18-07-2013, 02:24 PM
Refrigeration & Air Conditioning
Refrigeration.ppt (Size: 2.02 MB / Downloads: 273)
AC Systems
Air Conditioning (for comfort / machine)
Split air conditioners
Fan coil units in a larger system
Air handling units in a larger system
Refrigeration systems for industrial processes
Small capacity modular units of direct expansion type (50 Tons of Refrigeration)
Centralized chilled water plants with chilled water as a secondary coolant (50 – 250 TR)
Brine plants with brines as lower temperature, secondary coolant (>250 TR)
Refrigeration at large companies
Bank of units off-site with common
Chilled water pumps
Condenser water pumps
Cooling towers
More levels of refrigeration/AC, e.g.
Comfort air conditioning (20-25 oC)
Chilled water system (8 – 10 oC)
Brine system (< 0 oC)
Vapour Compression Refrigeration
Highly compressed fluids tend to get colder when allowed to expand
If pressure high enough
Compressed air hotter than source of cooling
Expanded gas cooler than desired cold temperature
Assessment of Air Conditioning
Indicative TR load profile
Small office cabins : 0.1 TR/m2
Medium size office (10 – 30 people occupancy) with central A/C: 0.06 TR/m2
Large multistoried office complexes with central A/C: 0.04 TR/m2
System Design Features
FRP impellers, film fills, PVC drift eliminators
Softened water for condensers
Economic insulation thickness
Roof coatings and false ceilings
Energy efficient heat recovery devices
Variable air volume systems
Sun film application for heat reflection
Optimizing lighting loads