Performance of a heat-and-vent electric dryer for textiles in household conditions: a New Zealand case study

Abstract

An electric clothes dryer is a common household appliance and its use contributes a large portion of energy consumption from household appliances. In some countries, dryers are labelled with an energy rating indicating their energy consumption relative to comparable dryers on the market. Standard performance testing for electric clothes dryers imported to New Zealand (NZ) requires an ambient temperature of 20 ± 2 °C and relative humidity of 60 ± 5%RH. However, the published literature shows that rooms in NZ homes tend to be colder than 20 °C, especially in winter months when a dryer is more likely to be used. We investigate the performance of a commercially available clothes dryer at the standard ambient moist air conditions, with standard calibrated textile loads, to measure the electrical energy consumption of the dryer. Tests are repeated for different sets of ambient temperature and relative humidity conditions. Lower ambient temperature operation shows a decrease in total energy performance of around 17% and 14%, for 2.1 and 6.1 kg loads, respectively, compared with drying at the standard conditions. Operation at a higher relative humidity for a fixed ambient temperature shows an 8% increase in total energy consumption. Tests were also carried out with the dryer wrapped in thermal insulation, and results show that energy performance did not change significantly. These results indicate that changing AS/NZS2442.1:1996 to better match moist air test conditions typical of a NZ home may improve energy performance characterisation of dryers operating in these homes, and contribute to removal of less efficient dryers from the NZ market.