Odabir rješenja i dimenzioniranje sustava solarnog daljinskog grijanja

master's thesis

• Title (english): Design and sizing of solar district heating system
• Author: Tihomir Capan
• Mentor: Damir Dović (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2020-04-10, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Process Energy Engineering

Abstract

Za ostvarivanje klimatsko-energetskih ciljeva Europske unije nužno je kontinuirano poboljšavati učinkovitost energetskih sustava i integrirati obnovljive izvore energije. U tom kontekstu sektor grijanja i hlađenja predstavlja veliki potencijal pri čemu se značajniji napredak očekuje u sustavima daljinskog grijanja. U ovom trenutku u Republici Hrvatskoj se u najvećem broju sustava daljinskog grijanja koriste fosilna goriva, a od obnovljivih izvora napredak je postignut u primjeni biomase, dok je primjena solarne topline ograničena na samo jedan sustav. U isto vrijeme solarna se toplina u značajnijoj mjeri iskorištava u kućanstvima, ugostiteljskim objektima i procesnoj industriji.
U ovom radu razmotrena je integracija solarnog toplinskog sustava u sustav daljinskog grijanja manjeg kapaciteta u klimatskom području grada Zagreba. Izrađen je model koji se sastoji od proračuna sunčevog zračenja na nagnutu plohu te modela kolektora i toplinskog spremnika sukladno normama HRN EN 15 316-4-3:2017 i HRN EN 15 316-5:2017. Koristeći podatke o vremenskim uvjetima, prostornim i tehničkim ograničenjima, toplinskim potrebama i tehničkim karakteristikama komponenti odabrano je rješenje s najkraćim periodom povrata. Prema proračunu odabrano je rješenje s 280 vakuumskih pločastih solarnih kolektora ukupne površine 548,8 m2 te s toplinskim spremnikom zapremine 45 m3. Kolektori su postavljeni uspravno pod kutom od 30° u odnosu na horizontalu pri čemu razmak između redova iznosi 4,54 m. Ukupna godišnja količina prikupljene energije iznosi 414,69 MWh čime se pokriva 14,05% toplinskih potreba sustava daljinskog grijanja. Prosječna učinkovitost solarnih kolektora u opisanom slučaju iznosi 0,5293, a jednostavni period povrata investicije iznosi 18,39 godina.
Usporedbom rezultata dobivenih prema modelu s izmjenjivačem topline pomoćnog izvora smještenog unutar odnosno izvan spremnika primijećene su razlike u ostvarenim temperaturama u spremniku kao i prikupljenoj energiju u karakterističnim periodima tijekom godine, no na godišnjoj razini razlika u iznosu prikupljene toplinske energije je manja od 1%. Osnovni razlozi tome su relativno mali nagib krivulje učinkovitosti solarnog kolektora, visoka temperatura povrata koja sprječava pojavu većih temperaturnih razlika po visini spremnika i mala potreba u ljetnim mjesecima. Usporedba rezultata s programom EnergyPRO također je rezultirala malim razlikama u iznosu prikupljene energije na godišnjoj razini.

Abstract (english)

In order to achieve the EU's climate and energy goals, it is essential to continuously improve the efficiency of energy systems and to integrate renewable energy sources. In this context, the heating and cooling sector presents great potential, with significant progress expected in district heating systems. At present, fossil fuels are used in most district heating systems in Croatia, and while progress has been made in the use of biomass, the use of solar heat is limited to only one district heating system. At the same time, solar heat is used to a greater extent in households, hospitality and process industry.
In this thesis the integration of the solar thermal system into a low capacity district heating system in the Zagreb climate zone is discussed. A model consisting of a calculation of solar radiation on an inclined surface, and models of solar collectors and heat storage tank in accordance with the standards HRN EN 15 316-4-3: 2017 and HRN EN 15 316-5: 2017 have been developed. Based on the known data on weather conditions, space and technical constraints, thermal needs and technical characteristics of the components, the solution with the most favourable payback period was selected.
According to the results of the calculation, a solution with a total of 280 vacuum plate solar collectors with a total area of 548.8 m2 and with storage tank 45 m3 in capacity was selected. The collectors are mounted upright at an angle of 30° to the horizontal, with row spacing of 4.54 m. The total annual amount of collected heat equals 414.69 MWh, which covers 14.05% of the district heating systems' heat demand. The average efficiency of solar collectors in the case described is 0.5293, and the simple return on the investment equals 18.39 years.
Comparison of the results obtained by the model with the auxiliary heat exchanger located inside or outside the tank revealed differences in the achieved temperatures in the tank as well as the energy collected during the characteristic periods during the year. However, the difference in the amount of heat collected on an annual basis is very small (<1%). The main reasons for this are the slight slope of the curve of vacuum plate solar collectors, high return temperature which prevents high temperature difference in the storage and low heat demand in the summer period. Comparison of the results with the EnergyPRO also resulted in small differences in the amount of energy collected annually.

• Keywords: solarni kolektor; solarni toplinski sustav; toplinski spremnik; daljinsko grijanje; HRN EN 15316-4-3:2017; HRN EN 15316-5:2017
• Keywords (english): solar thermal collector; solar thermal system; heat storage; district heating; HRN EN 15316-4-3:2017; HRN EN 15316-5:2017
• Language: croatian
• URN:NBN: urn:nbn:hr:235:254794
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-04-08 08:37:33