Experimental investigation on heat transfer and air flow behavior of latent heat storage unit in a facade integrated ventilation system

All-air central HVAC systems are widely applied to provide fresh and conditioned air, which is very important for users to lead healthy and productive lives. Decentralized systems are another mechanical solution to ensure indoor air quality and thermal comfort with a heat recovery ventilation system integrated into the building wall. These commercially available systems store sensible energy in the heat exchanger. In this study, an experimental real-size staggered tube bundled prototype with phase change material (PCM), which stores latent thermal energy, was proposed/designed and full-scale experiments were carried out in laboratory conditions. The experimental setup includes two spaces that simulate indoor and outdoor conditions that are separated by an insulated aerated concrete wall. In the prototype, two ducts embedded in the wall contain staggered tube bundles filled with PCM, which are positioned perpendicular to the airflow to recover heat for supply and exhaust ventilation modes. The thermal performance of this prototype is investigated for different operating times, namely, 15, 20, and 30 min. The average air energy change of the latent heat recovery ventilation system values is between 20 and 35 kJ approximately for the operating times. The supply mode efficiency result is an average of 50% and exhaust mode efficiency is 25%.

Automated summary

All-air central HVAC systems and decentralized systems are common solutions for heating, ventilation, and air conditioning. The study proposed an experimental prototype with phase change material to improve thermal energy storage efficiency and indoor air quality. The results showed the thermal performance of the prototype under different operating times.