As the entire world is struggling with global warming, Sweden continues to work hard to reach net zero emissions from greenhouse gas emissions by year 2045. The housing and service sector in Sweden is responsible for most of the total emissions and is thus a good stepping point for higher efficiency. Examining ventilation systems is usually a good way to get more efficient, thus the creation of this project.
HSB Norr has a commercial property in Umeå with a ventilation system consisting of three separate FTX units, and the purpose of the project is to investigate the possibility of replacing the existing units with a single unit from Swegon GOLD. The project will clarify the economic benefits of the new system by examining factors such as energy savings, life cycle benefits, payback time and environmental impact. This will be done with the assumption that existing piping systems are correctly dimensioned and that nothing beyond the ventilation units themselves is changed, no adjustments are made to the building's shell to increase savings.
Air flows and pressure changes in the current system are identified using both physical on-site surveys as well as measurements from the system's DUC as well as data from previous energy declarations and OVK, as well as how large the new unit may be physically. With this knowledge, a new unit from Swegon is assessed, which then was simulated by Swegon's technicians to see what heat savings and electricity consumption may look like.
The new system, which can manage air flows of up to 4.6 m3/s and has a simulated average heat recovery of 87.5%, is expected to save 111 071 kWh/year, which with an energy cost of 1 SEK/kWh results in 111 071 SEK/year. With the investment costs of 2 120 000 SEK, the new unit expects a payback period of 20,4 years. The life-cycle benefit of the system is calculated to be 73 687 SEK after a 30-year unit repayment period, and the environmental savings amount to 4 470 kg CO2e/year with an environmental payback period of 1,74 years. Comparisons between the current system and the new unit show that over the next 30 years, the new unit can be expected to save more than 50% of the emissions from the current system, which has a heat recovery of 49%.
Factors that affect the results of this project include the air flow and heat requirements for the current system, which have had to be estimated due to the lack of detailed measurements.
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