the present invention relates to a plastic tube heat exchanger suitable for refrigerant use is provided by wrapping a layer of tubes around a curved surface , on a base which is generally perpendicular to the surface . several to many tubes can be in each layer . then , further layers can be wrapped continuously by overlaying the first layer . heat exchangers , including refrigerant apparatus , condensers and evaporators , can be made in this configuration . processes and articles of manufacture are parts of the invention .