Two articles from new new issue of Building Simulation sound particularly interesting:

Comparing computer run time of building simulation programs, by Tianzhen Hong, Fred Buhl, Philip Haves, Stephen Selkowitz and Michael Wetter.

This paper presents an approach for comparing the computer run time of building simulation programs. The computing run time of a simulation program depends on several key factors, including the calculation algorithm and modeling capabilities of the program, the run period, the simulation time step, the complexity of the energy models, the run control settings, and the software and hardware configurations of the computer used to run the simulation. To demonstrate this approach, we ran simulations for several representative DOE-2.1E and EnergyPlus energy models. We then compared and analyzed the computer run times of these energy models.

DeST—An integrated building simulation toolkit Part II: Applications, by Xiaoliang Zhang, Jianjun Xia, Ziyan Jiang, Jiyi Huang, Rong Qin, Ye Zhang, Ye Liu and Yi Jiang.

This is the companion paper of part I of DeST overview. DeST was developed as a building simulation tool with the aim of benefiting both design of and research on building energy efficiency. During its development, DeST has been applied to many projects, development of building regulations, and research. This paper gives examples of several areas in which DeST has been applied, including building design consultation, building commissioning, building energy conservation assessment, a building energy labeling system, and scientific research. Examples from a demonstration building are presented to demonstrate the entire process of aiding design with DeST. Additional projects and regulations are also mentioned to introduce other applications of DeST.

More papers directly relevant to the main topic of this blog:

Monitoring and modelling of manually-controlled Venetian blinds in private offices: a pilot study by Vorapat Inkarojrit

This study presents results from a window blind usage survey and field study that was conducted in California, USA during a period spanning from the vernal equinox to the winter solstice. A total of 113 office building occupants participated in the survey. Twenty-five occupants participated in the field study. In this study, 83 measurements of physical environmental conditions were cross-linked with participants’ window blind controlling preferences. A total of 13 predictive window blind control bivariate and multivariate logistic models were derived. As hypothesised, the probability of a window blind closing event increased as the magnitude of physical environmental and confounding factors increased (p < 0.01). The main predictors were window/background luminance level and vertical solar radiation at the window. The confounding factors included MRT, direct solar penetration and participants’ self-reported sensitivity to brightness. The results showed that the models correctly predict between 72-89% of the observed window blind control behaviour. This research extends the knowledge of how and why building occupants manually control window blinds in private offices, and provides results that can be directly implemented in energy simulation programs.

The following papers from Building and Environment Volume 43, Issue 12, December 2008 are relevant to the field of building automation and simulation.

Photometry and colorimetry characterisation of materials in daylighting evaluation tools by M. Bodart, R. de Penaranda, A. Deneyer, G. Flamant.

This paper presents a methodology for evaluating the photometric and colorimetric characteristics of internal building materials, for daylight evaluation. The assessment of these characteristics is crucial both for modelling materials accurately in daylight simulation tools and for building correct daylight mock-ups. The essential photometric and colorimetric parameters that influence the reflection of light from and its transmission through building materials are identified and described. Several methods for evaluating these parameters qualitatively and quantitatively are then proposed and discussed. Our new methodology was fused to create a database of materials in a freely accessible web tool which compares full-size materials to scale-model materials in order to help architects and lighting designers choose materials for building daylight scale models.

On the behaviour and adaptation of office occupants by Frederic Haldi, Darren Robinson.

During the warm summer of 2006 a comprehensive longitudinal field survey of the adaptive actions of occupants, their thermal satisfaction and the coincident environmental conditions was conducted in eight Swiss office buildings. We have applied logistic regression techniques to these results to predict the probability of occupants’ actions to adapt both personal (clothing, activity and drinking) and environmental (windows, doors, fans and blinds) characteristics. We have also identified, for each type of control action exercised, the increases in temperature at which thermal sensation votes are reported. These “empirical adaptive increments” have also been defined for combinations of control action. In this paper we present the field survey methodology as well as the results relating to the above, which we discuss along with scope for further related work.

Minimisation of life cycle cost of a detached house using combined simulation and optimisation by Ala Hasan, Mika Vuolle, Kai Siren.

In the current study, minimisation of life cycle cost (LCC) for a single family detached house is achieved by combined simulation and optimisation. The house has a typical Finnish construction with initial U-values in accordance with the Finnish National Building Code C3 of 2003. The implemented approach is coupling the IDA ICE 3.0 building performance simulation program with the GenOpt 2.0 generic optimisation program to find optimised values of five selected design variables in the building construction and HVAC system. These variables are three continuous variables (insulation thickness of the external wall, roof and floor) and two discrete variables (U-value of the windows and type of heat recovery).

This investigation shows the advantages gained from the implemented approach of combining simulation and optimisation. The solution suggests lowering the U- values for the external wall, roof, floor and the window from their initial values. The exact values of the optimised design variables depend on the set up of the LCC data for each case. Reduction of 23–49% in the space heating energy for the optimised house is obtained compared with the reference case. Verification of the GenOpt results is made by comparison with results from a brute-force search method, which indicates that GenOpt has found, or has come very close to, the global minimum in the current study.

Modeling sky luminance using satellite data to classify sky conditions by S. Janjaia, I. Masiria, M. Nunezb, J. Laksanaboonsong.

Many traditional models of vegetation canopy reflectance have commonly used one of two approaches. Either the canopy is assumed to consist of discrete objects of known reflectance and geometric-optics are then used to calculate shading effects, or, as in the turbid medium approach, the canopy is treated as a horizontally homogeneous layer of small elements of known optical properties and radiative transfer theory is used to calculate canopy reflectance. This paper examines the effect of solar zenith angle on the reflectance of red and near-infrared radiation from forests using a combination of these modelling approaches. Forests are first modelled as randomly spaced eucalypt crowns over a homogeneous understorey and the fractional coverage of four components: shaded and sunlit canopy and shaded and sunlit understorey are calculated. Reflectance from each fraction is then modelled for a range of solar zenith angles using the Verhoef SAIL model. The overall scene reflection as seen by a nadir viewing satellite sensor is compared for three forest types representing a gradient of crown density from open dry grassy woodlands to dense wetter closed forest with an understorey of mesophytic plants. Modelled trends in scene reflectance change are consistent with aircraft measurements carried out at three different solar zenith angles. Results indicate that an increase in both tree density and solar zenith angle leads to an increase in the dominance of shaded components. In the visible band, both the sparsely treed woodland and the medium density dry forest show similar trends to that predicted by a turbid medium model, however, the wet forest shows a less rapid decrease in reflectance with solar zenith angle. In the near-infrared band, as tree density increases from woodland to wet forest, overall scene reflectance shows increased departure from that modelled using the traditional assumption of smooth homogeneous canopies, changing from an increase with solar zenith angle for the woodland to a decrease with solar zenith angle for the forest types.