Design and Engineering Economic Analysis of a Variable Refrigerant Flow (VRF) and Mini-Split Air Conditioning System

Abstract

Design and Engineering Economic Analysis of two widely used Air-Conditioning (AC) systems, Mini-Split and Variable Refrigerant Flow (VRF), in the new Engineering Complex Building under the same indoor and outdoor conditions for an entire year is carried out by using Carrier Hourly Analysis Program software for cooling load estimation, and the Net Present Worth Analysis for Economic Analysis of both systems. Both systems are direct expansion air conditioning systems; hence the cooling load estimation was done using the ASHRAE transfer function method embedded within the Carrier software. Equipment to be used in analysis were selected from the Toshiba selection catalogues (Mini Split system), while that for the VRF system was selected using Toshiba simulation software. The annual energy analysis of both systems indicated that the VRF system will require more energy to run on an annual basis than the Mini Split system. However, the analysis was carried out without considering the part load potential energy savings of the VRF system. Net Present Worth Analysis carried out also favoured the Mini Split system in terms of Net Present Value of the systems. Based on the Engineering Economic Analysis carried out on the two systems, the overall Net Present Value for the VRF system is N77,891,808.66, while that of the Mini-Split system is N46,641,828.74. This result shows that the VRF system has a higher cost implication than the Mini-Split system. Hence, in terms of cost, the Mini-Split system is a more viable option.