Lighting Systems
Plant and office lighting can also be a significant source of energy savings. Here, management will most likely be con- fronted with some capital costs to realize energy savings, though the ability to tackle those costs in manageable steps can be realized.
Today’s lighting technologies are highly efficient in their use of electrical power as compared to the past lighting tech- nologies available. If this technology has a fault, the fault is in that it is improving so rapidly it makes recently installed upgrades “obsolete.”
However, the cost of not acting now to streamline your light- ing systems far outweighs any concerns in this area. Because lighting is universal to all industries, and its improvement is easily measured by the difference between the previous and new fixtures, many governmental agencies and power providers have made this an area with significant available rebates and tax incentives.
Today’s lighting fixture designs drive light deeper into the plant and provide truer colors for better employee comfort. Beyond the selection of appropriate fixtures, lighting fixture layout acts as a primary tool for efficiency improvements via a qualified engineering review. Motion sensing and centralized automated control also offer op- portunities for significant improvements, in both energy usage and in maintaining consistent levels of light where and when it is needed.
Both the deposition of dust and high heat can be a problem with incompatible lighting fixtures and sensors in an operating foundry if not managed properly. Tolerant specialized fixtures exist that will perform well in these areas. However, “easy” plant areas such as offices, core rooms, pattern vaults, shipping warehouses, maintenance shops, and similar low dust areas are prime candidates for the first phase of lighting retrofits.
Compressed Air Systems
Compressed air also represents a significant area of potential energy efficiency improvement. The generation and delivery of compressed air is highly inefficient, with one third of all compressed air horsepower being lost in the process. Every foundry should develop an in-depth understanding of the functioning and limitations of their compressed air system, and work to improve its performance. A supply and demand side audit, as well as a system leak evaluation, can yield tremendous benefits. Savings are typically realized in these low-capital activities such as leak repairs, piping changes, air storage sizing, and proper compressor sequencing.
Many of us are guilty of just tapping new processes into an existing system without much thought on how they may add to the inefficiency of air delivery. Beyond the modest im- provements just described, a well designed evaluation and re-engineering will often yield even greater benefits in en- ergy use reduction and system delivery/reliability.
Melt Savings
Never forget that every area of the foundry operation is fer- tile ground for green savings.Buying the right scrap can net energy savings even before melting materials are received at the foundry. Ferrous foundries have long been comfortable with receiving post consumer steel scrap that contains a mod- erate amount of surface rust, paint, adhering non-metallics, and other non-steel attachments. Sheared scrap can contain 5–8% by weight of tramp non-metallic materials. Eliminat- ing the non-metallic materials can yield significant savings. The savings in this example are experienced throughout the melting process. Energy is consumed in shipping this mate- rial. Charge weights are affected by non-metallics. One of- ten unrecognized energy loss is that it takes 1.7 to 2 times the energy to melt slag than iron. Thus, by purchasing a clean scrap created by shredding rather than shearing one reduces energy consumption (of the steel scrap portion of charge) by 15% to 20%. Shredded materials often cost more than sheared scrap but paybacks in other areas can offset these costs while promoting the plant’s sustainability effort.
Figure 5. Retrofit of facility HID lighting to T-5 high bay fluorescent and benefit chart.
12
Further melting savings can be achieved by cleaning gates and risers of sand by passing them through a properly designed rotary drum, or for very clean returns, a quick shot blasting of the returns. Reclamation of this sand may be desirable from the aspect of recovering the thermally expanded and, there- fore, more dimensionally stable sand adjacent to the gating.
International Journal of Metalcasting/Summer 10
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81