Energy Retrofitting Strategies and Economic Assessments: The Case Study of a Residential Complex Using Utility Bills

Abstract

Promotion of retrofit actions on existing buildings is a goal in Italy, since most of them were built before the 80 s when little attention was paid to energy saving. This paper presents an integrated passive design approach to reduce the heating demand and limit the costs of a representative existing residential complex located in Bologna, in the northern part of Italy. To this purpose, we explored different scenarios upon actions taken on the building structure: (1) High efficiency windows; (2) additional insulation on the external walls; or (3) the simultaneous application of high efficiency windows and improved thermal envelope, on both external walls and roofing. The numerical optimization has been performed dynamically using TRNSYS simulation tool, to evaluate energy consumptions in different structural conditions. Then, the developed model has been calibrated by the real consumption data deduced from energy bills (years 2009-2015). Finally, the energy results obtained in the above mentioned different scenarios have been evaluated under an economic assessment of cost investment: It has been highlighted that the payback time (PBT) results to be strongly influenced by the national policies of fiscal incentives. According to the present model, the most profitable condition is obtained when additional insulation on the external walls is applied: The total amount of energy saving resulted to be equal to 930.4 MWh, with an optimal PBT of roughly six years, when tax refund was contemplated.

Simplified Neural Network Model Design with Sensitivity Analysis and Electricity Consumption Prediction in a Commercial Building

“…For closed loop, the transfer function satisfies T(s) = G(s)C(s) 1+G(s)C(s) ; then, the sensitivity function is defined as S = ∆T(s)/T(s) ∆G(s)/G(s) [27]. From a social and environmental viewpoint, SA has been used in energy management for residential areas and buildings [28,29]. Electrical energy purchase and sales price was settled with the help of SA [28].…”

“…Electrical energy purchase and sales price was settled with the help of SA [28]. Another study proposed the use of insulation in external walls, which is the most cost-effective way to save total energy [29].…”

“…residential areas and buildings [28,29]. Electrical energy purchase and sales price was settled with the help of SA [28].…”

A Study of Energy Simulation Integrated Process by Automated Extraction Module of the BIM Geometry Module

“…In the field of energy including dynamic energy simulation [11,12], such as Energy Plus and Trnsys, research on information exchange through BIM can be divided into two types: (1) Research on the construction of a database by directly converting neutral files and (2) research on the improvement of the compatibility of the neutral file format. Among these, the extraction of the geometry data belongs to the direct conversion of the neutral file format, and there have been studies on the extraction of the geometry data through the IFC file format for the calculation of the energy load and the evaluation of the energy performance of a building [13,14].…”

Energy Performance Assessment According to Data Acquisition Levels of Existing Buildings

“…Thus, first of all, apart from occupant behavior, building operations, and system maintenance, the performances of the envelope, lighting, hot water supply, and heating, ventilation, and air conditioning (HVAC) systems need to be objectively assessed to effectively reduce the energy consumption of an existing building [15][16][17]. Many studies have been conducted on energy retrofitting strategies and economic assessments for various types of existing buildings such as residential and non-residential buildings [18][19][20][21].…”