Do all heat pump systems use Freon-22 or is there an environmentally friendly alternative?

There is a company called Enviro-safe that makes a replacement called es-22a. I cannot vouch for it's effectiveness since I haven't tried it. It is also marketed by different companies and can be found on Ebay. It is advertised as compatible with R-22 and R-22 systems, including oils, compressors, etc.