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English to Malay: Modeling and Simulation of HVAC Faulty Operations and Performance Degradation due to Maintenance Issues General field: Tech/Engineering Detailed field: Mechanics / Mech Engineering
Source text - English Modeling and Simulation of HVAC Faulty Operations and Performance Degradation due to Maintenance Issues
Liping Wang, Tianzhen Hong*
Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
ABSTRACT
Almost half of the total energy used in the U.S. buildings is consumed by heating, ventilation and air conditionings (HVAC) according to EIA statistics. Among various driving factors to energy performance of building, operations and maintenance play a significant role. Many researches have been done to look at design efficiencies and operational controls for improving energy performance of buildings, but very few study the impacts of HVAC systems maintenance. Different practices of HVAC system maintenance can result in substantial differences in building energy use. If a piece of HVAC equipment is not well maintained, its performance will degrade. If sensors used for control purpose are not calibrated, not only building energy usage could be dramatically increased, but also mechanical systems may not be able to satisfy indoor thermal comfort. Properly maintained HVAC systems can operate efficiently, improve occupant comfort, and prolong equipment service life.
In the paper, maintenance practices for HVAC systems are presented based on literature reviews and discussions with HVAC engineers, building operators, facility managers, and commissioning agents. We categorize the maintenance practices into three levels depending on the maintenance effort and coverage: 1) proactive, performance-monitored maintenance; 2) preventive, scheduled maintenance; and 3) reactive, unplanned or no maintenance. A sampled list of maintenance issues, including cooling tower fouling, boiler/chiller fouling, refrigerant over or under charge, temperature sensor offset, outdoor air damper leakage, outdoor air screen blockage, outdoor air damper stuck at fully open position, and dirty filters are investigated in this study using field survey data and detailed simulation models. The energy impacts of both individual maintenance issue and combined scenarios for an office building with central VAV systems and central plant were evaluated by EnergyPlus simulations using three approaches: 1) direct modeling with EnergyPlus, 2) using the energy management system feature of EnergyPlus, and 3) modifying EnergyPlus source code. The results demonstrated the importance of maintenance for HVAC systems on energy performance of buildings.
The research is intended to provide a guideline to help practitioners and building operators to gain the knowledge of maintaining HVAC systems in efficient operations, and prioritize VAC maintenance work plan. The paper also discusses challenges of modeling building maintenance issues using energy simulation programs.
Translation - Malay Modeling dan Simulasi Kerosakan Operasi HVAC dan Kemerosotan Prestasi kerana Masalah Penyelenggaraan
Liping Wang, Tianzhen Hong*
Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
ABSTRACT
Hampir separuh daripada jumlah tenaga yang digunakan di bangunan A.S. digunakan oleh pemanasan, pengudaraan dan penghawa dingin (HVAC) menurut statistik EIA. Antara faktor pendorong kepada prestasi tenaga pada bangunan, operasi dan penyelenggaraan memainkan peranan penting. Banyak penyelidikan telah dilakukan untuk melihat kecekapan reka bentuk dan kawalan operasi untuk meningkatkan prestasi tenaga bangunan, tetapi sangat sedikit yang mengkaji mengenai kesan penyelenggaraan sistem HVAC. Amalan penyelenggaraan sistem HVAC yang berlainan boleh menghasilkan perbezaan yang besar dalam penggunaan tenaga bangunan. Sekiranya sesebuah peralatan HVAC tidak dijaga dengan baik, keberkesanannya akan merosot. Sekiranya sensor yang digunakan untuk tujuan kawalan tidak ditentuukur, bukan sahaja kadar penggunaan tenaga bangunan akan meningkat dengan ketara, tetapi juga sistem mekanikal mungkin tidak dapat menyediakan keselesaan suhu di ruang dalaman. Sistem HVAC yang dikendalikan dengan betul dapat beroperasi dengan cekap, meningkatkan keselesaan penghuni, dan memanjangkan jangka hayat peralatan.
Dalam penerbitan ini, amalan penyelenggaraan sistem HVAC ini dibentangkan berdasarkan tinjauan literatur dan perbincangan dengan jurutera HVAC, pengendali bangunan, pengurus kemudahan, dan agen pentauliahan. Kami mengkategorikan amalan penyelenggaraan menjadi tiga tahap bergantung kepada usaha dan liputan penyelenggaraan: 1) penyelenggaraan yang proaktif dan penyelenggaraan prestasi yang dipantau; 2) penyelenggaraan pencegahan dan berjadual; dan 3) penyelenggaraan reaktif, tidak terancang atau tidak diselenggara. Sampel senarai masalah penyelenggaraan, termasuklah menara pendinginan rosak, pendidihan dandang / penyejuk rosak, cecair penyejukan terlebih atau di bawah cas, pengimbangan sensor suhu terkeluar dari julat, kebocoran peredam udara luar, penyumbatan skrin udara luar, peredam udara luar tersekat pada kedudukan terbuka sepenuhnya, dan penapis kotor adalah diselidik dalam kajian ini menggunakan data tinjauan lapangan dan model simulasi terperinci. Kesan tenaga dari kedua-dua isu penyelenggaraan individu dan senario gabungan untuk bangunan pejabat dengan sistem VAV pusat dan kilang pusat dinilai oleh simulasi EnergyPlus menggunakan tiga pendekatan: 1) dimodelkan secara langsung dengan EnergyPlus, 2) menggunakan ciri sistem pengurusan tenaga EnergyPlus, dan 3) mengubah kod sumber EnergyPlus. Hasil kajian menunjukkan pentingnya penyelenggaraan sistem HVAC untuk prestasi tenaga bangunan.
Penyelidikan ini bertujuan untuk memberikan garis panduan untuk membantu pengamal dan pengendali bangunan untuk memperoleh pengetahuan tentang penyelenggaraan sistem HVAC dalam operasi yang efisien, dan mengutamakan rancangan kerja penyelenggaraan VAC. Penerbitan ini juga membincangkan cabaran pemodelan masalah penyelenggaraan bangunan menggunakan program simulasi tenaga.
English to Malay: A Few Good Men General field: Art/Literary Detailed field: Military / Defense
Source text - English Lt. Daniel Kaffee (Tom Cruise) is a military lawyer defending two U.S. Marines charged with killing a fellow Marine at the Guantanamo Bay Naval Base in Cuba. Although Kaffee is known for seeking plea bargains, a fellow lawyer, Lt. Cdr. JoAnne Galloway (Demi Moore), convinces him that the accused marines were most likely carrying out an order from a commanding officer. Kaffee takes a risk by calling Col. Nathan R. Jessep (Jack Nicholson) to the stand in an effort to uncover the conspiracy.
Translation - Malay Leftenan Daniel Kaffee (Tom Cruise) adalah seorang peguam tentera yang membela dua tentera laut A.S. yang dituduh membunuh seorang rakan tentera di Pangkalan Tentera Laut Teluk Guantanamo di Cuba. Walaupun Kaffee terkenal mebuat tawaran hukuman lebih ringan, seorang rakan peguam, Letnan Cdr. JoAnne Galloway (Demi Moore), meyakinkannya bahawa tentera laut yang dituduh kemungkinan besar hanya melaksanakan arahan dari seorang pegawai pemerintah. Kaffee mengambil risiko dengan memanggil Kolonel Nathan R. Jessep (Jack Nicholson) untuk turut serta dalam usaha untuk mengungkap konspirasi itu.
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Years of experience: 18. Registered at ProZ.com: Oct 2021.
MY professional background is in engineering and enjoy reading a a variety of other subjects including arts, social science and technology. I have translation experience in the engineering and entertainment fields. It started when I have to translated various English to Bahasa Malaysia letters for government agency and vice versa for my expatriate colleagues.
Keywords: Bahasa Malaysia, Malay, technical, papers, engineer, technology, Malaysia,
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