Techno-Economic Analysis of Hybrid Solar-Assisted Air Source Heat Pump Systems in University Residences

This study addresses the high operational costs and inefficiencies associated with electric boilers used for sanitary hot water in South African university residences. With electricity tariffs rising due to the increasing cost of coal-based energy, traditional electric boilers remain energy-intensive and unsustainable. This research proposes retrofitting a 2000L (24kW) electric boiler with a Hybrid Solar-Assisted Air Source Heat Pump (HSAASHP) system, combining solar collectors and air source heat pump technologies to improve energy efficiency and reduce costs. The methodology involved designing and installing an HSAASHP system in the Mannheim Ladies’ Residence at the Central University of Technology, Free State, and deploying a Data Acquisition System (DAS) to monitor its performance. Comparative analysis of the baseline electric boiler and the retrofitted system revealed significant energy savings: annual electricity consumption dropped from 151,128.9 kWh to 41,036.8 kWh, with an Energy Factor (EF) ranging from 3.0 to 5.2, higher in summer. Techno-economic analysis demonstrated the system's viability, with a payback period of 2.19 years, a break-even point on the 3^rd year of the HSAASHP water life span, and a 15-year net present value of R10,503,958. The investment yielded an annualized Return on Investment (AROI) of 14.39% and a profit margin of 87%. The HSAASHP system offers a cost-effective and energy-efficient solution, addressing the pressing need for sustainable water heating in resource-constrained environments. This approach not only enhances energy efficiency but also provides a scalable model for reducing energy costs and environmental impact in similar settings.