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"The Brundtland Report (also known as Our Common Future) has placed sustainability of energy resources and environmental degradation on a common global agenda. Increasing awareness has spurred much research into alternative clean energy technologies. Thermoacoustic cooling as an environmentally friendly refrigeration system is one of the research areas being pursued. Although not commercially available, successful systems have been completed. There are, however, still many fundamental issues related to the thermoacoustic effects and the associated heat transfer that must be addressed. This paper reports a portable counter-top thermoacoustic cooling apparatus designed and fabricated at the Universiti Teknologi Malaysia (UTM). Based on a standing wave resonator tube, the system with a pvc resonator tube of 60 mm diameter which was initially at 24o C, accomplished cooling effects under a minute, up to 18.5o C, without the use of chlrofluorocarbons (CFCs) or other similar refrigerants which have been known to be hazardaous to our living environment. Another acrylic 110 mm diameter tube once recorded 8o C with the ambient held at 23o C. The cooling in the first system was repeatable but not significant enough for practical applications. However, with no refrigerants used and its relatively simple manufacturing, a thermoacoustic cooling system is a potentially clean cooling system to be further investigated for practical or specific applications."

"Tulisan dan penelitian ini dilakukan untuk melakukan perbandingan performa dari chiller dengan refrigerant R290 saat sebelum dan sesudah menggunakan sub-cooler/heat exchanger. Sehingga dapat memberikan perkiraan seberapa besar dampak penggunaan sub-cooler pada performa chiller. Penelitian ini dilakukan dalam rangka membantu pengembangan pemakaian chiller hidrokarbon di Indonesia, dimana minatnya sudah cukup tinggi dengan sifatnya refrigerant yang ramah lingkungan serta memiliki performa pendinginan yang lebih tinggi dari chiller dengan refrigerant R22 yang saat ini banyak digunakan. Melalui riset ini ditemukan bahwa penggunaan Sub-Cooler memberikan dampak kenaikan performa sebesar 6.9% pada beban pendinginan sedang, namun tidak memberikan perubahan signifikan pada performa saat beban pendinginan rendah.

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The purpose of this research is to compare the performance of R290 hidrocarbon Chiller with sub-cooler and without sub-cooler, so that could give an estimation on how significant the impact made by sub-cooler in increasing chiller performance. This research also intended to helps the development of hydrocarbon chiller in Indonesia, which it's environmentally friendly and have higher performance than chiller with R22 as it's refrigerant. By doing this research, it was found that the use of sub-cooler when using it on medium cooling load operation could increase performance by 6.9%, but did not have significant effect in performance when using it on low cooling load operation."

"Masalah pokok pengembangan energi mencakup kebutuhan energi, keterbatasan modal dan teknologi, keterbatasan tenaga terampil bangsa Indonesia di bidang energi, serta pemasaran dan keterkaitan harga minyak bumi dengan energi lainnya seperti gas bumi, panas bumi dan batubara. Tujuan penelitian ini adalah untuk menganalisis berbagai jenis energi untuk memenuhi kebutuhan energi dalam menunjang pembangunan nasional menjelang tahun 2000 dan menentukan strategi nasional di bidang energi. Penelitian ini menggunakan metode kajian literatur dan analisis data sekunder dari sumber-sumber yang relevan. dalam hubungannya dengan ketahanan nasional digunakan kajian antar gatra yang terkait dengan pengembangan energi dimaksud."

"Cooling towers are required in building HVAC systems that use water as the cooling condenser fluid. Cooling towers used in this study are of the forced draft, counter flow, indirect/closed evaporative type. This study sought to demonstrate the performance characteristics of a closed system cooling tower by its effectiveness value, Number of Transfer Units (NTU), cooling capacity, and overall heat transfer and mass coefficient of the cooling tower. Experiments were performed on a heat exchanger coil intercrossed with ? inch diameter intersections on parallel lines. Results of the experiment were then compared with the heat and mass transfer correlations taken from previous studies, and also combined with Computational Fluid Dynamics (CFD) simulations to examine the physical processes that occur in the cooling towers. All the experimental results, theoretical calculations and CFD simulations used variations of warm water mass, cold air, and water spray to present a clear description of the performance characteristics of a closed system cooling tower. The results of this study have shown that an increase in the amount of water spray mass flow causes an increase in the effectiveness value, heat transfer and overall mass transfer, as well as the cooling capacity of the cooling tower. The waste heat typically utilizes up to 80% of latent evaporation heat, and 20% of sensible air heat; however, waste heat in the closed system cooling tower utilizes 100% of latent evaporation heat. The mass transfer coefficient rate tends to be stable for a small mass of water spray."

"Penelitian ini berfokus pada sumber daya manusia yang ada di Jepang serta manajemen sumber daya manusia pada perusahaan Jepang, khususnya mengenai manajemen pekerja non-reguler. Masalah yang dikaji dalam penelitian ini adalah faktor-faktor yang mempengaruhi meningkatnya jumlah pekerja non-reguler serta bagaimana manajemen pekerja non-reguler yang dilakukan oleh perusahaan di Jepang.Data yang diperoleh merupakan data sekunder dari hasil penelitian kepustakaan serta pengumpulan data dari sumber-sumber publikasi lainnya seperti: artikel di internet maupun dari jurnal. Model analisis yang digunakan bersifat deskriptif eksploratif karena penelitian ini menggambarkan keadaan atau suatu fenomena.Berdasarkan penelitian dan analisis yang telah dilakukan dapat disimpulkan bahwa: 1) sumber daya manusia di Jepang mengalami diversifikasi, yaitu dengan semakin banyaknya bentuk-bentuk pekerja non-reguler yang berkembang di Jepang akhir-akhir ini; 2) meningkatnya jumlah tenaga kerja non-reguler di Jepang disebabkan oleh dua faktor yaitu perusahaan dan tenaga kerja itu sendiri; 3) meningkatnya jumlah tenaga kerja non-reguler juga dipengaruhi oleh pertumbuhan sektor jasa; 4) pada kenyataannya masih terdapat kekurangan dalam manajemen untuk para tenaga kerja non-reguler; 5) pekerja non-reguler akan tetap bekerja dengan baik jika mendapat kesempatan untuk mengembangkan kemampuan atau untuk dipromosikan sebagai tenaga kerja reguler.

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The focus of this research is the human resources in Japan and also the human resource management in Japanese companies especially concerning management for non-regular workers. The matter concerned studied in this research is the factors that influence the increasing number of non-regular worker and how the management for nonregular worker.The collected data was secondary data from the result of library work and also data collecting from other publication sources such as: articles on the internet or journals. The analysis model that used was descriptive explorative research because this research depicted a situation or a phenomenon.Based on research and analysis that have been done, found that: 1) human resources in Japan has diversified, this can be seen with so many forms of nonregular worker that recently growth in Japan; 2) the increasing numbers of nonregular workers in Japan was caused by two factors, by the company and by the worker itself; 3) the increasing number of non-regular workers was also influenced by growth of service sector; 4) in fact there is a lack in the management for non-regular workers; 5) non-regular workers will working better if getting the opportunity to self-development or to be promote as regular workers."

"Kebutuhan akan teknologi sistem pendingin diperkirakan akan meningkat secara signifikan selama beberapa dekade mendatang seiring dengan meningkatnya suhu global dan peningkatan standar hidup global. Penyejuk udara (AC) dipromosikan sebagai metode praktis untuk menurunkan tekanan panas dan mencegah paparan panas. Namun, sistem AC konvensional membutuhkan energi listrik yang relatif besar, menyebabkan efek Urban Heat Island (UHI) dan berdampak langsung pada kenyamanan berupa suhu di luar ruangan. Dalam konteks perumahan dan komersial, cairan kerja amonia - air telah digunakan untuk pendinginan dan pemanasan. Absorption chiller adalah jenis sistem pendinginan bertenaga termal yang menggunakan sumber energi tingkat rendah untuk menyediakan pendinginan. Untuk mengevaluasi kinerja sistem, penelitian komputasi pada sistem pendingin absorpsi yang menggunakan ammonia - air telah dilakukan selain pengembangan dan pengamatan menggunakan metodologi eksperimental. Penelitian ini berfokus pada pemodelan komposisi larutan refrigerant dan penyerap menggunakan metode numerik berupa simulasi dinamis terkait sistem yang diteliti, yang dilakukan pada aplikasi MATLAB dengan beberapa asumsi masukan berdasarkan aplikasi aktual dan kondisi lingkungan. Pemodelan bertujuan untuk mendapatkan jumlah ideal atau persentase massa muatan refrigeran/larutan refrigeran amonia-air dan karakteristik respon dari masing-masing komponen dalam sistem termasuk nilai Coefficient of Performance (COP). Model yang dibutuhkan akan diimplementasikan pada sistem pendingin absorption chiller tahap tunggal dengan campuran refrigeran dan penyerap ammonia-air yang menggunakan energi matahari sebagai sumber panas pada generator, sistem berpendingin udara sebagai sistem pendingin di kondensor dan absorber, serta kapasitas pendinginan sebesar 5 kW yang dapat digunakan di sektor perumahan (residensial).

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The need for cooling system technology is predicted to climb dramatically over the next several decades as global temperatures rise and global living standards rise. Air conditioning (AC) is promoted as a practical method for lowering heat stress and preventing heat exposure. However, Conventional AC systems require relatively large electrical energy, leads to the Urban Heat Island (UHI) effect and has a direct impact on outdoor thermal comfort. In both residential and commercial contexts, ammonia/water working fluid has been employed for cooling and heating. The absorption chiller is a type of thermally powered refrigeration system that uses low-grade energy sources to provide cooling. To evaluate the system performance, computational research on absorption chiller systems employing ammonia-water has been undertaken in addition to the development and observation using experimental methodologies. This research focuses on refrigerant-absorbent solution composition modeling using a numerical method in the form of dynamic simulations related to the system under investigation, which was carried out on the MATLAB application with several input assumptions based on the actual application and environmental conditions. The modelling aims to obtain the ideal amount or percentage of mass charge refrigerant/solution of ammonia-water refrigerant and the response characteristics of each component in the system including the Coefficient of Performance (COP) value. The required model will be implemented on a refrigerant-absorbent mixture of single stage ammonia/water absorption chiller system that uses solar energy as a heat source in the generator, a water-cooled system as a cooling system in the condenser and absorber, and a cooling capacity of 5 kW that can be used in the housing sector (residential)."

"Solar thermal cooling system yang diharapkan mampu menggantikan pemakaian cooling system konvensional berupa vapor compresion system karena lebih hemat dalam pemakaian listrik, ramah lingkungan dan juga dapat memanfaatkan energi matahari yang potensinya sangat besar. Namun, perlu dilakukan simulasi dan juga optimasi pada solar thermal cooling system supaya kenerjanya lebih optimal. Untuk itu, pada tugas akhir ini penulis akan berfokus terhadap tahapan simulasi pemakaian solar thermal cooling systempada gedung MRC FTUI beserta optimasi solar collector menggunakan software EnergyPlus dan GenOpt. Posisi dan kemiringan solar collector menjadi objek optimasi untuk meningkatkan penyerapan energi matahari yang berefek terhadap kenaikan temperatur solar hot water dari solar collector yang akan digunakan sebagai sumber energi pada chiller.Efek dari optimasi tersebut adalah memaksimalkan pengunaan hot water sebagai energi untuk chiller.

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Solar thermal cooling system that is expected to replace the use of conventional cooling system in the form of vapor compresion system because it is more efficient in the use of electricity,environmentally friendly and also can utilizing potential solar energy. However, the simulation needs to be done and also optimization of solar thermal cooling system in order to more optimally performance. Therefor, in this paper the authors will focus to the simulation stage on the use of solar thermal simulation cooling system at the MRC building FTUI along with optimization of solar collector using EnergyPlus software and GenOpt. Position and tilt the solar collector to be the object of optimization to increase the absorption of solar energy that affect the temperature rise solar hot water from the solar collector to be used as an energy source in the chiller. The effect of the optimization is to maximize the use of hot water as the energy for the chiller."

"Penghematan energi pada gedung merupakan satu potensi yang besar mengingat konsumsi energi pada gedung dapat mencapai 37 dari total konsumsi energi di dunia. Cooling load sendiri atau space conditioning berperan penting di dalam konsumsi energi secara keseluruhan di dalam gedung, yaitu antara 40 - 70. Penelitian kali ini adalah membandingkan besar cooling load pada suatu gedung lembaga pendidikan antara tipe Baseline dan tipe Design dengan menggunakan perhitungan EEC GBCI serta dengan menggunakan software EnergyPlus dan OpenStudio. Pada tipe Design terdapat pengurangan nilai lighting power density, pengubahan material kaca dari yang awalnya memilik nilai SC sebesar 0,73 menjadi 0,4, serta penambahan shading aluminium extrusion sepanjang satu meter. Hasil yang didapatkan adalah terjadinya pengurangan cooling load sebesar 187,2 kW EEC GBCI dan 225,2 kW simulasi.

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Energy savings on a building is a huge potential since it could be 37 of the world total energy consumption. Cooling load or space conditioning is major part of energy consumption in a building, roughly 40 ndash 70 of the total building consumption. This research aims to compare cooling load of the school, between Baseline type and Design type using EEC GBCI worksheet and using EnergyPlus and OpenStudio softwares. For the Design type there are reductions of lighting power density, glazing window material change from the initial that has 0.73 SC to 0.4 SC, and an addition of 1 meter aluminum extrusion shading. The result shows there are 187,2 kW EEC GBCI and 225,2 kW simulation reductions of the cooling load."