This chapter discusses various refrigerant systems that have been mentioned only briefly, or not at all, earlier in the handbook. These systems are specific, and have different application areas for heat exchangers. Some areas covered in this chapter are mentioned below.
True dual systems meet the need to be able to change the cooling capacity in large systems. Indirect systems are suitable if the aim is to keep the refrigerant charge at a minimum or avoid leakage in the system. The chapter also deals with reusing waste energy, heating or cooling buildings, cooling at very low temperatures and drying air.