was added to the pellets. The results indicate that the addition of an increased amount of kraft lignin to the pellets increases their mechanical durability and their lengths. The results also indicate that dry kraft lignin yields pellets with higher durability as compared to wet kraft lignin. The energy demand was unaffected by the increased use of kraft lignin. The general results presented in this paper are useful for producers of lignin, pellet producers and end-users of pellets, who are interested in developing their products and/or improving the production processes.

Further increasing the production of processed biofuel also increases the demands on drying capacity. With the aim of increasing the heat capacity flow, experimental tests have been performed on the process of drying sawdust in a continuous spouted bed dryer with nine different draft tube designs. The results showed that a draft tube with an increased length and an increased disengagement height decreased the dry substances' flow rate throughout the dryer. The results also showed that the mass of the material in the dryer was approximately the same in all the tests. This means that the draft tubes, no matter their size, do not influence the amount of material in the dryer.

Spouted bed drying technology shows promising results for the drying of unscreened sawdust in superheated steam. In this paper, the experiences from designing, running and evaluating two spouted bed continuous feed dryers are presented. Stable running conditions and drying results have been achieved. This has been particularly important for sawdust that will be compressed into pellets or briquettes. The spouted bed superheated steam dryer also shows high potential for energy efficient integration into sawmills. Our recommendation is thus, to use the outlet steam temperature as the control parameter for the outlet moisture content. A drying rate above and one below the fibre saturation level, can be identified. Visual observations through the viewing glass in the drying zone in both the dryers clearly showed that not all of the material participated in the spout at all times; there were, however, no indications of dead zones. A heat transfer analysis indicated that only about 70% of the surface area of the material was in thermal contact with the steam. This paper sums up the experiences regarding drying properties, control and system properties obtained when sawdust is dried using superheated steam as the drying medium. Further work on standardised dryers in series or in parallel is necessary to increase the capacity in the spouted bed dryer.

Historically, domestic chores such as washing dishes were all done by hand. Today it is estimated that 44% of the households in the EU are equipped with a dishwasher. In this article, we discuss the connections between technical developments, consumer behaviour and the test standard for energy labels. The aim of this study is to provide recommendations for future work that would strengthen the role of the energy label in order to promote the more sustainable technical development of household appliances. Technical developments are compared with the consequences of different consumer behaviour. It was found that technical developments could reduce annual energy use, but depending on the implemented technology, this is often complex and requires additional components. On the other hand, a consumer can easily increase energy usage by 50% without being aware of doing so, when goods are pre-treated, appliances incorrectly loaded, or inappropriate programs selected. Our recommendation is first of all to encourage the use of dishwashers as they consume less energy and water compared with washing up manually. A holistic approach should be taken to updating the energy labelling system. Actual consumer behaviour must be taken into account and, perhaps most importantly, as dishwashers are becoming ever more energy efficient, consumers must be educated in using the machines in an environmentally friendly way. We conclude that the energy labelling system is outdated; it must be fundamentally revised and must take into account consumer behaviour.

Att använda flippat lärande i undervisningen har blivit mer och mer vanligt i högre utbildning. Studier pekar på att den formen av undervisning leder till ökad förståelse, ett ökat engagemang och motivation hos studenterna. Dock finns ett uttalat behov av ytterligare forskning inom området. I denna studie ligger fokus på hur de pedagogiska mötena i en typisk teknisk grundkurs kan utformas för att vara aktiva och främja lärandet i de högre kunskapsnivåerna. Den nya utformningen bygger på att traditionella möten med studenter såsom föreläsningar och lektioner har bytts ut mot diskussionstillfällen och laborationer. Räkneövningar finns i båda upplägg men fokus i det nya ligger i att arbeta med koncept och hur problem ställs upp. Den operativa räkningen lämnas alltid till studenterna. Resultaten blir att lärarna idag kan möta studenterna och agera som en coach i deras lärande, studenterna är mer aktiva och vi arbetar med kunskapsmål där vi analyserar, kritiskt utvärderar, utformar system och gör avvägda antaganden. Genomströmningen har ökat från mellan 40-50% till mellan 60-70% trots ett ökat krav på förståelsen i examinationen.

The use of wood fuel pellets has increased worldwide in recent years, and pellet producers conclude that the lack of drying capacity is a barrier to increased production. In this study, we develop a concept of two different dryers called the two-step drying technique. The aim is to show the potential for increasing the drying capacity and improving energy efficiency when introducing a second dryer into the pellet plant. The study is theoretical and based on an industrial packed moving bed dryer. It shows that the drying capacity increased by 22% when a pneumatic second dryer was used.

Large amounts of thermal energy are required for different unit operations in the pulp and paper industry. Typically, this energy is distributed by means of steam. In this study, introduction of in-situ-generated syngas as an energy carrier in parallel to the predominant steam has been investigated. The examined systems use dual fluidized-bed gasification integrated with a solid fuel boiler of a paper mill together with impingement drying in combination with cylinder drying, a concept enabling higher specific drying rates. The studied systems exhibit reduced overall energy use when compared to the present situation with conventional steam-heated cylinder drying. Cold tar cleaning by condensation/absorption and firing of the syngas in a gas turbine followed by utilization of the exhaust gases for drying are interesting options because this results in reduced biomass consumption with maintained power production.

With reference to the reduction of carbon dioxide emissions, biofuel is pointed out as an important substitute for fossil fuels. The Swedish Government favours the use of biofuel by imposing taxes on fossil fuels. However, biofuel is a limited resource and it is therefore important that we develop efficient systems for the production and utilization of this limited resource.



This thesis is based on six papers out of which five are experimental and treats the drying of wood in spouted bed co-generation dryers. The sixth paper deals with the integration of a co-generation dryer into the energy system of a sawmill.

I högre utbildning är akademiskt skrivande något som studenter behöver stöd att utveckla genom hela sin utbildning. Handledningen är en central del i denna process men det finns en risk att handledaren i stället för att lyfta halvfärdiga texter i själva verket drar ner studenter eller lämnar otydliga synpunkter. Det finns även en risk att handledaren över skrivarbetet och gör det till sitt.

Vi arbetar med en handledningsmodell som vi kallar ”Direkthandledning”. Modellen ger stor frihet för förändringar och stora delar avutbildningsmiljön arbetar med liknande modeller. Drivkraften är att göra handledningen effektivare, att öka studenternas respons för lärarnas synpunkter samt ge studenterna egna strategier för sitt skrivande. Direkthandledningsmodellen används i hela utbildningen och i denna artikel presenteras introduktionen. I handledningsmodellen separeras innehåll och form. I introduktionen handleds enbart formen, hur rapporten är formaliserad, strukturerad och skriven.I direkthandledningsmodellen får studenten alltid en tydlig process och kravspecifikation på vad som förväntas. I introduktionen genomförs en individuell studie och först när studenten skrivit en inledning, metod och resultat som är i läs- och kommentarbart skick, får studenten handledning. Texten skall då följa en utskickad och kommunicerad mall och struktur. Återkopplingen utgår från kravspecifikationen. När studenten kommer till handledningen har handledare och student en diskussion kring hur arbetet är presenterat, inget annat. Under handledningen får studenten tydlig information om hur denne ligger till i förhållande till kravspecifikationen.

Modellen har lett till betydande förbättringar av responsen på synpunkter. Studenter uppger att de börjat utveckla egna strategier för sitt skrivande.

Drying is an energy demanding industrial process and methods for reducing the energy consumption of drying is of interest to industry as well as society. This article presents the drying system of a biofuel factory. Steam is used as the refrigerant. Superheated steam is used as drying gas in a flash dryer with 28.8 tons/h dewatering capacity. The system includes an energy recovering water heat pump that receives its heat from the excess drying steam and heats the dryer. The SMER of the drying process ranges between 3 and 4 and the COP of the heat pump process ranges between 4 and 5.5 during one production season of peat drying. Variations in performance can be explained by variations in inlet moisture content and production rate. The example of this drying system shows the feasibility of drying in superheated steam, heat pump drying and water as refrigerant in high-temperature heat pumps.