Casa Sani Barvitius, Vedole di Colorno (PR), Italy - progetto ID 2759

Transcription

1 Casa Sani Barvitius, Vedole di Colorno (PR), Italy - progetto ID 2759 Single-family building Project Designer Passive House Planner: Architecture: Structure: Systems: RGA - Raffaele Ghillani architect ( RGA - Raffaele Ghillani architect CST Engineering srl Simone Dalmonte engineer This single-family house was realized after the demolition of a pre-existing rural building in Vendole (Candassa), a small village located in the southern area of Colorno, province of Parma, Italy. The climate is mostly sub-continental, characterized by cold winters with presence of ice and fog (temperature seldom below -10 C) and by humid summers with temperatures over 30 C and RH over 60-70%. The passive house has two heated levels over ground; the carport consists in a shelter covered by photovoltaic panels. Bearing walls made of aerated concrete blocks, a wood rafter pitched roof and an intermediate floors make up the structure. The family occupied the house in September Special features: Photovoltaic field and solar thermal plant to fully feed electrical needs for heating, cooling and hot water demand, underground cistern for recovering rainwater and irrigation. U-value external wall U-value floor U-value roof U-value window W/m 2 K W/m 2 K W/m 2 K 0.80 W/m 2 K PHPP Annual heating demand 12 kw/m 2 a PHPP Annual cooling demand 3 kw/m 2 a PHPP primary energy demand 63 kw/m 2 a Pressure test n50 0,52 h -1 Passive House Object Documentation House Sani Barvitius Page 1 of 13

2 2.1 Description of the construction task The demolition project and the new construction were authorized by the local administration under the bind of reaching a low-consumption standard (KlimaHouse Gold Standard, Italian voluntary classification standard, or Passiv Haus). The owner decided to certify the building with the PHI protocol, and the certification was successfully achieved. 2.2 Pictures of the exterior Southeast/northeast prospect Southwest/southeast prospect Northwest/southwest prospect Passive House Object Documentation House Sani Barvitius Page 2 of 13

3 2.2 Pictures of the interior Entry and living room Kitchen and dining room Bedroom Passive House Object Documentation House Sani Barvitius Page 3 of 13

4 Studio 2.4 Floor plan: structure and constructional details The house has its main side orientated southwest (210 ) and has two levels. The ground level consists in: the living room (on the left), where the main entrance is and where stairs lead to the upper floor; the kitchen, that serves also as dining room (on the right) and is connected to the pantry; the bathroom; a multiuse heated room. In this room the installations (heat recovery ventilation system, heat pump, electric meter, etc) are located, and stairs lead to the studio in the upper level. On the upper level, a vestibule reached by the main stairs leads to the bathroom and the bedroom with a walk-in closet. The roof in this part of the building extends over the porch and is higher then the part of the roof that covers the open space (studio). On the southwest side PHV panels cover the wood shelter carport. Passive House Object Documentation House Sani Barvitius Page 4 of 13

5 2.5 Sections and prospects: constructional details Bearing walls are made of aerated concrete blocks and are partially reinforced to perform earthquake standards. Intermediate floors are made of wood rafters and bricks. The pitched roof has the same structure of intermediate floors. From the various stratigraphy of the building comes complex constructive connections, that has been carefully investigated throughout the FEM check for thermal bridges and to assure an airtight envelope. The shape of the building is stretched along a SE-NW axis; most of the SE side windows overlook the porch. To suitably resolve the problems coming from the scarce compactness of the building (due to his shape) and the reduction of free solar gains, measures has been undertaken: the envelope has been over-insulated, structural thermal bridges have been eliminated, and window assembling system has been optimised installing an additional insulation to cover the window frame. Passive House Object Documentation House Sani Barvitius Page 5 of 13

6 2.6 Constructional details: stratigraphy External wall Slab foundation Passive House Object Documentation House Sani Barvitius Page 6 of 13

7 2.6.3 Wood rafter pitched roof (Str.04) and pitched roof with rafter insulation (Str.05) Str. 05 Str Windows and dormers Window type U g [W/m 2 K] Ψ g [W/mK] g [%] U f [W/m 2 K] Ψ ein [W/mK] Wood/aluminium windows: STABIL Ambiente Passiv 0,481 0, % 0,700 Lat. 0,042 / inf. 0,021 / sup. 0,047 Wood/aluminium dormer ROTOWDF R8 H Uw , % 1,300 Door type U d [W/m 2 K] Ψ ein [W/mK] Wood door EDITION THERMO 100 0,81 0,04 Passive House Object Documentation House Sani Barvitius Page 7 of 13

8 2.6.5 Airtightness In order to neutralize heat losses caused by the infiltration (fissures, connections between constructional elements, scarce sealings, etc..), specific attention has been paid on the airtightness of the envelope both in pre-audit (design of the constructional connections, compatibility of the materials) and under construction (laying of connections between different materials, the turn-up of the sheets, taping, etc..). With the Blower Door Test, carried out according to UNI EN 13829, Method A, a value n50 = 0.51 h -1 has been detected. During the Blower Door Test, the anemometer has detected small heat loses on the entrance threshold (o.46 m/s), on the dormer placed in the attic (0.29 m/s) and the TV antenna junction box (0.26 m/s). Losses are to be eliminated through the adjustment of the seals and by applying silicone on the pleated of the antenna cables. The wood-fired stove boosts up value n50 of about 30%, due to the holes it has on top of the plates and on the seals of the oven door. Indeed, measurements done without counting the stove results n50 = 0.36 h Constructional details: connections Connection between external walls and slab foundation The slab foundation are insulated by a layer of foam glass granulate, which extends 1,5 meters out of the building perimeter. This permits to take advantage of the lake of heat determined by thermal inertia of the ground. Insulation in XPS (24 cm thick) reaching the foam glass granulate layer encloses the slab, eliminating the thermal bridge. The air tightness between slab foundation and walls (detail A) is provided by a vapor barrier placed under the acoustic insulation and turned up on the floor perimeter through the help of PET-fleece tape with attached plaster reinforcement. Passive House Object Documentation House Sani Barvitius Page 8 of 13

9 2.7.2 Connection between internal wall and slab foundation Connection between external walls and slab foundation porch Insulation in XPS (12 cm thick) on the slab and a thermal cut in XPS (5 cm thick) has been used to eliminate the perimetral thermal bridge Connection between windows and external walls Windows without counterframe are flush fastened on the bearing walls by metal supports. The frame is almost totally included in the insulation on the left side, right side and the top. On the bottom side the frame is fixed to a beam in wood and purenit (detail C), which is fixed, in turn, to the bearing walls. The airtight envelope between walls and window frame (detail B) is provided by PET-fleece tape with attached plaster reinforcement. Beside singleside adhesive tape in the perimeter of the frame, expanding tape has been used in the internal side and the perimeter border between insulation and frame to provide an airtight envelope from the outside. Passive House Object Documentation House Sani Barvitius Page 9 of 13

10 2.7.5 Connection between intermediate floor and external walls Mineral fiber insulation has been used to eliminate the perimeter thermal bridge. To provide the airtight envelope, the vapor barrier is turned up (under the acoustic insulation) and fixed on the internal plaster with PET-fleece tape with attached plaster reinforcement. Another vapor barrier layer has been applied on the concrete beam and turned up, after laying the wood rafters, through the internal side of the walls up to the start of the plaster Connection between roof and external walls The connection between mineral fiber insulation of the external walls and wood insulation of the roof eliminates the thermal bridge. To provide the airtight envelop in the internal side, the vapor barrier has been applied on the concrete beam and turned up, after laying the wood rafters, on the bricks, under the first layer of insulation of the roof in wood fiber. Beside the vapor sheath turned up on the roof border and on the internal and external side of the insulation, expanding tape has been used on the internal and external side of the insulation. Passive House Object Documentation House Sani Barvitius Page 10 of 13

11 2.7.7 Ventilation plan for the ductwork The typical distribution plan, with indication of the ventilation grilles and the respective air-flow, is sketched below: Fig. 1: ventilation plan, ground floor Fig. 2: ventilation plan, first floor Ventilation plan for the central unit / type /specific values It was used the Zehnder ComfoAir 550 ventilation unit with the following characteristics: Comfort ventilation for dutys up to 550 m³/h Heat recovery with an efficiency of up to 95% Moisture recovery with the Zehnder enthalpy exchanger Low power consumption thanks to EC direct current motors Automatic 100% summer bypass Infinitely variable frost protection function: efficient even at low temperatures Digital control unit with weekly timer as standard Passivhaus Institut accredited (heat recovery efficiency 84% ) Fig. 1: technical room Passive House Object Documentation House Sani Barvitius Page 11 of 13

12 2.7.9 Heat supply The house is heated / cooled through the ventilation system. A post treatment air/water exchanger is installed after the ventilation unit in order to raise the supply air temperature in cold season, and to cool it down in hot season. In winter, circulating water is distributed at a temperature of 45 C. In case of emergency there is an additional electric heating. During the summer it is important to de-humidify the supply air, thus water circulating within the post-treatment exchanger shall guarantee the air condensation. Therefore, 7 C circulating water is distributed. Production of heated / cooled water and hot sanitary water is made by a air/water heat pump from manufacturer ROTEX. Fig. 2: hydraulic scheme 2.8 PHPP Results 2.9 Costruction costs 1500 / m² Treated Floor Area according to PHPP 2.10 Building structure costs 1660 / m² total demand 2.11 Year of construction The project started July 2011 and finished July Architectural design The architectural project has met the typological standards, constructional materials and the aesthetic characteristics of the rural typical buildings of the zone (that is regulated by landscape and environmental requirements). Passive House Object Documentation House Sani Barvitius Page 12 of 13

13 2.13 Structural analysis The building has been conceived as a three-dimensional structure and the aerated concrete blocks are connected to the foundation in order to resist horizontal and vertical actions. The construction system is not a frame structure, but a structure of concrete low reinforced walls. To guarantee a box-like behaviour of the whole structure, walls and ceiling joists have been conveniently linked up together by concrete reinforced stringcourses. The foundation is superficial continuous with concrete reinforced slab. Intermediate floors and the roof have a bearing wood rafter pitched structure linked up by stringcourses with bounded intersections Experiences In September 2012 Family Sani Bartius occupied the house. Overall user feedback is positive, especially in terms of comfort. Users found no inconsistencies between planned and real behaviour (at the end of November, after systems switching off because of a period of vacation, from starting temperature of 20,5 C, the user at his return has found a temperature of 19,5 C). Monitoring will start in January Bibliography This project was presented at: - 1 Convegno Passivhaus Friuli Venezia Giulia, APE, Udine, Italy, July 3, 2012; - 6 Convegno Nazionale Case Passive, TBZ, Bari, Italy, September 7-8, 2012; - Settimana della Bioarchitettura e Domotica, Agenzia per l Energia e BIOECOLAB, Modena, Italy, November 12-16, 2012; and published in the relevant proceedings; - reference Ytong, KlimaHouse Bozen, Italy, 25-27, Author: Raffaele Ghillani Architect Date: Passive House Object Documentation House Sani Barvitius Page 13 of 13