Greywater heat recovery to the refill water of a dishwasher via paraffin wax and steel wool aided segmental baffle heat exchanger

Abstract

In this study, the recovery of household dishwasher greywater thermal energy into dishwashing water using paraffin wax and steel wool supported segmental heat exchanger was experimentally investigated. The heat exchange performance was 40% in rapid, economy, and intensive modes and the heat recovery was 0.048, 0.031 and 0.082 kWh, respectively. Efficiency increased by 5.01%, 3.84%, and 6.5%. Time and energy were saved, and hygienic washing was accomplished by raising the washing temperature and reducing the cycle time nearly 97, 113, and 240 s. It is estimated that by using heat exchangers on 16,954,196 dishwashers in use in Turkey, small, medium, and large families can save an average of 127.366, 254.733 and 509.466 GWh per year, respectively, provided they use the three dishwasher modes equally. The annual economic size of the gain and its contribution to emission reduction in CO₂ equivalents are $15.793 million, $31.586 million, $63.173 million and 112.974 kt, 225.948 kt, 451.897 kt, respectively. Energy efficiency index of dishwasher increased from 48.84 to 46.97.

Disclosure statement

No potential conflict of interest was reported by the author(s).