Influence of load profiles and climatic zones on the installations of SOFC-based cogeneration systems in commercial buildings

Even if significant efforts are being supported by a great part of Occidental Countries to switch from traditional thermochemical systems, based on fossil fuels to produce electrical and thermal power, to renewable energy sources-based technologies, according the latest international agreements between Countries aiming to mitigate the climate change, right now it is not possible to rely only on RES’s to meet the energy needs of all the people in the word. In this context a combined heat and power (CHP) energy system based not on thermochemical but on more efficient electrochemical processes, could help the energy transition, using as well a fossil fuel as methane, but resulting in a strong reduction of pollutants and greenhouse gases (GHG) emission with respect to traditional fossil fueled energy systems. This work wants to evaluate Solid Oxide Fuel Cell based systems potential in the context of distributed generation systems, applied on two different types of commercial buildings, evaluating priorly what kind of buildings are more suitable in terms of electrical and thermal load profiles and climatic conditions, to switch from the actual case, where most of them buy the electricity from the grid and produce thermal energy for space heating using fossil fuels fired boilers or electrical heat pumps, to combined heat and power systems fuel cell based. The entire analysis has been made using in input modeled end use load profiles of a typical meteorological year contained in a dataset supplied by The National Renewable Energy Laboratory (NREL). Firstly, comparisons in the electrical and thermal energy yearly demands of each type of commercial building are done, examining energy end uses and load profiles of different types of building in the same climate and for the same category of building, the influence of the climate zone on their energy behavior as magnitude and shape of load profiles, as well the ratio of electrical to thermal energy demand. At the end of the aggregate analysis, four different climate zones from warm climates to colder ones and two categories of building are selected, among those that could be more suitable to a CHP SOFC based system installation, the average energy behavior per climate zone and building type is investigated and compared. A total of eight buildings modeled are analyzed, namely four hospitals and four hotels, selected as the most representative buildings per each category and climate, using a MATLAB code based on the minimization of the Euclidian distance for each building selected from the average electrical and thermal energy yearly consumptions of its category and climate of belonging. Finally, a techno economic analysis is made for the eight buildings, evaluating the Levelized cost of electricity (LCOE) priorly on the SOFC system volume control, then on the control volume composed by the SOFC and the specific building. Buildings in cold climates, with a consistent electrical base load performs better with lower LCOE values. The lowest LCOE value among all buildings investigated, was obtained for the largest hospital in the coldest climate(0,258 €/kWh)climate, , while regarding hotels an LCOE of 0.255 €/kWh was calculated for the largest hotel but located in the warmest climate. A sensitivity analysis is also performed varying technical and economic input data, showing how much competitive could become a similar energy system in a near future.