thermal simulation

This paper presents a thermal simulation validation study of the typical precision that a trained thermal simulation engineer can expect to obtain for the simulation of a room connected to a naturally ventilated double skin facade. The open source building thermal simulation tool EnergyPlus is used to predict air and surface temperatures in a free running weather exposed test cell.

The research objectives of this study are to develop and validate a detailed simulation model of a test cell which was used to measure heat balances for comfort evaluation. 

Excessive air leakage through the building envelope increases the infiltration heat loss and therefore lowers the energy efficiency. Therefore, very good airtightness is required in case of well insulated buildings equipped with a mechanical ventilation system with heat recovery (e.g. n50 < 0.6 h-1 for passive houses). Although the building industry has progressively adopted strategies to comply with such strict limits, it is still important to study how and how much the airtightness influences the energy efficiency of different types of buildings in different climatic conditions.

Overheating is an unwanted consequence of modern building designs and internal gains that will be aggravated by the effects of climate change on local climates within urban and suburban areas. To minimise the energy cost of limiting overheating several different approaches exist for passive cooling dissipation techniques. Free cooling by ventilation, or Ventilative Cooling, (VC), is a generally accepted effective, energy efficient, mitigation strategy to building overheating. There are many factors that influence the design and selection of suitable VC strategies.

In this paper, the numerical and experimental performance of a new Thai Modern Façade (TMF) are investigated. Two configurations were considered namely, the Thai Modern Façade wall (TMF) and the Thai modern façade wall with fin (TMF-WF). The coupled governing equations as well as boundary conditions are solved using the finite element method (FEM) via COMSOLTM Multiphysics. Temperature profiles and flow field of the TMF and TMF-WF are reported and discussed.

Buildings do not perform as modelled. There are many reasons for this, for example change of scope, functions, assumptions, weather, user behaviour and so forth. This paper investigates the latter. It turns the use of Post Occupancy Evaluation (POE) around and asks: what is the impact of people on building performance?  Based on IES modelling, the researchers identified those areas of performance that were sensitive to user behaviour and used the process of post occupancy evaluation to observe this as well as the standard elements related to user satisfaction.

This application paper outlines some innovative building simulation methodologies used to predict thermal performance of complex energy efficient systems using commercially available softwares. Industry case studies are presented to demonstrate how simulation can influence the design process with requirements varying from zero carbon emissions to optimum thermal comfort. Simplifications used to reduce computational time and handle software limitations are assessed in regards to model accuracy and the ability to influence the design decision process.

With the increasing need for higher energy efficiency in buildings, airtightness and ventilation systems choice become major performance issues in well insulated buildings. Buildings energy requirements lead to adapt ventilation strategies in order to reduce energy losses through mechanical balanced or extract ventilation. With the new French thermal regulation, the use of energy-efficient ventilation systems is implicitly required; low air infiltration is explicitly required in residential buildings through minimum airtightness levels.

This paper presents the development and implementation of an Energy-based Decision Support System (EDSS) that will enhance the selection process of replacement building features. EDSS includes dynamic databases that utilize data/web mining concepts, Knowledge Base System (KBS) and a thermal simulation engine. The system allows decisions to be made based on a long-term vision incorporating energy cost savings rather than immediate needs. A stand-alone application was implemented based on EDSS.

The performance of a passive heating system was evaluated as part of design works for the project of an office building. The passive heating system incorporates an array of buried pipes together with a solar chimney. The solar chimney collects solar energy, heating fresh air and pulling it from an array of buried pipes. The array of buried pipes was used as an open loop earth-to-air heat exchanger and air circulation inside pipes is due to the action of the solar chimney. We studied the heating fractions due to the solar chimney and to the buried pipes.