The optimization of a solar heating system for domestic hot water using detailed energy model

Zadatak ovog rada bila je analiza i optimizacija sunčanog sustava za zagrijavanje potrošne tople vode korištenjem računalnog alata TRNSYS za detaljno energijsko modeliranje sustava na primjeru tipične obiteljske kuće. Računalne simulacije provedene su na satnoj i minutnoj bazi za tipičnu meteorološku godinu za klimatsko područje grada Zagreba i grada Splita. Rezultati analize pokazali su da sunčani sustav na području Zagreba pokriva 54%, a sustav na području grada Splita 71% potreba za zagrijavanje potrošne tople vode. Također, ispitan je utjecaj modeliranja spremnika tople vode kao spremnika s jednolikom razdiobom temperature te modeliranje spremnika s temperaturnom stratifikacijom. Utvrđeni su manji dobici energije sunčanog sustava s modelom spremnika s jednolikom razdiobom temperature u iznosu od 8% za sustav na području grada Zagreba te 5% za sustav na području grada Splita. Uz navedeno, u radu je također analiziran utjecaj režima potrošnje tople vode na energetsku bilancu sunčanog sustava te utjecaj povećanja zapremnine spremnika potrošne tople vode. Povećanjem zapremnine spremnika dobici energije sunčanog sustava porasli su za 9%. Analizom utjecaja navika ukućana pri potrošnji tople vode utvrđeno je da navike u potrošnji imaju vidljiv utjecaj na učinkovitost sunčanog sustava. Konačno, uspoređeni su rezultati detaljnih računalnih simulacija provedenih korištenjem računalnih programa TRNSYS i MATLAB s rezultatima proračuna prema normi HRN EN 15316-4-3. U usporedbi s normom, dobici sunčeve energije prema rezultatima računalnih simulacija veći su za 12,5% za sunčani sustav na području grada Zagreba te 4% za sustav na području grada Splita.The purpose of this study was to analyze and optimize a solar heating system for domestic hot water by using TRNSYS, a detailed energy modeling tool on the example of a typical family home. Simulations were performed on an hourly and minute basis for a typical meteorological year for the climate area of the city of Zagreb and the city of Split. The results of the analysis showed that the solar system in Zagreb covers 54% and system in Split covers 71% of heating needs for domestic hot water. Also, the influence of modeling a hot water tank as a fully mixed tank and modeling a tank with temperature stratification was studied. The results showed 8% and 5% lower energy gain of a solar system with a fully mixed tank for the city of Zagreb and city of Split respectively. Furthermore, the influence of a hot water consumption regime and the effect of a water tank increase on the solar energy balance was analyzed. By increasing the volume of the hot water tank by approximately 50%, solar energy gains increased by 9%. The analysis of the occupants’ habits in the usage of the hot water showed that usage habits have notable impact on the efficiency of a solar system. Finally, the results of detailed computer simulations conducted by using computer programs TRNSYS and MATLAB were compared with calculations according to the norm HRN EN 15316-4-3. Compared to the norm, a solar gains according to computer simulations were 12,5% and 4% higher for the solar systems in the city of Zagreb and the city of Split respectively