Heat recovery is a process of converting wasted heat, which would otherwise be lost to the environment into useful work to power other thermal systems thereby, improving the power generation while saving overall energy costs. The paper is aimed at sharing the methodological approach employed in a heat recovery research based on recoverable heat computation analysis conducted on various heat recoverable systems using specific key computational indicators and comparing the results with that obtained in Heating-Ventilation and Air-conditioning (HVAC) appliances which are powered by Photovoltaic (PV) and Photovoltaic Thermal (PV/T) cells. The design elements considered in this research were informed by existing heat regeneration and conversion processes. The heat regeneration process typically found in gasoline turbines, and those found in PV cells were considered. The workability of these systems for heat reuse is an integral part of the study. The relevance of this research is that the findings informed the design of a heat recovery unit for a PV solar air-conditioning system. Through computation analysis, the benchmarks obtained forms part of the building block that supports the design phase of a heat recovery system. The principles applied as presented in this paper will guide researchers who are considering venturing into projects related to heat recovery.