choosing heating and cooling systems...© 2005 building science corporation choosing heating and...
TRANSCRIPT
© 2005 Building Science Corporation
Choosing Heating andCooling Systems
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 1 of 23
© 2005 Building Science Corporation
Ducted Systems vs. Radiant Systems• Radiant hot water systems use boilers - Ducted systems can use boilers or
furnaces for heat
• Radiant systems can distribute heat through baseboard fin-tubes, radiantpanels or radiators, or floors - Ducted systems can move conditioned air throughductwork located within the conditioned enclosure
• Ducted systems allow for conditioned air to be continually mixed for morehomogeneous interior temperatures and accommodate outside air change,filtration, and dehumidification of air -this can be good
• Ducted systems provide the opportunity for unbalanced airflows - this can be bad
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 2 of 23
© 2005 Building Science Corporation
Ducted SystemsThings to Avoid
• Air handlers or ducts in vented (to the outside)spaces - why?
• Building cavities used as ducts - why?
• Air handlers or return ducts in garage - why?
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 3 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 4 of 23
© 2005 Building Science Corporation
Mechanical System Interactions thatLead to Moisture Problems
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 5 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 6 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 7 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 8 of 23
© 2005 Building Science Corporation
Building Enclosure - Mechanical SystemInteraction
• Buildings are hollow and moreinterconnected with complex airdistribution systems that leak.
• Building mechanical systemsinadvertently connect the buildingenclosure to the breathing zone ofthe occupant.
• The building enclosure is thepollutant.
• The HVAC system is the pollutantinterstate.
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 9 of 23
© 2005 Building Science Corporation
Efficient Distribution of Pollutants
• The enclosureis now thepollutant• And ducts in
the enclosureefficientlydistribute thepollutant
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 10 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 11 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 12 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 13 of 23
© 2005 Building Science Corporation
Panned Floor Joist or Stud Cavity Returns
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 14 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 15 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 16 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 17 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 18 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 19 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 20 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 21 of 23
© 2005 Building Science Corporation
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 22 of 23
© 2005 Building Science Corporation
Mechanical SystemsTop Ten Improvements
1. Fan powered exhaust and general ventilation2. Sealed-combustion/fan powered combustion device exhaust3. Use MERV 11 or better filters4. Seal ducts with mastic (<5%)5. Size heating and cooling equipment using Manual J6. External duct insulation7. Pressure balance distribution8. Provide access for inspecting and cleaning coils and ductwork down
stream of coils9. Locate air handlers in conditioned space10. Dehumidification during part-load and in damp spaces
PR-0510d: BuildBoston 2005—Choosing Heathing and Cooling Systems Page 23 of 23