Life Cycle Assessment of an Active House: Sustainability concepts by integrating energy, environment and well-being
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An emerging interest in constructing ultra low energy buildings, with low impact materials and maximizing the potential of using renewable energy reflects the potential in building industry to significantly contribute towards reducing environmental impacts. Life cycle assessments of the different green building prototypes provide a means to estimate the impacts of such buildings as well as provide suggestive improvements. The Active house in Stjørdal, Norway is one such prototype of a green building. This is a single family residence which is built with a concept of solar architecture in ultra low-energy buildings. It is challenging to harness solar energy at high latitudes. The Active house uses the fundamental construction details for a Passive house as mentioned in Norwegian regulatory standard, with specific changes in increasing the glazed surface to promote passive solar heat gain as well as increase daylighting , but also making it vulnerable to heat loss. The house is based on timber framework. Apart from electricity the house uses solar collectors which are connected to the hot water storage and hydronic floor heating. Space heating is also compensated by use of wood stoves. In the LCA results suggest that, based on the construction the Active house requires ten percent more energy than an equivalent Passive house which uses only electricity and wood. However, due to the effectivity of the solar collectors, it compensates for the need of the extra energy and in a lifetime of 60 years, it performs 15 % better , contributing to lesser environmental impacts than an equivalent Passive house. It is understood that extra embodied energy does not affect the environmental performance of a building if it results in better environmental performance (1). However, it is important to create demonstrable value of the building for the end user. Lifecycle assessment results from simulated operational use carries considerable error with respect to how the building actually performs. The results in this study have also been estimated with an approximate error factor derived from previous studies (2). There is a necessity to make every stakeholder of the building participative in the functioning of the building, inclusive of the end user, and maintaining the well-being. The case has also been scored in the basic categories of a sustainibility certification, with the results available from the lifecycle assessment and energy simulation.