Jooseng (Gavin) Gui

Bio: Jooseng (Gavin) Gui is an academic researcher from Arizona State University. The author has contributed to research in topics: Emissivity & Volumetric heat capacity. The author has an hindex of 2, co-authored 2 publications receiving 213 citations.

Impact of Pavement Thermophysical Properties on Surface Temperatures

Abstract: A one-dimensional mathematical model was developed, based on the fundamental energy balance, to calculate the pavement near-surface temperatures using hourly measured solar radiation, air temperature, dew-point temperature, and wind velocity data. An analysis was conducted to predict the diurnal temperature effects of pavement thermophysical properties with the aim of seeking an optimum composition of paving materials for future infrastructure projects. Appropriate paving materials not only ensure stability and safety for road users, but also the ability to mitigate heat absorption and high surface temperatures contributing to the Urban Heat Island Effect and human comfort. This paper evaluated the effects and sensitivities of the thermophysical properties on the pavement surface temperatures. The results indicated that both albedo and emissivity have the highest positive effects on pavement maximum and minimum temperatures, respectively, while increasing the thermal conductivity, diffusivity, and volumetric heat capacity help in mitigating the maximum but not the minimum pavement near-surface temperature.

Impact of Pavement Thickness on Surface Diurnal Temperatures

Abstract: Simulations of pavement surface temperature were carried out using a one-dimensional mathematical model developed previously based on a fundamental energy balance. By altering the parameters input to the model, an analysis was conducted to study the effects on the diurnal pavement temperatures caused by varying paving material and thicknesses. Such study offers an understanding of the optimum thicknesses for the materials to yield cooler surface temperatures by reducing heat absorption. This model can assist in determining appropriate mitigation strategies for the Urban Heat Island effect and human discomfort. The results indicated that there exists a critical layer thickness at which the maximum surface temperature is minimized. Further increase beyond the critical thickness results in adverse maximum and minimum surface temperatures. The study also shows that high albedo concrete cement surfaces have cooler surface temperatures as compared to lower-albedo asphalt-based surface pavements.

Using cool pavements as a mitigation strategy to fight urban heat island—A review of the actual developments

Abstract: Heat island phenomenon rises the temperature of cities, increases the energy demand for cooling and deteriorates comfort conditions in the urban environment. To counterbalance the impact of the phenomenon, important mitigation techniques have been proposed and developed. Pavements present a very high fraction of the urban areas and contribute highly to the development of heat island in cities. The use of cool pavements presenting substantially lower surface temperature and reduced sensible heat flux to the atmosphere, appears to be one of the most important proposed mitigation solutions. The present paper investigates and describes the actual state of the art on the field of cool pavements. The main thermal and optical parameters defining the thermal performance of pavements are analyzed. Almost all of the developed technologies, where data and results are available, are considered while emphasis is given on the presentation of reflective and permeable/water retentive pavements. The main technological achievements on both fields are reviewed while existing applications are described and performance data are given when available. The existing results clearly show that the mitigation and cooling potential of cool pavements is very significant and can highly contribute to decrease temperature on the urban environment.

A review of urban energy system models: Approaches, challenges and opportunities

Abstract: Energy use in cities has attracted significant research in recent years. However such a broad topic inevitably results in number of alternative interpretations of the problem domain and the modelling tools used in its study. This paper seeks to pull together these strands by proposing a theoretical definition of an urban energy system model and then evaluating the state of current practice. Drawing on a review of 219 papers, five key areas of practice were identified – technology design, building design, urban climate, systems design, and policy assessment – each with distinct and incomplete interpretations of the problem domain. We also highlight a sixth field, land use and transportation modelling, which has direct relevance to the use of energy in cities but has been somewhat overlooked by the literature to date. Despite their diversity, these approaches to urban energy system modelling share four common challenges in understanding model complexity, data quality and uncertainty, model integration, and policy relevance. We then examine the opportunities for improving current practice in urban energy systems modelling, focusing on the potential of sensitivity analysis and cloud computing, data collection and integration techniques, and the use of activity-based modelling as an integrating framework. The results indicate that there is significant potential for urban energy systems modelling to move beyond single disciplinary approaches towards a sophisticated integrated perspective that more fully captures the theoretical intricacy of urban energy systems.

A review on hydronic asphalt pavement for energy harvesting and snow melting

Abstract: Solar energy is undoubtedly the environment friendly and inexhaustible energy resource for humans. The concept of hydronic asphalt pavement (HAP) is an emerging renewable energy technology, which provides an interesting method for solar energy utilization. The innovation of HAP is to mitigate a series of realistic problems related to the asphalt pavement as well as the depletion of fossil energy resource. Fluid circulating through the pipes network imbedded in the asphalt pavement can capture the solar energy and store for later use. This paper summaries the major achievements of the existing literatures about the HAP and gives some proposals for further investigations. Studies have confirmed the feasibility of harvesting solar energy, cooling the pavement, snow melting/deicing as well as air conditioning of buildings by applying innovation technologies on asphalt pavement. As seasonal energy storage technology is relatively mature at present, most of the literatures reviews focus on the influences of variables associated with system behavior as well as the heat transfer processes during snow melting and solar energy collection. Future work should aim to do more urgent issues involved with HAP application: construction technology, maintenance technology, and long-term performance. Solving these problems can strengthen the theoretical and practical understanding of HAP, and lead to more extensive applications.

On the Use of Cool Materials as a Heat Island Mitigation Strategy

Abstract: The mitigation of the heat island effect can be achieved by the use of cool materials that are characterized by high solar reflectance and infrared emittance values. Several types of cool materials have been tested and their optical and thermal properties reveal that these materials can be classified as “cool” with the ability to maintain lower surface temperatures. Cool materials can be used on buildings and other surfaces of the urban environment. Based on these results, a modeling study was undertaken to assess the urban heat island effect over Athens, Greece, a densely populated city, by trying to analyze the impacts of large-scale increases in surface albedo on ambient temperature. Numerical simulations were performed by the “urbanized” version of the nonhydrostatic fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5, version 3-6-1). Two scenarios of modified albedo were studied: a moderate and an extreme increase in albedo scenario. It was found that large-scale increas...