Energy saving, environmental-friendly, washing/drying process for industry and households

The core in the new unit is a zeolite based adsorber and heat exchange unit. An analysis of the possible energy saving using the new process indicate the concept to be considerably more interesting in connection with self-service laundries than for small household laundries. For a standard German self-service laundry it should be possible to obtain an energy saving of 40% (760 kWh/day) and a water saving of approx =0.9 m3/day assuming use can be found for an 6 m3/day excess of 60 deg. C hot water. If there is no use for the excess hot water, the energy saving will be only 400 kWh/day according to the calculations. For small household laundries the new process will only be interesting if the excess of 60 deg. C hot water can be used for heating or in the normal hot-water supply. The laboratory work carried out include the collection of reference data for the Nyborg 166 T electronic tumble drier used, fabrication of zeolite A bodies for making the honey comb structure forming the core of the new device, characterization of the water adsorption capacity of the zeolite bodies prepared as a function of temperature and of the kinetics for water adsorption under different conditions. A full-scale prototype of the zeolite-based unit has been designed, constructed and tested. The unit is conatined in a approx =15 cm high box with the same width and length as the original tumble drier. The testing of the complete system showed it to be unsatisfactory due to air leakage in the original tumble drier (47% of the air passed through the zeolite unit). Due to this problem, it proved impossible to heat the outlet air from the zeolite unit to the desired air inlet temperature for the tumble drier. However, in the best experiment the outlet air showed an integrated energy increa se of 2.94 kW, which is larger than the sum of energy used to evaporate the water in the drying process (2.23 kW) and the energy lost in heating the tumble drier (0.49 kW). Thus, if the undesired air leaks in the tumble drier can be reduced to less than 10% of the present value it should be possible to make the system work in practise. Also, the water adsorption and heat generation in the zeolite unit occurs in a more complicated way than originally thought. Thus, by a redesign of the zeolite unit and through further materials development further improvements of the system may be obtained