Performance Investigation Of An Active Thermoelectric Wall Based On The Large Size Thermoelectric Cooling Chip

The building envelope is the interface that separates the indoor and outdoor environment,it has an important influence on building energy consumption while regulating the flow of indoor and outdoor environmental energy.The active wall based on the principle of thermoelectric cooling can eliminate the load of the traditional building envelope structure,and c an also provide a certain amount of cooling and heating capacity for the indoor.In recent years,various countries have developed different types of thermoelectric buildings integrated with envelope structures.However,the current thermoelectric cooling chips are usually designed for the heat dissipation of electronic chips or small refrigeration systems,they have the characteristics of high heat flux density and sma ll volume.When they are used in building envelopes,they need to be dispersedly arranged,which is difficult to integrate with building walls.In this paper,large-sized thermoelectric cooling chips are combined with the building wall,and the ceramic surface of the thermoelectric cooling chips is directly used as the inner surface of the building wall.An active thermoelectric wall(ATEW)system was constructed.The theoretical model of ATEW system was established,and the accuracy of the model was verified.Based on this,the performance of ATEW system was optimized.The main research content and results are as follows:Firstly,the working principle of the ATEW system is introduced.Large-sized thermoelectric cooling chips ares combined with a building wall.An experimental platform was built in Changsha,and conducted experimental research on ATEW system.The performance of the system at different operating currents and outdoor temperatures was tested.Secondly,the one-dimensional unsteady heat transfer model of the ATEW system was established,and the simulation results of the model were compared with the experimental results to verify the accuracy of the model.The results show that the simulated values agree well with the experimental values,and the theoretical model established in this paper has high accuracy.Finally,the performance of the ATEW system was optimized and analyzed using the established theoretical model.Simulat ing and analyzing the performance of the system under different working current,outdoor temperature and heat dissipation capacity of the hot side.The results show that the cooling coefficient and heating coefficient of the system increase first and then decrease with the increase of the working current.The cooling coefficient of the system increases with decreaseing outdoor temperature,and the heating coefficient increases with increasing outdoor temperature.The cooling coefficient and heating coefficient of the system increase first and then hardly change with the increase of the heat dissipation capacity of the hot end.When the indoor temperature and outdoor t emperature are 25℃and 30℃respectively,and the optimal current is 0.8A,the maximum cooling COP of the ATEW system is 0.231.The indoor temperature is 20℃,the outdoor temperature is 15℃,the optimal current is 0.8A,and the maximum heating COP of the ATEW system is 0.539.Under heating conditions,the COP of the ATEW system is less than 1,the main reason is that the heat exchange strength of the hot side on the indoor is insufficient.When the heat transfer coefficient of the indoor hot side increases from 10W/(m~2-K)to 130W/(m~2-K),the maximum heating COP increases from 0.539 to 2.321.When the large-sized thermoelectric cooling chips are combined with the building wall and the ceramic surface of the thermoelectric cooling chips is directly used as the inner surface of the building wall,the required cooling cap acity and heating capacity per unit area are very small.Because the large-sized thermoelectric cooling chips currently selected are not designed for building walls,it is difficult for ATEW to operate the system in a higher operating efficiency range while meetin g cooling capacity and heating requirements.Therefore,the thermoelectric cooling chips can provide the indoor with corresponding cooling capacity or heating capacity,and the system can obtain large cooling coefficient and heating coefficient by reducing the number of P-N junctions per unit area of the thermoelectric cooling chips.The ATEW system integrates the large-sized thermoelectric cooling chips into the wall,which can eliminat the load of the traditional wall and provide a certain amount of cooling and heating capacity for the indoor.The research results of this paper provide a reference for the design of the combination of large-sized thermoelectric cooling chips and building walls.