Select and test air-conditioning refrigerant to ensure performance and minimize contributions to ozone depletion and global warming.
11.1 Refrigerant charge test. Provide proof of proper refrigerant charge of the air-conditioning system (unless home has no mechanical cooling system).
11.2 Appropriate HVAC refrigerants (1 point). Do one of the following:
a. Do not use refrigerants.
b. Install an HVAC system with non-HCFC refrigerant (e.g., R-410a).
c. Install an HVAC system with a refrigerant that complies with the following equation. (See Table 1 for examples of the equation applied to R410a used in different system sizes.)
LCGWP + LCODP x 10^5 ≤ 160
LCODP = [ODPr x (Lr x Life + Mr) x Rc]/Life
LCGWP = [GWPr x (Lr x Life + Mr) x Rc]/Life
LCODP = Lifecycle Ozone Depletion Potential (lb CFC11/ton-year)
LCGWP = Lifecycle Direct Global Warming Potential (lb CO2/ton-year)
GWPr = Global Warming Potential of Refrigerant (0–12,000 lb CO2/lbr)
ODPr = Ozone Depletion Potential of Refrigerant (0–0.2 lb CFC11/lbr)
Lr = Refrigerant Leakage Rate (0.5–2.0%; default of 2% unless otherwise demonstrated)
Mr = End-of-life Refrigerant Loss (2.0–10%; default of 10% unless otherwise demonstrated)
Rc = Refrigerant Charge (0.50–5.0 lbs of refrigerant per ton of cooling capacity)
Life = Equipment Life (10–35 years; default based on equipment type, unless otherwise demonstrated)
Table 1 Examples of Residential Refrigerants Eligible for EA 11.2
|Refrigerant||Combined LCGWP+ LCODP score||System size||Refrigerant charge||Leakage rate||Equipment life|
|R410a||152||2 tons||3.7 lb/ton||1.5%||15 years|
|R410a||151||3 tons||3.0 lb/ton||2.0%||15 years|
|R410a||151||4 tons||3.0 lb/ton||2.0%||15 years|
|R410a||121||5 tons||3.0 lb/ton||2.0%||15 years|