Dennis Johansson

Simulating space heating demand with respect to non-constant heat gains from household electricity

It is crucial to perform energy simulations during the building process to design a building that meets requirements regarding low energy use. In a low energy building, internal heat gains such as excess heat from household electricity are a large part of the heat balance of the building. The internal heat gains depend on the occupants and are not constant, although they are often assumed constant in simulations of space heating demand. This article analyses how different usage patterns of household electricity affects simulated space heating demand. Parametric studies of energy use-related parameters were done to study the influence from different designs. The results show that the different energy use patterns affect the space heating demand, especially in low energy buildings and during the colder parts of the year. To make accurate energy simulations of low energy buildings, household electricity use patterns should be taken into account.

Measured indoor hygrothermal conditions and occupancy levels in an arctic Swedish multi-family building

As requirements regarding energy efficiency are getting tougher, buildings in the arctic, as well as the rest of the world, need to be more energy efficient without compromising a good indoor climate. This article presents measured moisture supply and occupancy level in a Swedish arctic multi-family apartment block. Measurements were done over 1 year every 30 minutes in a building consisting of 51 apartments located in Kiruna, at latitude 67.9°. Averages and typical variations on different timescales, year and day, are presented for the different parameters, as well as correlations between the parameters; for example, moisture supply as a function of occupancy level. The results can be used when input data for simulations of energy use, moisture conditions and indoor climate are chosen, as well as a reference to compare measurements to during verifications. In energy efficient buildings, occupant behavior generally has an extensive impact on building performance, which means that the characteristics of behavior related parameters are important to be able to describe.