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Heating, ventilation, and air conditioning (HVAC)
systems are often the largest electricity consumers in
hotels. When hotel managers attempt to lower operation
costs, they immediately look to reduce electrical energy
consumption. The amount of electricity used for running
air conditioning systems constitutes approximately 30
percent or more of total costs. Thus, by ensuring that
the air conditioning system is operating efficiently,
hotel managers can lower the costs of operation.HVAC systems provide heating, cooling, humidity control, filtration, fresh air, building pressure control, and comfort control. Properly-operating HVAC systems are essential in hotels and contribute to employee productivity and guest satisfaction.
HVAC operating costs can be reduced effectively through practical strategies, such as payback, which is the process of upgrading controls or replacing outdated HVAC systems with more efficient ones.
HVAC retrofitting should be considered if, for example, lighting technologies have been changed to conserve electricity. When more energy-efficient lighting is installed, the sensible loads (that is, heat loads one can "sense") from the lighting are reduced, since compact fluorescent lamps produce less heat than equivalent-light-output incandescent lamps, for example. However, when changing from less efficient (and hotter) lights to cooler-operating, more energy-efficient lights, the change will also reduce the amount of "latent heat" (that is, wetness) in the air which the HVAC system must then overcome. If the HVAC system is changed without consideration of the lighting, and the lighting is changed later on, the building may become damp and uncomfortable —with an HVAC system sized according to the contributions of the old lighting loads. The lighting and the HVAC system should be considered as linked operations with significant reciprocal savings and operational impacts.
Here are some examples of energy-saving opportunities which can improve HVAC system efficiency:
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Insulation: Insulate all heating and cooling lines/vessels using appropriate insulation thickness to minimize heat gains or losses.
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Building Envelope: Optimize the effective space requiring air conditioning through measures such as false ceilings and segregation of critical areas for air conditioning by air curtains.
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Building Heat Load Minimization: Minimize the air conditioning loads by measures such as roof cooling, roof reflectance, efficient lighting, optimal thermostat setting of temperature of air conditioned spaces, sun film applications, etc.
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Solar Heat Gain Control: Install awnings, overhangs, or low e-coated windows with low Solar Heat Gain Coefficient (SHGC) for renovation and new construction. See windows technology for more details (LINK to WINDOWS).
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Select high-efficiency units when replacing HVAC equipment: Reduce energy bills by selecting higher-efficiency air conditioning units. Although some high-efficiency units may be more expensive than average-efficiency units, the higher initial payment can be recovered through increased energy savings in as little as two to five years.
It is also important to ensure proper maintenance of
HVAC systems, such as cleaning filters and maintaining
proper refrigerant charge on wall units and packaged
systems.
References
ASHRAE Standard 62 (ventilation), Standard
90.1 (energy performance), others; American Society
of Heating, Refrigerating and Air-Conditioning
Engineers, Atlanta, GA.
www.ashrae.org
India Bureau of Energy Efficiency (BEE). Course Material
for energy managers/energy auditors examination. Book
III — Energy efficiency in electrical utilities and
Book IV — Energy performance assessment for equipment
& utility systems. Available online at
www.em-ea.org/gbook1.asp.
Space Heating Technology Atlas (1996) and
Commercial Space Cooling and Air Handling Technology
Atlas (1997), E Source, Inc., Boulder, CO. (303)
440-8500.
www.esource.com and
www.BuildingGreen.com