Development of an office tenant electricity use model and its application for right-sizing HVAC equipment

As a consequence of considerable uncertainty about occupancy, occupant behaviour, and the corresponding effect on thermal loads in buildings, it is difficult to correctly size heating, ventilation, and air-conditioning (HVAC) equipment. Mechanical engineers avoid liability of potential under-capacity and corresponding thermal discomfort by making conservative assumptions about occupants. Meanwhile, there has been a surge in research on characterizing occupants through increasingly advanced modelling approaches to support building performance simulation, but these have focused on agent-based models representing individual occupants, which may be impractical for building-level HVAC equipment sizing. This paper describes the development of a data-driven stochastic tenant model using 15 months of data from 17 independent commercial tenants. The model is implemented in EnergyPlus to examine its potential for an improved HVAC equipment-sizing procedure. The results show: the standard schedules are reasonable though conservative; oversizing equipment does not greatly improve comfort; and the tremendous importance of modelling inter-tenant diversity.     

Integrated simulation through the source-code coupling of component models from a modular simulation environment into a comprehensive building performance simulation tool

No single building performance simulation program contains sufficient capabilities and flexibility to fully respond to the full complexity of modern building design and analysis. Consequently, considerable efforts and advances have been made to facilitate the integrated use of multiple simulation tools to provide more extensive modelling capabilities. The research reported in this article has made a contribution towards the goal of integrated simulation by focusing on the internal coupling of component models from a modular simulation environment into a comprehensive building performance simulation tool. A flexible and extensible facility has been designed and developed to enable the use of HVAC component models (TYPEs) from the TRNSYS simulation program within the ESP-r simulation platform. With this, the source code for any number of TRNSYS TYPEs can be compiled with the ESP-r source code to produce an integrated simulation tool that possesses greater capabilities than either simulation program alone.     

Building simulation as assistance in the conceptual design

In order to realize the “design by simulation” concept in the building design, the methodology of applying the building simulation in the building’s conceptual design stage is the main theme discussed in this paper. The conceptual design stage is divided into four sub-stages, and the framework of the design is built by way of the simulation in the conceptual design stage. Moreover, the energy saving potential assessment by the simulation in the preliminary conceptual design stage is also discussed in detail, including the input/output information, the calculation method and procedure, and the requirements and information from architects, etc. The natural ventilation design is used as the first trial in this study, and the difference between the detailed conceptual design and the preliminary conceptual design is also discussed, and the new simulation methodology is further described. The main objective of this paper is to help avoid an incorrect decision in the conceptual design stage, as well as to provide a better base for the energy efficient design in the next stage by means of the building simulation tool.     

A framework to integrate object-oriented physical modelling with building information modelling for building thermal simulation

This paper presents a framework for integrating building information modelling (BIM) and object-oriented physical modelling-based building energy modelling (BEM) focusing on thermal simulation to support decision-making in the design process. The framework is made of a system interface between BIM and Modelica-based BEM and the visualization of simulation results for building designers. The interface consists of the following two major features: (1) pre-processing BIM models to add required thermal parameters into BIM and generate the building topology and (2) translating BIM to Modelica-based building energy modelling automatically and running the thermal simulation. The visualization component presents the simulation results in BIM for designers to understand the relationship between design decisions and the building performance. For the framework implementation, we have created a ModelicaBIM library and utilized the Modelica Buildings library developed by the Lawrence Berkeley National Laboratory. We conducted a case study to demonstrate and validate the framework simulation results.     

Simulation of a building and its HVAC system with an equation solver: Application to audit

A series of building energy simulation tools are being developed to help the building energy auditor in establishing his diagnosis (including benchmarking and detailed analysis of actual energy consumption) and in evaluating the selected energy conservation opportunities (ECOs). A first simulation tool, dedicated to benchmarking, has been presented in a previous paper. The present paper focuses on the second simulation tool, dedicated to inspection and evaluation of ECOs. This Building-HVAC System global model includes simplified models of building zones and of HVAC (heating, ventilation, and air conditioning) equipment. Only a limited number of easily identifiable parameters are required. The simplicity of the models and the use of an equation solver to run the simulation ensure good robustness and full transparency. The development, the implementation and the application of these models are discussed. Focus is also given to the calibration of the tools to monthly utility bills.     

Method for modelling space conditioning aggregated daily load curves: Application to a university building

Physically based load modelling methodologies have been widely developed and used because of their ability to predict the energy load dynamic response. Most building energy programs predict energy consumption and energy system performance through a whole building energy simulation as well as a global analysis of building thermal processes and heating, ventilation and air-conditioning (HVAC) system performance. A different approach is presented in this paper by introducing a new method for modelling the daily load profile of a group of air-conditioning systems. This method is based on the simulation of a single HVAC system, a set of end-use electrical measurements, and a detailed walk-through and energy audit. The basic methodology allows deducing the aggregated load of a group of space conditioning devices by the addition of the daily simulation of each individual physical system. As an application, the space conditioning daily demand curve of a university building is studied and results are presented.     

Housing management matters: Citizenship and managerialism in the new welfare market

This paper addresses three neglected issues in the restructuring of housing policy and provision in the UK in the 1980s and 1990s: first, the relationship between welfare restructuring and management regimes; second, the nature of local variations in the impact of welfare restructuring; and third, the significance of human agency interpretations of change. The paper starts by summarizing the main features of welfare state restructuring and then considers recent manifestations of citizenship and managerialism in housing. Three competing conceptions of citizenship rights are used to examine changing notions of welfare: “market efficiency”, “institutionalized rights” and the “radical challenge” provided by social movements. A four-part typology of the main concepts and themes in the “new public management”—“efficiency”, “downsizing and decentralization”, “excellence” and “public service”—is used to present the main components of change in management regimes. The paper draws on literatures on housing management, citizenship and “the new public management” and on recent research into tenant participation, housing rights and housing advice services. Conclusions are drawn about how tensions between different conceptions of citizenship and public management are implicated with national and global influences at the local level to create particular welfare outcomes.     

Information-theoretic environment features selection for occupancy detection in open office spaces

Knowing the presence or the actual number of occupants in a space at any given time is essential for the effective management of various building operation functions such as security and environmental control (e.g., lighting, HVAC). As occupants “interact” with the indoor environment, they will affect environmental conditions through the emission of CO₂, heat and sound, and relatively little effort has been reported in the literature on utilizing this environmental sensing data for occupancy detection. This paper presents the findings of a study to address this question by exploring the most effective environmental features for occupancy level detection. A sensor network with robust, non-intrusive sensors such as CO₂, temperature, relative humidity, and acoustics is deployed in an open-plan office space. Using information theory, the physical correlation between the number of occupants and various combination of features extracted from sensor data has been studied. The results show significant correlation between features extracted from humidity, acoustics, and CO₂, while little correlation with temperature data. Using features from multiple sensors increases correlation further, and nearly 90% information gain is acquired when nine of the most informative features are combined.     

Disaster risk management in development projects: models and checklists

In Latin America and the Caribbean, the available information about the causes and consequences of risk is scarce and barely meets the needs of project engineers and decision makers. Although local governments and communities typically who bear the brunt of the losses, they do not participate in the definitions and are not informed about the “acceptable” level of risk or how to reduce it. The formulation and adoption of risk management criteria (supported by engineering geological modelling), throughout the cycle of development/investment projects, should take account of the affected communities and how they can play a part in the decision making. This requires an increased awareness and understanding of both natural hazards and vulnerability. The paper analyses best practices based on experiences from Latin America and the Caribbean, which may be useful for the evaluation of hazards and vulnerability and lead to proactive risk management.     

Review of modelling approaches for passive ceiling cooling systems

Passive ceiling cooling systems can lead to reduced cooling requirements, less fan energy and downsized ductwork, compared to conventional all-air systems. Additionally, radiant cooling of occupants allows for improved comfort while allowing for higher operating temperature, improving chiller efficiency. This paper presents a comprehensive review of current modelling approaches for passive ceiling cooling systems in order to document the state of the art and identify current research gaps and modelling development needs. Modelling methods are separated in three main categories, based on the domain of interest: component or “passive ceiling cooler” models, “indoor environment” models and “integrated” models. Simplified, detailed and empirical models are presented for each category. Different modelling approaches may be appropriate for different purposes (design vs. control analysis, and system simulation vs. whole building performance). The study summarizes useful findings, modelling limitations and applications, and presents needs for further modelling and simulation research, including passive chilled beams.     

Co-simulation of innovative integrated HVAC systems in buildings

Integrated performance simulation of buildings' heating, ventilation and air-conditioning (HVAC) systems can help in reducing energy consumption and increasing occupant comfort. However, no single building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to analyse integrated building systems and to enable rapid prototyping of innovative building and system technologies. One way to alleviate this problem is to use co-simulation, as an integrated approach to simulation.

This article elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in the here described co-simulation prototype. The prototype is validated with the results obtained from the traditional simulation approach. It is further used in a proof-of-concept case study to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analysed to give a guideline for the required coupling time step.     

Spatial dimensions of the demand for homeownership. A Danish rural–urban perspective

This paper introduces the concept of “spatial location satisfaction” and examines its relation to the individual demand for homeownership. Based on a Danish questionnaire survey carried out in a rural study area (N = 1,000) and in an urban study area (N = 1,015), a tenure choice model was estimated relating spatial location satisfaction to homeownership, while adjusting for control variables. The spatial location satisfaction variable was constructed from two questionnaire items asking respondents to state their actual and preferred place of settlement given five location type options: large city, medium-sized city, small town, village, and “in the countryside”. As hypothesised, the study shows a strong association between spatial location satisfaction and the individual demand for homeownership. This association is robust across study areas. Spatial location satisfaction is highest in the rural study area and explains about 6% of the rural–urban difference in homeownership rates. The identification of a positive association between spatial location satisfaction and homeownership adds credibility to population surveys that measure the correspondence between actual and preferred location type. This, in turn, provides increased impetus to use such survey data as one of the tools in formulating regional planning policies.     

An evaluation of the effects of various parameter weights on typical meteorological years used for building energy simulation

In this paper, we evaluate the influence of different parameter weights in creating “typical year” weather data following the typical meteorological year (TMY) methodology, by studying two sets of 3600 alternate weather files created using different parameter weights for Beijing (China) and New York City (USA). A “typical year” weather file consists of twelve distinctive months, each considered typical for that month of the year. Such a typical month, named “typical meteorological month (TMM),” is commonly identified by using a certain combination of parameter weights, such as 4:4:4:12, for dry bulb temperature, dew point temperature, wind speed, and solar radiation as in the TMY weather files developed by US National Climate Data Center (NCDC), or 4:4:2:10 in the newer TMY2 and TMY3 weather files developed by National Renewable Energy Laboratory (NREL). In this study, we investigate the influence of varying the parameter weights on the TMMs and the resultant new TMY weather files (nTMY). We found that the distribution of new 3600 TMMs tend to cluster within one or a few years for each month, and that the probabilities are very high for significant overlap between the new TMMs and the original TMMs chosen using the TMY/TMY2 weighting. Compared to the TMM data in TMY, the deviations of air temperatures and solar radiation values of the new TMMs and nTMYs derived from the 20-year weather data are less than 10% for both Beijing and New York. This confirms that the creation of “typical year” weather data is not very sensitive to the weighting of the different weather parameters, and that most nTMYs created and evaluated in this study are empirically close to the TMY data intended for use of simulating building energy consumption.     

Mechanisms of large-scale landslides in China

Large-scale landslides in western China are famous for their size, complex formation mechanism and serious destruction. Data were collected from some typical large-scale landslides in mainland China in the 20th century. A number of geo-mechanical models have been identified: the “three sections” model (sliding; tension cracking; shearing), “retaining wall collapse”, “horizontal-pushing” in horizontal strata; large-scale toppling in counter-inclined strata; the creep-bending–shearing model etc. Large-scale rock landslides are generally accompanied by sudden brittle failure of the “locking section” along the potential sliding surface. The paper discusses the importance of this “locking section” which is key to assessing slope geohazard and to the development of control/mitigation measures.     

Product development, innovation networks, infrastructure and agglomeration economies

The continuos inflow of new products is a fundamental condition for a well-functioning market economy. It has been argued that new products are the outcome of a process which is based upon the principle “novelty by combination”. This characterization applies well to the type of product development analyzed in this paper, which comprises the development of new products and the renewal of old products in the Swedish engineering industry through the adoption of a specific type of innovation, namely the incorporation of information technology based components and their pertinent software, i.e. microelectronics. According to the theoretical perspective presented in the paper, a new or a renewed product may result from “random collisions” or from a cautious matching between technical opportunities and customer needs. A necessary condition for such “collisions” or matching to occur is communication and, hence, communication in innovation networks is one key factor in product development. The empirical part of the paper contains an empirical test of the role of establishment characteristics, innovation networks, infrastructure endowment and agglomeration economies for the first use of micro-electronics in product development at the plant level. The empirical results seem to confirm the importance of innovation networks as well as of infrastructure endowment and agglomeration economies for an early use of micro-electronics in product development. Received: October 1994 / Accepted in revised form: November 1996     

Overheating in English dwellings: comparing modelled and monitored large-scale datasets

ABSTRACT

Monitoring and modelling studies of the indoor environment indicate that there are often discrepancies between simulation results and measurements. The availability of large monitoring datasets of domestic buildings allows for more rigorous validation of the performance of building simulation models derived from limited building information, backed by statistical significance tests and goodness-of-fit metrics. These datasets also offer the opportunity to test modelling assumptions. This paper investigates the performance of domestic housing models using EnergyPlus software to predict maximum daily indoor temperatures over the summer of 2011. Monitored maximum daily indoor temperatures from the English Housing Survey’s (EHS) Energy Follow-Up Survey (EFUS) for 823 nationally representative dwellings are compared against predictions made by EnergyPlus simulations. Due to lack of information on the characteristics of individual dwellings, the models struggle to predict maximum temperatures in individual dwellings and performance was worse on days when the outdoor maximum temperatures were high. This research indicates that unknown factors such as building characteristics, occupant behaviour and local environment makes the validation of models for individual dwellings a challenging task. The models did, however, provide an improved estimate of temperature exposure when aggregated over dwellings within a particular region.     

A design method for seepage barriers with allowance for the initial filtration gradient

A method is presented for calculation of the basic parameters of an anti-seepage “wall” with allowance for the initial filtration gradient of the filler material. The case of plane-radial seepage through a contour “wall” of the perfect and imperfect type, which is constructed by various modifications of the “wall-in-the-ground” method and using kinematic jet energy, is discussed. Computational analytical relationships and working equations for a number of special cases are derived in general form for the schemes under consideration. A software package, which makes it possible to make a rational projection of structural parameters of the “wall” and determine the position of the depression curve ahead of the “wall,” is developed. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, Nos. 4–5, pp. 37–42, July–October, 1998.