Energy and comfort analysis of building energy models: comparison between an early design simplified tool and a detailed approach

Buildings and their related energy consumption represent a strong fraction of anthropic carbon emissions in the world, typically around 30%. The world population is increasing at exponential levels, and it is therefore crucial a strong abatement of the carbon footprint of the building stock all over the world, both in the construction of new facilities, and in the retrofit of the oldest. Indeed, many countries all over the world are promoting stringent regulations regarding comfort and carbon emissions in the building sector. This refers to heating, ventilation, air conditioning, hot water, lights, appliances, etc. Detailed energy modeling of buildings is becoming the primary activity to foster high efficiency and sustainability in the design and operation process. It allows predicting and monitoring with a high level of detail the energy consumption of buildings, CO2 emissions, energy demand peaks, energy costs, and renewable energy production. Unfortunately, detailed energy modeling represents a complex solution, especially due to the high level of input detail and the relatively high computational time. For this reason, this thesis aims to verify the possibility of using simplified building energy models that can provide results in a fast, easy, and intuitive manner, to be used in the early decision design process. To achieve this, two building energy modeling tools are analyzed. First, IES VE is used as a detailed tool; second, EUReCA, the Energy Resistance Capacitance Approach, is exploited to run simplified building energy analyses based on the lumped parameters approach. The latter is a Python-based tool designed to run efficient urban energy simulation analyses, aiming to assist stakeholders and public administrators in the decision-making process. The comparison between the two tools is made considering three case study buildings in the context of the ENSNARE Horizon 2020 EU project. Specifically, the three buildings are located in Tartu (Estonia), Sofia (Bulgaria), and Sassa Scalo (Italy), covering a wide variety of climatic conditions. Finally, it is possible to study the so-called 'Building Energy Simulation TEST' in three different situations, where two of them are based on two different setpoints (600 and 640), while the third one is based on a case study with the plants turned off (600FF). For every simulation, internal heat gains were defined in compliance with EN 16798-1:2019 standards, ensuring the accurate assessment of internal thermal contributions. Subsequently, standard efficiency values for the efficiency of the heating and cooling system were set. The definition of the weather database for each case and the creation of detailed thermal profiles of the system contributed to a comprehensive understanding of daily and seasonal thermal variations. To conclude, the two simulation tools are compared both considering energy consumption and indoor air comfort parameters, during occupied and unoccupied hours.