HVAC for Energy Advisors & Raters

Brett Dillon CEO

Midwest Regional Energy Conference

About Me• Author of:

• Guide to HVAC Design, Construction & Commissioning

• Developer of:

• ACCA RSI Verifier Manual & Certification Program

• NATE HVAC Verifier Training Program

AHRI Capacity vs OEM Capacity

Manual J

Manual S

Manual D

AHRI Data• Region IV

• 80°F indoor cooling test temperature

• 67°F indoor wet bulb temperature

• 90°F outdoor test temperature

• 47°F outdoor heating test temperature

• 17°F outdoor heating test temperature

Code Requirements

Manual J Manual S Manual D

Blueprints & Specifications

Design Temperatures

Orientation

Internal Loads

Ventilation

Infiltration

Duct System

Manual JOEM Performance

Manual JMaterial

Devices

Length

2009 IRC Requirements• Outdoor Thermostat for heat

pumps

• N1103.1.2

• R-8 ducts in attics

• N1103.2.1

• Ducts sealed and tested

• N1103.2.2

• Repairs/replacements of existing systems

• M1202.1

• HVAC sizing based upon Manuals S & J

• M1401.3

• Heat Pump return area

• M1403.1

• Duct Design according to Manual D

• M1601.1

Replacement / Repairs of Systems

• Meet requirements for new installations

• M1202.1

Code Required• Manual J & S, M1401.3 (2009)

• Manual D, M1601.1 (2009)

• Ventilation, M1507.3 (2012)

• 403.5 Mechanical ventilation (Mandatory). Outdoor air intakes and exhausts shall have automatic or gravity dampers that close when the ventilation system is not operating.

Cod

e

System Concept

Load Calculation

Equipment Selection

Air Distribution

Duct Size Calculation

Adjust, Test & Balance

Manual RS

Manual J

Manual T

Manual S

Manual D

Manual J

Manual J

• 99%

• 1%

• Room-by-Room

• Process, not software

Cod

e

Manual J• Indoor Design

Temperatures

• Outdoor Design Temperatures

• Windows

• Walls

• Ceilings

• Floors

Cod

e • Infiltration

• Appliances

• Occupants

• Ducts

• Ventilation

Infiltration

• 2009 IRC

• Maximum 7 ACH50

Cod

e

Internal Loads• Appliances

• 1200 Btu/hr

• 2400 Btu/hr

• 3600 Btu/hr

• Occupants

• BR + 1

• 230 Btu/hr x occupants

Cod

e

Duct Loads

• Location

• Leakage

• Code maximum

Cod

e

Ductwork

• R-8

• R-6

• Sealing

• Outside air inlets

Cod

e

2009 IRC

• N1103.2.2 Mandatory duct testing

• Post-Construction, 8% leakage to outside or 12% total leakage

• Rough-in, 6% total leakage, 4% if air handler not installed

Cod

e

Manual S

Systems• Furnace, > 0.50 i.w.c.

• Condensate drain

• Secondary drain pan

• Suction lines insulated

• Combustion air

• Heat pump returns

Cod

e

Systems

• Furnaces = programmable T-stat

• Heat pumps = outdoor T-stat

Cod

e

Equipment Selection• Heating output, Btu/hr < 140% load

• Total Cooling, Btu/hr <115% load

• Sensible capacity

• Latent capacity

• Airhandler CFM

• Auxiliary Heating

Cod

e

OEM Performance Data!!!

Manual D

Manual D• Sizing Ducts

• Friction Rate

• (pressure drop x 100) / total effective length

• Slide rule

• Static pressure

Cod

e

Manual D• Peak loss = 1967 Btu/hr

• CFM = 1,967 / (1.1 x ∆T)

• ∆T = ℉ between return & supply

• Heat pumps, 25℉

• Furnaces, 55℉

• CFM = 1967 / (1.1 x 25) = 1967 / 27.5 = 72

• CFM = 1967 / (1.1 x 55) =

Cod

e

Manual D• Peak gain = 1189 Btu/hr

• Sensible gain = 932 Btu/hr

• Latent gain = 257 Btu/hr

• SHR = 932 / 1189 = 0.78

• CFM = 932 / (1.1 x ∆T)

• ∆T = ℉ between return & supply

• SHR < 0.80, 21℉

• CFM = 932 / (1.1 x 21) = 932 / 23.1 =

< 0.80 21℉

0.80 - 0.85 19℉

> 0.85 17℉Cod

e

Manual D• Required under IRC M1601.1

• Implies room-by-room load calculation must be performed

• CFM

• SHR

• ΔT supply-return

• Sensible load

• Friction rate

• Pressure drop x 100 / total effective length

Cod

e

Supply Duct Sizing

• What temperature does the air need to be to meet the load?

• How many CFM of air must be delivered to meet the load?

• Sensible Load / (1.1 x ΔT)

Return Airflow

• 350 fpm

• Return register face velocity < 400 fpm

• 90º bend between register & airhandler

Sizing Return Ducts• Sized according to Manual D

–Returns should be sized properly

•IRC M1403.1, heat pumps need > 6 sq in / 1,000 Btu/hour capacity (2 ton unit at least 14” duct)

–All areas that are conditioned should have an adequate return path

•And undercutting doors 1” isn’t enough!

Cod

e

Other Sources

• http://www.acca.org/standards/acca-speed-sheets/

• http://www.acca.org/qa/resources/

• RESNET/NATE HVAC Verifier Training & Certification

Questions?

Brett Dillon CEO

www.thedillongroupinc.com info@thedillongroupinc.com