Thermoelectric active window frame: Constructive integration and preheating analysis

Abstract

Building heating and cooling systems using thermoelectricity appear to be a feasible alternative, as it presents several features including versatility and high reliance. While most applications of thermoelectricity in buildings are found in wall systems, window integration shows excellent potential for enhancing the thermal performance of buildings at the façade level, compensating heat losses that take place in windows. Combining energy efficient ventilation with heat recovery leads to a significant reduction of the required energy, keeping desired comfort conditions inside buildings. Thus, the following study presents the design of an active window frame with an integrated thermoelectric system, attaining two functions: pre-heating the supply air, while simultaneously recovering the waste heat energy from exhaust air. Two full-scale prototypes were built, each featuring a different airflow pattern, and preliminary tests for heating mode were carried out under laboratory conditions. The results revealed a similar performance comparing both prototypes, achieving a COP ranging 1.56 to 2.71 for prototype A, while prototype B ranged from 1.62 to 2.65. The results showcase superior heating efficiency compared to a previous experiments conducted by the research group, where a maximum COP of 1.91 was achieved. From a building perspective, wider adoption of thermoelectricity applied to thermal conditioning is hindered by lack of suitable products for architectural integration. Therefore, the system's innovation stems from optimized design, integrated construction, and industrialized production, enhancing energy efficiency in buildings via a compact façade integrated system without space compromise.