HOW DOES A HEAT PUMP EVAPORATOR WORK?
A heat pump evaporator works like a normal air conditioner, with two heat sources (one hot and one cold) to evaporate and condense water. For it to function correctly and efficiently, a vacuum of 6-8 kPa and a temperature of 35-45 °C are essential conditions. The required thermal energies (hot and cold) are instead produced through the compression and expansion of freon gas. The compressed gas transfers, via the shell and tube heat exchanger (in the PC F series) or the heating jacket (in the PC R series), the necessary calories to the effluent to be treated. The same gas, expanded by the expansion valve, as it cools allows the condensation of the steam produced in the boiling chamber, which becomes liquid and is transferred to the distillate tank and also used to create a vacuum in the boiler.
HOW DOES A HOT AND COLD WATER EVAPORATOR WORK?
A hot and cold water evaporator works like a heat pump evaporator, with two heat sources (one hot and one cold) to evaporate and condense steam. In this case, however, hot and cold water available on site are used as the required thermal energy. The hot water transfers the necessary calories to the wastewater to be treated via the shell and tube heat exchanger (in the AC F series) or the heating jacket (in the AC R/S series). Cold water, on the other hand, is sent to the condenser, bringing the vapor produced in the boiling chamber to a liquid state, where there is a vacuum condition that is a function of the temperature of the cold water available. The vacuum conditions, and consequently the boiling temperature, are therefore variable.
HOW DOES A MULTI-EFFECT EVAPORATOR WORK?
A multi-effect evaporator uses the steam produced inside the first boiler to produce new steam in the second, at a lower temperature and pressure. This steam recycling can be cascaded (multiple effect) depending on the temperature of the first fluid heating step and the fluid cooling step during the last process. Although it is possible to go beyond two effects, above this number the investment cost becomes considerable and a solution involving a mechanical recompression evaporator becomes more efficient.
HOW DOES A MECHANICAL VAPOR RECOMPRESSION EVAPORATOR WORK?
A mechanical vapor recompression evaporator or MVR utilizes the vapor generated inside the boiling chamber. This is compressed adiabatically (energy consumption depends on the compressor) with very high efficiency, the temperature rises and condensation takes place in the main heat exchanger, which transfers latent heat to the fluid to be evaporated. Furthermore, an auxiliary heat recovery system further optimizes the already extremely low energy consumption (approximately 35-40Wh/liter water, 25 times less than atmospheric evaporation).