The unit shell is made of galvanized steel plate, and is bonderized and its surface is coated with epoxy resin so that it can stand sunlight, rain and wind. Or the unit shell is stainless steel shell if the user requires it, so that the shell is free of ambient affect forever. The unit is designed to have reasonable structure and occupy only small floor. It does not need special engine room for its installation and can be mounted in front of or behind the house or on the balcony or the roof. Excellent performance of the unit allows it to operate normally even at high or low temperature even in other harsh conditions. 
Unit and actual air-conditioning load is always in best matching, so that the unit can adjust actual export pressure in the form of module cell stepping ,and thus can obtain more apparent energy-saving effect. 
This kind of unit is manufactured with the design optimized by applying international latest heat pump technology, with wide operating condition range.