Business success through process based application of simulation

Progressive design practices are increasingly cognisant of the potential of building energy simulation to assist the delivery of energy efficient, sustainable buildings. However, the success of any building performance assessment hinges on the capabilities of the tool; the collective competences of the team formed to apply it; and, crucially, the existence of an in-house framework within which simulation can be applied with confidence (McElroy and Clarke 1999). There is also a need for the professions to set up mechanisms that facilitate dialogue with vendors in order to influence tool capabilities. And on the related issues of building an in-house competency and a framework for application, the two core issues facing the professions are: i) a need for the development of in-house procedures for management of simulation; and ii) quality assurance of the related models and appraisal results

Heat transfer and air flow in buildings

Summary available: p.xi

Complex energy simlulation using simplified user interaction mechanisms

Simulation of energy systems and associated thermodynamic domains is very powerful in delivering precise information at high resolution. Modelling software requires detailed information about the energy system. The specialised user usually has questions about specific aspects of the energy system and may not be interested in the complete set of outputs available from simulation results. Similarly the specialised user may only be concerned about a subset of the inputs provided to the software. This suggests an opportunity to develop an input / output scheme tailored for the specialised user. The power of simulation can be accessed through the use of simplified interfaces. Although these restrict flexibility in terms of model input / output data the specialised user is only interested in a subset of the capability of the underlying simulation tool. Robust results rely on a consistent underlying simulation context, this restricted interface ensures that only the parameters of interest to the users are modifiable and that other simulation parameters remain fixed ensuring a consistent and repeatable output. One such example of limited user interaction for both output and input is the ADEPT interface to whole building and plant dynamic modelling and simulation suite ESP­r (ESRU 2002). The interface was developed in the context of the UK domesticheating market. This paper describes the development of the ADEPT tool and associated spreadsheet templates in order to provide a readily usable platform for the study of domestic heating systems and controls for plant and control components manufacturers, regulatory authorities and research organisations

Development and validation of detailed building, plant and controller modelling to demonstrate interactive behaviour of system components

As plant modelling becomes capable of more complexity and detailed resolution, new opportunities arise for the virtual evaluation of discrete plant components such as flow control and energy conversion devices, and controllers. Such objects are conventionally developed and tested at the prototype stage in a laboratory environment. Designers now seek to use modelling technology to extend their understanding from limited laboratory test results to full building and plant system analysis. This paper describes the development of a modelling system, using ESP-r, for typical United Kingdom domestic house types with hydronic gas or oil fired central heating including radiator and underfloor heating systems, and with a variety of conventional or advanced control types. It demonstrates the ability of detailed building and plant modelling to reveal unexpected insights into how real control systems perform in combination with other plant items and in different building types, including estimation of their influence on annual energy consumption. Comparisons with measurements taken in test rooms confirm that the observed behaviour of controls is realised in practice. The authors conclude that the complex dynamic interactions that take place between the various elements that make up a real building energy system have an important influence on its overall energy performance, revealing causes of variance that cannot be identified by laboratory testing alone, or by simplistic energy assessment tools

A Phase III Trial of Tirasemtiv as a Potential Treatment for Amyotrophic Lateral Sclerosis

Objective: To assess the efficacy of tirasemtiv, a fast skeletal muscle troponin activator, vs. placebo in patients with amyotrophic lateral sclerosis. Methods: VITALITY-ALS (NCT02496767) was a multinational, double-blind, randomized, placebo-controlled clinical trial. Participants tolerating 2 weeks of open-label tirasemtiv (125 mg twice daily) were randomized 3:2:2:2 to placebo or one of three target tirasemtiv dose levels, using an escalating dosage protocol lasting 28 days. The primary outcome measure was changed in slow vital capacity (SVC) at 24 weeks. Secondary endpoints included a change in muscle strength and time to respiratory milestones of disease progression. Results: Of 744 participants, 565 tolerated open-label tirasemtiv and received randomized treatment. By 24 weeks, 23 (12.2%) placebo-treated participants discontinued study treatment vs. 129 (34.2%) randomized to tirasemtiv. SVC declined by 14.4% (95% CI: ˆ’16.8, ˆ’11.9) in the placebo group and 13.4% (95% CI: ˆ’15.3, ˆ’11.6) in the tirasemtiv group (p = 0.56). Secondary endpoints did not show significant differences. However, participants who tolerated tirasemtiv at their randomized dose showed a numeric trend toward a dose-related slowing of decline in SVC (p = 0.11). Dizziness, fatigue, nausea, weight loss, and insomnia occurred more frequently on tirasemtiv. Serious adverse events were similar across groups. Conclusions: Tirasemtiv did not alter the decline of SVC or significantly impact secondary outcome measures. Poor tolerability of tirasemtiv may have contributed to this result. However, participants tolerating their intended dose exhibited a trend toward treatment benefit on SVC, suggesting the underlying mechanism of action may still hold promise, as is being tested with a different fast skeletal muscle troponin activator (NCT03160898)

A Phase 2, Double-Blind, Randomized, Dose-Ranging Trial Of Reldesemtiv In Patients With ALS

To evaluate safety, dose response, and preliminary efficacy of reldesemtiv over 12 weeks in patients with amyotrophic lateral sclerosis (ALS). Methods: Patients (≤2 years since diagnosis) with slow upright vital capacity (SVC) of ≥60% were randomized 1:1:1:1 to reldesemtiv 150, 300, or 450 mg twice daily (bid) or placebo; active treatment was 12 weeks with 4-week follow-up. Primary endpoint was change in percent predicted SVC at 12 weeks; secondary measures included ALS Functional Rating Scale-Revised (ALSFRS-R) and muscle strength mega-score. Results: Patients (N = 458) were enrolled; 85% completed 12-week treatment. The primary analysis failed to reach statistical significance (p = 0.11); secondary endpoints showed no statistically significant effects (ALSFRS-R, p = 0.09; muscle strength mega-score, p = 0.31). Post hoc analyses pooling all active reldesemtiv-treated patients compared against placebo showed trends toward benefit in all endpoints (progression rate for SVC, ALSFRS-R, and muscle strength mega-score (nominal p values of 0.10, 0.01 and 0.20 respectively)). Reldesemtiv was well tolerated, with nausea and fatigue being the most common side effects. A dose-dependent decrease in estimated glomerular filtration rate was noted, and transaminase elevations were seen in approximately 5% of patients. Both hepatic and renal abnormalities trended toward resolution after study drug discontinuation. Conclusions: Although the primary efficacy analysis did not demonstrate statistical significance, there were trends favoring reldesemtiv for all three endpoints, with effect sizes generally regarded as clinically important. Tolerability was good; modest hepatic and renal abnormalities were reversible. The impact of reldesemtiv on patients with ALS should be assessed in a pivotal Phase 3 trial. (ClinicalTrials.gov Identifier: NCT03160898)

Ventilation of an enclosure through a single opening

Building ventilation is affected not only by the steady mean effect of air pressures and temperatures around and within the building, but also by the turbulent nature of wind causing a diffusion of air through openings and cracks in the building envelope. The ventilation of an enclosure with a single opening subjected to a turbulent impinging airstream is studied and simple theoretical models are derived to assist in understanding the physical phenomena causing airflow through the opening. These are compared with the results of experiments on a large scale model. The need for further work on this problem is stated

On the high resolution simulation of building/plant systems

Traditional modelling approaches have treated building and plant systems as existing in distinct domains, with quasi-steady state assumptions typically applied on the plant side. This paper discusses the benefits of treating the building/plant system as a single, integrated, high-resolution domain thereby adding plant-side thermal mass within the building and enabling the application of key physical process models that are already available for building models to plant components - such as explicit radiation exchange and fluid movement modelling. The approach taken is to establish a high-resolution building/plant model suitable for simulation by the ESP-r program in order to illustrate the performance appraisals then enabled. By applying simplifications that represent modelling approaches as generally practiced, the paper draws attention to the benefits of the unified, highresolution approach. The contention is that tool users need to demand better support for high-resolution building modelling, while tool developers need to agree mechnisms to provide this support. The paper concludes by briefly discussing the implications of high-resolution modelling for future extension of the building information model to support life cycle performance appraisal, and for the maintenance of compatibility with the design process given the increased computational burden