Refrigerant R134a has been widely utilized in automotive air conditioning systems (AACSs); R134a has a high global warming potential (GWP) of 1430 despite having zero ozone depletion potential (ODP). Coming refrigeration systems must include refrigerants with low GWP and zero ODP. The aim of this experimental study is to evaluate the thermal performance of an (AAC) with different values of compressor speeds, i.e., (1000, 1700, and 2400 rpm) and two thermal loads, i.e., (500 and 1000 Watt) with the absence and presence of liquid suction heat exchanger (LSHX) using R134a. The results showed that adding LSHX enhanced the COP cycle by 7.18%, 10.7%, and 3.09% for the first, second, and third speed, respectively, at 500 Watt, while the enhancements were 10.27 %, 23.3 %, and 11.5 % for the first, second, and third speed, respectively, at 1000 Watt. Increasing the compressor speed decreased COP due to a reduction in RE and increased the compression effect, increasing the work done by the motor on the compressor that caused a reduction in COP. The compressor exergy destruction (X des. Comp.) decreased when LSHX was added by 6.13%, 2.22%, and 18.8% for the first, second, and third speed, respectively. However, X des. comp. increased with compressor speed due to the system’s pressure difference rise because of decreasing evaporation and increasing condensation pressures. As a result, the entropy generation increased. The increase in discharge temperature and pressure of the compressor led to a high friction force between the moving part of the compressor and the refrigerant, so the energy losses increased. Increasing the compressor speed decreased the total exergy performance of the cycle by 5.8 %, 7.5 %, and 16.7 % for the first, second, and third speed, respectively, due to increasing the compressor discharge temperature, increasing the X des. comp. and thermostatic expansion device and decreasing condenser and evaporator. Increasing X des. comp was higher than the destruction in the condenser and evaporator, which canceled the effect of others, so the total exergy performance of the cycle decreased.
Abstract
The current research problem includes a variety of research motivations to serve the private health sector, which is witnessing a great competition from internal and external environments. In this regard, private medical clinics are increasingly seeking to attract and retain customers through the quality of their service offerings represented by health services. Innovative and effective marketing methods to improve performance and stay in competition, by relying on the physical evidence of the product as a component of the marketing mix of services and its role in particular in packaging and supporting the health service with concrete evidence that affects the customer an
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The research aimed to test the relationship between the size of investment allocations in the agricultural sector in Iraq and their determinants using the Ordinary Least Squares (OLS) method compared to the Error Correction Model (ECM) approach. The time series data for the period from 1990 to 2021 was utilized. The analysis showed that the estimates obtained using the ECM were more accurate and significant than those obtained using the OLS method. Johansen's test indicated the presence of a long-term equilibrium relationship between the size of investment allocations and their determinants. The results of th
... Show MoreNumerical simulations have been carried out on the solar chimney power plant systems. This paper gives the flow field analysis for a solar chimney power generation project located in Baghdad. The continuity, Naver-stockes, energy and radiation transfer equations have been solved and carried out by Fluent software. The governing equations are solved for incompressible, 3-D, steady state, turbulent is approximated by a standard k - model with Boussiuesq approximation to study and evaluate the performance of solar chimney power plant in Baghdad city of Iraq. The different geometric parameters of project are assumed such as collector diameter and chimney height at different working conditions of solar radiation intensity (300,450,600,750
... Show MoreThis study aims to propose a novel research model to test the nexus between green human resource management processes, strategic excellence and the sustainability of educational institutions in Iraqi academic settings.
This examination in Iraqi higher education is finalised across three key stages: determining the knowledge gaps, reviewing the literature and building the hypothesised conceptual model. A case study complemented by a quantitative methodology using Statistical Package for the Social Sciences (SPSS) and Analysis of Moment
The developments accelerated in technology and rapid changes in the environment and increase numbers industrial countries and different desires and requirements of customers, lead to be produced in large quantities is not feasible due to changes listed above as well as the need to product variety and change in tastes and desires of consumers, all above led not to enable companies to discharge their products in the case of mass production and created the need to devise ways and new methods fit with the current situation, and accounting point no longer the traditional accounting systems able to meet the requirements needed by the companies to make decisions and know where waste and loss of resources resulting to invent new style away from
... Show MoreBetween the duality of sound and image, the completeness of the actor’s personality at the director comes to announce the birth of the appropriate theatrical role for that character as the basic and inherent element of the artwork, within his working system in the pattern of vocal behavior as well as motor/signal behavior as he searches for aesthetic and skill proficiency at the same time.
This is done through the viewer’s relationship with the theatrical event, which the director considers as an area of active creative activity in relation to (the work of the actor) through vocal recitation and the signs it broadcasts in order to fulfill the requirements of the dramatic situation and what it requires of a visual vision drawn in t
The research aims to identify and diagnose the public relations strategies in its digital online communications by the United Nations High Commissioner for Refugees (UNHCR) in managing the crisis of Iraqi refugees in Turkey. A content analysis form was designed for the digital content of the UNHCR's website dedicated to topics and issues concerning Iraqi refugees that were covered by the site, adopting a comprehensive enumeration approach. The study covered the period from 01/03/2022, to 30/06/2022. The research yielded several key findings, including the predominant use of media, advertising, and education strategies in managing the crisis of Iraqi refugees in Turkey. News and reports ranked first among the media
... Show MoreThe theory of the psychologist’s Piaget states that man passes through four stages; other says that mankind passes through five. At each stage, human learn new characteristics, values, skills, and cultures from different environment that differ from one society to another. Therefore, the cultures of societies vary according to the diversity of the environments. These environments also vary depending on the circumstances surrounding them, e.g., in war environment, the individual learns what he does not learn from living in safe environment. As the environment changes, the communicative message also changes. This message is subject to person, groups, organizations and parties and directed to a diverse audience in its orientations and bel
... Show MoreNeuro-ophthalmology, bridging neurology and ophthalmology, highlights the nervous system’s crucial role in vision, encompassing afferent and efferent pathways. The evolution of this field has emphasized the importance of neuroanatomy for precise surgical interventions, presenting educational challenges in blending complex anatomical knowledge with surgical skills. This review examines the interplay between neuroanatomy and surgical practices in neuro-ophthalmology, aiming to identify educational gaps and suggest improvements.
A literature search across databases such as PubMed, Scopus, and W