Design tool

About: Design tool is a research topic. Over the lifetime, 3864 publications have been published within this topic receiving 46401 citations.

General shading model for solar building design

Abstract: This paper describes a general principle for accurate calculation of the effect of shading objects on surfaces exposed to direct solar radiation. The principle used is known as polygon clipping, a technique for determining every subpolygon that arises when two or more polygons overlap one another. In this case, the obstructing objects are approximated by polygons in space, projected as seen from the sun, at any given time of the year, onto the exposed surface of interest, so that every sunlit region and the fully or partly shaded regions of the plane surface can be determined. The technique has been implemented in a PC software application, which can function as a stand-alone design tool or may be integrated with programs for thermal simulation of buildings or solar systems. The paper gives examples of the use of application, shows its functionality when integrated with a thermal simulation tool, and presents comparative validations against the standard ASHRAE algorithms for calculations of overhangs and side fins.

Cognitive Modelling For Engineers

Abstract: Computer modelling software endeavours to generate technically accurate and sometimes photo-realistic models of design intent. A significant time investment is devoted to becoming proficient in the use of one or more CAD software and other modelling packages, in the design, production and modification of products for design and manufacture. The creative use of CAD software, depends greatly on the users cognitive ability to visualise the design intent and to interact with the developing model of the product. The research shows that cognitive modelling capacity is not an innate skill of the engineer but that it can be developed by appropriate intervention strategies. At the University of Limerick, interactive tutorial software has been developed to improve the users spatial modelling capacity. It works in tandem with other intervention strategies. The results show significant improvements in the users spatial ability and visualisation skills - resulting in greater creativity and more productive use of CAD modelling systems as a design tool. Improved cognitive modelling skills, enables the engineer to perform on a higher creative plane in most areas of engineering activity.

Investigation and development of advanced models of thermoelectric generators for power generation applications

Abstract: With developing interest in power generation applications of thermoelectrics and the growing influence of advanced materials on thermoelectric device fabrication, there is an increased demand for better understanding of module-level behavior. Likewise, novel module geometries are being explored for higher performance and require sophisticated modeling methods. In addition to new geometrical design, transport phenomena, such as Thomson heating and contact resistances, aggravate the complexity of modeling thermoelectric modules (TEMs) and thus limit design capability. Typically, these effects are either approximated (or in some cases neglected entirely) with little exploration in to the validity of the underlying assumptions associated with the approximation. As such, standard models are often predicated on assumptions that cannot be made beyond very limited operating regimes. Consequently, most TEM analysis generally utilizes simplistic methods of modeling on a module-level scale, which introduce inaccuracies that must be redressed. Particularly with larger temperature gradients, typically negligible effects could begin to impact overall system performance. Material property temperature-dependency, combined with leakage effects, leave much to be desired of the simple property-average-based models. Additionally, one-dimensional (1-D) models neglect the contribution of three-dimensional (3-D) module facets that can significantly impact TEM performance. To compound the analytical issue, complex material technologies are emerging that will require robust models for module design. With burgeoning focus in using thermoelectrics for waste heat recovery in automobiles, industrial processes and power plants, new application and commercial development of high temperature TEMs is imminent. However, modeling design and optimization of TEMs has been piecemeal at best. Hence, it is imperative that a comprehensive model be developed for TEMs that addresses some of the analytical problems stemming from over-simplification. The primary intention of this work is to develop and validate a comprehensive model that can be used as a TEM design tool and to quantify the error in the simple 1-D analytical models. The scope of this work is multifaceted. First, several models are developed, implemented and compared to each other as design tools that are useful for determining material performance and also for optimizing TEM performance. An improved 1-D analytical model, a unique asymptotic model and a comprehensive 3-D finite element (FE) model are created and established. These models are compared to each other for both validation and for quantification of error in the analytical models. Secondly, the quantification of error in 1-D analytical models based on module parameters, called error mapping, can be used as a design tool in and of itself to either identify regimes where a 1-D model is inaccurate (and thus establish when 3-D FE modeling is required), or as a corrective factor to a 1-D model. Thirdly, an experimental test stand is developed for device characterization, to be used either for system-level integration or for future model validation. Finally, the Thomson effect is analytically explored and detailed, and its contribution to the overall performance of a TEM is quantified. The role of the Thomson effect in previous analyitical models is nebulous, but has been elucidated in this thesis both with derivation and the development of the asymptotic model, which is the first analytical solution to the non-linear thermoelectric governing equations. Ultimately, this thesis defines the advantages and limitations of current TEM models, quantifies their error and provides several new design tools that can be used for material selection, module optimization and system-level design. These new design tools will provide new leverage to advance thermoelectrics as a robust power generation technology at a time when such capability is critical.

Exploring sketch beautification techniques

Abstract: Beautification of vague, imprecise sketchy ink input is an interesting area for exploration, especially with the emergence of pen-based systems, such as the Tablet PC. Fifty percent of the total time spent creating drawings on a computer is on formalisation operations [3], why waste this time when the same result is achievable via recognition and beautification techniques? We examined beautification and its value in supporting the design process by prototyping a design tool incorporating several beautification techniques. The following is a description of the design, construction and evaluation of our grid based design environment.