Estimated Energy Consumption of the Finnish Building Stock Using Representative Building Types

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1 Estimated Energy Consumption of the Finnish Building Stock Using Representative Building Types Riikka Holopainen Senior Scientist VTT Technical Research Centre of Finland, Finland Pekka Tuominen, VTT Technical Research Centre of Finland, Finland, Juha Jokisalo, Aalto University, Finland, Lari Eskola, Aalto University, Finland, Summary The energy consumption of different types in the stock was estimated using a twofold modelling approach. First representative s of various types and ages were modelled to establish their energy consumption using dynamic modelling. Then the cumulative energy consumption of these types was calculated based on the modelled development of the stock using the REMA model at VTT. According to the estimate produced by the calculation for the year 2012 the stock will consume GWh of energy (including electricity for ) and in GWh of electricity (excluding ). For 2020 a similar calculation suggests a consumption of GWh of energy and in GWh of electricity for the whole stock. The results fit reasonably well within the variation present in past calculations, with somewhat higher consumption in single-family homes than other studies have suggested. Keywords: Energy, Energy consumption, Building stock, Modelling 1. Introduction The objects of the Finnish SPF (Seasonal Performance Factor) project are to define a national seasonal performance factor calculation for heat pumps and to estimate the energy saving and renewable energy potential of heat pumps on the Finnish stock. The project duration is from to and the project is financed by the Finnish ministry of employment and the economy, the Finnish ministry of the environment and SITRA. This paper presents results from Task 2 Energy use of the Finnish stock, where the energy consumption of the Finnish stock was estimated using standard types (detached, apartment, office and summer cottage) for different decades. The energy consumption of different types in the stock was estimated using a twofold modelling approach. First representative s of various types and ages were modelled to establish their energy consumption using dynamic simulation tool IDA-ICE. Then the cumulative energy consumption of these types was calculated based on the modelled development of the stock using the REMA model at VTT. The results were compared with the national statistics [1] and previous estimates ([2], [3], [4]) and four rounds of iteration were completed resulting in calibrated types, a new estimate for the composition of energy consumption in the stock and a forecast for expected changes in energy consumption.

2 2. Methods Four model types where chosen to represent the major types that constitute the stock: detached s (about 38 % of the total floor area in the stock), apartment s (31 %), commercial and public s, represented by an office (26 %), and holiday homes (5 %). The model types are presented in Figures 1-3. The living area of the detached was 134 m 2, the living area of the apartment was 814 m 2, the net area of the office is m 2 and the living area of the cottage was 134 m 2. Fig. 1 Model type for the singlefamily and the summer cottage Fig. 2 Model type for the apartment Fig. 3 Model type for the office The s were further divided into four age groups and individually modelled: s built before 1960 (subgroup A), between (subgroup B), between (subgroup C1), and between (subgroup C2). The stock in the year 2010 is presented in Table 1. Future construction was modelled as norm s built according to 2010 regulation (subgroup D1), low-energy s (subgroup D2) and very low-energy s (subgroup D3). The airtightness of the envelope is presented in Table 1. For s with natural ventilation (*) the air-leakage through the envelope is included in the air-change rate. The heat loss values (U-values) of different structures are presented in Table 2. Table 1. Air-tightness of the envelope n50, 1/h Detached Cottage A * * * * B * 2.3 [5] 2.3 [5] * C1 4.0 [6] [7] C2 3.5 [6] 0.9 [7] 0.9 [8] 5.8 [7] D [7] D D The detached is heated and ventilated constantly. The apartment is also constantly heated and ventilated, but in apartment s with mechanical exhaust ventilation system the ventilation rate is 50 % of the full rate during 18:00 7:00 and 9:00 16:00. s D1, D2 and D3 have a mechanical system in the case of detached s but not in the case of apartment s.

3 Table 2. Heat loss values of the buiding structures. OW = outer wall, UF = upper floor, BF = base floor, W = window A B C1 C2 D1 Detached OW 0.69 [10] UF 0.41[10] OW 0.42[10] UF 0.24[10] OW 0.28 UF 0.22 BF 0.36 W 1.6[10] OW 0.25 UF 0.16 BF 0.25 W 1.4 OW 0.17 UF 0.09 BF 0.16 W 1.0 OW 0.83[10] UF 0.42[10] OW 0.47[10] UF 0.29[10] OW 0.28 UF 0.22 BF 0.36 W 1.6[10] OW 0.25 UF 0.16 BF 0.25 W 1.4 OW 0.17 UF 0.09 BF 0.16 W 1.0 OW 0.83[a] UF 0.42[a] W 2.2[a] OW 0.47[a] UF 0.29[a] W 2.2[a] OW 0.28 UF 0.22 BF 0.36 W 1.6[a] OW 0.25 UF 0.16 BF 0.25 W 1.4 OW 0.17 UF 0.09 BF 0.16 W 1.0 D2 OW 0.14, UF 0.08, BF 0.12, W 0.9[11] D3 OW 0.08 UF 0.07 BF 0.09, W 0.7[12] Table 3. Set indoor temperatures Detached Cottage Cottage A 21.0 C [1] 22 C [2] 21.5 C 21.0 C B 21.0 C [1] 22 C [2] 21.5 C 21.0 C C C [1] 22 C [2] 21.5 C 21.0 C C C [1] 21.5 C [2] 21.5 C 21.0 C in subgroup A in subgroup A in subgroup B in subgroup C1 according to Finnish code, part C3 (2010), log wall U- value 0.4 in subgroup D2 in subgroup D3 D1, D2, D C [1] 21.0 C [3] 21.5 C 21.0 C [1] bathroom and sauna set temperatures 21 C, [2] cellar and staircase set temperatures 19.0 C, WC and bathroom set temperatures 23 C, [3] cellar and staircase set temperatures 17.0 C, WC and bathroom set temperatures 23 C. The office is heated continuously. In subgroups B and C1 the ventilation is on during week-days between 6:00 and 20:00. In subgroups C2, D1, D2 and D3 the ventilation is on during week-days between 6:00 and 20:00. In other times only the social spaces are ventilated with the ventilation rate of 0.15 dm³/s,m². s C1, C2, D1, D2 and D3 have a mechanical system operating during weekdays between 6:00 and 20:00. The recreational cottage is a private free-time home used annually an estimated typical length. Heating and ventilation is on during the usage time, outside the usage time there s a base load. The usage time is whole July, every weekend in June and August, and every third week-end from September to May. The indoor temperature set-values are presented in Table 3. The ventilation systems are presented in Table 4 and the ventilation rates in Table 5. The warm usage is presented in Table 6. The device electricity use of the different types was according to the Finnish Building Code, part D3 (2012).

4 Table 4. Ventilation systems. NV = natural ventilation, ME = mechanical exhaust ventilation, MSE = mechanical suppy and exhaust ventilation, HR = heat recovery (temperature efficiency ) Sub-group Detached A NV NV NV NV B NV ME ME NV C1 ME ME MSE + HR (50%) ME C2 MSE + HR (60%) MSE + HR (60%) MSE + HR (80%) ME Cottage D1 MSE + HR (60%) MSE + HR (60%) MSE + HR (80%) MSE + HR (60%) D2 MSE + HR (80%) MSE + HR (80%) MSE + HR (80%) MSE + HR (80%) D3 MSE + HR (85%) MSE + HR (85%) MSE + HR (85%) MSE + HR (80%) Table 5. Air-change rate, 1/h Detached Cottage A 0.41 [13] 0.62 [13] 0.62 [13] 0.41* B 0.41 [13] 0.43 [14] 0.43 [14] 0.41* C [13] 0.5 [15] 0.5 [15] 0.46* C [6] 0.56 [6] 0.5 [16] 0.40* D1 0.5 [17] 0.5 [17] 0.5 [17] 0.5* D2 0.5 [17] 0.5[17] 0.5 [17] 0.5* D3 0.5[17] 0.5[17] 0.5 [17] 0.5* * during usage time, in other times only air-leakage through the envelope. Table 6. consumption Detached, dm 3 /pers,day, dm 3 /pers,day, dm 3 /rm 2,a A 42 [18] 64 [19] 100 [20] B 42 [18] 62 [19] 100 [20] C1 42 [18] 59.2 [19] 100 [20] C2 42 [18] 57.6 [19] 100 [20] D1, D2, D3 42 [18] 56 [19] 100 [20] Cottage

5 3. Results The energy demands of the different standard types and subgroups were simulated using IDA ICE 4.2 dynamical simulation program with the test weather data 2012 of Jyväskylä, Central Finland (Kalamees 2012). The and energy use is presented in Table 8 for the detached, in Table 9 for the apartment, in Table 10 for the office and in Table 11 for the cottages. Table 8. Heating and energy net demands of the detached, kwh/m 2 A B C C D D D Table 9. Heating and energy net demands of the apartment, kwh/m 2 A B C C D D D Table 10. Heating and energy net demands of the office, kwh/m 2 A B C C D D D Table 11. Heating and energy net demands of the cottage, kwh/m 2 A B C C D D D The cumulative energy consumption of the whole stock was calculated based on the modelled development of the stock using the REMA model developed at VTT. The simulated energy demand results of each standard type and subgroup were used as an input for the REMA model to calculate the total energy consumption of the stock in each year, taking into consideration the estimated changes in the future development of the

6 Table 1. Modelled size of stock in 2010 according to the REMA model, in millions of m 2. Inconcistences in totals are due to rounding. Detached s s s Cottages A B C1 + C Total stock According to the estimate produced by the calculation for the year 2012 singlefamily s will consume, in terms of delivered energy, GWh of energy (including electricity for ) and 5200 GWh of electricity (excluding ), multi-family s consume GWh in and 5600 GWh of electricity, commercial and public s GWh in and 7500 GWh of electricity and, finally, holiday homes 2800 GWh in 300 GWh of electricity, totalling in GWh of energy and in GWh of electricity for the whole stock. For 2020 a similar calculation suggests that single-family s will consume GWh of energy (including electricity for ) and 5600 GWh of electricity (excluding ), multi-family s consume GWh in and 5800 GWh of electricity, commercial and public s GWh in and 8100 GWh of electricity and, finally, holiday homes 2700 GWh in 400 GWh of electricity, totalling in GWh of energy and in GWh of electricity for the whole stock. 4. Conclusion Fig. 2 The results (Modelled estimate) compared to Statistics Finland [1], revised statistics [2], Ekorem project [3] and ERA project [4]. comfortable temperature. The numbers correspond to an increase of 5 % in energy consumption and 6 % increase in electricity consumption in the stock by the year This is in agreement with a slowing growth of energy consumption with a growing emphasis on electricity consumption. The results fit reasonably well within the variation present in past calculations, with somewhat higher consumption in single-family homes than other studies have suggested. This might be because a significant part of the singlefamily home stock might be underused or in disuse and thus kept in lower than A major benefit of the approach chosen here is that each type and subtype of s is individually modelled and therefore their contribution to the total energy consumption can be traced to the modelled physical characteristics of the s. This allows the study of individual modifications and their effects to energy consumption on a large scale.

7 5. References [1] STATISTICS FINLAND, Energiatilasto Vuosikirja 2010, Tilastokeskus, Helsinki, [2] STATISTICS FINLAND, Asumisen (kotitalouksien) energian kulutus -loppuraportti, Tilastokeskus, Helsinki, [3] HELJO J., NIPPALA E., NUUTILA H., Rakennusten energiankulutus ja CO2-ekv päästöt Suomessa, Tampere University of Technology, [4] VEHVILÄINEN I. ET AL., Rakennetun ympäristön energiankäyttö ja kasvihuonekaasupäästöt, Sitra, [5] POLVINEN M., KAUPPI A., SAARIMAA J., HAALAHTI., LAURIKAINEN, M., Rakennusten ulkovaipan ilmanpitävyys. VTT. Tutkimuksia [6] VINHA, J., KORPI, M., KALAMEES, T., ESKOLA, L., PALONEN, J., KURNITSKI, J., VALOVIRTA, I., MIKKILÄ, A., JOKISALO, J., Puurunkoisten pientalojen kosteus- ja lämpötilaolosuhteet, ilmanvaihto ja ilmatiiviys. Tampere, Tampereen teknillinen yliopisto, Talonrakennustekniikan laboratorio, Tutkimusraportti s liites [7] VINHA, J., KORPI, M., KALAMEES, T., JOKISALO, J., ESKOLA, L., PALONEN, J., KURNITSKI, J., AHO, H., SALMINEN, M., SALMINEN, K., KETO, M., Asuinrakennusten ilmanpitävyys, sisäilmasto ja energiatalous. Tampere, Tampereen teknillinen yliopisto, Rakennustekniikan laitos, Rakennetekniikka, Tutkimusraportti [8] SUOMELA M., Toimistotalon ilmatiiviyden mittaaminen. Seinäjoen ammattikorkeakoulu. Opinnäytetyö [9] ESKOLA, L., KURNITSKI, J., PALONEN, J., Building leakage rate measurement with 's own air handling unit. Healthy Buildings 2009, Syracuse, NY, USA, September p. [10] NYKÄNEN, V. & HELJO, J., Rakennusten energiatalous Suomessa. Tampereen teknillinen korkeakoulu, rakentamistalous. Sarja d:83. Kauppa ja teollisuusministeriö, energiaosasto. Helsinki 1985 [11] Typical U-values for low energy s: [12] NIEMINEN J., JAHN J. JA AIRAKSINEN M., Passiivitalon rakennesuunnittelu. Promotion of European Passive Houses [13] RUOTSALAINEN, R., Indoor climate and the performance of ventilation in Finnish residences. Indoor Air, 2, [14] DYHR R., Asuinrakennusten ilmanvaihtoselvitys. Helsingin kaupunki [15] D2. Suomen rakentamismääräyskokoelma. Rakennusten sisäilmasto ja ilmanvaihto. Määräykset ja ohjeet 1987, Ympäristöministeriö, [16] D2. Suomen rakentamismääräyskokoelma. Rakennusten sisäilmasto ja ilmanvaihto. Määräykset ja ohjeet 2003, Ympäristöministeriö, Rakennetun ympäristön osasto [17] D2. Suomen rakentamismääräyskokoelma. Rakennusten sisäilmasto ja ilmanvaihto. Määräykset ja ohjeet 2010, Ympäristöministeriö, Rakennetun ympäristön osasto [18] MOTIVA OY, Pientalon lämmitysjärjestelmät. Helsinki, [19] VIRTA, J. JA PYLSY P., Taloyhtiön energiakirja. Kiinteistöalan kustannus oy [20] D5 Suomen rakentamismääräyskokoelma, Rakennuksen energiankulutuksen ja lämmitystehontarpeen laskenta Ohjeet Ympäristöministeriö, Asunto- ja rakennusosasto. Helsinki 19.kesäkuuta 2007.