A Shell and Tube Vertical Heat Exchanger (Chiller) have been developed that has smaller footprint than a Plate and Frame Heat Exchanger. The idea behind it is to force the boiling refrigerant such as Ammonia, Carbon Dioxide or any other refrigerant to a thin boiling regime thus resulting in higher heat transfer.
The Chiller does not require a surge drum or accumulator to protect the compressor against liquid carry over because it works under the principle of dry expansion. There is also no requirement for level control, which makes the control system simple.
The first such Chiller was installed in Minnesota for cooling propylene glycol with Carbon Dioxide as shown in the picture.