Finnish heat exchanger manufacturer Vahterus has launched a new compact plate-and-shell evaporator that adds a superheater at Chillventa 2026 in Nuremberg.
The new product, called Combined+, is designed for applications requiring both the efficiency of flooded evaporation and outlet gas superheating. It includes a droplet separator, which is also featured in previous evaporator models (the Combined models).
Superheat and droplet separators both improve heat transfer and prevent liquid refrigerant from entering compressors, which would obstruct their performance, both when starting up and during variable-load conditions and other situations where condensation may occur in the suction line.
By combining these functions, Combined+ “simplifies installation, reduces footprint and minimizes piping requirements,” said Vahterus in a statement. Typical applications include industrial refrigeration and heat pump systems using natural refrigerants such as ammonia (R717), CO2 (R744) and hydrocarbons.
“There's a bigger and bigger demand from customers to add some superheat to the suction gas because of the utilization of heat pumps,” said Vahterus R&D Manager Kalle Vähätalo. He was speaking in an interview with NaturalRefrigerants.com at his company's booth at Chillventa, where the unit was being launched. He added that when hydrocarbon refrigerants are employed, there is a greater need for superheat.
The integrated model also offers an opportunity to cut equipment costs compared to using a separate heat exchanger, noted Vähätalo.
Hot condensate for superheating
The superheater can use either an external heat source or high-pressure condensate, which is consequently subcooled. When hot condensate is used as the heat source, the result is typically “COP-neutral,” said Vahterus. For maximum operating flexibility, the manufacturer recommends incorporating a condensate bypass option.
“When you are utilizing the condensate, then you will get less flash gas and more refrigerant is used for the evaporation,” said Vähätalo
There's a bigger and bigger demand from customers to add some superheat to the suction gas because of the utilization of heat pumps.
Kalle Vähätalo, Vahterus R&D Manager
The Combined+ concept is available across a range of Vahterus Combined evaporator models, including: 5/3, 6/4, 7/5, 8/6, 9/7 and 14/9. In selected applications, larger shell sizes can also be used to provide increased superheating capacity and support specific system requirements.
The shell pressure and temperature ratings remain in line with standard Vahterus Combined designs. The integrated superheater section is available with design pressures of 16, 25, 40 or 60barg (232, 363, 580 or 870psi) , with higher ratings available on request. The superheater pressure rating can be selected independently of the shell and plate pack design pressure, providing greater flexibility for system design.
Vähätalo noted that the superheat functionality can support evaporation capacity up to 5MW (1,422TR)
