Isabel Rodríguez Casanova
BIBLIOGRAFÍA A LFARO , C., 1988, Las monedas de Gadir-Gades, Madrid
1.1_“Panels” as dwelling units in Hungary
The name “panel” is a term used in Hungary referring to the prefabricated (mainly residential) block of buildings built between 1950-1990. Since this was the main urban housing type of the Socialist era, it is a common sight in the former “Eastern block” countries, often dominating the townscapes. The panel technology widely used in the former Soviet Union was actually in- vented at first in Western Europe. It was applied in Denmark, England, France and other countries. The Soviet Union bought the technology and developed its own system. In Hungary Soviet and partly Danish systems were used more or less modified by Hungarian engineers (Preisich 1998).
After the II. Word War fast population growth and urbanisation occurred which resulted a housing crisis. Budapest and other bigger towns became overcrowded. The town and city cores this time consisted mainly single or few-storey dwelling units or worker houses. To answer the problems the gov- ernment bought the “large panel” technology to be able to rapidly construct standardized dwelling units often by demolishing the existing fabric or creat- ing entirely new neighbourhoods on former farmlands (Perényi 1967). These buildings often provided improved living conditions for the inhabitants with piped hot water, flush toilets and district heating.
The ratio of condominiums built by panel and other industrialized technologies slightly exceeds the ¼ of the number of the total condominiums in the coun- try. Prefabricated and panel buildings still dominate the Hungarian cityscape. The share of panel dwellings is 31% in Budapest, 39% in Debrecen, 52% in
Miskolc, 38% in Szeged, 42% in Pécs, 41% in Győr, 50% in Székesfehérvár and 60% in Dunaújváros (Census 2011).
There are totally 829 177 prefabricated concrete flats in Hungary of which 66,1%, 548 464 flats are in large-panel system buildings, the remaining 33,9% in other similar precast concrete buildings (Figure 1). The majority of these units were built between 1960-1980, only the 5,8% were built in the ‘90s. The last panel building was finished in 1993. Out of the total number of dwellings, the panel flats make up 18.9%, which is home to 1,741,577 people (17.5% of the total population) (Census 2011).
Figure 1. Number of flats in buildings of different material.
Total number of flats in Hungary (Census 2011): 4 390 302
1.2_“Panel” types in Hungary
The first buildings made with industrialized technology were built in 1954. The first form of mass housing was the block building. This contained half-sto- rey high blocks, used mainly in the close proximity of the factory. Later the 1-storey high, 30 cm thick dross foam concrete blocks were used to construct 5-storey residential buildings.
The cast technology was typically used to create 10-storey high buildings. The load-bearing walls were made of dross foam. The planning mistakes signifi- cantly deteriorated the buildings’ heat insulation and vapour barrier capability. In case of the tunnel-mould technology the wall and slab formwork are com- bined into a single system. Construction mistakes were often made mainly during the casting, for example blocked aggregates or using different type of concretes in a single structure which thus became heterogeneous. The above errors are significantly influenced the structural strength and thermal insulating ability.
During the seventies and the eighties the prefabricated sandwich panels be- came the dominant technology (Figure 2). In Hungary multiple “house fac- tories” operated, mainly in bigger cities. Each one of these factories had its distinct solutions and improvements, thus it is difficult to talk about “panel buildings” in general. Most commonly, the panels were manufactured from high-strength gravel concrete with relatively weak reinforcement. The façade wall panels were first 25, later 30 cm thick and contained a 15 cm thick reinforced concrete inner plate, an 8 cm polystyrene thermal insulation and a 7 cm reinforced concrete cover plate.
The load carrying capacity of the structure is good, however the nodes are considered weak points of the technology where thermal brides and leaking frequently occurs (Dulácska 2013).
Within the boundaries of the Tabula Episcope Project a (TABULA) residential building typology was created. The primary question was to acquire informa- tion about how many building can be found in the country of different type. After developing the building types, model buildings were created which re- flect the statistically average properties and specific technical parameters of the given type.
The goals of the project was to develop renewal packages for the types so the available savings and the renovation expenses may be determined. The 15 building types covers the entire domestic residential building stock and provides opportunity for deeper energetic analysis of the residential sector (NÉES).
Within the 15 types the type Nr 12, 13 and 14 contains the industrialized res- idential building stock. Type 12 describes the block buildings, Type 13 shows the panel buildings built between 1946-1980, while Type 14 describes the pan- el buildings built after 1981. Table 1. clearly shows that the Type 13 contains the biggest quantity of buildings and apartments, however it has the lowest rate of good condition flats. Most of the buildings in every type can be found in residential districts (NÉES).
Figure 2. Panel condominiums in Óbuda, Budapest (1986) (FORTE).
Table 1. Industrialized building types in the Hungarian building typology (NÉES). Ty pe Cons tr uc tion d at e Cons tr uc tion te chno log y B ui ld in g q ua nt ity i n H un ga ry (pc ) A pa rt m en t q ua nt ity i n H un ga ry (pc ) To ta l a re a (m 2) To ta l a re a / b ui ld in g (m 2) To ta l N r o f a pa rt m en ts / bu ild in g (pc ) G oo d c on di tion Sa tis fa ct or y c on di tion 12 not specified middle or big blocks 8.345 185.256 11.346.937 1.360 22,2 68,30% 23,30% 13 1946-1980 panel 14.881 330.094 16.174.606 1.087 22,2 65,90% 22,10% 14 1981- panel 7.271 187.428 9.877.417 1.358 25,7 73,50% -
1.3_“Panels” in Central Europe
Other Eastern-European countries have even bigger stock of prefabricated buildings and flats than Hungary: In the Czech Republic there are 1.170.000 panel apartments where one third of the population lives. In Slovakia the number of panel flats is 778.000 representing 40% of the apartment units in the country (Talamon 2011). In the former Eastern-Germany more than 2 mil- lion such flats were built. In Poland there are 6.171.000 panel flats that is 49% of the stock (Novák 2007). In Romania, more than 3 million apartments can be found in prefabricated concrete buildings which is almost 40%of all dwellings (Figure 3) (EUSTAT).
Figure 3. Number of panel flats in central European countries (million flats).
1.4_Panel problem
The “panel problem” is a well know term to summarize the questions regard- ing the large number of panel buildings in Eastern-Europe.
The expected lifetime of the frame is 100 years, but the fenestration and other elements like plumbing and heating system are mostly aged. The high heating cost, which is partially caused by the high cost and losses of district heating is an important factor which is in Hungary closely connected to the buildings - the expensive heating is commonly paired with the panels. These systems are today obsolete and poorly efficient, but nearly all panel build- ings are heated by them. On the other hand sandwich panels are common- ly assembled with a 5-8 cm inner thermal insulation layer resulting a better U-value than a brick wall, however through the past 2-4 decades the inner layer deteriorated, which clearly increases the already high energy losses of the extensive amount of thermal bridges.
Other significant problems are the extremely high summer temperature, the overheating in winter accompanied with dry air (Talamon 2011).
As mentioned before whole new residential areas were built of panel build- ings offering home to hundred-thousands of inhabitants. Besides dwelling units parks, walkways, public facilities were built to serve the needs of the residents. Through the years passed these buildings and green surfaces aged and the parks became mostly untended.
Because of the great number of apartments these buildings represent in the aforementioned countries, the demolition of the panels is not realistic solution (Hermelink 2006). Although the buildings were originally built for the middle class of the society, today more and more socially handicapped peo- ple leave there resulting financial and social problems, leading to the further declination of flat prices, accelerating the degradation process.
2_Retrofitting
2.1_Goals and directives
In 2009, European households were responsible for 68% of the total final en- ergy use in buildings. According to European-scale surveys, the 48% of the Central-Eastern housing stock was built between 1960-1990, and only 17% was built after 1990. Investigation on the heating consumption of the existing stock shows that the largest energy saving potential is associated with the older building stock where in some cases buildings from the 1960s are worse than buildings from earlier decades. This is caused by the newer, thinner but unin- sulated structures compared to the historical buildings greater structural size. The residential building stock renovated annually is only 1,3% in Hungary. The ratio is slightly bigger in Poland (2,5%) and in the Czech Republic (3,6%). (EBUM 2011)
The European Commission published the Europe 2020 Strategy in March 2010 in which the main objectives are to reduce the greenhouse gas emissions by 20%, or if possible by 30% compared to the 1990 level, furthermore to reach a 20% share of the renewable energy sources of the total energy consumption and to realize 20% energy saving (NÉES).
Table 2. Demanded U value in case of different countries (DHUB).
The 2010/31/EU directive on the energy efficiency of buildings prescribes for the Member States that the near-zero demand is required to be applied in case of new buildings after 1st of January 2021, in case of public buildings from the 1st of January 2019. In addition the near-zero level must be taken into account when considering new constructions instead of the renovation of existing buildings. (NÉES)
The National Strategy on Building Energetics of Hungary prescribes by taking the National Energy Strategy 2030 into account that within the energy con- sumption of the buildings the primary energy savings are to reach the 49 PJ/ year until 2020, and 111 PJ/year until 2030. In the boundaries of this prescrip- tion 380.000 prefabricated flats are planned to be retrofitted until 2020 by in- vesting approximately 1,7 billion Euro for a complex retrofit of these buildings. (NÉES)
2.2_Retrofitting scenarios
Two demand levels were created for retrofitting to match the aforementioned European demands in Hungary:
The cost-optimal or standard refurbishment version means refurbishment considering the values of “TNM” (Ministerial Decree No. 40/2012. (VIII. 13.) on the establishment of energy characteristics of buildings) regulation com- ing into force on 1st January 2015. According to the regulation in case of sub- stantial renovation the requirements of the newly built buildings are to be complied.
Since either the original structures, engineering systems and the numeric values of the requirement are different The technical solutions necessary to meet the requirements differ in each building type. (NÉES)
The near-zero or ambitional refurbishment version means refurbishment con- sidering the same or better values prescribed in the aforementioned TNM regulation, besides at least 25% of the annual primary energy demand is to be created by renewable energy sources produced on or near site. The calculat- ed values of possible retrofitting are summarized in Table 3.
Table 3. Primary Energy usage and retrofitting cost (NÉES).
Ty pe Cons tr uc tion d at e Cons tr uc tion te chno log y Pr es en t s ta te pr ima ry ener gy u se kW h/ m 2/a Pr im ar y e ne rg y u se i n c as e o f Co st o pt im al r et ro fit tin g kW h/ m 2a Pr ima ry ener gy s av ing kW h/ m 2a Es tim at ed c os t o f m od er ni za tio n p er h ea te d a re a Eur o/ m 2 12 not
specified middle or big blocks 244 85 159 68 13 1946-1980 panel 218 84 134 61
14 1981- panel 200 80 120 61
2.3_Past retrofittings in Hungary
Previous methods of panel retrofitting in Hungary. The energy rationalization in Hungary started already in the second half of the nineties by modernisation of the heating system. Thermostatic valves and heat cost allocators were installed first without any support from the state.
In 2001 the “Panel Program” was launched providing 1/3 non-refundable funds for thermo-modernization actions that were often completed with an- other supplementary 1/3 by the municipalities. Today there are great differ- ences in the ratio of retrofitted panels between cities, because joining the program was depending on the decision of the cities: Győr, Székesfehérvár and Kaposvár already retrofitted most of their panel buildings however Budapest and Debrecen managed less than 20 % (Talamon 2011).
Most of the projects have reached 10-40% energy savings only, because until 2008 the support program did not motivate the owners for a complex retro- fit or deep renovation. Because of the lack of monitoring the achieved sav- ings are mostly rough estimations (Talamon 2011). Unlike other retrofitting programs in Europe (for example in Germany) the renewal mostly achieved
building by building not considering the surrounding green areas, parks or public facilities which are commonly found in panel residential districts. The aesthetic upgrade is mainly contains only the colouring of the façade, al- though it is already a huge step forward compared to the monotone greyness of the concrete blocks. The first retrofitted buildings got simpler colouring (Figure 3), but nowadays more and more creative designs are made (Figure 4). Today, the 20% of the panels has full additional insulation and 50% is partly insulated (TABULA).
2.4_Case study of Hungarian panel retrofitting
Within the boundaries of the Green Investment Scheme (GIS) an extensive study was created by surveying the energy efficiency values of 70 refur- bished panel buildings of Hungary between 2009 and 2012. The investigated buildings were not chosen according to the aforementioned types but as a collective representation of the prefabricated building stock of Hungary. The following values were investigated: specific heat loss coefficients, spe- cific final energy use of heating, specific primary energy use of heating, spe- cific final energy use of domestic hot water, specific primary energy use of
domestic hot water, total specific primary energy consumption, specific CO2
consumption of the buildings. The specific heat loss coefficient represents
Figure 3. Top: earlier retrofitted panel (DSZ, PF).
Bottom: recently retrofitted panel (PF, NF).
the energetic quality of the building envelope. It gives a rough information about the insulation level of the building. Almost half of the analysed buildings are in Budapest, only 54% are in the countryside. The average construction year of the buildings is 1980. The earliest one was built in 1962, the last one in 1992 that was one before the last year of the panel construction indus- try. Among the projects there are all technologies represented among the industrialized technology. Approximately two thirds are panel buildings built before 1982 (typically worse insulation level), one sixth are panel buildings built after 1982 (typically better insulation level) and the remaining on sixth are other types (e.g. pre-cast concrete buildings, buildings made with medi- um-sized blocks) (Talamon 2011).
The results of the case study are compared to the values of the types of the TABULA project (Table 4). The calculated values of the case study show the average values of pre-refurbishment primary energy demands of the TABULA numbers – proving that the buildings of the case study were chosen well as representation. The average primary energy demand (total of the heating and
domestic hot water demands) before refurbishment was 221 kWh/m2a. After
renovation of the building stock, the calculated primary energy demand was
116 kWh/m2a, which is only slightly higher than the demanded 112 kWh/m2a of
the TABULA projects’ standard refurbishment values. The average 83 kWh/
m2a primary energy demand value of the ambitious refurbishment scenario
was approached in neither refurbishment (Talamon 2016). Table 4. Total primary energy
demand for heating and domestic hot water [kWh/(m2a)].
3_Summary
In case of prefabricated residential buildings the near-zero energy demands could be reached by using the materials and retrofitting techniques de- scribed in the TABULA and the National Building Energy Strategy. However, the previous refurbishments made between 2008-2015 mostly do not reach this level because on one hand the residents of the houses are not motivated to aim for near-zero energy levels. On the other hand the planning mistakes, the materials used and the lack of full financial support the reached energy efficiency values only closing on the demanded values of the standard (cost optimal) refurbishment, which is not equivalent to the near-zero demands. Without greater consideration of the aforementioned, the near-zero demands will not be reached. Moreover considering the wider environment in the pan- el residential area would be desirable. Modernizing the public facilities and parks surrounding the buildings would add to the value of the flats and create a pleasant environment.
4_Acknowledgments
Present paper was supported by the Hungarian Academy of Sciences Centre for Energy Research, the University of Debrecen and the Szent István University Ybl Miklós Faculty of Architecture and Civil Engineering.
5_References
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