ALBERT

Description: Thermoelectric (TE) based cooling and heating systems offer significant advantages over conventional vapor compression systems including no need for refrigeration or major moving parts, high controllability, and scalability. The purpose of the present study is to provide an energy and economic assessment of the performance of a TE-based radiant cooling and heating system for building applications. It is considered that TE modules are integrated in the ceiling to lower/increase the ceiling temperature through the Peltier effect during the hot/cold season to provide thermal comfort for the occupants via radiation and convection. The study explores the possibility of using rooftop PV panels to produce electricity required for the operation of TE modules. An actual office building located in Melbourne, FL, USA is considered for a test study, and the hourly cooling and heating loads of the building are calculated through building energy simulation in eQuest. Various operating conditions, including different input voltages and temperature gradient across TE modules, are considered, and the system is sized to properly address the year-around cooling/heating demand. It is shown that a nominal cooling capacity of 112.8 W and a nominal PV capacity of 31.35 W per unit area of the building is required to achieve the target goal when the system operates at the optimal condition. An economic analysis is also performed, and estimated cost, as well as potential savings, are calculated for each operating condition. The optimal operating condition with minimum cost is selected accordingly. The results demonstrated that the initial cost of the proposed system is considerably higher than conventional heating/cooling systems. However, the system offers other benefits that can potentially make it an attractive option for building cooling/heating applications.

Description: The present paper investigates the performance of a thermoelectric (TE)-based radiant ceiling panel with an additional layer of phase change material (PCM) for building cooling application through numerical and experimental analyses. The design of the ceiling panel consisted of an aluminum sheet with TE modules installed on the back to maintain a relatively low ceiling temperature that provided cooling through radiation and convection. A three-dimensional model was developed in COMSOL Multiphysics, and the system’s performance in several different configurations was assessed. The effect of the number of TE modules, as well as incorporating different amounts of PCM under transient conditions, was investigated for two modes of operation: startup and shutdown. It was shown that for a 609.6 mm × 609.6 mm ceiling panel, the use of four TE modules reduced the average surface temperature down to the comfort range in less than 5 min while producing a relatively uniform temperature distribution across the ceiling panel. It was also shown that the addition of a 2 mm thick PCM layer to the back of the ceiling panel enhanced the system’s performance by elongating the time that it took for the ceiling panel’s temperature to exceed the comfort range when the system shut down ,which in turn reduced the number of on/off cycling of the system. The numerical results demonstrated a good agreement with the experimental data. The results from this study can be used for the optimal design of a TE-based radiant ceiling cooling system as a promising technology for smart buildings.