Wednesday, July 29, 2009

Allegiance® 20 Communicating Air Conditioner

American Standard Air-Allegiance 20 Communicating Air Conditioner Two-stage cooling helps you save up to 60% on energy bills.* Includes AccuLink™ connectivity for greater control and convenience.

Key Benefits:

  • Automatically communicates and coordinates with your other system components via the AccuLink™ Communicating System
  • Charge Assist™ charging simplifies service and improves system refrigerant charge accuracy
  • Among the highest efficiency in the industry, significantly surpassing government efficiency standards and helping you save up to 60% on your energy bills while reducing greenhouse gas emissions**
  • Contains two compressors that provide two-stage cooling, running at an energy-saving 50% capacity most of the time, which may help lower your cooling bills**
  • Runs quietly and keeps temperature even from room to room with its variable speed fan motor
  • Cools with an environmentally friendly refrigerant that’s ozone-safe.
  • Removes unwanted humidity from the air, leaving you feeling cooler and more comfortable
  • Provides more efficient and reliable cooling, thanks to durable woven Spine Fin™ coil and dual Duration™ compressors
  • Rust-resistant coating, screws and basepan protect system from the elements

*An American Standard 900 Series Comfort Control with communicating indoor unit is required for Allegiance 20 communicating air conditioners.

**Potential energy savings may vary depending on your lifestyle, system settings, equipment maintenance, local climate, home construction and installation of equipment and duct system.

Friday, July 10, 2009


R-410A Puron

Genetron R410A and AZ-20

R-410A, sold under the trademarked names Puron, Genetron R410A, and AZ-20, is a near-azeotropic mixture of difluoromethane (CH2F2, called R-32) and pentafluoroethane (C2HF5, called R-125), which is used as a refrigerant in air conditioning applications. Unlike many haloalkane refrigerants it does not contribute to ozone depletion, and is therefore becoming more widely used as ozone-depleting refrigerants like R-22 are phased out. However, it has a high global warming potential of 1725 (1725 times the effect of carbon dioxide),[1] similar to that of R-22.

While R-410A was invented and patented by Allied Signal (now Honeywell) and Honeywell continues to be the leader in 410A capacity and sales, other producers around the world have been licensed to manufacture and sell the product. R-410A was successfully commercialized in the air conditioning segment by a combined effort of three companies. Carrier Corporation, Emerson Climate Technologies, Inc. with Copeland Scroll Compressors (a division of Emerson Electric Company), and Allied Signal worked together in developing the refrigerant for practical use in air conditioners in the United States. R-410A is also the preferred refrigerant for use in residential and commercial air conditioners in Japan and Europe, replacing R-22.

Carrier Corporation was the first company to introduce a R-410A-based residential air conditioning unit in the marketplace in 1996. Carrier holds the trademark Puron and is still the leading supplier of energy efficient R410A air conditioning systems for residential, commercial and chiller applications in the United States today.

R-410A is incompatible with R-22 refrigerant. R-410A is used at much higher operating pressures than R-22 and other newer refrigerants.

Although the United States Environmental Protection Agency has mandated that R-22 (chlorodifluoromethane) along with other hydrochlorofluorocarbons (HCFC's) be phased-out in the U.S., few window-mounted air conditioners are available that use R-410A. All of the largest central air conditioning systems manufacturers in the U.S. offer systems that use R-410A. As an alternative to window-mounted systems, a ductless "split" system is available with R-410A refrigerant, and can be installed with a 3-inch hole through the wall (or window opening).[5]

R-410A designed systems employ thicker walled tubing, and compressors capable of withstanding the higher pressures of R-410A. R-410A systems require different installation and service procedures.

New equipment that uses R-410A will require service personnel to acquire different tools and equipment, safety standards and fundamentals when installing, replacing older split A/C systems, and repairing systems in the field.

HVAC service persons need to understand the safe handling, proper charging, operating characteristics, proper applications, and general use of R-410A refrigerant.

R-410A should only be used in equipment specifically designed and constructed for higher pressure refrigerants. Operates at considerably higher pressures and requires the use of special tanks, gauges and recovery equipment.

R-410A requires training of installation and service personnel in the proper and safe handling of R-410A.

R-410A needs service personnel to understand why all refrigerant flow controls, valves and driers have changed and must be properly applied with newly designed and built compressors.

Many equipment manufacturers are well aware of the concerns and safety issues of working with R-410A and other HFC refrigerants and are requiring installation and service professionals who purchase their R-410A systems to be R-410A Certified.

In order to prepare air conditioning professionals for the challenges presented by R410A, some of the major organizations in the HVACR created the AC&R Safety Coalition.

Physical properties

Property Value
Formula 50% CH2F2/50% CHF2CF3
Molecular Weight (Da) 72.6
Melting point (°C) -155
Boiling point (°C) -48.5
Liquid density (30°C), kg/m3 1040
Vapour density (30°C), air=1.0 3.0
Vapor pressure at 21.1°C (MPa) 1.383
Critical temperature (°C) 72.8
Critical pressure, MPa 4.86
Gas heat capacity @ 1 atm, 30°C (kJ/(kg·°C)) 8.8
Liquid heat capacity @ 1 atm, 30°C, (kJ/(kg·°C)) 1.8