Healthy Buildings 2017 Europe July 2-5, 2017, Lublin, Poland

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1 Healthy Buildings 217 Europe July 2-5, 217, Lublin, Poland Paper ID 89 ISBN: THERMAL RETROFIT OF A RESIDENTIAL BUILDING IN ROMANIA TO REACH LOW-CONSUMPTION ENERGY TARGETS Andrei DAMIAN 1,*, Norana PETRE 2, Aurelia AXENTE-STAN 2, Szabolcs VARGA 3, Vlad PETEAN 4, Andreea VARTIRES 1 1 Technical University of Civil Engineering Bucharest, Romania 2 Atelier 1, Romania 3 V&V Projekt, Romania 4 AIR Design Construct SRL, Romania * Corresponding adamian7@yahoo.com SUMMARY This paper is focusing on the thermal retrofit of an existing building located in Timisoara, a city from the western part of Romania. The building was erected during the communist era and has low-energy performance in terms of heating, domestic hot water and electrical consumptions. The present status of the building could be summarized as follows: Multi-family dwellings, 2 apartments, total developed area of 1322 m 2 ; Year of construction: , the building never being renovated; The residents are the owners of the apartments; Four-storey building unheated basement, no thermal insulation of the envelope; In order to reach the criteria adapted to the Passive House EnerPHit, for existing buildings, several measures of major renovation have been proposed, followed by a numerical simulation for annual energy consumptions. The results showed an important reduction of the total primary energy requested by the retrofitted building, relatively to the existing building. KEYWORDS Energy efficiency, Retrofit, Passive houses, Solar panels 1 INTRODUCTION The European Union (EU) has focused on the buildings energy performance since early 2 s. The Directive 22/91/EC of the European Parliament and of the Council of 16 December 22 on the energy performance of buildings (E.P. and C., 22) was the first European regulation to talk about the legal framework of this acute problem. This Directive has been renewed and completed in 21, with the release of the Directive 21/31/EC on the energy performance of buildings (E.P. and C., 21). In Romania, the legal framework of the buildings energy performance was set-up in 25 by the Romanian Parliament (R.P.), by the release of the Law 372/25 (R.P., 25), completed later by the Law 159/213 (R.P., 213), as well as by the National Action Plan for the

2 Energy Efficiency , which was the subject of the Government Order (GO) no.122/215 adopted by the Romanian Government (R.G.) (R.G., 215). The energy efficiency legal framework of the overall economy sector (buildings and industry) has been settled up by the Law 121/214 on Energy Efficiency (R.P., 214), completed later by the Law 16/216 (R.P.,216). It should be noted that the GO no.122/215 defined the nzeb building as a very highperforming building, characterized by very reduced energy consumptions from conventional resources, and for which the energy need would be mostly covered by renewable energy sources, available on-site or remotely. Accordingly, the percentage of use of renewable energy sources should be at least 1% fom the total primary energy requested by the building. The residential buildings in Romania represent about 86% of the building sector. The percentage of single-family residences (flats) is about 6% from the total residential sector. In the last decade, an important number of multi-family, collective residential buildings (blocks of flats) have suffered a process of thermal retrofit, meaning high improvement of thermal insulation, as well as some changes made on the internal installations. These works had been performed by assuming that this type of buildings are big energy consumers and energy waste. Unfortunately, due to some cost restrictions, the ventilation systems of these buildings have rarely been refurbished, meaning to poor indoor air quality for the occupants, knowing that the replacement of old windows and joinery had increased significantly the building airtightness and, reduced the fresh air intake by infiltrations from the outside environment. These were enough reasons for our team to search a solution to change an old residential collective building, with poor energy efficiency, into a modern and energy-performing building, by using the latest techniques and procedures for buildings retrofit. The opportunity to do this work has arised with the call for projects for the NeZeR (Nearly Zero Retrofit) competition (E.U., 214), co-funded by the Intelligent Energy Europe Programme of the European Union and organised in Romania by the Institute for Power Engineering (ISPE). In order to reach a high-energy performance of the chosen existing building, several modern renovation measures have been applied, according to the requests of the European EnerPHit Standard criteria. These measures involved: The reach of a high thermal insulation degree of the building envelope by using: - High thermal performance insulation materials; - Balconies with independent structure; - A new storey above the existing 4 th storey; Changes in HVAC building installations by using : - Ventilation unit with heat recovery for each apartment; - An unique individual gas boiler used only for the peak heating periods. Renewable energy technologies: solar thermal and PV panels; The results of this energy retrofit simulations, performed with the PHPP software (PHI, 216) adapted to Passive Houses EnerPHit criteria, showed the following energy demands: - For the space heating: 17,4 kwh/m 2 year (62,64 MJ/m 2 year) - For the domestic hot water production: 21,2 kwh/m 2 year (75,67 MJ/m 2 year) - For lighting and other electrical appliances: 4,32 kwh/m 2 year (15,55 MJ/m 2 year) These results showed the respect of the EnerPHit criteria and could be a good starting point of an extended retrofit programme for residential collective building in Romania.

3 2 MATERIALS/METHODS The main goal of this project is the thermal retrofit of an outdated residential collective building (block of flats), constructed during the communist era, more precisely between 1968 and 1969, in order to reach the newest energy efficiency criteria for passive houses indicated by the EnerPHit standard. This standard was conceived by the Passive House Institute (PHI) from Darmstadt and proposes criteria to be reached after the retrofit of existing buildings. For new-built passive-house buildings, other criteria established by PSI are mandatory. As a result, our architectural and technical proposal has strictly respected the principles defining passive houses: high energy performance building materials, high degree of thermal insulation, good ventilation with energy recovery, avoidance of thermal bridges, good airtightness of the whole building envelope. The respect of these principles and of the EnerPHit standard will transpose the existing, high-energy consumption building, into a lowenergy building, with good indoor thermal comfort and indoor air quality. The project, named ZeRoPHit Zero Energy Romanian Passive House Retrofit, intends to show a best-practice example for the energy retrofit of a residential collective building very usual for the Romania building sector, in order to raise the awareness of Local and Central Public Authorities in their preoccupation to decrease the big energy expenses for the non-industrial field. The big opportunity of implementing this project in practice would be the obtention of the Certified Retrofit label form the PSI, that could attest the corectness of the energy retrofit measures, along with the fulfilment of the EnerPHit standard criteria, outlined in table 1. On middle-term and long-term time projection, this label could raise the financial value of the building, but it s for sure it will considerably improve the quality of life of the building occupants, the most important goal of the energy retrofit. Table 1 : EnerPHit Standard criteria for existing building energy consumptions Annual specific heating load [kwh/ m 2 K] <25 Annual specific cooling load [kwh/ m 2 K] <25 Primary Energy Consumption (including electrical appliances and Classic: 6 equipment) [kwh/ m 2 K] Plus: 45 Premium: 3 Renewable energy used [kwh/ m 2 K] Classic: - Plus: 6 Premium: 12 Airchanges per hour of fresh air at 5 Pa [1/h] 1, Thermal transmittance of the building opaque envelope [W/m 2 K],15 -,3 Thermal transmittance of the glazed elements [W/m 2 K],85 1,5 Overheating Risk (>25 C) Max 1% Efficiency of the ventilation system with heat recovery > 75% The present situation of the existing building studied is the following one : Geographical location: Timisoara, a Romanian town located in the Western part of the country, having an outdoor winter base design temperature of -15ºC (climatic zone II, according to the standard SR 197/214) Type of building, number of dwellings, floor area : Multi family dwelling, 2 apartments, 1322,17 sqm total constructed area ;

4 Year of construction / last renovation : / the building was never renovated Ownership situation / residents : The residents are the owners of the apartments Technical characteristics, general : Four-storey building with an unheated basement; Structure type : The structure is composed of reinforced concrete pillars, beams and slabs, the masonry (walls) is made of solid traditionnal bricks (non-aerated), while thermal insulation of these walls is absent ; Windows: The great majority of apartment windows are old double-pane type (one glazing/pane) with wooden joinery and weak airtightness. In figure 1 it could be seen the new HVAC systems and renewable energy sources (solar panels) proposed for integration in the renovated building. Figure 1 : General sketch of the building studied by applying several energy retrofit measures The solutions for the renovation followed the EnerPHit Standard principles: Use of building materials with low-embodied energy ; Final energy consumptions lower than the EnerPHit criteria outlined in Table 1 ; High thermal performance of the building envelope, including good airtightness ; Ventilation with heat recovery units ; Use of renewable energy sources (RES) for domestic hot water (DHW) preparation and electricity production, with solar thermal panels and PV panels In addition, from architectural point of view, it had been studied the opportunity to implement a new floor above the existent 4 th floor, a new elevator, as well as balconies with independent structure. In table 2 is shown a comparison between existing building and new retrofittedbuilding characteristics.

5 Table 2 : Comparison between existing building and new retrofitted-building characteristics Building element Existing building Building after energy retrofit according to the EnerPHit criteria Walls No thermal insulation U ~ 1,66 W/m 2 K Thermo-system with 2 cm-thick mineral wool U <,16 W/m 2 K Floors No thermal insulation U ~ 2,5 W/m 2 K Thermal insulation on the outer part of the lower slab, with 15 cm-thick glass wool U <,23 W/m 2 K Roof Aerated concrete blocks as insulation layer U ~,88 W/m 2 K Replaced with 25 cm-thick layer of extruded polystyrene (XPS) U <,14 W/m 2 K Windows Old double-pane windows Uw ~ 2,32 W/m 2 K Replaced with triple-glazed windows Uw <,92 W/m 2 K HVAC 17 air-conditioning mono-split units without fresh air intake Replaced with Mechanical Ventilation with Heat Recovery (MVHR) units for each apartment RES Without systems using RES Solar thermal panels and photovoltaic panels 3 RESULTS In table 3 are outlined the main results of the PHPP simulation, that show important reduction of the energy consumptions for the existing building after the renovation measures proposed. Table 3 : Results obtained after the PHPP building simulation Total energy consumption by end-users : For heating For DHW production For lighting and other electrical utilities Total energy consumption at the building level : For heating For DHW production For lighting and other electrical utilities Total energy produces from local RES: Heat produced by use of RES Electricity produced by use of RES Type and quantity of energy supply for the whole building Heat from district heating point with fossil fuels Heat from RES use Electricity from the National Energy System Electricity from RES use Primary energy consumption after building major retrofit Heat Electricity Reduction of the primary energy consumption after building retrofit compared with the existing building (%) Value (kwh/year) SI value (MJ/year) 18,4 4,52 12,82 1,6 441,45 18,41 37,62 25,42 267,42 183,6 83,82 232,42 183,6 25,42 255,66 255,66 84,1 84,1

6 4 DISCUSSION The simulation results for the retrofitted building proposed by our team show an important reduction of the primary energy consumptions at the building level, as outlined in the table 3. The PHPP software allowed a detailed description of the building envelope (walls, windows, floors), as well as of the internal heat gains (humans, electrical appliances and lighting), along with the use of monthly climatic data for Timisoara, the geographical location of the building. Authors strongly recommend applying this type of analysis for other residential buildings, in order to offer to the stakeholders (Local Public Authorities) the possibility to put them into practice, improving thus the life quality of the majority of town s residents. 5 CONCLUSIONS The main conclusion of our study relies on the necessity to take urgently major renovation measures of residential collective buildings from Romania, in order to reduce drastically the primary energy consumptions for this sector and to improve the life quality of their occupants, meaning a good thermal comfort and a better indoor air quality. This goal could be reached only by applying up-to-date techniques for thermal retrofit, as well as some architectural principles for new buildings, for the design stage. The application of renovation measures for an old collective building in order to reach the Passive House criteria for existing buildings, has demonstrated the opportunity of this work and could show to the Public Local Authorities the way to gather financing resources to implement them at larger scale. 6 ACKNOWLEDGEMENT The present paper is the result of a study performed under the NeZeR project competition, cofunded by the Intelligent Energy Europe Programme of the European Union. 7 REFERENCES E.P. and C. 22. Directive 22/91/EC on the energy performance of buildings, European Parliament and Council E.P. and C. 21. Directive 21/31/EC on the energy performance of buildings, European Parliament and Council E.U. 214, NeZeR Promotion of smart and integrated NZEB renovation measures in the European renovation market, European Union and Intelligent Energy Europe Programme. PHI 216., PHPP (Passive House Planning Package) release 9, Passive House Institute, Darmstadt R.G Government Order no.122/215 for the approval of the National Action Plan for the Energy Efficiency , Romanian Government R.P. 25. Law no.372/25 on the buildings energy performance, Romanian Parliament R.P Law no.159/213 on the buildings energy performance, Romanian Parliament R.P Law no.121/214 on the Energy Efficiency, Romanian Parliament. R.P Law no.16/216 on the Energy Efficiency, Romanian Parliament.