Life Cycle Assessment of Ventilation Systems

Abstract

AbstractThree different analyses are conducted in this thesis. First there is made a database of ventilation components with life cycle inventory (LCI) data that can be used to optimize duct work systems based on LCA. These values are from cradle to use. Transport, installation, maintenance and demolition are commented. The second part is an example of optimization done on a small duct work system with pressure drop and fan power taken into account. The third part is a case study where kg CO_2-eq/m^2?year is found to see how much a given ventilation system affects the environment. All gathering of LCI-data of components are done based on weight and assumption of material composition. All components are simulated separately in Simapro and the results are presented per component and per meter duct. The compounding of material pieces into the finished components are assumed done in Trondheim, Norway. All components are analyzed with three electricity-mixes; UCTE, NORDEL and Norwegian. For the second part, the LCA of a small duct work system, the LCA is divided into different phases. The gathered LCI-data from the first part are used to optimize the duct work system. The duct work system is a simple system existing of three lengths of ducts and two bends. The main idea with the optimization part is to show the method with using pressure drop in duct work system, find the primary energy factor (PEF) of the fan and optimize the duct work system based on PEF of LCI-data of the components and the PEF of fan. For the third part a case is used; the ventilation systems of Multiconsult offices in Bergen, Norway. This office building is highly energy efficient, and is marked with the grade excellent from Breeam. The results from the LCI-data show that, naturally, the environmental impact increases as the weight and dimension of the component increases. The optimal dimension of the duct work system depends on operation hours, lifetime and electricity-mix used in fan and in the LCI-data for the components. With an operation time of 12 hours a day for a year and a lifetime of 30 years, the optimal duct dimension is found to be 160 mm for both UCTE and NORDEL electricity-mix and 125 mm for Norwegian electricity-mix. The last part, the case part, gave a value of 0, 64, 0, 62 and 0, 62 kg CO_2-eq/m^2?year for the UTCE, NORDEL and Norwegian electricity-mix, respectively with a lifetime of 30 years.