Evaluation of the Energy and Comfort Performance of a Plus-Energy House under Scandinavian Summer Conditions

The thermal indoor environment and the energy performance of a plus-energy house are evaluated in the present study. The study case is EMBRACE, a two-storey dwelling of 59 m2 designed to host a single family. The building includes a semi-outdoor space covered by a glazed envelope, where the thermal environment is also investigated. The house is located in Nordborg, Denmark, where it is undergoing a year-round measurement campaign, of which are presented hereafter the results ranging from June to September 2015.
The thermal environment proved to be satisfactory, with 58 and 15 hours above 26°C respectively in the first and ground floors. In general, the indoor climate was quantitatively better during the heating period (June and September) than in the cooling period (July and August). Overheating did not result to be an issue, which suggests that the installation of a cooling system could have been avoided. The energy balance proved to be positive, with a total of 1563 kWh of electricity produced by the photovoltaic cells installed on the roof, and 333 kWh used by the mechanical systems of the house during the four studied months. The air temperature in the semi-outdoor space frequently reached 2 to 3°C higher than outdoors, which increases the amount of comfortable occupancy hours in this space. The results suggest that the house could perform effectively as a plus-energy house during the whole year.