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Decarbonizing UBC’s District Energy System : District Energy Heat Pump Technology

University of British Columbia. Department of Chemical and Biological Engineering; University of British Columbia. Energy and Water Services; University of British Columbia. Campus and Community Planning

UBC is working on initiatives to meet its climate action target of achieving carbon neutrality by the year 2050. A major percentage of UBC’s GHG emissions occur in buildings operations, specifically, in space heating and domestic hot water heating to meet the thermal demand of the campus. Though UBC’s steam power plant for campus heating has been replaced with natural gas boilers of high efficiency and biomass plants that utilize clean wood waste, there is still a significant amount of GHG emissions released during the operation of natural gas boilers. Hence, there is a need to reduce the reliance on natural gas for district heating to aid GHG emissions reduction on campus. Integrating renewable sources of energy such as sea water heat pumps into UBC’s District Energy System (DES) can be one possible solution to reduce or eliminate the fossil-fuel reliance for district heating. Four different sea water heat pump technologies were studied that could meet the thermal demand of the campus, and the operating temperature of the DES. Each heat pump was integrated separately into the business as usual model, and the related energy consumption, operational costs and GHG emissions were analysed and compared with the business as usual scenario from the year 2024 till 2050. The business as usual scenario consists of the natural gas boilers, the biomass plant, the new biomass expansion plant to be installed by 2024 and the cogeneration plant. The new model consists of all these facilities along with the sea water heat pump unit. By comparing both the models technically and financially, the GHG emissions savings, operational expenses savings, the payback periods, and other financial parameters were calculated. It was observed that the heat pumps contributed to around 32% to 83% of GHG reduction when compared with the base case under different carbon tax scenarios. There was also notable reduction in operational expenses from the business as usual scenario. However, one major financial challenge encountered was the longer payback period, which was more than the actual replacement period or life span of the heat pumps. On the other hand, under circumstances where carbon taxes could go as high as 200$/tCO2, the payback period declined drastically. Therefore, it can be interpreted from the study that the sea water heat pump technology can help UBC progress towards its carbon neutrality goal, but a financial trade-off must be made in terms of longer payback periods if the carbon taxes do not increase and stay as consistent as now. However, under high carbon tax scenario, the results showed that the sea water heat pumps would become both technically and financially viable to UBC. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”

Report

eng

2020-07-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/75337

Unreviewed

http://creativecommons.org/licenses/by-nc-nd/4.0/