IBPSA2011

In this paper a user model for the use of windows based on measurements in residential buildings is developed. Detailed literature review provides an overview of existing user models. Most of them base on measurements in office buildings and their validity for residential buildings is questionable. All models are based on different kinds of statistical methods.  After detailed assessment of these methods and the analysis of their applicability to the measurements, a new methodological approach is applied, to take the auto-correlation in the longitudinal data into account.

The study, conducted in composite climate of India, exhibits improvement in energy efficiency of a conditioned building block with the use of energy conservation measures (ECMs) recommended by National Energy Conservation Building Code (ECBC). In first part of it, subject building model was individually applied with five ECMs and two combinations of these ECMs by using constant thermostat settings. Similarly in second part of the study the same was done with adaptive thermostat settings.

The paper presents combined approaches dedicated to assess the thermal comfort in a tropical climate. UrbaWind, an automatic computational fluid dynamics code, was developed to model the wind in urban environments. A module was recently added to assess the buildings’s natural cross ventilation.

This paper describes a modelling comparison between three very similar medium sized educational buildings located in the temperate climate of Nelson, New Zealand, each designed using structural systems made primarily of timber (actually built), concrete or steel (both hypothetical).  The buildings were analysed using two different insulation values in the thermal envelope, one sufficient to comply with the New Zealand Building Code and another with ““best practice”” insulation levels.

Discrepancies between simulated and actual occupant behaviour can offset the actual energy consumption by several orders of magnitude compared to simulation results. Thus, there is a need to set up guidelines to increase the reliability of forecasts of environmental conditions and energy consumption. Simultaneous measurement of the set-­‐point of thermostatic radiator valves (trv), and indoor and outdoor environment characteristics was carried out in 15 dwellings in Denmark in 2008. Linear regression was used to infer a model of occupants’ interactions with trvs.

A mathematical model to simulate an unsaturated highly capacitive porous medium on roof (sand) is considered in order to predict its effects on building passive cooling. The present methodology is based on the theory of Philip and De Vries, using the thermophysical properties for different types of porous medium (building envelope) with different chemical composition and porous size distribution. The governing equations were discretized using the finite-volume method for describing the physical phenomena of heat and mass transfer in unsaturated porous medium.

The pollution problems caused by fungi in indoor environments are usually recognized at a stage where colony formation has progressed to a level already enabling visual identification. Thus, the prediction of mould growth risk in early stage is very important for prevention of adverse health effects due to mould growth. This paper presents the results of mould growth risk at specific trouble spots in an apartment house with variation of indoor ventilation rates and internal moisture production using hygrothermal and biohygrothermal simulation approaches.

We present a new analysis and optimisation procedure to aid decision-making regarding Combined Heat and Power (CHP) and Combined Cooling, Heat and Power (CCHP) installations. Our holistic model incorporates analysis of plant operation (including part-load perfor-mance) and provides guidance regarding applicability, sizing and phasing of plant.A multi-objective genetic algorithm has been used to optimise a set of possible configurations. This produces a “trade-off front” of solutions. The outputs are reported for a case study.

This paper describes the implementation of the room heat transfer model in the free open-source Modelica “Buildings” library. The model can be used as a single room or to compose a multizone building model. We discuss how the model is de-composed into submodels for the individual heat transfer phenomena. We also discuss the main physical assumptions. The room model can be parameterized to use different modeling assump-tions, leading to linear or non-linear differential algebraic systems of equations.

This paper describes the investigation of the existing VRF system renewal using energy simulation. Both the renewal to the latest VRF systems and to proper capacity VRF systems were examined. The effect of changing the evaporating temperature of the VRF systems was also examined as an example to evaluate the energy saving effect by the operation improvements. In the simulation, the annual energy saving effect of the renewal to the latest VRF systems was 31%.