Investigating the impact of Trombe wall parameters on thermal performance and room temperature in the Iraqi climate

Abstract

Trombe wall serves as an effective passive heating element, and its performance is heavily reliant on local climate conditions. This study involved both experimental and numerical analyses of a full-scale test room equipped with a Trombe wall under Iraqi climate conditions. To facilitate this investigation, an experimental test room was constructed in Kirkuk city with dimensions of 4.0 m × 3.0 m × 2.75 m. In addition, a numerical simulation method based on computational fluid dynamics was developed and a computer code was created to investigate the performance of the system. The accuracy of the developed numerical approach was validated against experimental data collected from the test room. This analysis was conducted specifically for the period of February 17–18, which represents the coldest month of winter in the study area. The performance of the system was assessed with respect to various parameters; air gap width variations (2, 4, 6, and 10 cm), massive wall thickness ranging from 15 to 35 cm with 5 cm increments, channel width options (3, 5, 10, 15, and 20 cm), and vent heights ranging from 5 to 20 cm in 5 cm increments. Furthermore, an investigation of the impact of replacing the air in the air gap with inert gases, specifically argon, krypton, and a mixture of these gases with air was conducted, as well. The outcomes indicate that both the channel width and vent height do not have a significant impact on the system's performance. However, the width of the air gap has a modest effect on system performance, and the best performance was observed with a smaller gap width, specifically 2 cm. The most significant impact on room temperature is observed when the storage wall thickness is varied. In the case of wall thickness of 15 cm, there is a notably higher fluctuation in room temperature between the maximum and minimum values, reaching approximately 16°C. For a wall thickness of 35 cm, however, this fluctuation is significantly reduced to about 3°C. The system efficiency as determined after 24 h of operation period improved significantly when the air was replaced by an inert gases or a mixture of gases in the air gap. Compared to air, the increase in efficiency is about 14.8% for argon, 17.7% for krypton, and 20.6% for the mixture of gases.