Performance study of a novel indirect evaporative/air-cooled thermoelectric cooling air conditioning system

A novel hybrid air conditioning system with combination of indirect evaporative cooling and air-cooled thermoelectric cooling technologies (i.e. IEC/air-cooled TEC system) is proposed, in order to make full use of natural cold source and increase the energy efficiency and environmental performance of the air conditioning system. The effects of main operational parameters (such as the electric current I and number n of the TEC modules, inlet temperature, relative humidity and mass flow rate of the primary air, as well as the mass flow rate ratio of the secondary air to the primary air) on the performance of the hybrid system are experimentally investigated. A numerical model is also established and validated by using the experimental results. The performance optimization of the hybrid system is conducted numerically. The results indicate that the primary air temperature can be reduced below the dew point temperature by selecting appropriate operational parameters. Under fixed dew point effectiveness, maximum coefficient of performance (i.e. COP) can be achieved by optimizing I and n of the TEC modules. Moreover, there exists an optimal mass flow rate ratio and an optimal ratio of the IEC channel number to the TEC channel number that maximize the COP of the hybrid system. Additionally, comparative analysis on the performances of hybrid systems with and without spray water in the TEC's primary air channel is also made. It is found that, on the whole, introducing spray water into the TEC's primary air channel could enhance the system's performance.