The introduction of dynamic envelope components and systems can have a significant reduction effect on heating and cooling demands. In addition, it can contribute to reduce the energy demand for artificial lighting by better utilization of the daylight. One of these promising technologies is Phase Change Materials (PCM). Here, the latent heat storage potential of the transition between solid and liquid state of a material is exploited to increase the thermal mass of the component. A PCM layer incorporated in a transparent component can increase the possibilities to harvest energy from solar radiation by reducing the heating/cooling demand and still allowing the utilization of daylight. Measurements have been performed on a state-of-the-art window that integrates PCM using a large scale climate simulator. The glazing unit consists of a four-pane glazing with an integrated layer that dynamically controls the solar transmittance (prismatic glass) in the outer glazing cavity. The innermost cavity is filled with a PCM, contained into transparent plastic containers. The introduction of dynamic components in the building envelope makes the characterization of static performance (e.g. the thermal transmittance, U-value; the solar heat gain coefficient) insufficient in giving the full picture regarding the performance of the component in question. This article presents a series of measurements, and the related methodologies, carried out on a window with incorporated PCM. The tests have been carried out using several test cycles comprised of temperature and solar radiation cycling, where the aim has been to delve deeper into the possibilities for characterization of dynamic building envelope components by full scale testing in a climate simulator.

Experience with low-energy and passive house buildings forms the basis for the further development of zero-emission buildings. A post-occupancy evaluation of the Løvåshagen cooperative is therefore conducted by means of user surveys and measurement of indoor climate parameters, energy use and window opening time.

The goal of the post-occupancy evaluation is to obtain information about how occupants use and experience low-energy and passive house dwellings, especially with regard to heating and ventilation. In addition, the impact of user behavior on the indoor climate and energy use will be assessed.

In this paper, the results of the user survey regarding user habits and occupant satisfaction are presented.

The results show that low-energy and passive house apartments are used in ways that have a substantial impact on the indoor climate and energy use. The assessed extent of window ventilation and use of floor heating throughout the year around definitely increase energy use substantially and therefore partially explain the difference between the calculated and measured energy use. This difference will be quantified by measurements and parametric simulation in the continuation of the study.

Most respondents are satisfied or very satisfied with living in a low-energy or passive house dwelling. Nevertheless, a clear need for improvement with respect to heating and ventilation systems is detected.

It can be concluded that increased attention to the interaction between the occupant, the building design and the technical installation is needed in the development of zero-emission buildings.

The main definition of a Powerhouse is a building that shall produce at least the same amount of energy from on-site renewables as the energy used during construction, manufacturering of materials, renovation, demolition and operation exclusive energy used during manufacturering of equipment such as PCs, coffee machines etc. In addition the exported energy shall in average not have less quality than the imported energy. This implies that produced and exported electricity can offset corresponding amount of imported energy for both electricity and thermal purposes, while produced and exported thermal energy cannot offset imported electricity. The building shall also as a minimum fulfil all the requirements of the Passive House standard according to NS 3701.

The first Powerhouse renovation building will be built at the Kjørbo site in Bærum, and start of construction was in March (2013). For the Powerhouse Kjørbo project, PV panels will balance the energy needed during it’s lifetime. The two buildings will thus export more electricity than it will use for operation. A geothermal heat pump, in addition to waste heat from the data/server room, will cover the heating and cooling demand. There will be no export of thermal energy. In a broader environmental perspective, an aim of this project is also to achieve the classification “Outstanding” in the BREEAM-NOR environmental certification scheme.

The heated useful floor area of the two office buildings at Kjørbo, which will be renovated to plus-energy standard, is about 5.180 m2, distributed on 3 or 4 floors. Energy efficiency measures and materials with low embodied energy have been crucial for obtaining the energy goal. A very efficient ventilation concept has been developed.

Powerhouse Kjørbo is a ZEB pilot building, i.e. a pilot within the Research Centre on Zero Emission Buildings (www.zeb.no). Therefore an aim is also very low greenhouse gas emissions during the building’s lifetime.

Calculations indicate that the energy balance during the building’s lifetime, and within the defined definition, fulfils the goal of plus-energy.