OVERHEATING PROBLEM IN SINGLE FAMILY PASSIVE HOUSE Jana Mlakar and Janez Štrancar

Introduction Living conditions comfort, efficiency, health Fanger 1972 Air temperature, relative humidity ANSI/ASHREA 55-1992: Comfort zone: 20-26°C, 30-60 % RH Higher temperatures overheating: Extensive solar radiation High external temperatures Internal energy sources

Aim Identify strategies to reduce overheating problem To what extent the internal temperature could increase if residents would not cool house with opening of windows at night and would not shade the windows Appropriateness of a pasive house strategy in hot summer climate

Description of test house passive house in Limbuš, Slovenia – hot summer climate wooden skeleton, cellulose insulation, U 0,1 W/m2 K TFA 113 m2 the ridge is oriented in the direction east–west triple glazed windows, two low emissive coatings, krypton, thermal transmittance: 0,8 W/(m2 K) S: roof extension, E and W: Venetian blinds tightness of the house at 50 Pa 1/h heat recovery unit: 83 % efficiency, preheaters 100 W and 200 W, additional heater 280 W floor heating system: max 29 °C, 1800 W sensory control system is performed with the USB microcontroller

Acquisition system External temperature Internal temperature Solar flux Temperature in pipelines of the mechanical engeneering systems

Description of model

Simulation of internal temperature Minute time scale

Fitting the response of the house in winter

Fitting the response of the house in summer Simulation of internal temperature Shading: E and W windows Cooling of the house during the night: When Text < Tint

Results Text temperature oscillations Increased ventilation during hot periods and also first cold days Simulations without shading or cooling

Conclusions Real passive house can resist excessively hot periods. Shading and ventilation through opened windows can keep Tint within a comfort level. Neglecting these strategies would result in serious overheating.

Thanks Janez Štrancar, Jožef Stefan Institute Mirko Škvorc, Eko produkt d.o.o. Other coworkers European Social Fund for financial support