A FAÇADE INTEGRATED MICRO-HEAT PUMP – ENERGY PERFORMANCE SIMULATIONS Georgios Dermentzis 1 , Fabian Ochs 1 , Dietmar Siegele 1 , Wolfgang Feist 1,2 1 University of Innsbruck, Energy Efficient Buildings, Innsbruck, Austria 2 Passive House Institute, Darmstadt, Germany Technikerstrasse. 13, A-6020 Innsbruck, email: Georgios.Dermentzis@uibk.ac.at ABSTRACT A façade integrated micro-heat pump in combination with mechanical ventilation with heat recovery is developed in the framework of the European project iNSPiRe. A set of system simulations (building combined with HVAC) has been performed to investigate the energy performance of a micro-heat pump. The performance of the system is investigated for different renovation standards (EnerPHit with 25 kWh/(m 2 ∙a) and Passive House with 15 kWh/(m 2 ∙a)) and for seven different European climate conditions. The potential of the micro-heat pump and the system optimization are investigated within dynamic simulations. Different control strategies using standard hysteresis on/off or PI controller are investigated. INTRODUCTION - MOTIVATION The majority of existing building stock in Europe and worldwide is low energy performance buildings. Deep renovation solutions in combination with integrated Heating Ventilation and Air Conditioning (HVAC) systems are developed within the framework of the European project iNSPiRe. The present study focuses on one approach about a façade integrated micro-heat pump (HP) in combination with mechanical ventilation with heat recovery (MVHR). The main advantages of the proposed system are the compactness, providing the possibility of integration into the façade, and cost reduction. A prototype will be later monitored in a demo building in Ludwigsburg, Germany. It is an example of social housing built in the 1970s, which contains four flats on four stories. During the renovation process a timber frame façade will be fitted onto the building. The HP with the MVHR will be integrated into the prefabricated façade. The prefabricated unit is designed as a compact system for minimal space use. Renovations with minimum intervention are enabled (minimum invasive renovation). A minimal installation effort is desirable for economic reasons. By means of this system, cold ducts inside the thermal envelope can be completely avoided.As the whole solution will be façade integrated and prefabricated,construction and installation time can be kept very short. Building physical aspects have to be carefully investigated (avoiding/reduction of thermal bridges, avoidance of moisture related damage, sound protection). Solutions for easy maintenance need to be developed and tested. The performance of the mechanical ventilation unit with heat recovery and the micro-heat pump are tested in two PASSYS test cells and in an acoustic test rig at university of Innsbruck. CONCEPT The considered system is developed and integrated in a test façade. The heat pump uses the exhaust air of the MVHR as source and provides heat to the supply air of the ventilation system (Figure 1). Thus, one compact unit can be used for combined ventilation and heating or cooling. Fresh outdoor air flows into the MVHR, where it is heated with an energy recovery coefficient of up to 95 %. It is then further heated by the micro-heat pump up to maximum 52 °C in order to supply space heating (reverse operation for cooling would be possible in future versions). Figure 1: Simplified concept of the micro-heat pump (µHP with MVHR) The concept addresses very good building standards (e.g. EnerPhit 25 kWh/(m² a) (see [Zeno et al., 2012]) or better), corresponding to a specific heat load in the range of 10 W/m². Hence, the typical heat power of the heat pump will be in the range of 1 kW. The proposed system is suggested with a radiator in the bathroom for comfort reasons. If the capacity of the HP is lower than the design heating load of the building an additional backup heater has to be used. Fifth German-Austrian IBPSA Conference RWTH Aachen University - 344 -