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A sink-diffusion model to describe the interaction between material surfaces and volatile organic compounds (VOCs) in indoor air has been introduced. The model is based on adsorption/desorption on the material surfaces and diffusion into the materials. Test chamber experiments with exposure of nylon carpet and polyvinyl chloride (PVC) covering against alpha-pinene and toluene were used to validate the model and to make comparisons with a sink model based on the Langmuir adsorption isotherm. The results showed that the sink-diffusion model gave a better description of the desorption curve than the Langmuir model. The model predictions improved with increasing sorption effect. The Langmuir model gave good predictions of relative weak sorption effects, whereas the sink-diffusion model improved the predictions for stronger sorption effects. In this case, nylon carpet showed substantial stronger sorption than PVC covering and alpha-pinene showed stronger sorption than toluene. Controlled field experiments with combinations of building materials and a mixture of VOCs, encountered in real indoor environments, are needed to further validate the sink-diffusion model.

This paper presents the case study of a newly constructed 1600 m 2 kindergarten building in Oslo, Norway. The building has been designed within the framework of the Norwegian Research Council Project LowEx, which aims at engineering solutions to achieve a seasonal coefficient of performance (SCOP) of 6-10 for heating, a seasonal energy efficiency ratio (SEER) of 80-100 for cooling, and an 80% reduction in the purchased electric energy for heating and cooling of the buildings. Several architectural and technical measures have been implemented in the case study building to meet these requirements. This paper first provides an account of the design measures implemented in the building to achieve the ambitious energy performance targets. It then focuses on the design of the ground source heating and cooling system for the building and presents the preliminary design of the borehole system to provide low-temperature heating and high-temperature cooling to the kindergarten. The possibility of improving the borehole system design by optimizing the solar heat gains through the building envelope to balance the ground thermal loads is explored next. Finally, the effect of uncertainties in the design input values of ground thermal conductivity, effective borehole thermal resistance, and undisturbed ground temperature on the final design of the borehole system is evaluated. ARTICLE HISTORY

Displacement ventilation is a proven method of providing conditioned air to enclosed spaces with the aim to deliver good air quality and thermal comfort while reducing the amount of energy required to operate the system. Until now, the practical applications of displacement ventilation have been exclusive to providing ventilation and cooling to large open spaces with high ceilings. The provision of heating through displacement ventilation has traditionally been discouraged, out of concern that warm air supplied at the floor level would rise straight to the ceiling level without providing heat to the occupied space. Hence, a separate heating system is regularly integrated with the displacement ventilation in cold climates, increasing the cost and energy use of the system. This paper goes beyond the common industry practice and explores the possibility of using displacement ventilation to provide heating without any additional heating system. It reports on experimental investigations conducted in laboratory and field settings, and numerical simulation of these studies, all aimed at investigating the application of displacement ventilation for providing a comfortable indoor environment in winter by preheating the space prior to occupancy. The experimental results confirm that the proposed concept of providing space heating in unoccupied periods without a separate heating system is possible with displacement ventilation.

and 22 96 55 08 www.sintef.no/byggforsk M IL JØ MERK E T 2 4 1 Tr ykksak 3 7 9 3 PrefaceThis report presents guidelines for energy efficiency concepts in office buildings in Norway. The report gives an overall view of and explains the important tasks and factors that must be attended when planning and designing for energy efficiency in office buildings. A design strategy in several steps is proposed, described and explained.The report is also a summary report of the work carried out in Work Package 2 Design guidelines for sustainable energy-efficient building envelopes in the Strategic Research Project Climate Adapted Buildings (CAB).Documentation of the fulfillment of ambitious energy performance criteria and/or the requirements of the building code for a building is normally done by simulations. The design of 12 different new energy-efficient office buildings in Norway with different energy concepts has been studied in the project with a number of different simulation tools. This research has shown the need for a clear simulation and reporting strategy as the variations and differences in the input and output of the simulated results are considerable. In particular, the prediction of energy consumption and summer overheating conditions vary over a large range. References to further readings are given.Future energy use in buildings dependency on predicted external climate change is also shortly attended in the report. A predicted increase in cooling degree days makes the awareness of overheating conditions and thermal comfort criteria during summer months even more important.References to further readings are given.In order to identify the most important design parameters in relation to energy performance a sensitivity analysis has been evaluated and applied to determine a robustness factor. The work is briefly introduced in the report and further readings are given.The project is financed by the Norwegian Research Council and is organized at SINTEF Building and Infrastructure. The authors gratefully acknowledge the Research Council of Norway. A special thanks to our colleague Noralf Bakken for helping collecting information about the office buildings and the office building owners for sharing the information.