Heat recovery unit
Heat recovery with indirect adiabatic cooling.
Principle of operation
To improve the performance of sensitive heat exchangers in summer mode, combine them to an indirect adiabatic cooling system (IAC).
Rhoss has developed a state of the art recovery system that integrates indirect adiabatic cooling with high efficiency static heat recovery. Through this system, the exhaust air can be cooled in a sensitive way in one or more stages of humidification by obtaining a lower delivery air temperature than the ambient temperature without using any cold coils, thereby continuing to recover heat also if the outdoor air temperature is lower than the room temperature.
This cooling method is extremely cheap and sustainable. It also allows you to reduce the size of the cooling unit or even remove it.
Summer mode and intermediate warm season
During the hot season, the system activates the indirect adiabatic humidifier automatically, which cools the expulsion air down before entering the heat recovery unit.
This way, the temperature difference between expulsion air and outdoor air is maximised as is system efficiency. If intervention is required, the regulator activates the cooling coil and possibly the reheating one to obtain the exact temperature and humidity conditions required.
Winter mode and intermediate cold seasons
In winter the system maintains all the energy benefits arising from free-cooling and/or recovery of sensitive heat, thereby guaranteeing maximum energy savings in any environmental condition.
According to an enthalpic comparison between outdoor air and room air, and according to the required percentage of fresh air, the system regulation selects the most economic operating mode between total free-cooling, partial free-cooling, and partial and total heat recovery.
During the machine start-up stage, the unit works in full recirculation mode in order to reach the required room temperature as fast as possible.
Parameters that influence system operation
The parameters that most affect the process are room temperature and humidity and heat recovery efficiency.
Outdoor air is also important, because the lower it is, the more the room can be maintained at a lower relative humidity, thereby increasing system efficiency. It is important for energy saving assessments to be made considering the real values of system operation.