A Fast Analytical Method for the Dynamic Energy Simulation of Energy Piles with Short Time Resolution

This paper proposes an analytical method for the dynamic thermal simulation of energy piles with a short time resolution (e.g., tens of minutes) as an alternative to numerical approaches, which require relevant computational resources. The discussion is tailored to the implementation of analytical models in dynamic energy simulation software for buildings and HVAC systems. The main modeling challenges consist of accounting for the pile thermal capacity, pipes configuration, and time-varying inlet temperature and flow rate values. The heat transfer process occurs in three characteristic periods, each of them characterized by a 2D or 3D geometry of the heat transfer process. The first period concerns the evolution of the fluid temperature and heat transfer over the length of the pipes, the second period concerns the thermal diffusion within the heat capacity of the foundation, and the third period is driven by pile geometry and ground source characteristics. For short time resolution analyses, we proposed a general linear set of equations based on the e-NTU theory for heat exchangers, the infinite composite-medium line source solution, and the finite line source for the ground source. The proposed method is compared with a full transient 3D numerical simulation. The maximum deviation in terms of return temperature to the heat pump is 0.2 K. The general dimensionless form, the short time resolution, and the limited computational time make the method suitable for building simulation software and optimization codes for thermal analysis and energy pile design.

Understanding the energy performance GAP: case studies of energy efficient homes

The energy performance gap between the predicted and actual energy consumption of 3 LEED for Homes certified buildings were investigated. The actual energy consumptions of the homes were found to be 23 to 77% higher than the initial energy consumption predictions made during the design stage. Revisions to the HOT2000 models to account for changes made between the design and occupancy phase of the buildings helped reduce the gap (9 to 40%). The sources of the discrepancies were found to be related to the energy modeling program’s limitations, inconsistency between the energy model and the actual building, and additional loads in the homes. The HOT2000 program, which is used for obtaining the EnerGuide rating for LEED certified homes, was compared against a dynamic energy simulation program to assess the applicability of the use of the former for energy efficient homes. The use of EnergyPlus not only allowed for a more accurate representation of the actual homes in the energy models, but an increase in the EnerGuide rating for the home was seen, which in turn equates to additional points for the home under the “Energy & Atmosphere” category for the LEED for Homes certification process

Understanding the energy performance GAP: case studies of energy efficient homes

The energy performance gap between the predicted and actual energy consumption of 3 LEED for Homes certified buildings were investigated. The actual energy consumptions of the homes were found to be 23 to 77% higher than the initial energy consumption predictions made during the design stage. Revisions to the HOT2000 models to account for changes made between the design and occupancy phase of the buildings helped reduce the gap (9 to 40%). The sources of the discrepancies were found to be related to the energy modeling program’s limitations, inconsistency between the energy model and the actual building, and additional loads in the homes. The HOT2000 program, which is used for obtaining the EnerGuide rating for LEED certified homes, was compared against a dynamic energy simulation program to assess the applicability of the use of the former for energy efficient homes. The use of EnergyPlus not only allowed for a more accurate representation of the actual homes in the energy models, but an increase in the EnerGuide rating for the home was seen, which in turn equates to additional points for the home under the “Energy & Atmosphere” category for the LEED for Homes certification process

Overview and Analysis of the Overheating Effect in Modern Sudanese Buildings

Sudan is suffering from harsh summers, but most of the modern buildings in urban areas are not compatible with the recent and future climate phenomena. Application of cooling devices is relatively expensive and therefore beyond reach. The main objective of this research is to give an overview on the overheating problem and the thermal comfort in buildings. A dynamic energy simulation has been performed for a selected case study using Design Builder Code. The results show that the share of discomfort hours for a typical modern building is 78% and 33% above 26 °C and 32 °C per year, respectively, but after using a combination of different ventilation, shading and building materials options the discomfort hours can be reduced to 77% and 26%, respectively.

DIGITAL ENERGY SIMULATION OF BUILDINGS PROTECTED BY MUNICIPAL HERITAGE POLICIES IN THE FRAMEWORK OF ENERGY RENOVATION PROJECTS

The energy simulation is a key tool when designing renovation actions on buildings. In the framework of the InterregMed SHERPA project, bound to trigger and manage energy renovations in public buildings, the digital analysis of an educational building affected by the municipal heritage protection has been carried out. The building is the CIPFP Blasco Ibáñez, catalogued as a monument of local interest in Valencia (Spain) city planning, where the heritage value of its facades (main and interior), roof and internal spatial structure is identified.The methodology used consists in performing an energy audit of the building in order to be able to customize a digital energy model. By means of an hourly dynamic energy simulation tool, the current status of the building and its systems can be determined, and energy renovation actions can be outlined. The use of digital analysis tools is of utmost interest in buildings declared as municipal heritage sites since enables the study to be performed in a non-intrusive manner. Several points of energy improvement are identified. There are some actions that can be performed without affecting parameters protected by the heritage status, and some others which need to be modified in order to be compliant with it. Furthermore, the digital analysis through energy simulation tools also allows to perform detailed calculations about the energy, environmental and economic savings associated with the measures. The assessment has proved the need to promote research and testing of new solutions and technologies to improve the energy efficiency of heritage buildings.

Parametric Optimization of Window-to-Wall Ratio for Passive Buildings Adopting A Scripting Methodology to Dynamic-Energy Simulation

Counterbalancing climate change is one of the biggest challenges for engineers around the world. One of the areas in which optimization techniques can be used to reduce energy needs, and with that the pollution derived from its production, is building design. With this study of a generic office located both in a northern country and in a temperate/Mediterranean site, we want to introduce a coding approach to dynamic energy simulation, able to suggest, from the early-design phases when the main building forms are defined, optimal configurations considering the energy needs for heating, cooling and lighting. Generally, early-design considerations of energy need reduction focus on the winter season only, in line with the current regulations; nevertheless a more holistic approach is needed to include other high consumption voices, e.g., for space cooling and lighting. The main considered design parameter is the WWR (window-to-wall ratio), even if further variables are considered in a set of parallel analyses (level of insulation, orientation, activation of low-cooling strategies including shading devices and ventilative cooling). Finally, the effect of different levels of occupancy was included in the analysis to regress results and compare the WWR with corresponding heating and cooling needs. This approach is adapted to Passivhaus design optimization, working on energy need minimisation acting on envelope design choices. The results demonstrate that it is essential to include, from the early-design configurations, a larger set of variables in order to optimize the expected energy needs on the basis of different aspects (cooling, heating, lighting, design choices). Coding is performed using Python scripting, while dynamic energy simulations are based on EnergyPlus.

3D scanning data use for modular building renovation based on BIM model

Nowadays new and modern tools should be actively used in buildings energy retrofitting processes. Handmade measuring and 2D design process should be minimized as possible and by replaced by advanced computer technologies such as automated data proceedings, 3D scanning and automated production lines. All these measures will allow significant minimization failures in design, energy simulation and construction. Available computing capacities allows data proceeding in reasonable time and quality. 3D building model is an efficient tool to develop precise retrofitting project and to make correct energy consumption estimation3D building model allows precise dynamic energy simulation using such software as IDA-ICE, RISUKA, IES, EnergyPlus etc. This research provides detailed analysis of existing buildings whole 3Ddevelopment process from scanning to creation of model.