Avid Boustani

Remanufacturing and energy savings.

Remanufactured products that can substitute for new products are generally claimed to save energy. These claims are made from studies that look mainly at the differences in materials production and manufacturing. However, when the use phase is included, the situation can change radically. In this Article, 25 case studies for eight different product categories were studied, including: (1) furniture, (2) clothing, (3) computers, (4) electric motors, (5) tires, (6) appliances, (7) engines, and (8) toner cartridges. For most of these products, the use phase energy dominates that for materials production and manufacturing combined. As a result, small changes in use phase efficiency can overwhelm the claimed savings from materials production and manufacturing. These use phase energy changes are primarily due to efficiency improvements in new products, and efficiency degradation in remanufactured products. For those products with no, or an unchanging, use phase energy requirement, remanufacturing can save energy. For the 25 cases, we found that 8 cases clearly saved energy, 6 did not, and 11 were too close to call. In some cases, we could examine how the energy savings potential of remanufacturing has changed over time. Specifically, during times of significant improvements in energy efficiency, remanufacturing would often not save energy. A general design trend seems to be to add power to a previously unpowered product, and then to improve on the energy efficiency of the product over time. These trends tend to undermine the energy savings potential of remanufacturing.

Experimental investigation of nanofluid shear and longitudinal viscosities

Dilute nanoparticle suspensions of alumina in decane and isoparaffinic polyalphaolefin (PAO) exhibit thermal conductivity and shear viscosity that are enhanced compared to continuum models that assume well-dispersed particles. An optical technique has been used to measure the longitudinal viscosity of these suspensions at frequencies from 200to600MHz and evaluate an effective hydrodynamic particle size. The measurements indicate that for the decane-based nanofluids the nanoparticles do not form clusters. In the case of PAO nanofluids, the measurements of longitudinal viscosity and the corresponding values of the particle size are consistent with a picture of nonclustered particles in a weakly shear-thinning viscous oligomeric oil.Dilute nanoparticle suspensions of alumina in decane and isoparaffinic polyalphaolefin (PAO) exhibit thermal conductivity and shear viscosity that are enhanced compared to continuum models that assume well-dispersed particles. An optical technique has been used to measure the longitudinal viscosity of these suspensions at frequencies from 200to600MHz and evaluate an effective hydrodynamic particle size. The measurements indicate that for the decane-based nanofluids the nanoparticles do not form clusters. In the case of PAO nanofluids, the measurements of longitudinal viscosity and the corresponding values of the particle size are consistent with a picture of nonclustered particles in a weakly shear-thinning viscous oligomeric oil.

Appliance remanufacturing and life cycle energy and economic savings

In this paper we evaluate the energy and economic consequences of appliance remanufacturing relative to purchasing new. The appliances presented in this report constitute major residential appliances: refrigerator, dishwasher, and clothes washer. The results show that, despite savings achieved in production, appliance remanufacturing is a net energy-expending end-of-life alternative. Moreover, we find that economic incentives can be an influential driver for consumers to remanufacture and re-use old appliances.

Reusing personal computer devices - good or bad for the environment?

The energy saving potential of reusing / reselling personal computer (PC) devices was evaluated relative to the choice of buying new. Contrary to the common belief of reuse leading to energy savings, with the advent of more efficient laptops and liquid crystal displays (LCD), reuse of an old personal computer device can lead to relative energy expenditure. We found that in certain scenarios this expenditure could be as large as 300% of the lifecycle energy inventory for the new device. As a result, it is essential to assess the reuse of personal computer devices more critically, incorporating the different factors that influence the analysis as discussed below.