Microsoft Word 2012, Källén, M.,-Energy Efficiency Opportunities within the Heat Treatment Industry

5.2.3  Production Planning 

The results in table 3 were used to find measures to decrease the electricity consumption by 

production planning. According to the specific electricity consumption for each hardening 

furnace the following priority order could be stated: 

1.  126 

2.  123 

3.  124 

4.  122 

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31 

 

Using the priority order for the hardening furnaces and the assumption that the utilization 

ratio could be up to 90%, it was found that the electricity consumption could be decreased 

with 219.5 MWh/year. This high number is due to that 122 could be turned off when the 

production was relocated to the other furnaces. The difference between the saved 

electricity/year and the total consumption in 122 during one year amounts to the increased 

consumption of the other furnaces when they were given a higher utilization ratio. This may 

not be possible to do continuously, since the oil bath in 122 contains a different cooling oil 

than the other furnaces and this oil is preferred for some batches. 

The utilization ratio of 38% in the preheating furnace in the large line was considered to be 

unnecessary low. Five preheating furnaces are assumed to be used in the large line and if the 

batches for one of the preheating furnaces could be relocated to the other furnaces, 66.3 MWh 

of electricity could be saved each year.