Publication

PUBLICATION

Ing. LUKÁŠ BOSÁK

Advanced Materials Research Vol. 1057 (2014) pp 27-34 © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.1057.27

Submitted: 15.09.2014 Accepted: 15.09.2014

Energy Saving Building in Mountain Area Lukáš Bosák 1, a*, Milan Palko2,b 1

Bernolákova 39A, 920 01 Hlohovec, Slovak Republic

2

Slovak University of Technology in Bratislava, Faculty of Civil Engineering, Radlinského 11, 813 68 Bratislava, Slovak Republic a

lukasbosak@gmail.com, b milan.palko@stuba.sk

Keywords: energy-saving, building, concept, photovoltaic, cross-laminated, timber

Abstract The main intention of this report is solution of energy-saving building in mountain area, which uses the resources of the natural environment. It is the building of the mountain hotel in this concrete case. Firstly, there is solved the energy concept of the building which uses natural resources. There is also described the design of a building, which is designed in an overwhelming majority as a wooden building. The constructions are handled with an aspect of their thermal properties. There has been solved the thermal analysis of the major structural compositions. The connections between compositions of layers can be seen in the construction details. Those connections form together a single thermal insulated coverage of the building. There has been also solved 2D thermal analysis of the temperatures for the opening structures, especially windows. The windows are considered in two positions of mounting.

Introduction The building has 3 upper storeys and an underground storey. There are rooms for wellness, locker rooms, facilities for staff, warehouses, room for technical facilities of the hotel and a garage for snow groomer on the first underground storey. There is a restaurant for guests and the public on the first floor. There is also the kitchen for a restaurant, sanitary room, ski storage and a warehouse tools. There are the units on the 2nd and 3rd floor. There are double, triple and eight-bedded rooms on these floors. There are also stores on the third floor. Attic space is created by the sloping roof.

Roofing of the building consists of various kinds of roofs. Roofing of major form is created by sloped roof with wooden support structure. Other roofs are made with a flat roof over the ejecting parts of project above underground floor. One of these serves as a roof terrace for restaurant. The other is designed like a green roof.

Energy concept of the building Due to the location of the building, it was a clear goal that it should be completely energy self-sufficient with its own sources of renewable energy. Energy concept left a clear mark on the form of the building. It is compact, sheltered from the wind, has a highly-insulated building envelope, and is consequently oriented towards the south to ensure maximum passive solar gain. An inverter handles energy storage on environment-friendly batteries with 48 V/ 1,000 Ahr capacity.

The outlets and lights in the rooms are powered by the photovoltaic system. The slope of the south facade ensures that the integrated photovoltaic unit will produce an adequate electricity. Effectivity of the PV panels is calculated by PVGIS system. -slope 19°, azimuth 0°, total surface area: 70 m2, nominal power: 8.85 kWp (crystalline silicon) Other roof areas and terraces serve like a water collectors from rainfalls and melted snow.

All rainfalls are collected, filtered and cleaned. The rainwater is stored in two rainwater cisterns with a capacity of 50 m3. It is made potable by coal filter and UV-systems. The restaurant has a All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 178.41.160.83-22/10/14,20:37:18)

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wood stove (25 kWh) that serves for heating of this area. The heating of other areas are designed as a low temperature floor heating. There are two buffer tanks for hot water. Sophisticated technology allows the waste heat from the cooker in the kitchen to be used to heat indoor air and water. Highlyefficient LED lights complete the ambitious energy concept. An Active House is evaluated on the basis of the interaction between energy consumption, indoor climate conditions and impact on the external environment. [1]

Fig. 1 Energy concept Construction solution The supporting structure is designed by wooden columns and girders of cross laminated timber on the first storey above ground, and by a load-bearing walls of cross laminated timber combined with a massive wood-concrete slab construction. The untreated local wood that has been used for walls, floors and ceilings gives the building a very cozy and homely atmosphere. The entire support system is combined with a monolithic reinforcing core created by reinforced concrete walls.

The load-bearing system on the 1st floor is designed by reinforced concrete walls and slabs. The whole building is based on a reinforced concrete foundation slab.

Cross laminated timber will be the most important wooden material in short time. It will be convenient in massive wooden constructions, in apartment buildings and multistory constructions.

The reason is an escalating trend in energy saving and effort to decrease negative effects to the environment. The application of wood is directly predestined in some type of constructions, because of its favorable effect to physical properties. The wood construction system are characterized by effective thermal protection. The wood itself eliminates a thermal bridges because of its low thermal conductivity. In the evaluation of several environmental rating (LEED, BEES, SBTool etc.), wooden structures have better results as the other common structures. Another significant fact is permanent renewability of wood. The oxygen is created and carbon dioxide is reduced during the growth of wood. Whereby the carbon is accumulated in the biomass. [2]

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Fig. 2 Construction Benefits and advantages of wooden buildings: -

applying of environmental and health harmless materials, biological removability, fast construction of building, short production time and installation, dry construction process allows to build even in winter, all building elements are dried and treated against attack by wood-destroying insects and fungi, wooden houses provide a comfortable indoor climate throughout the year, wood is an excellent thermal insulator, keeps cool indoor climate in summer and warm in winter, wood is able to balance its moisture and regulate indoor air humidity, wooden structures meet the fire resistance requirements according to the relevant standards, excellent acoustic properties of sandwich structures, small thickness of external walls, because the insulation is inserted between the supporting elements, internal layout can be changed very easily, low cost of construction, money savings on transport materials, mechanisms, better thermal insulation properties compared to the other structures, they have a high thermal resistance, wooden buildings belong to the low-energy houses with an annual energy consumption in the range of 50-70 kWh/m2/year, they saving energy for heating, they require up to 30% less energy for heating than the brick buildings [3]

When we make construction joints in timber construction, there must be ensured tight detail work, because the overall air tightness of the building.

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Fig. 3 Air tightness Š KLH Massivholz GmbH [4] Thermal report The building envelope is created by cross laminated timber combinated with a blown thermal insulation between joists. Highly insulated, prefabricated parts were used wherever possible to ensure high quality of the building in short construction time. The thickness of the insulation depends on the concrete fragment of the construction. All constructions have to contain a vapor barrier. The vapor barrier prevents water vapor from the interior of the house filtering through the wall and condensing on the warm side of the insulation. Wall and roof containing a ventilated air gap. The wall is sheathed by the wooden cladding, sloped roof is sheathed by the titan zinc roofing sheets. The flat roofs are insulated by the PIR insulation boards. Timber aluminum windows are used as opening constructions. All thermal properties of the building constructions are designed beyond common standards and they are close to energy passive standards.

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3D fragment of the roof

3D fragment of the wall

Fig. 4 Cross-section detail

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External wall CLT (cross laminated timber) 1-cross laminated timber 2-thermal insulation 3-hardboard 4-vapor barrier 5-air gap 6-wooden cladding 7-wooden lamellas Interior

Exterior

θi = 20 [°C] φi = 50 [%]

θe = -16 [°C] φi = 84 [%] Rse = 0,04 [m2.K/W]

Rsi = 0,13 [m2.K/W]

Table 1 The results of the calculation of thermal parameters (wall) The results of the calculation of thermal parameters according to STN EN ISO 6946:2008 Thermal resistance

R = 8,42

Diffusion resistance

Rd = 27,27

Heat transfer coefficient

U = 0,12 θsi = 19,46

The inner surface temperature

[m².K/W] .109 [m/s] [W/(m².K)] [°C]

Sloped roof Exterior

θe = -16 [°C] φe = 84 [%] Rse = 0,04 [m2.K/W]

Interior

1-cross laminated timber 2-vapor barrier 3-thermal insulation 4-hardboard 5-waterproof insulation 6-ventilated air gap 7-OSB board 8-separation foil 9-titan zinc roofing sheets

θi = 20 [°C] φi = 50 [%] Rsi = 0,10 [m2.K/W]

Table 2 The results of the calculation of thermal parameters (sloped roof) The results of the calculation of thermal parameters according to STN EN ISO 6946:2008 Thermal resistance

R = 10,91

Diffusion resistance

Rd = 588,25

Heat transfer coefficient

U = 0,09

The inner surface temperature

θsi = 19,67

[m².K/W] .109 [m/s] [W/(m².K)] [°C]

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Window structures The windows have been solved in 2D thermal analysis. The Windows were considered in two positions of mounting. Both of the variants was convenient to indoor surface temperature of the construction. However, the window mounted at inner position in wall, had higher indoor surface temperature than the other variant. Because of that the second alternative was chosen in the result.

(Uf= 0,8 [W/(m2.K)], Ug= 0,6 [W/(m2.K)], ψg= 0,024 [W/(m.K)])

17,2° C

14,3 °C 14,9 °C

Fig. 5 Window alt. 1

17,0° C 16,6° C 15,0°

Fig. 6 Window alt. 2

C

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Summary Energy-saving buildings in the mountain area are convenient mainly because of using available natural resources in the area. When the appropriate building materials are being used, we can talk about an individual, energy-independent building. The type of these buildings is especially suited to the mountain environment, because traditional energy sources are largely limited in this area. These buildings will not have negative effect to the natural environment, when the natural construction materials will be used.

Acknowledgment The authors express their thanks to the project VEGA agency for financial support of the project No. 1/0281/12 References [1] VELUX A/S. A house for nature lovers Knofeleben, Schneeberg [online]. VELUX A/S, 2013 [cit. 2014-09-14]. Available at: https://www.velux.com/SiteCollectionDocuments/_PDFDocuments/PHB/V0011944-092_VAP_Knofeleben_booklet_EN_web.pdf [2] SANDANUS, J., AUGUSTIN, M.: KRÍŽOM LEPENÉ DREVO - RIEŠENIE AJ PRE VIACPODLAŽNÉ STAVBY (1. ČASŤ). [online]. 2012 [cit. 2014-09-14].

Available at: http://www.asb.sk/stavebnictvo/drevostavby/krizom-lepene-drevo-riesenie-aj-previacpodlazne-stavby-1.-cast [3] KUJANOVÁ, K.: Drevostavby – Vieme o nich všetko?. [online]. [cit. 2014-09-14].

Available at:http://www.domabyvanie.eu/page/index.php?log=clanok&uid=44 [4] KLH MASSIVHOLZ GMBH. Component Catalogue for Cross laminated timber Structures [online]. KLH Massivholz GmbH, 2011, 01/2011 [cit. 2014-09-14]. Available at: http://www.klh.at/fileadmin/klh/kunde/2011/Technische%20Anwendungen/Konstruktion/E N/120223_Konstruktion_engl.pdf

B Periodical: Main Theme:

Advanced Materials Research (Volume 1057) Advanced Building Construction and Materials II

Chapter: Paper Title: ISBN print: Pages: Authors:

Chapter 1: Energy Saving and Ecological Buildings Energy Saving Building in Mountain Area 978-3-03835-315-7 from 27 to 34 (8 pages) Lukáš Bosák, Milan Palko

Advanced Materials Research Vol. 1057 (2014) pp 27-34 © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.1057.27