Comparative analysis of different technical solutions for HVAC systems

Comparative analysis of different technical solutions for HVAC systems for residential and business facilities is presented in this paper. Traditional systems with central air handling unit (AHU) only, combined systems with central air handling unit (AHU) and fan-coilers and VRF systems are included in the performed analysis. All of the presented systems use heat pumps to produce energy for heating and cooling. Configurations of the analyzed systems and their thermal characteristics are presented. The positive and the negative sides of the presented systems regarding energy efficiency and air quality are thoroughly examined. The direct and indirect heat transfer from the refrigerant to the treated air influences the evaporation and condensation temperatures of the heat pump which are crucial for its energy performance. COP of the systems is calculated for different types of refrig- erants that are commonly used in commercial applications. The different types of heat transfer in the systems that are considered results in difference in exergy dissipation which is discussed using p-h and T-s charts. Processes of air treatment in summer and winter mode for the different HVAC systems are presented and discussed using Mollier psychrometric diagrams. Utilization of highly efficient motors and fans and installation of heat recovery units is predicted in the presented systems.