×
The submission system is temporarily under maintenance. Please send your manuscripts to
Go to Editorial ManagerThe heat exchanger is a device used to transfer heat energy between two fluids, hot and cold. In this work, an output feedback adaptive sliding mode controller is designed to control the temperature of the outlet cold water for plate heat exchanger. The discontinuous gain value of the sliding mode controller is adapted according to a certain adaptation law, where the only information required is the measurement of the outlet cold temperature. A sliding mode differentiator was design to estimate time derivative of outlet hot water temperature. Two constraints which imposed on the volumetric flow rate of the hot water (control input) were considered within the rules of the proposed adaptation law in this work. These are the control input is positive only and has a maximum value. For constructing the sliding variable, the outlet hot water temperature and its time derivative are required. The maximum allowable desired outlet cold water has been estimated as function of heat exchanger parameters and maximum control input. The simulation results demonstrate the performance of the proposed adaptive sliding mode control where the outlet cold water was forced to follow desired temperature equal to . Additionally, the robustness of the proposed controller was tested for the case where the cold inlet temperature is not constant. The results reveal the robustness of the proposed controller.
In recent decades, many factors have emerged in the building design field, as the technology development after the industrial revolution has left many environmental problems affecting building environments and turning them into unhealthy ones. Also, the issues of consuming natural resources required innovative and modern solutions to address, which needed the guidance and focus of researchers, engineers, and many other relevant disciplines to find the best treatments to solve them. One of the essential treatments was using advanced smart technology to solve the environmental problems of buildings, such as providing thermal comfort and reducing energy consumption. The concept of adaptive smart envelopes is one of this manifestation of advanced technology in the field of building design characterized by interaction and adaptation to the surrounding environment through the application of many technologies which it works to improve its environmental efficiency. The research aim was to simulate the changes in the building environment, which is treated by covering the building with an adaptive smart envelope by using the Rhinoceros Grasshopper programme.
Contemporary urban discourse is paying increasing attention to the issue of urban resilience, due to the stresses, disasters and disturbances (natural and human) that the cities of the world are experiencing and facing, which confirms the need to be familiar with the concept of urban resilience, its dimensions, practices, and characteristics at different levels; In order to reach the aspects of developing the urban energy sector in them, and in a way that supports the preparedness of cities to face potential expected and unexpected disturbances in the future, as cities are usually formed from many main and sub-systems that are dynamically intertwined with each other, such as: the social and economic system, infrastructure systems, land use, and media Various transports, which have a high level of direct interactions with the natural environment; ; It is therefore necessary to understand how the city deals with the odds of threats and challenges in an integrated manner; To overcome its weaknesses and enhance its resilience of use, which aims to make cities more secure, resilient and sustainable in the future, as well as that requires rethinking the field of expanding the use of renewable energies and the general urban landscape. To become a search problem “Failure to exploit the potential of natural energies on the possibility of exploiting renewable natural energies with their components (active and passive) in the production of resilience urban formations in cities.” The aim of the research is to try to "extract an integrated theoretical framework on the characteristics of urban energy resilience from international and Arab experiences, and to diagnose its most important planning and design pillars and indicators, which can be adopted to evaluate the reality of urban energy resilience in local cities." The research hypothesized that “the exploitation of energy systems produced from renewable natural resources, for the purposes of environmental treatments for resilient cities, especially in the buildings of housing projects and their urban surroundings, reduces the consumption of fossil energies for the city, frees its sites from linking to depleted energy transmission networks, and reduces potential environmental pollution problems, which contributes to in the production of flexible energy systems and helps in the generation of flexible cities." The descriptive analysis method was adopted.