Agenda - 06-05-2001-9e - Laserfiche WebLink

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Fundamental Series Item :Choosing the Best HVAC System file:///c~windows/TEMP/0,2637,162$ 7,C 21 HVAC Selection The first step in the selection process is for the designer to ascertain and document owner the desired environmental conditions for the building or conditioned space. The designer must also learn and document the restrictions placed on the system de example, what is the required equipment space for a particular system versus what i Unfortunately, it is the nature of the business that very few projects allow as much dE evaluation of all conditions and alternatives as some would like. Therefore, the desig also rely on common sense and subjective experience to narrow the choice of systei Step two in the selection process is determining the building's heating and cooling to example, is the cooling load mostly sensible or latent? Is the load relatively high or Ic square foot of conditioned area as compared to other similar buildings? Is the load u distributed throughout the conditioned spaces, and is it relatively constant or does it greatly? How does the load vary with time and operating conditions? Determining the heating and cooling loads establishes the system's capacity requires Cooling loads and humidity requirements are used to size air-conditioning (comfort a cooling) systems. In other systems, heating and/or ventilation may be the critical factors in sizing and s For example, a building may require a large air handling unit and duct system to prop quantities of outside air for ventilation or as makeup air to replace air exhausted fron building. In other buildings, in colder climates for instance, heating may be the deterr factor on equipment size. The physical size of the equipment can be estimated from and cooling load information alone. This information can help to reduce the choice o' those that will fit the space available. There are also choices to be made depending on if the system is to be installed in a building or an existing building. In existing buildings, for example, the HVAC system designed for the loads when the building was built. This means if new systems are tc integrated with existing ones (in order to keep costs down or for other reasons), the i retrofitted systems must be adaptable to existing equipment, ductwork and piping, ai equipment or systems must fit into existing spaces. If new systems are to pertorm pr when tied in with existing systems, the old and the new must be looked at carefully a entirety. The designer will need to determine how a change to one part of a system v another part and a how a change in one system will afFect another system. The number of choices is narrowed further to those systems that will work well on pr given application and size and are compatible with the building architecture.