Modelling of the life cycle of products with data acquisition features

Domestic appliances are long-lived and relatively expensive products that c ome under the new EC electrical waste recovery directive. In the UK, washin g machines in particular tend to be unreliable; increasing the reuse of com ponents could improve the economics of end-of-life operations. Trends in ap pliance design are towards more sophisticated control and networking; this makes adding functions to record data on the use of the machines feasible. The data would also have value for life cycle environmental assessment. This paper reports on the development of self-contained data acquisition un its for washing machines based on a microcontroller and non-volatile memory . The data has applications in design, marketing and servicing as well as e nd-of-life. A batch of units have been manufactured and tested on limited f ield trials in washing machines. Ten parameters are continuously monitored, timed and/or recorded during appliance operation; error conditions are als o logged for use during servicing. The data is then downloaded, either duri ng servicing or at end-of-life; the dynamic data from use is combined with static data from manufacture. The information system which links all partie s interested in the data is the key aspect of life cycle data acquisition. Two models are described which evaluate the economic benefits of adding suc h functions to products: a steady-state model as used by previous authors w ho were concerned with end-of-life product treatment and a more sophisticat ed transient model that accurately reflects the limited life of designs. Re sults show that in this case, more reusable components arise from servicing rather than from end-of-life recovery of parts. The cost savings from incr eased reuse are also estimated to be comparable to the additional cost of t he system; greater savings could well arise from the use of the use data in marketing. (C) 2001 Elsevier Science B.V. All rights reserved.