IBPSA2009

Air quality in aircraft cabins has long been criticized. Current widely-used air distribution systems on airplanes dilute inside generated pollutants by promoting air mixing and thus impose risks of infectious airborne disease transmission. In addition, low moisture content in cabin is believed to be responsible for headache, tiredness and lots of other unknown symptoms.

In order to assess the influence of energy reduction initiatives, to determine the expected annual cost, to calculate life cycle cost, emission impact, etc. it is crucial to be able to assess the energy consumption reasonably accurate.  The present work undertakes a theoretical and empirical study of the uncertainty of energy consumption assessment of domestic buildings. The calculated energy consumption of a number of almost identical domestic buildings in Denmark is compared with the measured energy consumption.

In practise many buildings show significant deviation between the predicted annual energy consumption and the actual energy consumption. One of the main reasons for the discrepancy is the difference between the assumptions made during the calculations and the actual conditions including occupants’ behaviour.  This paper presents two methods to consider uncertainty and spread of energy consumption calculations in practise, namely a simulation approach and a safety factor approach.

Increasing attention is being paid to the application of uncertainty and sensitivity analysis methods to model validation and building simulation. The idea is to let users to apply uncertainty bands to their model input data. These bands are then propagated through the model to determine the uncertainty bands of the simulation results. Mathematical methods to deal with uncertainties in computer simulations are well developed.

In this paper, a sensitivity analysis has been carried out on a set of variables identified during the building conceptual design stage. The sensitivity analysis is performed on a simple intermediate floor of a typical multi-storey office representative of the office building sector for different Italian climatic zones. The conclusions are drawn in terms of sensitivity indexes of energy performance indicators for a set of different design variables and for different climatic zones.

Sensitivity analysis is a key part of a comprehensive energy simulation study.  Monte-Carlo techniques have been successfully applied to many simulation tools. Several sampling techniques have been proposed in the literature; however to date there has been no comparison of their performance for typical building simulation applications. This paper examines the performance of simple random, stratified and Latin Hypercube sampling when applied to a typical building simulation problem.

Shading devices used to protect from unwanted solar radiation acting on interior surfaces change air velocity and volume flow rates depending on their geometry and position on the building exterior. Changes in volume flow rates, interior velocities and the amount of solar radiation can be advantageous or disadvantageous depending on the time of day.

The use of operable shading devices impacts building loads significantly. The need exists for an explicit treatment of window shading devices in the design of energy efficient buildings through simulation. A general framework for modeling complex fenestration systems has recently been implemented in ESP-r. The underlying models have been developed with emphasis on computational efficiency and straightforward input requirements.

This study compares three different control strategies for double-skin systems. The analyzed control strategies are (1) rule-based approach, (2) exhaustive search and (3) gradient-based search. The fundamental principle of the rule-based approach is “if this, do that” under certain circumstances, and the rules are generally based on expert knowledge. The disadvantage of this approach is that it does not reflect the transient behaviour of the system.

This paper deals with the calibration of models capa-ble of simulating the performance of MicroShadeTM. The function of MicroShade is similar to Venetian blinds, however, MicroShade is a microstructure em-bedded in a metal foil with a thickness of less than one mm. MicroShade has been modelled using a novel module in ESP-r for modelling bidirectional transmission through transparent multilayered con-structions. Windows with and without MicroShade have been tested in two dedicated test rooms. The measurements from the test rooms have been used to calibrate the model of MicroShade.