INGENIEUR
INGENIEUR
main factors to be considered during cooling load calculation are :
1 . Conduction ( heat gain from walls , roofs , windows , etc ).
2 . Radiation ( solar heat radiated through the glass ).
3 . Internal heat gain ( from people occupying the building , the lighting and other heat generating equipment , e . g . servers ).
4 . Infiltration ( air leaking into or out of a space through doors , windows and small cracks ).
5 . Ventilation ( introduction of outdoor air into a space to dilute or remove contaminants from the indoor air ).
For conduction and radiation , the climate data used is based on the geographical location and the orientation of the building . For instance , for a row of terraced shop houses in which the building is located with a west facing wall , the afternoon heat load will be more significant than the morning heat load . On the other hand , in the case of internal heat gain , the schedules of occupancy have to be taken into consideration when estimating the cooling load . Estimating the cooling load taking into account these detailed inputs will ensure that the equipment is sized according to the real peak load of the building space to be air-conditioned .
The cooling load estimation phase is followed by the equipment selection phase . This process involves sizing the Cooling Tower , Chiller , Air Handling Units , Condenser Water Pump , Chilled Water Pump , Air-Side Ducting and Water-Side Piping . Engineers are challenged to make energy efficiency a top priority during equipment selection and to select the latest energy efficient technologies which can meet the design specifications . One of such technologies is the variable speed drive design for the motors on Chillers , Pumps , Cooling Towers and Fans which can save a significant portion of the energy consumption in ACMV systems . Furthermore , equipment that use chlorofluorocarbon ( CFC ) and hydro-fluorocarbon ( HCFC ) refrigerants must be avoided as they cause harm to the environment .
Another issue is the location for the installation of the Cooling Tower because it requires an open space to discharge heat to the environment , a substantial amount of water , chemical treatment handling and generates noise . If there are residential buildings adjacent to the Cooling Tower , then noise pollution is a design concern .
Last but not least , during the construction phase , safety requirements must be adhered to in order to avoid site accidents . Safety officers must be in place to enforce the safety requirements . The ACMV system shall be installed in accordance with the requirements of the local authorities having jurisdiction over the work . These include :
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Tenaga Nasional Berhad ( TNB ).
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Jabatan Bomba dan Penyelamat Malaysia ( BOMBA ).
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Jabatan Kesihatan dan Keselamatan Pekerja Am ( DOSH ).
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Jabatan Alam Sekitar ( DOE ).
Summary
In summary , this article describes the common design issues concerning ACMV systems in Malaysia . It highlights the design guidelines and best practices for ACMV design with the objective of reducing design errors , omissions and providing ACMV services that better meet the needs of the society . This should lead to improvements in both the efficiency of the design process and in the subsequent implementation of ACMV design .
REFERENCE
[ 1 ] W . S . Stoecker & J . W . Jones . Refrigeration and Air Conditioning . New York , NY : McGraw- Hill , Inc ., 1982 .
[ 2 ] Jabatan Kerja Raya Malaysia . Guideline on Air-Conditioning System Design ( Bab 3 – Kerja M & E ). Unit Ukur Bahan CKM Ibu Pejabat JKR Kuala Lumpur , 2005 .
[ 3 ] 1997 ASHRAE Handbook : Fundamentals . American Society of Heating , Refrigerating and Air-Conditioning Engineers , 1997 .
[ 4 ] Malaysia Standard MS 1525:2014 . Energy Efficiency and Use of Renewable Energy for Non-Residential Buildings - Code of Practice . Department of Standards Malaysia , 2014 .
[ 5 ] System Design Manual . Carrier Air Conditioning Company . Carrier Corporation , 1972 .
[ 6 ] Arthur A . Bell Jr .. HVAC Equations , Data , and Rules of Thumb . McGraw-Hill , 2000 .
38 VOL 71 JULY - SEPTEMBER 2017