## 3 Methods
### Reassembly Phase  
The following section presents the description of the reassembly phase. This phase starts by verifying the quality of the recovered parts. Both inspection and testing are conducted on all parts before they are placed in reassembly. Once the parts pass the inspection process, they then go on to the next step in the reassembly phase. Failed parts as well as parts that need upgrading are replaced with new ones. Figure 6 demonstrates the reassembly steps. In this stage of the remanufacturing of an AC, the following steps are followed to reassemble the AC back into a functional unit, which are:  
1. Assembly of the evaporator and condenser to the base;
2. Assembly of the motor and fans;
3. Assembly of the compressor;
4. The brazing and welding of pipes and joints;
5. Assembly of the front electrical panel along with the wiring;
6. Refrigerant charging. It is important to note that all parts are assembled with the base (i.e., parts themselves were not disassembled--they were treated as one unit). Additionally, as the dimensions and sizes of the units are different due to the different types of ACs, the assembly process is conducted manually with the aid of power tools. These tools are different to those used for new ACs. Tools that are necessary to finish the assembly include:  
* Welding tools (brazing);
* Refrigerant injection tools. All parts are moved from one stage to another using an electrical roller conveyor. Brazing tools are used to weld the pipes together as well as joints that were cut during the disassembly process. An example of the tools needed for that can include a liquefied petroleum gas (LPG) welding kit. A refrigerant charging method similar to the one used in manufacturing new ACs can be used in the case of remanufacturing. Finally, a roller conveyor is needed to facilitate the moving of units after they are assembled since the process is manual. Figure 5: The cleaning phase modeling using GaBi software. The design parameters and assumptions for this stage are as follows: after the parts are cleaned, they are put together to be ready to be sold again, and all of the parts need to be inspected and tested as discussed in the following section:  
* Visual inspection, wherein the inspector visually investigates each component for apparent damage, cracks, or inconsistencies. This inspection requires no electricity or input materials. * Leak test: In addition to the visual testing, a pressure test is performed for all components of the AC including the compressor, evaporator condenser, and pipes. Reassembly can be facilitated using a power screwdriver. The same type of powered screwdriver that is used in the disassembly is used for the reassembly, hence the same design parameters and assumptions apply. In the brazing process, LPF is used as a source of heat to heat the copper pipes and to melt the brazing rod. Due to the large heat losses inherent in the process, the calculated energy for copper pipe heating and the brazing rod melting is very low compared to the losses. The total energy expended would be estimated based on an expert's judgement, which was estimated at 0.001 MJ. In the stage of refrigerant charging, an R22 refrigerant is charged to the unit. The unit was connected to a reservoir of R22 at a particular pressure. Charging lasts until the pressure in the reservoir and the AC unit become equal. The studied model requires 1 kg of refrigerant. In the case a new type of refrigerant is used, the charged mass needs to be determined. For the final inspection, the final assembled unit is tested to verify its functionality and to ensure it is free of any defects. The unit is tested under its normal working condition. In this test, the installed compressor of the AC itself performs the job. It will compress and circulate the refrigerant throughout the unit. The consumed electricity depends on the compressor power rating, which in this case has a power rating of 1.75 kW. The pressure test is run approximately for 330 s and so the power consumption is 0.16 kWh.