Dynamic simulation and parametric analysis of green roofing in buildings

Abstract

Enhancing energy efficiency and performance of the buildings and improving the air quality are acquisition during the cooling and heating seasons. According to the 2010 report by General Electricity Company of Libya, electrical energy consumption by residential sector account for approximately 39% of total demand in Libya. The green roof technologies in buildings are one of the main methods for using energy economically and reducing CO2 emission. The economic parameters such as the vegetation thickness and its thermal conductivity for the green roof, the electrical energy cost, coefficient of performance and EER all affect CO2 emission and total cost of the buildings. This study focuses on the impact of these parameters on the application of green roofs as well as degerming the optimum vegetation thickness and thermal conductivity of vegetation layer. Tripoli's degree days were used as one of methods to achieve these calculations or the results. The green roof and mathematical models were performed to find energy savings, and payback, and CO2 reductions. This study focuses on investigating these parameters that affect the green roof for external building based on life-cycle cost analysis (an economic model). As a result, the total cost increased from 6.7 to 23.05 $/m2; while CO2 emission decreased from 2.5 to 1.52 kg/m2/years with increasing the electricity costs which includes the effects of Interest rate on CO2 emission and total cost. Total cost decreased from 16.7 to 14.9 $/m2; while CO2 emission increased from 1.85 to 1.94 kg/m2/years with increasing the Interest. An increase in COP (Coefficient of Performance) and EER (Energy Efficiency Ratio) causes the CO2 emission to decrease from 2.2 to 1.51 kg/m2/years and from 2.08 to 1.37 kg/m2/year and total cost to decrease from 18.3 to 12.9 $/m2 and from 17.4 to 11.76 $/m2. The total cost and CO2 emission are increased from 13.7 to 16.5 $/m2 and from 0.34 to 1.74 kg/m2/years with increasing the thermal conductivity of vegetation. And the effects of degree day on CO2 emission and total cost, the total cost and CO2 emission are decreased from 18.6 to 14.67 $/m2 and from 2.45 to 1.55 kg/m2/years with increasing the degree day.