IBPSA2011

The need to reduce radically the energy used by buildings is leading to new design practices.  Current design and simulation software are used in very different ways, with energy simulation generally employed to check energy code compliance after the design stages are mostly finished.  This linear approach to working practices, the modelling methods used and poor interoperability inhibit iterative design practices.  This paper outlines a case study to elicit early software requirements for combined simulation and design software.

The purpose of the CEBO research project is to propose a tool to assess the Effective Consumption of Occupied Buildings by calculation, which will be adjusted by measurement parameters that are limited in number and monitoring time. In this paper the method to identify the parameters that have to be measured is presented on a single family housing, using the TH-CE ex model (French regulation model for existing buildings).  The method is based on uncertainty analysis with fractional factorial design.

A coupled analysis of heating, ventilation and air-­conditioning (HVAC) system simulation tool and computational fluid dynamics (CFD) model was carried out to assess the mixing energy loss in an air-­conditioned room where heating and cooling operate in the perimeter and interior zones simultaneously. To evaluate the mixing energy loss, we conducted two simulations;; one was the case with airflow mixing between the perimeter and interior zones and the other was the case without airflow mixing between the zones.

This paper reports how the coefficient of performance (COP) of air-cooled chillers can be improved by adopting variable condensing setpoint temperature control and using mist evaporation to pre-cool ambient air entering the condensers to trigger a lower condensing temperature. Chiller models without and with water mist system were established, and the former was validated by using measured operating data of an installed screw chiller.

The main objective of this paper is to analyse the thermal comfort of users of a naturally ventilated building, located in the city of Florianópolis, Brazil. The analysis was performed by using the EnergyPlus computer programme. Different window areas, with automated and manual control of windows were simulated in order to improve the natural ventilation efficiency. The assessment of thermal comfort of users for the actual building and for the models simulated was performed by using the method proposed by Givoni and the method indicated in ASHRAE Standard 55.

This report describes the utility of coupling an energy simulation tool and computational fluid dynamics (CFD) for modelling a heating, ventilation and air-conditioning (HVAC) system, and demonstrates the application of this method in the design phase. A case study was conducted for the design phase of an air-conditioning system with an under floor air distribution system.  First, the cooling load for the target room was estimated, and the air-handling unit was designed based upon the estimated peak load.

To predict the mould growth risk during the design stage, a mould prediction model can be used. Several models are found in literature (e.g. temperature ratio, isopleth systems, biohygrothermal model, ESP-r mould prediction model, empirical VTT-model). Each of these models includes however different assumptions. Consequently, a different conclusion may be drawn depending on the used prediction model. In the current paper, a comparison between the different mould prediction models is made.

In this paper, heating energy saving strategies for winter are proposed for office buildings with a multi-story double skin façade. Based on a model that was validated with measured data, two alternative operation strategies were analyzed. A model that introduces heated air in the cavity to the indoors by openable windows control(Case 2) and a model that combines it with HVAC by using a cavity as a preheating space(Case 3) were compared with the conventional model(Case 1).

The aim of the present work is to improve night venti-lation control strategies, specially for the mid-season periods where an unadapted control scheme can re-sult in undesirable heat loads. We present a method based on developing an adaptive algorithm suitable for different types of buildings having different thermal masses. The algorithm, mainly based on the history of outside and inside temperatures, is characterized by a set of parameters that we attempt to identify: a coef-ficient related to building time constant and a couple of fixed set-point temperatures.

Providing thermal interior comfort in buildings in temperate climate zones is an energy-demanding task that can be optimized through refurbishment. We compare four refurbishment strategies to convert an existing residential building with high primary energy demand into a low-exergy building. The strategies differ in the balance of passive and active refurbishment measures, respectively in the balance of improving the building envelope and installing low-exergy building systems.