Reviews on heat recovery technologies for building applications

In recent years, the interest in the heat recovery systems for building applications has resurged due to the concerns about energy crisis and global climate changes. This review has presented current development of four types of heat recovery systems for building applications. An extensive investigation on the heat recovery integrated in energy-efficient systems of buildings has also been covered, including passive systems, mechanical ventilation systems, dehumidification systems and PV/solar panel systems. Based on this review, the key issues have been listed as follows: 1.The combination of heat recovery and energy-efficient systems could be considered as a promising approach to reduce greenhouse gas emissions and make the building meet high performance and comfort requirements. However, air flow control and real-life evaluation with economic analysis of these systems are insufficient; 2. When heat recovery is applied to mechanical ventilation systems, issues such as pressure leakage and air shortcuts should be addressed. Besides, very few literatures cover the study of dealing with air pollution which would influence the interior air quality and human health; 3. Further studies on innovative defrosting methods, heat recovery integrated with PV hybrid systems and heat recovery combined with building structure are needed to achieve a better thermal performance of heat recovery.