Air Conditioning Contractors of America
WHO IS ACCA????
Industry Manuals Residential D, J, S, H, RS, T, P A manual J load calculation is a measurement of how much heating and cooling capacity a home will need under project design conditions Manual T (Air Distributions Basics for Residential and Small Commercial Buildings) This volume is for the proper sizing/selection of registers, diffusers, and grilles so that thermal comfort and noise concerns can be properly addressed. Manual D: (Residential Duct Systems) Proper Duct design and layout. Manual S: (Residential Equipment Selection Manual) This manual shows how to properly use OEM comprehensive performance data to select heating and cooling equipment to properly meet the Manual J load requirements.
What happens when a heating & cooling system is oversized? Increased system installation costs Short cycling Shortened equipment life Decreased efficiency=increased energy bills Increased service calls Moisture problems Uneven temperatures Occupants feel and look cold and clammy Uneven heating or cooling of spaces Increased sound
Reading a Manual J & S Load Calculation 12,000 BTU s = 1 Ton Latent Cooling Load Sensible Cooling Summer Design Conditions Cooling Equipment Summary Equipment Total Load Required Total Capacity.70SHR
Sensible Cooling Load Sensible Cooling Load is heat due to heat conduction, convection and radiation from the exterior to the interior Glass windows or doors Sunlight striking windows, skylights, or glass doors and heating the room Exterior walls Partitions (that separate spaces of different temperatures) Ceilings under an attic
Sensible Cooling Load (cont d) Sensible Cooling Load is heat due to heat conduction, convection and radiation from the exterior to the interior Roofs Floors over an open crawl space Air infiltration through cracks in the building, doors and windows People in the building Equipment and appliances operated in the summer Lights
Latent Cooling Load Latent Cooling Load is heat put into the air by moisture People Equipment and appliances Air infiltration through cracks in the building, doors and windows
Requirements Without a manual J calc. a system will most likely be OVERSIZED Require Manual J load calculation be done room by room Require design temperatures not be adjusted from 68 and 76 degrees, and seasonal temperatures not change from 22 and 91 degrees and 113 Summer Grains of Moisture (3% design criteria) Require that the make and model numbers of proposed equipment be included in the proposal Require sealed ducts to perform at < 6 cfm to outside per 100 sq. ft. List this as a Performance Requirement Require proper commissioning to be done during cooling season with Super Heat and Cooling charge Require product literature to be left near the mechanicals for future service.
Compare Load Calculations to Equipment on the Proposal
Compare Load Calculations to Equipment on the Proposal
Compare Load Calculations to Equipment on the Proposal
Decipher Correct Size from Model Numbers or Rated Load Amperage (RLA) Equipment size interpreted by deciphering the model number on cooling equipment in tonnage Cooling equipment tonnage is divisible by 12, for example 24=24,000 Btu=2 tons RLA is listed on data plate of eqpt. and a reciprocating compressor will be rated at 5-8 amps per ton. This is an approximation as newer high efficient units will be on the lower end of the scale To verify correct coil to condenser matching request an ARI rating sheet
Compare Load Calculations to Equipment on the Proposal
Example of an ARI Rating sheet
A/C Commissioning, Start-up, QIV (Quality Installation Verification) Proper commissioning to be done after the home is occupied and the system has been operating during cooling season The process of inspecting a new air conditioning installation and verifying that the new system is running efficiently. Technician will visually inspect: Ducts Wiring Conduit Runs Fans Supply Voltage Safeties Thermostat Settings
Adjust Refrigerant Charge Check and adjust the airflow Measure the static pressure Check and adjust the refrigerant charge SuperHeat and SuperCool need wetbuld temp Beer can cold is not good enough!
Field Adjusted SEER [SEERFA] HVAC BEST PRACTICE INSTALLATION 14 13 12 11 10 9 8 7 6 Courtesy of Advanced Energy Corp. Typical Installation 11 12 13 14 15 Rated SEER
Field Adjusted SEER [SEERFA] HVAC BEST PRACTICE INSTALLATION 14 13 12 11 10 9 8 7 6 Courtesy of Advanced Energy Corp. Typical Installation 11 12 13 14 15 Rated SEER
Field Adjusted SEER [SEERFA] HVAC BEST PRACTICE INSTALLATION 14 13 12 11 10 9 8 7 6 Courtesy of Advanced Energy Corp. Typical Installation 11 12 13 14 15 Rated SEER
Field Adjusted SEER [SEERFA] HVAC BEST PRACTICE INSTALLATION 14 13 12 11 10 9 8 7 6 Courtesy of Advanced Energy Corp. Typical Installation 11 12 13 14 15 Rated SEER
Field Adjusted SEER [SEERFA] HVAC BEST PRACTICE INSTALLATION 14 13 12 11 10 9 8 7 6 Courtesy of Advanced Energy Corp. Typical Installation 11 12 13 14 15 Rated SEER
Field Adjusted SEER [SEERFA] HVAC BEST PRACTICE INSTALLATION 14 13 12 11 10 9 8 7 Typical Installation 6 11 12 13 14 15 Courtesy of Advanced Energy Corp. Rated SEER
Field Adjusted SEER [SEERFA] HVAC BEST PRACTICE INSTALLATION 14 13 12 11 10 9 8 7 Typical Installation 6 11 12 13 14 15 Courtesy of Advanced Energy Corp. Rated SEER
Right-Sizing Air Distribution HVAC QUALITY INSTALLATION CHECKLISTS: HVAC QUALITY INSTALLATION Equipment (ACCA Manual J/S) Ducts (ACCA Manual D) Terminals (ACCA Manual T) Duct Leakage Static Pressure Flow Across Coil Air Flow Refrigerant Charge Duct Installation Testing TXV Valve Installation R-8 Ducts in Attic Leakage to Outdoors and Total Pressure Balancing
The Essential Contacts To order ACCA materials or products call: (888) 290-2220 or Go to www.acca.org and select the ACCA Online Store To learn more about ACCA materials or products: Contact Chris Hoelzel at: (703) 824-8851 or chris.hoelzel@acca.org To learn more about ACCA Student Chapters: Contact Kimya Cajchun at: (703) 824-8845 or kimya.cajchun@acca.org To learn more about ACCA s Workforce Development: Contact Michael Honeycutt at (518) 492-07082 or michael.honeycutt@acca.org