engleski

Seasonal courses of monthly changes of heating and cooling demands in Croatia

The extension of study that discovered seasonal decreasing demand for heating and seasonal increasing demand for cooling in Croatia, is the study of monthly trends in heating (HDD) and cooling (CDD) degree-days, as well as in number of heating (HD) and cooling (CD) days during the heating and cooling seasons. Trend analysis has been performed for five locations in different climatic regions (Osijek, Zagreb, Gospić, Crikvenica and Hvar) for the period 1901-2008. Over the heating season (October-April) negative monthly trends in HDD prevail, showing the longer period with decreasing than with increasing demand for heating. Mostly positive HDD trends in December showed that first winter month generally is getting colder and need for heating is increasing which is the most emphasized in Hvar. Generally, need for heating in January and February is decreasing much more than in other months. However, proportionally to the appropriate HDD averages, relative January and February trends are not the largest. The largest are relative decreases at the beginning and at the end of heating season and the lowest are mostly relative changes in December. The most important contribution to seasonal negative HD trends is from the beginning and from the end of heating season. Over the cooling season (May-September) positive monthly CDD trends prevail, which show the longer period with increasing than with decreasing demand for cooling. Positive trends show the highest CDD increases in June in the inland of Croatia, in July in Hvar and in August in Crikvenica. Negative trends are considerably lower than positive trends and negative are only September trends in the inland and in some cases in Adriatic area. Relative monthly trends in CDD, with regard to the appropriate averages, exhibit the highest relative monthly CDD increase in May or June and lower increases and decreases towards the end of cooling season. Shapes of courses of monthly trends in CD are rather different between themselves during the cooling season, depending on the applied temperature threshold in CD calculation, but with negative trends mainly only in September.

heating degree-day; cooling degree-day; number of heating days; number of cooling days; Mann-Kendall rank test

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