Zeolite based energy saving environmentally friendly washing/drying process
A full scale laboratory unit based on a commercial tumble drier (Nyborg 166T electronic) and a zeolite based adsorption/regeneration system has been build and tested except for the final heat exchanger for recovery of the heat during regeneration of the zeolite unit. The test results show it to be possible to do a standard drying of 5 kg cotton (1.5 kg water) in 57 min. if the zeolite unit has been regenerated at 210 deg. C and then cooled to an average temperature of 157 deg. C before initiation of the drying period.
The consumpyion of electricity for washing and drying represent an important part of the electrical power used in private households, institutions and self-service laundries. Theoretical calculations done in the first phase of the project indicate that an energy saving of 40% should be possible if a zeolite-based heat exchanger is used. The purpose of the present project is to: 1) Collect the performance data on the monolithic zeolite bodies used, which are necessary in order to optimize the heat exchanger/adsorber unit, 2) to design, build and test an improved full-scale laboratory model in order to collect realistic data for the evaluation of the energy saving possible, and the cost for a possible later commercialization
For the reference tumble drier, the nominal drying time is 52 min. using the same program. Theoretical calculations based on the experimentally observed heat losses and a regeneration temperature of 160 deg. C show the energy consumption for the two systems to be identical if the final heat exchanger has an efficiency sufficient for ecovery of 40 % of the heat, which theoretically may be extracted as 100 deg. C hot water. If the heat exchanger has an efficiency of 60% it should be possible to save from 10% (present losses) to 50% (after optimization) of the energy consumption of the reference system. This corresponds to saving of 0.45 kWh to 2.25 kWh per drying cycle. Unfortunately, the high-quality heat (cf. electric) needed for regeneration of the zeolite unit at 160 deg. C is the same as required for heatting the reference tumble drier (#approx =# 4.5 kWh/cycle). This makes the zeolite-based system less attractive for practical applications, unless a source for high-quality waste heat is available. In total it is concluded: the energy savings possible with the zeolite-based system are marginal compared to the implementation costs. The zeolite-based system definitely has a future in heat pumps for exploitation of low-grade waste heat and solar thermal energy, but it is not a realistic alternative where electric regeneration to 160 deg. C or higher is necessary. The report also contain all the experimental result on fabrication, water adsorption, heat of adsorption for zeolite A obtained during the project, as well as the results of literature studies on these subjects and the use of zeolites in heat pumps for heating and air conditioning
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Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| Nyborg Vaskerimaskiner A/S |
Contact
Kullinggade 31
DK-5700 Svendborg, Denmark
Engell, John (adm.dir.), 62800008, ird@post4.tele.dk
Øvr. Partnere: Nyborg Vaskerimaskiner A/S
