Performance evaluation and optimal design of supermarket refrigeration systems with supermarket model "SuperSim", Part I: Model description and validation

This is the post-print version of the final paper published in International Journal of Refrigeration. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.Conventional supermarket refrigeration systems are responsible for considerable CO2 emissions due to high energy consumption and large quantities of refrigerant leakage. In the effort to conserve energy and reduce environmental impacts, an efficient design tool for the analysis, evaluation and comparison of the performance of alternative system designs and controls is required. This paper provides a description of the modelling procedure employed in the supermarket simulation model ‘SuperSim’ for the simulation of the performance of centralised vapour compression refrigeration systems and their interaction with the building envelope and HVAC systems. The model which has been validated against data from a supermarket has been used for the comparison of R404A and CO2 refrigeration systems and the optimisation of the performance of transcritical CO2 systems. These results are presented in Part II of the paper.DEFR

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Vapor compression systems are the most widely used system type in heating, ventilation, air-conditioning, and refrigeration (HVAC&R) applications. Experimental and numerical modeling techniques are used to analyze the performance of the vapor compression systems. With the introduction of high-performance computers, numerical modeling techniques are used extensively to develop cost-effective and efficient HVAC&R equipment. Experimental iterations on the design of vapor compression systems are costly; however, numerical techniques can reduce the number of experimental iterations, substantially decreasing the development cost and time. Because of the benefits associated with the numerical simulation, many researchers working in the HVAC&R field have attempted to develop efficient, robust, and accurate simulation models. This paper provides an in-depth review of heat exchanger modeling techniques as well as integration strategies to develop holistic system models

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Lee Kuan Yew (LKY) negarawan unggul Asia Tenggara yang berjaya menggerakkan tindakan-tindakan pragmatik dengan nilai dan gaya kepimpinan berkesan demi mencapai visi pembangunan Singapura. Memiliki pengalaman politik hampir 60 tahun (1955-2011) menjadikan beliau tokoh politik tanpa tandingan di Singapura dan di Asia Tenggara. Kredibiliti kepimpinannya berjaya membawa masyarakat Singapura berkembang maju dari satu tahap ke satu tahap yang lain. Walaupun meletakkan jawatan sebagai Perdana Menteri pada tahun 1990 namun masih terus relevan di arena politik perdana Singapura apabila dilantik sebagai Menteri Kanan (1990-2004) dan Menteri Mentor (2004-2011). Beliau membimbing Singapura pada sebelum dan selepas Singapura dipisahkan daripada Persekutuan Malaysia (1963-1965). Konsep Malaysian Malaysia nya sangat meresahkan dan menjadi penyebab utama Singapura akhirnya perlu membina negara sendiri. Walau bagaimanapun gagasan Malaysian Malaysia telah bertukar menjadi resipi paling ampuh dalam mengurus masyarakat majmuk di Singapura yang merdeka. Sekali gus membentuk gaya kepimpinannya tersendiri. Penulisan ini cuba melihat sepintas lalu legasi LKY dalam mengurus masyarakat majmuk di Singapura. Secara umumnya, masyarakat majmuk akan menghasilkan pelbagai tuntutan dan perjuangan khususnya terhadap hak dan ketuanan. Persoalan sensitif ini berjaya diuruskan LKY dengan gayanya tersendiri. Pendirian asas LKY, dasar keselamatan, dasar pendidikan dwibahasa, sistem politik, sistem demokrasi, konsep “peluang sama rata”, patriotisme dan pembangunan bangsa Singapura, kepercayaan dan pengurusan agama, ekonomi dan modal insan dan nilai Asia akan dibincangkan satu persatu. Adalah diharapkan satu pengkayaan pengetahuan baru berkaitan pengalaman mengurus sebuah masyarakat dan negara khususnya di Asia Tenggara terhasil bagi tujuan rujukan pada masa akan datang