Facilities Management and Design
Chapter 7
HVAC Systems
Thermal Comfort
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Balancing heat produced by one’s body with
surrounding environment.
Body heat lost by convection, radiation, and
evaporation
Factors that influence comfort
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indoor temperature
humidity
air movement
room surface temperatures
overall air quality
Comfort zone
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Insert comfort zone chart
Heat sources
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Electricity– Used in all electric heaters. Requires no
flue. Usually most expensive.
Natural gas – Clean burning. Flue required. Very
efficient. Delivered via underground pipe
Liquefied petroleum – relatively clean burning. Requires
on-site storage tank. Delivered via truck.
Fuel oil – tendency to create dirt/smoke. Requires onsite storage tank. Delivered via truck. Various grades
available.
Steam – more common in urban areas where available
from local utility or in large complexes with central
steam plant. Supply and return lines required.
Heating equipment
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Furnaces and Boilers
Combustion efficiency
Flue
Furnace
Heat
Exchanger
Cooling Systems
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Boyles Ideal Gas Law
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Pressure
Temperature
Volume
Certain gases react more
actively
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Refrigerants
CFC’s
HCFC’s
The Refrigeration Cycle
Compressor
Evaporator Coil
Condenser Coil
Expansion Valve/ Metering Device
Cooling system operating and
maintenance concerns
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Types of compressors
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Reciprocating
Centrifugal
Rotary
Energy efficiency ratio (EER)
Integrated part load values (IPLV)
Environmental Protection Agency
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supervises aspects of refrigeration equipment maintenance
importance of eliminating or reducing refrigerant leaks
Cooling system operating and
maintenance concerns
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Types of compressors
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Reciprocating
Centrifugal
Rotary
Energy efficiency ratio (EER)
Integrated part load values (IPLV)
Environmental Protection Agency
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supervises aspects of refrigeration equipment maintenance
importance of eliminating or reducing refrigerant leaks
HVAC system types
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Centralized systems; quiet
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Decentralized systems; not as quiet
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two-pipe
three-pipe
four-pipe
heating and cooling sources in guestroom itself or along
outside wall
Hybrid systems
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characteristics of centralized and decentralized systems
System types and maintenance needs of
HVAC systems for other building areas
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Air handling units
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Packaged air conditioning units
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Isolation of zones (housekeeping, kitchen, maintenance…)
usually mounted on roof
Maintenance issues
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Filter replacement
belt checking and replacement
cleaning of fans and heat transfer surfaces
HVAC controls
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Today’s controls are often electronic
Thermostat
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enthalpy or economizer control
Older control sensors—mechanical sensing
Digital control systems
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variable air volume (VAV) systems
load sensing equipment
EMS sensors
Cooling towers
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Startup and shutdown concerns
Inspection and lubrication of pumps and fans
Removal of dirt and other debris
Treatments to reduce bacteria, scale, and
corrosion
Inspection of metal surfaces