This section will be focusing on saving in terms of cost and CO2, which is used as the indicator for environmental burden. In this study, the product ending in disposal is the default path in manufacturing; given OEMs act in accord with the take-back regulations.

Life Cycle Cost Analysis

Recovering the EoL product always involves a cost, and this cost can vary depending on the choice of product recovery process. A simple rule of thumb is that the product recovery cost shall not exceed the cost of manufacturing a new product or the cost of disposal. Thus, it is critical that one considers all the costs incurred for recovering the EoL product from EoL product collection, logistic, EoL product evaluation, recovery process, recovered EoL product packaging and marketing, etc.
The cost calculation for a new product can be seen in Eq. 1, where the cost of manufacturing a new part is one of the cost components in the disposal cost (Eq. 2) and recovery cost (Eq. 3). Operational cost in Eq. 4 is one of the cost components in manufacturing and recovery cost:

Life Cycle (Environmental Impact) Assessment

Life cycle assessment (LCA) is a widely used technique for assessment of environmental impacts throughout the entire product life cycle. Of the entire life cycle of crankshaft (from refrigerator compressor) as a case study, LCA is applicable to the material extraction, transportation, and manufacturing process of the product. The main contributors to ecological burden are energy usage (in the form of electricity) in material extraction and manufacturing process, as well as fuel consumption in transportation. These inputs are shown in Table 3.
In view of the above inputs, the following values, unique to this case study, are keyed into the SimaPro program for each of the reprocessing options:

1.    1 kWh of electricity in Singapore is comprised of (Tan et al. 2010):
  i. 0.758 kWh natural gas, burned in power plant
ii. 0.219 kWh electricity, oil, at power plant
iii. 0.023 kWh electricity, waste, at municipal waste incineration plant
2. Power consumed for recycling using induction furnace: 700 kWh/tonne (Gandhewar et al. 2011)
3. Transportation used: transport, lorry, 3.5–7.5 tonne, EURO 3

Global warming is used as the impact category; thus the environmental impact to be obtained is the sum of the carbon dioxide (CO2) emission from all types of energy consumed.
The environmental impact caused by recovery activities is calculated using equation (5)

where
the electricity grid emission factor (Singapore NEA 2012) is
1 kW electricity = 0.5716 kg CO2e/kWh
and the direct GHG emission factor (Guidelines to Defra 2012) is
1 litre of diesel = 2.6763 kg CO2e/l

The environmental impact caused by carbon emission from making new product is calculated using Eq. 6, carbon emission from product disposal is calculated with Eq. 7, and carbon emission from product recovery options is determined using Eq. 8. Carbon emission from recovery operation in Eq. 9 is one of the carbon components in all of the above equations:

where:
EInew = Environmental impact caused by making new product
EIdis = Environmental impact caused by product disposal
EIrec-i = Environmental impact caused by recovery option i,
i = 1 (Reuse); i = 2 (Reman.); i = 3 (Recycle)
EIprocess-j = Environmental impact caused by process j, j = 1, 2, 3. . .

The LCA is done using SimaPro program, and ReCiPe (midpoint) is utilized as the assessment method. Among the three cultural perspectives, egalitarian is chosen for it represents long-term and conservative environmental mindset. Furthermore, the environmental impact calculation is reflected in kg CO2 equivalent, which is located under the “climate change” impact category (Flowers et al. 2003). LCA is done for all options – reuse, remanufacture, recycle, and dispose. In the end, the procedure generates various environmental impact indicators, as shown in Fig. 9.