Low-Energy Industrial Buildings for Climates of Emerging Countries

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1 Low-Energy Industrial Buildings for Climates of Emerging Countries Pascal Brinks Oliver Kornadt René Oly TU Kaiserslautern, Germany TU Kaiserslautern, Germany Lindab S.A., Luxembourg Lindab S.A., Luxembourg ABSTRACT The economic growth of developing and emerging countries pushes particularly the industrial sector, why a large demand for new industrial buildings arises. Though in many of these markets there is no traditional climate adapted architecture for industrial buildings as it mostly exists for dwellings. Thus many buildings for industrial applications are mainly built after European or American standards without respecting the local climate. Missing or misleading building regulations as well as missing general awareness and know-how in the local communities enhance this problem. The risk is to build a new generation of industrial buildings in these countries, having an unnecessary high energy demand for heating and cooling just by neglecting the climatic characteristics. Therefore this study proves the applicability of European concepts for low-energy industrial buildings for different climates for example from Russia and North Africa. Parameters such as air-tightness, window quality, solar orientation, thermal insulation and radiation reflectivity are analyzed and adjusted for optimizing the energy demand. The reduction of summer overheating is further under consideration because the postinstallation of air conditioning systems should be avoided at any rate. For this purpose transient building simulations and air-flow-network simulations are used. As the basis for simulations of airinfiltration by appropriate product specific models, typical industrial building components are measured in an air-tightness test stand. The project focuses on light steel structure buildings which are often exported from Europe and the U.S. to emerging and developing markets. It is demonstrated how the energy demand of such buildings can be decreased already by small but efficient design changes. INTRODUCTION Emerging Countries mainly gain their economic growth by the industrial sector for which low labor cost and natural resources are usually the push factors. Thus a particular demand for new industrial buildings arises in these countries. However as large scale industry has often no tradition in these newly industrializing countries there is even little experience in buildings for industrial applications. For dwellings there is usually a long building tradition that was adapted for the local climate. But production buildings or plants are often imported from western regions such as Europe or the US. Due to the shipping constraints such imported buildings are usually built in light steel structure. Their design is typically executed in the producing country why the local climate and environment is often not well considered. Furthermore many of the companies settling down in threshold countries are global players who have already standardized their production buildings based on western climate requirements. Often only the insulation thickness is simply increased or decreased whether the building will be erected in a P. Brinks is a PhD student at the Technical University Kaiserslautern, Germany and in the R & D of Lindab S.A., Diekirch, Luxembourg. O. Kornadt is a professor and head of the department Building Physics / Low-Energy Buildings at TU Kaiserslautern, Germany. R.Oly is R & D Director at Lindab S.A., Diekirch, Luxembourg. 1

2 warm or cold climate. Other parameters such as window orientation or air-tightness are rarely recognized. Moreover the local authorities do not always have the expertise to assist and building regulations setting an energy standard as in Europe mostly do not exist or are at least less elaborated, as e.g. in Russia where the last recast of the building regulations dates from 2003 (SNiP , 2003). That goes along with a still missing awareness for the need for reducing GHG-emissions. The risk is to build a new generation of industrial buildings having an unnecessary high energy demand. Hence in this project the energy demand for heating and cooling of light steel industrial buildings was analyzed for different climates. These analyses were determined by transient building simulations using the software package TRNSYS. CLIMATE As every climate needs an individual design, only general advises can be given in this project to make designers aware for how to reduce the energy demand dependent on the climate. For this purpose two hot North African climates (Casablanca, Morocco and Dar El Beïda, Algeria) and three cold Russian climates (Moscow, Samara and Irkutsk) were selected. Besides Ankara (Turkey) was chosen as this climate is hot in summer and cold in winter. A typical climate for exporting Central European countries is Würzburg, Germany. Exemplary the data for Irkutsk, Dar El Beïda and Ankara is shown in figure 1-3. Most important is the outside temperature, but also the solar radiation, the wind velocity and the temperature difference between day and night have a certain impact on the building performance. Figure 1 Radiation, temperature and wind velocity (Meteonorm) for Irkutsk (South Siberia) Figure 2 Radiation, temperature and wind velocity (Meteonorm) for Dar El Beïda (Algeria) Figure 3 Radiation, temperature and wind velocity (Meteonorm) for Ankara (Turkey) 2

3 BUILDING PERFORMANCE Industrial buildings in warm climates as Dar El Beïda or Casablanca usually never have any heating device. The temperatures during daytime are usually high enough also in winter and the temperature requirements in such buildings are in general quite low. Also cooling devices are still rare due to high investment and energy costs even if a cooling demand actually exists. But the economic growth will allow the installation of more and more air-conditioning systems in the future. To reduce the costs and the emitted GHGs, and of cause to improve the thermal comfort, the focus must therefore be set on overheating protection. Post-installation of cooling devices caused by misleading building design should be avoided at any rate. For the cold Russian climates cooling is not required, even if some hot summer days exist in the continental Siberia, but these temperature peaks are usually buffered by the thermal mass of the interior and the concrete slab. Most difficult is the design for climates like in Ankara, where the average temperature in July and August reaches 23 C and in January it goes down to 0 C. To find the right balance between a passive solar building and reduced summer overheating is the challenge. Summer Overheating The main summer overheating problems arise by wrong orientation of glazed surfaces. Movable shading devices are often not applicable and usually too expensive for industrial buildings. As summer overheating is a minor problem in Central Europe and as illumination is easy to ensure with horizontally oriented glazed surfaces, many exported industrial buildings have skylights. Figure 4 shows the simulated influence of the orientation and size of glazed surfaces in a typical light steel industrial building (1950 m 2 ground area, concrete slab). Internal loads by machines were considered with 40 W/m 2, as also used for production buildings in (DIN V 18599, 2011), based on (VDI 3802, 2003). In figure 4 the overtemperature degrees over 27 C are shown. This method is used in Germany to limit overheating (DIN , 2013). It sets a limit of 500 Kh per year which must not be exceeded if no air condition exists. Figure 4 shows that this limit is usually not reached in Central European climate why skylights are less critical. In warm climates like Ankara or Casablanca the horizontal orientation of glazed surfaces causes vast overheating if no air-condition exists and no controlled ventilation is used. If vertical glazed surfaces are used and oriented to the north the overheating is reduced significantly compared to skylights. The vertical south orientation also improves the overheating but for buildings without any heating demand the north should always be preferred. West and east oriented glazing is usually critical as well why for deeper buildings a combination of north and south oriented glazed surfaces in the facades is reasonable for North African Climate. For maritime climates like Casablanca the climate can already get tolerable by avoiding skylights. But for continental climates like Ankara other actions are required. Figure 4 Overtemperature degrees (Kh/a > 27 C) for different climates and glazing orientations 3

4 Figure 5 shows the impact of a controlled ventilation which is always turned on when the inside temperature exceeds the outside Temperature. Costs and energy demand of such ventilations are much lower than of air-conditions. Such mechanical ventilation should also be supported by natural ventilation to save energy, which can reach high ventilation rates like shown for the ventilation of industrial buildings in (Kistelegdi and Háber, 2012). Already existing openings like industrial doors and smoke vents can be used for it. How openings can be optimized for summer ventilation is e.g. analyzed in (Stephan, Bastide and Wurtz, 2011). Cross-ventilation though large openings like industrial doors including wind influences is discussed in (Seifert et al., 2006). Figure 5 Influence of controlled ventilation on the summer overheating The simulations in figure 5 show that even the German overheating requirements can be met for Ankara with glazed surfaces in the south façade, if there is a strong controlled ventilation. This is mostly due to the high temperature difference between day and night visible in figure 3. For Casablanca with its coast to the Atlantic Ocean the summer overheating is quite easily to reduce by controlled ventilation. At the Algerian coast to the Mediterranean Sea (Dar El Beïda) overheating is again much more difficult to avoid. Here the north orientation should always be chosen for window orientation. In addition to the window orientation and the ventilation also the solar absorptance of the building envelope and the thermal capacitance of the interior are deciding for the thermal comfort in summer. Figure 6 (a) shows that an overheating reduction by low absorbing coatings is possible but the effect is not as important as e.g. night ventilation. Figure 6 (a) Influence of the solar absorptance of the building envelope (roof, walls) (b) Influence of the capacitance of interior on summer overheating (glazing south) 4

5 Figure 6 (b) shows the other important parameter, the thermal capacity of the interior. This of course interacts with the ventilation, as a higher capacitance can only reduce the inside temperature if the thermal mass is regularly cooled down by ventilation. The considerable effect is visible but anyway the simulation results can just be seen as an indicator for the importance of thermal mass. The real influence depends on many parameters such as the surface of the interior, the material and its heat-transmission resistance. These parameters will never be assessable in a design process but it is clear that an empty building overheats much easier than a filled storage. The impact of air-tightness on summer overheating and the cooling demand is very low. In the simulations the differences between the cooling demand of an untight building (n 50 = 5 h -1 ) and a very tight building (n 50 = 0.5 h -1 ) was only about 2 %. Anyway big leakages should always be avoided. Heating Demand Air-tightness. Aside from the thermal insulation of a building the air-tightness is a major parameter for the energy performance. In many European countries like Germany, UK and France, tightness requirements already exist also for industrial buildings D: (EnEV, 2014), UK: (The Building Regulations 2010, 2013), F: (Méthode de calcul Th-BCE 2012, 2012). Even if these requirements are not always mandatory to meet, verifying the tightness allows lowering the infiltration losses in the energy performance calculation. In Russia unfortunately only tightness requirements for single building components of industrial buildings exist (SNiP , 2003). To check if these single requirements are met is not possible on site and also fan pressurization tests after erecting the building are usually not carried out. This leads to a lower workmanship on site and probably increases the infiltration. In particular for cold Russian climate this is very critical. As air infiltration is caused by wind pressure and stack effects, beneath the wind velocity also the difference between the internal temperature and the ambient temperature is deciding for the amount of infiltration losses (Brinks, Kornadt, and Oly, 2014a), (Younes et al., 2011). Thus the infiltration in cold climates like Russia is even much higher than in temperate European zones. In warm climates like North Africa, where buildings are not heated and the climate inside and outside is similar during the year, infiltration is rather small (see figure 7). Adapted from measurements in an air-tightness test stand and air-flow network simulations, an infiltration model described in detail in (Brinks, Kornadt, & Oly, 2014b) was developed. This model was used to simulate the infiltration for typical light steel industrial buildings in the here mentioned climates. Detailed information about the air-flow network model is given in (University of Wisconsin Madison, 2009) and (Weber et al., 2003). In figure 7 the results for the infiltration of an 8 m high building (65 m x 30 m) with an n 50 -value of 3 h -1 are shown. Due to the low temperatures in Irkutsk the infiltration is much higher during winter than for warm climates like Dar El Beïda. Figure 7 Air infiltration for an industrial building (n 50 = 3 h -1 ) in different climates 5

6 Figure 8 Heat energy demand dependent on the tightness and the wall and roof insulation quality Figure 8 shows the impact of the tightness on the heat energy demand. Especially for Siberia it is even more important to tighten the building than to increase the insulation thickness of the roof and walls. Reducing the n 50 -value from 3.0 h -1 to 1.5 h -1 saves as much energy as reducing the U-value of the roof and all walls from 0.4 W/m 2 K to 0.2 W/m 2 K. In general promising methods for air-tightness design in light steel buildings were already developed e.g. described in (Brinks, Kornadt, and Oly, 2013). But tightness is not only a question of design but of workmanship, thus it cannot be assured, that European standards are realized in Russia as well. Anyway tightness requirements for Russian industrial buildings are currently not existing even if requirements for Russian dwellings are in the range of European standards (SNiP ). Another important aspect is that infiltration losses via open doors are not recognized at all in any known building regulations or codes. For dwellings such losses may mostly be negligible but losses via large industrial doors can have a large impact on the energy balance. This lack was already discussed in (Brinks, Kornadt, & Oly, 2014c) where rough simulations based on (Dascalaki, E. et al ) were carried out. These calculations already show a significant impact for Central Europe but it seems to be even higher for Russia due to larger buoyancy effects. Solar Gains and Orientation of Glazed Surfaces. The orientation of glazed surfaces is not only important for summer overheating, but passive solar gains can reduce the energy demand of buildings considerably. For residential and office buildings this is already shown by many studies as (Cappaletti et al., 2014) or (Boubekri and Boyer, 1993) and also first analysis for industrial buildings in Central European climates exist (Brinks, Kornadt, & Oly, 2014d). Figure 9 shows how the heating demand changes for different oriented glazed surfaces (40 mm polycarbonate, U = 1.10 W/m 2, g = 0.56) in Russian climates. Here a low-energy production building with 17 C inside temperature, 40 W/m 2 internal gains, an n 50 -value of 0.5 h -1 and a U-value of walls and roofs of 0.20 W/m 2 K was simulated. Due to the high solar radiation in Irkutsk during winter (approximately twice as high as in Central Europe), here the orientation has the most significant impact. Figure 9 Energy demand for heating dependent on the glazed surfaces for Russian climates 6

7 Installing large glazed surfaces on the south façade instead of skylights can reduce the energy demand by up to 30 % if the façade is not shaded. For Moscow the effect is smaller as the solar radiation is lower. Anyway in Russian climates it is advised to use as much glazed surfaces in south façades as possible if facades are not shaded. The glazing quality, particularly a high g-value, is of course to be respected. In climates like Ankara with hot summers and cold winters the situation is more complex. Thus the impact of the glazing orientation and surface on the energy demand for both, heating and cooling, was simulated. The results in figure 10 show that increasing the glazed surface in general decreases the heating demand and increases the cooling demand. But the leverage effect of this parameter is different for all orientations. For the south façade the total energy demand (heating + cooling) decreases with a larger glazed surface. For the north façade it increases slightly and for the horizontal (skylights) it increases considerably. This means that increasing the horizontal glazing area should usually be avoided. Anyway general advises to increase the glazed south façade area in such climates cannot be given. This decision depends on if a cooling device is installed at all and which (primary) energy is used for heating and cooling. Thus a decision has to be taken individually for any project. Figure 10 Energy demand for heating and cooling dependent on the glazed surfaces for Ankara CONCLUSION The building simulations carried out show the consequences of exporting industrial buildings designed for Europe without adapting the building envelope design to the local climate. In hot climates it is mandatory to avoid skylights and replace them by glazed surfaces in the façade. If summer overheating is not critical and a heating demand exists in winter, the glazed surfaces should be oriented mainly to the south, otherwise to the north. To keep the cooling demand low or even avoid it, controlled night cooling is an energy-saving solution. Especially at night high ventilation rates are required that should be ensured by mechanical ventilation supported by natural ventilation. Reflective coatings of the roofs can be a small added value as well. Buildings with little thermal capacity are usually more susceptible for overheating why overheating protection becomes more complex. In cold climates like in Russia the saving potential by orienting vertical glazed surfaces to the south is very high. Due to very high solar radiation in winter especially in Siberia these glazed surfaces should be increased as much as possible as overheating usually is no problem in such regions. Furthermore the air-tightness of industrial buildings in Russia is very important but is unfortunately not considered sufficiently by current building regulations. Improving the tightness is even more effective here than increasing the insulation thicknesses. Moreover this solution is also low cost, but appropriate quality controls like fan pressurization tests should become mandatory also for production buildings and warehouses. Here the most important need for action exists. Most difficult is the design for regions with hot summers and cold winters like Turkey. Here building simulation should be used, as general advises are difficult to give and the design also depends a lot on the kind of energy used. A potential for heating in these countries is surely the use of solar energy. Here further research for seasonal thermal solar storages is required. Due to the long heating period and the high solar radiation in South Siberia this could also be interesting as a heating support for Russia. 7

8 ACKNOWLEDGMENTS This research was carried out in the framework of the project Concepts for Nearly-Zero-Energy Industrial Buildings supported by the Fonds National de la Recherche Luxembourg and the company Lindab S.A. in Diekirch, Luxembourg. REFERENCES SNiP Thermal Performance of the Buildings. СТРОИТЕЛЬНЫЕ НОРМЫ И ПРАВИЛА РОССИЙСКОЙ ФЕДЕРАЦИИ. Meteonorm Climate Data Software Meteonorm Version , measured data without interpolation. DIN V Energetische Bewertung von Gebäuden - Berechnung des Nutz-, End- und Primärenergiebedarfs für Heizung, Kühlung, Lüftung, Trinkwarmwasser und Beleuchtung. VDI Air conditioning systems for factories. Düsseldorf: Verband Deutscher Ingenieure. DIN Thermal protection and energy economy in buildings Part 2: Minimum requirements to thermal insulation. Kistelegdi, I., Háber, I.. Gebäudeaerodynamische Untersuchungen einer Plusenergie-Produktionsstätte mit passiven Lüftungstürmen in Sikonda (Südungarn). Bauphysik Heft Stephan L., Bastide, A., and Wurtz, E.. Optimizing opening dimensions for naturally ventilated buildings. Applied Energy Seifert, J., Li, Y., Axley, J., and Rösler, M.. Calculation of wind-driven cross ventilation in buildings with large openings. Journal of Wind Engineering and Industrial Aerodynamics EnEV Zweite Verordnung zur Änderung der Energieeinsparverordnung. Bundesregierung der Bundesrepublik Deutschland. Méthode de calcul Th-BCE CSTB Centre Scientifique et Technique du Bâtiment. The Building Regulations 2010, L2A Conservation of fuel and bower in buildings other than dwellings, 2013 Edition for use in England Her Majesty's Government. Brinks, P., Kornadt, O., & Oly, R a. Energy Balance Calculation and Nearly-Zero-Energy Standard of Industrial Buildings. 10th Nordic Symposium on Building Physics. Lund, Sweden. Younes, C., Abi Shdid, C. and Bitsuamlak, G Air infiltration through building envelopes: A review. Journal of Building Physics, 35(3) Brinks, P., Kornadt, O., & Oly, R b. Air Infiltration Assessment for Industrial Buildings. Energy and Buildings (2014). University of Wisconsin Madison TRNFLOW Manual: A module of an air flow network for coupled simulation with TYPE 56 (multi-zone building of TRNSYS) Version Weber, A., Koschenz, M., Dorer, V., and Hiller, M TRNFLOW, A new tool for the modelling of heat, air and pollutant transport in buildings with TRNSYS. Brinks, P., Kornadt, O., and Oly, R Luftdichtheit von Gebäuden im Industriebau. Bauphysiktage Kaiserslautern Kaiserslautern, Germany. Brinks, P., Kornadt, O., & Oly, R c. Ventilation Losses via large Industrial Doors of Low-Energy Buildings. European Nearly Zero Energy Buildings Conference Wels, Austria. Dascalaki, E. et al Predicting single sided natural ventilation rates in buildings. Solar Energy, Vol. 55 No. 5. F. Cappelletti, A. Prada, P. Rom, and A. Gasparella Passive performance of glazed components in heating and cooling of an open-space office under controlled indoor thermal comfort. Building and Environment, vol. 72. M. Boubekri and L. Boyer Multiple-Criteria Decisions for Sizing a Window in a Direct-Gain Strategy. Indoor and Built Environment, vol. 2. Brinks, P., Kornadt, O., & Oly, R d. Solar Architecture of Low-Energy Buildings for Industrial Applications. International Conference on Sustainable Architecture and Urban Design. Kyoto, Japan. 8