Applied Mechanics and Materials ISSN: 1662-7482, Vols. 725-726, pp 1512-1518 doi:10.4028/www.scientific.net/AMM.725-726.1512 © 2015 Trans Tech Publications, Switzerland

Submitted: 2014-10-13 Revised: 2014-11-09 Accepted: 2014-11-10 Online: 2015-01-29

Energy-plus House for the Climatic Conditions of Macedonia Meri Cvetkovska1,a, Vera Murgul2,b*, Ekaterina Aronova3,c, Nikolay Vatin4,d, Maxim Shvarts5,e 1

University Ss. Cyril and Methodius in Skopje, Faculty of Civil Engineering, Partizanski odredi 24, 1000 Skopje, Republic of Macedonia 3,5

Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021, Saint-Petersburg, Russia

2,4

St.Petersburg State Polytechnical University, 195251, Saint-Petersburg, Russia

a

[email protected], [email protected], [email protected], e [email protected]

d

[email protected],

Keywords: Passive house, Energy-plus house, solar power, photovoltaic systems, energy efficiency, Macedonia.

Abstract. In this paper the Energy-plus house project, functioning under the climate conditions of Macedonia, was presented. On the basis of previous studies carried out for a single-family house, the concept of a fully non-volatile home using solar photovoltaic modules for the operation of the electrical equipment was designed according to "Passive house". The estimates of solar resources of the territory, defined energy input of solar radiation on differently oriented surfaces and selected the optimum tilt angle of PV modules to the horizon were presented for this article. It is shown that the solar modules generated enough electricity to meet the needs of the considered house. At the same time in the summer there is surplus electricity. The calculations presented in this paper were based on the methods of thermodynamics, using MKS EN and DIN standards, the program packages PHPP 2007, as well as the algorithm developed for calculating the amount of solar radiation on differently oriented surfaces. Introduction Possibility of building a completely non-volatile buildings is relevant to Macedonia, where low population density is far away from the centralized energy networks areas. The report for the project in this article Energy-plus house has taken the concept of "passive house", supplemented by the possibility of electricity based on solar energy. The basic assessment criteria whether the building meets the standard “passive house” are as follows: specific energy demands for heating/cooling (QSH/QSC) [≤ 15kWh/(m2a)], or alternative: heating/cooling load (HL)/(CL) [≤ 10W/m2]; air impermeability [η50 ≤ 0.6 h-1]; specific primary energy demand (QSP) [≤ 120 kWh/(m2a)] and the emission of CO2. [1] The rate of 15 kW / (m² per year) is the typical one in matter of energy consumption needed to heat a «passive house» under weather conditions of Central Europe. In Stockholm it can reach 20 kW / (m² per year), and in Rome it can’t be over 10 kW / (m² per year). The concept is based on the statement to reduce heating costs to zero and achieve constant comfortable temperatures owing to efficient thermal insulation and impermeability of a building’s envelope, any home heat recovery and passive solar heating. [2-9] The concept is based on the statement to reduce heating costs to zero and achieve constant comfortable temperatures owing to efficient thermal insulation and impermeability of a building’s envelope, any home heat recovery and passive solar heating (Fig. 1).

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Figure 1. Basic components of the «Passive house» concept [10]. Object of research The macro location of the building falls in the eastern part of Macedonia, at an altitude of 600m and is located on a plateau. The architecture of the house has been taken from the famous house of Franz Freundorfer (Fig. 2).

Figure 2. Facade of the analyzed building.. Parametric analysis of the passive house The calculation of the passive house was made with the software package PHPP 2007. Dimensions of the insulation, windows and all other elements were defined to meet the criteria for a passive house and in same time to be as close as possible to the limit values for the Passive House (PH) standard. Comparison of the final calculation results with the maximum values defined by the Passive House standard is presented in Tab. 1 [1, 11]. Table 1. Comparison of calculation results from PHPP 2007 and standard values [1] Criteria Symbol Unites Design Max. value value (standard) 2 Specific energy heating QSH kWh/(m a) 14 15 demand Specific primary energy QSP kWh/(m2a) 78 120 demand Heating load HL W/m2 10 10 2 Cooling load CL W/m 7 10 Frequency of overheating h % 4 10

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An extremely low energy demand for heating enables the heat to be delivered through the ventilation system (the air is heated with electric heaters after the recuperator). The calculation results clearly show that there is a need additional heating device which will produce an additional 171 W. In the case of conventional energy sources, emissions of carbon dioxide from the heating system is 9 kg/(m2a) while the total emission is 19 kg/(m2a). Building, that are using only the solar energy, will be a CO2-neutral. Previously developed project standards of "passive house" is proposed to add energy-based photovoltaic modules. Influence of the building orientation The orientation of the building has direct impact on the energy balance of the passive building. The initial orientation (south of the house was rotated by steps of 30° clockwise and the results of PHPP 2007 for each of the defined positions of the house are presented in the Tab. 2.

Description Symbol Unites Prescribed values Design values Rotation 30o Rotation 60o Rotation 90o Rotation 120o Rotation 150o Rotation 180o

Table 2. Influence of building orientation [1] Specific energy demands Load Freq. of primary heating cooling heating Cooling overh. energy QSH QCS QSP HL CL h 2 2 [ kWh/(m a)] [W/m ] [%] 15 13.93 14.57 16.34 18.26 20.02 21.41 22.92

9.36 11.22 14.93 17.20 16.68 14.99 13.85

CO2 emision without Total equipem. CO2Qsh CO2Qsp [kg/(m2a)]

120

10

10

10

/

/

77.74 78.33 79.96 81.78 83.47 84.84 86.36

10.06 10.22 10.46 10.65 10.75 10.78 10.94

6.76 7.87 8.56 10.03 8.96 7.55 6.61

3.62 6.11 12.97 11.90 9.89 4.10 1.83

8.88 9.01 9.39 9.80 10.19 10.51 10.85

19.35 19.49 19.86 20.28 20.66 20.97 21.32

Based on the analysis of the results, it was concluded that the optimum orientation is the main facade of the building due south. Calculation of the incoming solar energy The territory of Macedonia is rich of the solar resources, which confirms the insolation map of the country, shown in Fig. 3 Meteorological observations conducted from April 2004 to March 2010, showed that almost all of the country's annual influx of solar energy is more than 1400 kWh/m², and for some areas is 1600 kWh/m². Therefore, the use of solar photovoltaic modules and systems based on them is relevant and energy-efficient way to produce additional electricity for Passive house. Solution of the task of placement of photovoltaic modules on the ground is based on the correct definition of the angle of inclination to the horizontal surface of the modules, for optimal security features of electricity (at a given orientation modules to the south, in accordance with the location of the house). Tab. 3 below presents data on the amount of solar radiation on surfaces inclined at different angles to the weather conditions, the Skopje with coordinates 41°59'N, 21°26'E [13].

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Figure 3. Global horizontal irradiation. Table 3. Receipt of the total solar radiation on differently oriented surfaces of photovoltaic modules, [kWh/m²] Angle of inclination of the modules to the horizon, Month [deg] 0 January February March April May June July August September October November December Year

27

42

57

52.08 79.67 89.28 93.93 68.04 91.56 98.28 99.68 106.33 126.17 128.65 124.62 126 133.2 128.4 117.9 158.41 157.17 146.32 128.65 183.6 174.3 159 136.5 192.82 188.48 172.98 149.42 170.5 177.32 168.64 151.59 122.1 140.4 140.7 133.8 85.25 110.05 115.94 115.94 50.4 72 78.9 81.6 41.54 63.86 71.92 76.26 1357.07 1514.18 1499.01 1409.89

90 85.87 84 94.55 79.2 78.43 78.3 85.25 94.55 96.6 95.17 72.3 70.37 1014.59

As can be seen from Table 3 the maximum annual amount of solar radiation is observed in the surface inclined at an angle of 27 ° to the horizon. However, when selecting the optimum angle modules should also take into account peculiarities of power consumption. In this project, “Passive house” the house lacks heating (171 W), which is proposed to be added by using the electric heater in the cold season. Therefore, in Fig. 4 shows the flow of radiation from season to season, and Fig. 5 discrepancy in the parish in relation to the horizontal plane.

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600

Solar radiation, kWh/m

2

0deg 27deg 42deg 57deg 90deg

400

200

0

winter

spring

summer

autumn

Season

Figure 4. Assessment of the amount of solar radiation on differently oriented surfaces by seasons.

Difference in incoming solar radiation, %

Analysis of the data presented in Fig. 4 and 5, led to the following conclusions: - The arrival of the solar radiation in the summer is maximum on a horizontal surface; - The arrival of the solar radiation in the winter is maximum on the surface with angle of 57 °; - The arrival of the solar radiation in the spring and autumn periods is highest on the surface at angles 27 ° and 42 °, respectively; - The amount of solar radiation on a vertical surface is practically unchanged from season to season, but it is minimal with respect to the horizontal surface of the spring and summer; - The difference in the flow of energy on the surface at angles of 42 ° and 57 ° are minimal. 75 27deg 42deg 57deg 90deg

50 25 0 -25 -50 -75

winter

spring

summer

autumn

Season

Figure 5. Shots incoming solar energy on differently oriented surface and a horizontal surface. Thus, the priority use of the energy generated by photovoltaic modules in the cold season, possibly with tilt angles of modules in 57° and 42 °. However, since the total annual flow in the second case, a 6% increase in the subsequent calculations will be used in a 42° angle to the horizon. In the second stage assess the effectiveness of solar panels to generate electricity in Macedonia weather conditions dealing with the following inputs: - Estimated area south oriented front roof pitch - 50 m²; - The efficiency of PV modules - 15%; - The angle of the modules to the horizon - 42°.

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Figure 6 provides an assessment of electricity generation by the solar modules of 50 m² in every month of the year. Annual electricity production will be 11242 kWh. Daily average values for each month of the year are shown in Fig. 7. The graph shows the minimum value for December is 17 kWh, which is enough to provide electricity for the heating device. 1400

January February March April May June July August September October November December Year

Power generation, kwh

1200 1000 800 600 400 200 0

2

4

6

8

10

12

Month

[kWh] 670 737 965 963 1097 1193 1297 1265 1055 870 592 539 11242

[%] 5.96 6.56 8.58 8.57 9.76 10.61 11.54 11.25 9.38 7.74 5.27 4.79 100

Figure 6. Evaluation of power generation by the solar modules (from the surface of the roof 50m2)

Energy production, kwh

45 40 35 30 25 20 15

2

4

6

8

10

12

Month

Figure 7. Evaluation of the average daily power generation solar modules by month (50m2) Summary Climatic conditions allow Macedonia to design buildings, known as «Energy-plus house». In addition, emission of carbon dioxide (CO2) is proportional to the increase in energy consumption for heating / cooling and total primary energy. «Energy-plus house» provide an environmentally safe operation of buildings. Evaluations insolation and receipt of solar radiation on differently oriented surfaces have shown the promise of using photovoltaic modules for electricity generation in Macedonia weather conditions. Optimum tilt angle of the module is 42°, which provides operational efficiencies of modules in the cold season and almost maximum energy production throughout the year. Evaluation

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of power generation modules with the surface of the building showed that the worst in terms of resource flows of solar radiation of the month - December solar modules will generate no less than 17 kWh electricity consumption per day. Thus, this work complements the earlier studies carried out under the project «Passive house», and skips to the next level creating a «Energy-plus house». This work was supported by the Russian Science Foundation (Grant № 14-29-00178) References [1] Cvetkovska, M., Trpevski, S., Andreev, A., Knezevic, M. Parametric analysis of the energy demand in buildings with Passive House standard (2013) Portugal SB13 - Contribution of Sustainable Building to Meet EU 20-20-20 Targets, pp. 303-310. [2] Feist, W., Schnieders, J., Dorer, V., Haas, A. Re-inventing air heating: Convenient and comfortable within the frame of the Passive House concept (2005) Energy and Buildings, Vol. 37(11), pp. 1186–1203. [3] Gabriyel, I., Ladener, Kh. Rekonstruktsiya zdaniy po standartam energoeffektivnogo doma (2011) SPb.: BKhV-Peterburg, 470 p. [4] Ostrowska, A., Sobczyk, W. Małgorzata Pawul Ocena efektów ekonomicznych i ekologicznych wykorzystania energii słonecznej na przykładzie domu jednorodzinnego (2013) Rocznik Ochrona Środowiska (Annual Set The Environment Protection), 15, pp. 2697–2710. [5] Žegarac Leskovar, V., Premrov, M. Design approach for the optimal model of an energyefficient timber building with enlarged glazing surface on the south façade (2012) Journal of Asian architecture and building engineering, vol. 11, no. 1, pp. 71-78. [6] Žegarac Leskovar, V., Premrov, M., Vidovič, K. Architectural geometry of timber-glass buildings and its impact on energy flows through building skin (2013) COST Action TU0905 MidTerm Conference on Structural Glass - Proceedings of COST Action TU0905 Mid-Term Conference on Structural Glass, pp. 133-139. [7] Leskovar, V.Ž., Premrov, M. An approach in architectural design of energy-efficient timber buildings with a focus on the optimal glazing size in the south-oriented façade (2011) Energy and Buildings, 43 (12), pp. 3410-3418. [8] Žegarac Leskovar, V., Premrov, M. Design approach for the optimal model of an energyefficient timber building with various glazing types and surfaces on the south façade (2011) WIT Transactions on the Built Environment, 118, pp. 541-552. [9] Žegarac Leskovar, V., Premrov, M. Influence of glazing size on energy efficiency of timberframe buildings (2012) Construction & building materials, vol. 30, pp. 92-99. [10] Murgul, V., Vuksanovic, D., Vatin, N., Pukhkal V. The use of decentralized ventilation systems with heat recovery in the historical buildings of St. Petersburg (2014) Applied Mechanics and Materials, Vols. 635-637, pp. 370-376. [11] Andreev A., Parametric analysis of the energy demand in buildings with Passive House standard (2013) Master thesis, University Ss. Cyril and Methodius, Skopje, 182 p. [12] Standards: MKC EN 410:200; MKC EN 673/A1/A2:2006; MKC ISO 6946:2009; MKC EN ISO 9288:2008; MKC EN ISO 13788:2006; MKC EN ISO 13947:2009; DIN 277; DIN V 4108-4; DIN EN 1283; DIN EN 13363 ; DIN EN 13829; DIN EN ISO 13790:2004; DIN ISO 13370 ; DIN V 18599-2; DIN V 4180-6; DIN EN ISO 10211-1:1995; DIN V 4701-10; DIN EN ISO 6946:1996 [13] Information on: http://solargis.info

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