Energy and Economic Analyses of Natural Gas Heating Systems

An immense amount of the energy consumed in residential buildings is used for heating purposes to ensure the thermal comfort of human beings. The daily average outdoor air temperature plays an important role in determining energy use for heating. Therefore, the climatic conditions in different regions considerably affect the energy needs for heating, and accordingly, fuel consumption. The method used during this study is heating degree-day (HDD) approach, which has been utilized in many buildings for energy analysis. Before calculating the HDD values, the total heat loss of a house on the ground floor of an insulated five-storey residential building was determined. This information was used toward this study’s main aim, to investigate the yearly heating energy requirements and fuel consumption for natural gas and air-source heat pump heating systems with the utilization of single, double, and triple-glazed windows. All calculations were carried out with different base temperatures to calculate HDD values at the İzmit/Kocaeli Meteorology Station in Turkey, so that the carbon dioxide emissions resulting from these heating systems could be identified. Ultimately, heating systems were compared in terms of economic feasibility utilizing the life-cycle cost analysis (LCCA) method. Based on HDD values with a 15oC base temperature, yearly fuel consumption and carbon dioxide emissions for natural gas heating were estimated to be approximately 15180, 13225, 11998 kWh, and 3552, 3095, 2808 kg CO2 for single, double, and triple-glazed windows, respectively. Furthermore, yearly primary fuel consumptions and carbon dioxide emissions for a heat pump were estimated to be 3441, 2998, 2720 kWh, and 1218, 1061, 963 kg CO2 per year for single, double, and triple-glazed windows, respectively. Considering the installation cost of a heat pump of 13,500 ₺, it was predicted for a newly built house that the savings-to-investment ratio (SIR) would be 1.5. For an existing house with installed natural gas heating system, upgrading to heat pump system could not be feasible. Additionally, economic feasibility indicators, such as net present value (NPV), internal rate of return (IRR), and simple payback (years) were estimated by using LCCA method. Keywords: Energy analysis, heating degree-day, heating energy requirement, fuel consumption, carbon emission, economic analysis, Turkey.