Exergy–economic evaluation of heat recovery device in mechanical ventilation system

Abstract

The paper presents new approach in evaluation of heat recovery devices in mechanical ventilation system. The evaluation is based on exergy balance equation and economic analysis, what requires application of one of multicriteria decision aid methods—weighted sum method. The proposed set of evaluation criteria consists of: driving exergy, simple payback time and investment cost. The proposed method is applied to compare the four variants of heat recovery device in inlet-exhaust mechanical ventilation system of the capacity of 10,000m3/h installed in residential part of hotel. The analysis is performed for four preference models. The results of the multicriteria evaluation indicate that counter flow plate heat exchanger and the rotating heat/mass regenerator are better solutions comparing with water loop heat exchanger and heat pipe heat exchanger. Counter flow plate heat exchanger is the most compromise solution for the two preference models PREF_00 (based on statistic approach) and PREF_03 (investment cost priority preference model). Rotating heat/mass regenerator is the most compromise solution for the preference model 01 (driving exergy priority preference model). The proposed method can be helpful in the choice of the most compromise solution of the heat recovery device in pre-design phase.