Hruštšovka renoveerimise võimalused SmartEnCity projekti raames

Käesolevas lõputöös on analüüsitud Tartu kesklinnas asuvat 1962.aastal ehitatud 4-korruselise telliskorterelamu energiatõhusust. Hoone visuaalsel vaatlusel tuvastati suuremate probleemidena praod fassaadikivides, niiskunud sokkel, ebatihe katus ning niiskunud ja osaliselt tallatud soojustus pööningul. Logerite mõõtmistulemustest selgus, et keskmine sisetemperatuur on ligikaudu 21⁰C, keskmine õhuniiskus 50%. Samas ületab mõnes korteris suhteline õhuniiskus sisekliima III klassi nõudeid 77% mõõtmisperioodi ajast, mis viitab korteris suurele niiskuslisale ja võib tekitada hallituse teket. Hallituse ja kondensaadi tekke ohule viitavad ka termografeerimise tulemused, mille alusel arvutatud fRsi < 0,7. Ventilatsiooni õhuhulkade mõõtmistega tuvastati, et loomulik ventilatsioon hoones ei toimi, mistõttu ei juhita kogunenud niiskust korteritest välja ja õhuvahetus toimib ebatihedate piirete kaudu. Toodud probleemide lahendamiseks on välja pakutud komplekssed energiasäästlikud renoveerimisettepanekud. Enne renoveerimistööde alustamist tuleb tellida analüüsitavale hoonele ehitusekspertiis, mille põhjal otsustatakse, kas hoone põhikonstruktsioonid vajavad enne renoveerimist põhjalikumat remonti. Hoone soojus-, elektrienergia ja tarbegaasi tarbimisandmete alusel on analüüsitud hoone energiatarbimist ja arvutatud hoone kaalutud energiaeritarbimine ehk KEK. Saadud tulemuse järgi - KEK 246,7 kWh/(m2a), kuulub hoone korterelamu kaalutud energiaerikasutuse skaalas klassi F. Hoone inventariseerimisplaanide ja tarbimisandmete alusel on koostatud IDA ICE programmis hoone simulatsioonimudel, mis on viidud tegeliku olukorraga vastavusse nii, et mudeli arvutuslikud soojus- ja elektrienergia tarbimised vastaksid mõõdetud tarbimisele. Tuginedes simulatsioonimudeli arvutustele on välja toodud kütteenergia kaod läbi välispiirete, infiltratsioonist ja keldri küttetorustikust ning vabasoojusenergia kogused päikesest, inimestest, seadmetest, valgustusest ja soojusinertsist. Kõige suuremad kütteenergia kaod on läbi hoone seinte 32%, läbi akende 21% ja läbi infiltratsiooni 19%. Suurim vabasoojuse allikas on päike 36%, seejärel seadmed 28% ja inimesed 20%. IDA ICE energiasimulatsiooni tulemusena on saadud hoone kütteenergia vajaduseks kokku ligikaudu 200 MWh, mis erineb tegelikust keskmisest kraadpäevadega korrigeeritud soojusenergia tarbimisest ~5%. Saadud vahe võib tuleneda sellest, et korterites hoitakse veidi kõrgemat temperatuuri kui uuritavad 3 korterit seda näitasid. Tuginedes simulatsioonimudelile ja seades eesmärgiks energiatõhususe arvu ETA < 90 kWh/(m2a) saavutamine, on välja pakutud lahendused hoone energiasäästlikuks renoveerimiseks, mis vastaksid ka SA KredExi 40% toetuse saamise nõuetele. Pakutud renoveerimislahenduste tulemusena saadi välisseinte keskmiseks soojusläbivuseks 0,17 W/(m²·K), katuse soojusläbivuseks 0,08 W/(m²·K), uste soojusläbivuseks 0,89 W/(m²·K) ja akende keskmiseks soojusläbivuseks 0,74 W/(m²·K). Keskmiselt vähendatakse kütteenergia kadusid 72%. Hoone sisekliima nõuete täitmiseks on ventilatsiooni lahenduseks planeeritud tsentraalse plaatsoojustagastiga kõrge efektiivsusega ventilatsiooniagregaat. Renoveerimistööde tulemusena on hoone prognoositav hoone kütteenergia vajadus 37,8 MWh ja energiatõhususe arv 124 kWh/(m²·a). Seatud eesmärki ületatava energiakoguse 34 kWh/(m²·a) katmiseks on arvutatud vajaminev energiapaneelide hulk, milleks on 96 tükki võimsusega 250 W/tk. Probleemne on vajamineva paneelide koguse mahutamine hoone katusele. Täpsemate arvutuste tegemiseks on vaja tellida konkreetsele hoonele renoveerimisprojekt. Lahendusena välja pakutud renoveerimisprojekti tasuvusaeg on 9 aastat, kui korteriühistul õnnestub saada vahendeid nii suurprojektist SmartEnCity kui ka KredExist.

The title of this thesis is the "Renovation Options for Khrushchev Era Buildings as Part of the SmartEnCity Project". The target of the study is a 4-storey brick apartment building located in the centre of Tartu that was built in 1962 in the Khrushchev era. At the start of 2016, Khrushchev era buildings in the centre of Tartu had the opportunity to apply for additional renovation funding from the major project SmartEnCity where the city of Tartu participates and that is unique in Europe. The building analysed in the thesis is located within the pilot area and as part of the project the apartment association is able to apply for grants for the renovation of the building from the city of Tartu from SmartEnCity funds and also for renovation grants issued by the KredEx Foundation. The first objective of the thesis is to propose an energy efficient renovation solution for the analysed building that enables the building to achieve a lower energy performance indicator than 90 kWh/(m²·yr) in order to meet the major project's funding criteria. The second objective of the thesis is to estimate the payback period of the proposed renovation solution. The first chapter of the thesis discusses the current condition of the building. Multiple flaws such as damage to the facade, roof and baseboard were highlighted as a result of a visual inspection of the building. Loggers, an air flow meter and thermal imaging camera were used for indoor climate analysis. The loggers' measurement results indicated that the average indoor temperature is approximately 21⁰C, average air humidity is 50%. However, the relative humidity in some apartments exceeds the Class III requirements of indoor climate for 77% of the time measured, which indicates there is significant excess humidity in the apartment that could lead to mould. The thermal imaging results, based on which fRsi<0.7 was calculated, also indicate the risk of mould and condensate. Measurements of ventilation air flow detected that natural ventilation does not function in the building, therefore the accumulated humidity is not expelled from apartments and ventilation occurs through the leaky building envelope. A set of energy efficient renovation proposals were made to resolve the indicated problems. Before renovation work begins, expert assessment must be commissioned for the analysed building, based on which a decision is made on whether the core structures of the building require more extensive repairs prior to renovation. The second chapter of the thesis analyses the thermal energy, electrical energy and natural gas consumption data of the building, which is then used to calculate the weighted specific energy use of the building. According to weighted specific energy use of 246,7 kWh/(m²·yr), the apartment building has the energy efficiency rating F. The third chapter of the thesis contains the simulation model of the building that was developed based on the measurement plans and consumption data using the IDA ICE application, which is applied to the actual situation to ensure that the calculated consumption of thermal and electrical energy correspond to the measured consumption. Based on the simulation model calculations, the chapter includes heat losses through the building envelope, infiltration and basement heating pipes and amounts of thermal energy released from the sun, humans, equipment, lighting and thermal inertia. The largest sources of heat losses are: 32% through the building walls, 21% through the windows and 19% through infiltration. The biggest source of released heat is the sun with 36%, followed by equipment with 28% and humans with 20%. The IDA ICE energy simulation indicated total heat requirement of the building to be approximately 200 MWh, which differs from the actual average degree-days adjusted thermal energy consumption by 5%. The resulting difference may arise from the fact that apartments maintain a slightly higher temperature than the 3 studied apartments indicated. Based on the simulation model and having the energy performance indicator of < 90 kWh/(m²·yr) as the objective, the fourth chapter proposes solutions for the energy efficient renovation of the building that would meet the KredEx Foundation's funding criteria. As a result of proposed renovation solutions, the average heat transfer coefficient of the external walls was 0.17 W/(m²·K), the roof's heat transfer coefficient was 0.08 W/(m²·K), the doors' heat transfer coefficient was 0.89 W/(m²·K) and the average heat transfer coefficient of the windows was 0.74 W/(m²·K). On average, heat losses are reduced by 72%. In order to meet the indoor climate requirements of the building, the planned ventilation solution is a highly efficient ventilation unit with a central plate heat exchanger. The estimated heat requirement of the building as a result of renovation work is 37.8 MWh and its energy performance indicator is 124 kWh/( m²·yr). In order to cover the amount of energy above the objective of 34 kWh/(m²·yr), the number of energy panels required has been calculated, which is 96 at the rate of 250 W. It is challenging to fit the required number of panels on the roof of the building. It is necessary to commission a renovation design for the specific building to perform more accurate calculations. A simple payback period has been calculated for the renovation project in the fifth chapter, which is 9 years if the apartment association is able to raise funding from the major project SmartEnCity and from KredEx.