2 resultados para Regional production circuits

em Dalarna University College Electronic Archive


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This master thesis presents a new technological combination of two environmentally friendly sources of energy in order to provide DHW, and space heating. Solar energy is used for space heating, and DHW production using PV modules which supply direct current directly to electrical heating elements inside a water storage tank. On the other hand a GSHP system as another source of renewable energy provides heat in the water storage tank of the system in order to provide DHW and space heating. These two sources of renewable energy have been combined in this case-study in order to obtain a more efficient system, which will reduce the amount of electricity consumed by the GSHP system.The key aim of this study is to make simulations, and calculations of the amount ofelectrical energy that can be expected to be produced by a certain amount of PV modules that are already assembled on a house in Vantaa, southern Finland. This energy is then intended to be used as a complement to produce hot water in the heating system of the house beside the original GSHP system. Thus the amount of electrical energy purchased from the grid should be reduced and the compressor in the GSHP would need fewer starts which would reduce the heating cost of the GSHP system for space heating and providing hot water.The produced energy by the PV arrays in three different circuits will be charged directly to three electrical heating elements in the water storage tank of the existing system to satisfy the demand of the heating elements. The excess energy can be used to heat the water in the water storage tank to some extent which leads to a reduction of electricity consumption by the different components of the GSHP system.To increase the efficiency of the existing hybrid system, optimization of different PV configurations have been accomplished, and the results are compared. Optimization of the arrays in southern and western walls shows a DC power increase of 298 kWh/year compared with the existing PV configurations. Comparing the results from the optimization of the arrays on the western roof if the intention is to feed AC power to the components of the GSHP system shows a yearly AC power production of 1,646 kWh.This is with the consideration of no overproduction by the PV modules during the summer months. This means the optimized PV systems will be able to cover a larger part of summer demand compared with the existing system.

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Foreign accent can be everything from hardly detectable to rendering the second language speech unintelligible. It is assumed that certain aspects of a specific target language contribute more to making the foreign accented speech intelligible and listener friendly, than others. The present thesis examines a teaching strategy for Swedish pronunciation in second language education. The teaching strategy “Basic prosody” or BP, gives priority to temporal aspects of Swedish prosody, which means the temporal phonological contrasts word stress and quantity, as well as the durational realizations of these contrasts. BP does not prescribe any specific tonal realizations. This standpoint is based on the great regional variety in realization and distribution of Swedish word accents. The teaching strategy consists virtually of three directives: · Stress the proper word in the sentence. · Stress proper syllables in stressed words and make them longer. · Lengthen the proper segment – vowel or subsequent consonant – in the stressed syllable. These directives reflect the view that all phonological length is stress-induced, and that vowel length and consonant length are equally important as learning goals. BP is examined in the light of existing findings in the field of second language pronunciation and with respect to the phonetic correlates of Swedish stress and quantity. Five studies examine the relation between segment durations and the categorization made by native Swedish listeners. The results indicate that the postvocalic consonant duration contributes to quantity categorization as well as giving the proper duration to stressed syllables. Furthermore, native Swedish speakers are shown to apply the complementary /V: C/ - /VC:/ pattern also when speaking English and German, by lengthening postvocalic consonants. The correctness of the priority is not directly addressed but important aspects of BP are supported by earlier findings as well as the results from the present studies.