A comparative analysis of heat pipe and rotary regenerative heat exchangers

In this study, a mathematical modeling study combined with experimental part of a heat pipe heat exchanger (THEX) was performed. Then, the rotary type regenerative heat exchanger (RHEX), which is widely used in heat recovery applications, is also analytically modeled. Using these models confirmed by experimental data from literature, a regenerative heat exchanger design with the same volume as the heat pipe heat exchanger has been designed. Using proposed designs, heat pipe heat exchanger and rotary type regenerative heat exchanger with the same mass flowrates and air inlet temperatures were compared in terms of air outlet temperatures, total effectiveness value, total fan power requirements, mass and material cost. In this context, effects of hot stream inlet velocity were investigated. Under the same operating conditions, the total effectiveness value of THEX is found to be 24.7% higher than RHEX, the total fan power requirement at RHEX is approximately 45 times higher than THEX, the total mass of RHEX is approximately 16 times higher than THEX. In addition, RHEX total material cost is approximately 4 times higher than THEX. In general, the heat pipe heat exchanger stands out in terms of effectiveness, total fan power requirement, and cost for heat recovery applications.