Hiki, ähky ja loikka - Osallistujien pedagogisia mietteitä ja ideoita hankkeen varrelta

DIGIJOUJOU-hankkeessa työskennelleet opettajat ovat hankkeen toimintavuosien 2017-2019 aikana pohtineet opetuksen ja oppimisen digitaalisuutta ja joustavuutta eri näkökulmista: mitä digitaalisuus ja joustavuus suomen ja ruotsin opiskelussa tarkoittaa, miten soveltaa, lisätä ja kehittää digitaalisuutta ja joustavuutta omassa opetuksessa ja opiskelijoiden oppimisessa. Hankelaisten blogikirjoituksissa näemme askeleita opettajien omasta ja yhdessä muiden kanssa oppimisesta hankkeen edetessä; epävarmuus muuttuu varmuudeksi, ajoittainen digiähky oman asiantuntijuuden kasvuksi ja joustavuus osaksi opettajan arkipedagogiikkaa. Antoisia ja inspiroivia lukuhetkiä! Lisätietoa: https://digijoujou.aalto.fi/Lärarna i DIGIJOUJOU-projektet har under projektets verksamhetsår 2017-2019 reflekterat över digitalisering och exibilitet från olika perspektiv; vad betyder digitalisering och exibilitet i lärandet av finska och svenska, hur ska man implementera, öka och utveckla dessa i den egna undervisningen och i hur studerande lär sig finska och svenska. I projektdeltagarnas bloginlägg får vi inblick i hur allas lärandeprocess i projektet framskrider; osäkerhet utvecklas till säkerhet, digikaoset får ordning och exibilitet blir en del av den egna sakkunnigheten och pedagogiken. Med önskan om givande och inspirerande läsning! Mer information: https://digijoujou.aalto.fi

Energy efficiency in ship design projects with case studies

This chapter discusses the role and practical aspects of energy modeling in modern ship design projects. The new environmental regulations in shipping are forcing the ships to lower their emissions in the future. The work towards energy and environmental efficiency demonstrates the level of ship sustainability and can suggest further improvement potential in processes.https://commons.wmu.se/lib_chapters/1025/thumbnail.jp

Risteilijälaivan energiataseen analysointi ja hukkalämmön käytön optimointi

A large part of the waste heat, in form of steam, high temperature cooling water and low temperature cooling water, that is produced as a by-product of passenger cruise ships' main engines is currently dumped, or it is utilized in thermodynamically inefficient processes. In order to find the most promising targets for the waste heat utilization, the energy balance of a passenger cruise ship was analyzed by conducting an entropy generation analysis of the energy balance. Also, an index for describing the waste heat dumping that considered the qualities of the dumped heat was developed. Consequently, the waste heat would be utilized optimally when both the waste heat index and the entropy generation in the processes utilizing waste heat were minimal. The calculations conducted for a model passenger cruise ship showed that optimal waste heat utilization could save more than 4% of the total fuel consumed onboard the ship. The main engines onboard a model passenger cruise ship were identified as the largest cause of entropy generation in the entire system, and the next largest cause was steam production in the oil fired boilers for additional heat producing. However, if a part of the hot water could be used in some of the heating processes onboard, the utilization of the oil-fired boilers could be minimized, and also the efficiency of the main engines would be enhanced. This alone would have saved 2% of the yearly consumed fuel onboard the model passenger cruise ship. In addition to heating processes, the waste heat could also be utilized for electricity production in Organic Rankine Cycle that in theory could be able to utilize a portion of all waste heat streams. Utilizing the waste heat steam in this process clearly decreased the overall entropy generation in the ship, mainly because it also decreases the need for producing electricity with the main engines. Also, the availability of the hot water in every situation could be assured by installing heat pumps onboard the passenger cruise ship that could use the lowest temperature waste heat as their driving force. The entropy generation in both heating processes utilizing hot water and heat production in heat pumps was clearly smaller than heating processes that utilized steam, and steam production in oil fired boilers. The cooling onboard could be realized with absorption chillers that utilize steam or hot water as their driving force. This process was proven to minimize the overall entropy generation of the entire system, but only in situations when waste heat is available. Producing additional heat in heat pumps or in oil fired boilers for absorption chillers was not profitable according to calculations, but the option to use this might be useful in possible emergency circumstances. Fresh water production with reversed osmosis was discovered in calculations to be more profitable than production in evaporators, especially when steam is required for firing the evaporators. The real installations should be designed in a way that they can utilize the waste heat in all situations. This might require combining these different solutions that should be as thermodynamically efficient as possible, without making large tradeoffs with the economic aspects. This way can the waste heat be utilized optimally and the efficiency of the entire ship's energy system is enhanced

Modeling ship energy flow with multi-domain simulation

Ship energy efficiency is becoming more and more attractive to ship owners, builders and researchers due to the increasingly high fuel cost and the accumulatively strict international maritime rules. It is especially evident for modern ships with complex power plants including mechanical, electrical and thermohydraulic systems. Marine engines, as the heart of ship power plant, play a key role in the fuel energy utilization. But, even for a very efficient marine engine, only less than 50% fuel energy can be converted to useful work. The other over 50% of fuel energy is mainly taken away in a form of heat energy by engine cooling water system and exhaust gas system during the combustion process. Practically, quite a many methods, such as waste heat recovery, have been already developed to enhance the total efficiency of ship power plants. However, there still is not a clear and thorough understanding of the operating efficiency of different processes due to their complexities, which is specifically true for the steam powered systems. In this paper, a new method is introduced to model the ship energy flow for thoroughly understanding the dynamic energy distribution of the marine energy systems. Due to the involvement of different physical domains in the energy processes, the multi-domain simulation method is employed to model the energy flow within Matlab/Simscape environment. The energy processes are described as multi-domain energy flow as function of time. All the main energy processes are to be modeled as subsystems only at a general and system level, and to be built as simple but comprehensive as possible to facilitate the simulation interaction among different main subsystems. For each subsystem, the developed model contains rather simple description of the energy processes involved. The operation and load profiles from real operation data can be given as inputs to examine the dynamic energy balance during the operation. The validation results have positively shown the feasibility and reliability of the energy flow simulation method. The developed energy flow simulation method could further help people better monitor the ship energy flow and understand ship energy systems. More importantly, it could give some valuable insights into how to design an energy-efficient ship power plant and how to operate the vessel efficiently. Furthermore, it could be easily utilized to test and verify new technologies, and hence to find possible ways to improve the energy efficiency of both the existing and new-building ships.©CIMA