Tests have been conducted in a wind tunnel with seven types of heat sinks including plate fin, strip fin, and pin fin heat sinks. In the case of strip fin, and pin fin heat sinks, both in-line and staggered arrays have been studied. The pin fin heat sinks had circular and square cross-sections. For each type, tests were run with fin heights ( ) of 10, 15, and 20 mm while the heat sink width ( ) was kept constant and equal to 52.8 mm. In total, 42 different heat sinks were tested. The width of the wind tunnel duct ( ) was varied in such a way that results were obtained for = 0 84, 0.53, and 0.33. The wind tunnel height ( ) was varied similarly, and data were recorded for = 1, 0.67, and 0.33 while the duct Reynolds number was varied between 2 000 through 16 500.An empirical bypass correlation has been developed for the different fin designs. The correlation predicts the Nusselt number and the dimensionless pressure drop and takes into account the influence of duct height, duct width, fin height, fin thickness, and fin-to-fin distance. The correlation parameters are individual for each fin design. Further, a physical bypass model for plate fin heat sinks has been developed to describe the bypass effect.

 Energy use and indoor climate of a building are studied before and after a renovation  The study numerically predicts, validates and evaluates energy use and indoor climate  Energy demand is reduced by 44% after renovation and indoor climate is improved  Assumed user behavior has significant impact on estimated energy-saving potential  System boundary affects climate and resource impact from selected renovation measures

This paper presents experiences from a recently built area with passive houses in Linköping, Sweden and compares them with conventional buildings, mainly from an indoor environment perspective, but also based on energy use. The built area consists of 39 recently constructed terraced houses, of which nine are built according to the passive house standard. The aspects of thermal comfort as well as local discomfort are studied. The methodology is based on on-site measurements and two types of simulations -CFD and Building Energy Simulation. In addition a post-occupancy evaluation was made using a standardized questionnaire to relate the occupant's perception of the indoor environment one year after the buildings were completed.The thermal comfort for these newly built passive houses is well within the limits in the local building code. However, some interesting findings related to local comfort such as cold floors are found in the post-occupancy evaluation as well as in the predictions. The occupants of the passive houses experience cold floors to a higher degree than in the conventional buildings. It was also shown that there are a higher number of complaints related to high temperatures during summer in the passive houses. It is worth noting that the buildings do not have external shading installed by default. The effect of varying temperatures was also observed in the passive houses to a higher degree than in the more conventional buildings, especially related to cooking and other heatgenerating activities, which is normal in a more well insulated and airtight building.

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