Epta’s Full Transcritical Efficiency system FTE provides high energy efficiency in transcritical refrigeration systems with medium and low temperature applications. With only standard components it allows an increase of the evaporation temperature and an elimination of superheat in the medium temperature loads.
This leads to an energy efficiency of 10% compared to a standard transcritical cycle.
In standard transcritical systems, the evaporating temperature of medium temperature applications is approximately -10°C to -7°C, depending on the used cabinets. For safety reasons, the superheat is set to minimum 8K.
With FTE, evaporating temperature is increased, and superheating is eliminated. In an additional receiver, the liquid which is leftover from the evaporating process is collected.
When the liquid receiver has reached the maximum filling level, the solenoid valve is closed and the liquid from the FTE receiver is automatically sucked into the negative applications.
When the receiver is fully drained, the solenoid valve is opening again and feeding the LT loads with liquid from the standard receiver.
The FTE receiver is filled and drained repeatedly. The advantages of the higher evaporating temperature and the lower super heating are used 365 days per year.
The advantages of evaporators overfeeding are:
- Evaporating temperature increased up to 6K
- Liquid refrigerant ensures excellent heat transfer
- Evaporating temperature increased 365 days up to 6K (2.5-3% energy saving per K)
- Optimal heat transfer rate: the entire evaporator heat transfer area is optimally used
- Energy saving guaranteed during the whole year (PSSM Permanent Super Saving Mode).
Between MT refrigerated loads and the MT compressor suction line
- Provides a gravity separation between liquid and vapor phase refrigerant
- Buffers the liquid from the MT refrigerated loads and delivers it to the LT loads
- When the liquid gets a specific set level inside the FTE, the solenoid valves switch off and the LT loads are fed with saturated liquid from the FTE module by pressure difference.
FTE 2.0 has the added advantage of being no longer physically present in the machine room. Less space required, reduced installation time, better quality and higher performance!
- Stops the liquid flow from the main liquid receiver when the liquid to the LT loads is delivered from the FTE module
- The LT loads are cooled alternatively either from the main receiver (LR) or from the FTE module
- Both LR and FTE module ensure that MT evaporator overfeeding is continuously maintained (PSSM Permanent Super Saving Mode)
- LT loads are supplied with sub-cooled liquid from the MT loads
- The difference of enthalpy of vaporization for the LT loads is increased
- After the FTE has delivered all the buffered liquid, the solenoids switch on again and the FTE starts to buffer new liquid from the MT loads
- FTE cycles emptying and filling all the time