The Waste heat is the excessive heat produced at a process at a temperature higher than that of foundry air. A few examples can be seen in various exhaust, castings cooling, heat-treating. Owing to the difficulty of this subject matter and rising energy prices, this issue should be handled by an outside expert consultant.
A few steps to study heat wastage are:-
- A comparative study of heat requirement and estimated wastage be done in quantitative terms.
- Evaluate as to how easily the wasted heat can be recovered for use.
- Study the nature and form of the wastage source.
- Determine the level by which the heat will have to be increased.
- Make a list of equipments that can be used.
- Study the cost factors.
The main parts in waste heat recovery are:-
- The equipment resulting in wastage of heat
- Heat exchanger
- System for heat supply
- The equipment which will receive the recovered heat
Few sources for recovery of heating and melting furnace, pouring and core baking etc. and sources of waste heat include dust collectors, cooling and process waters, various types of furnaces etc.
The recovered waste heat can be used in the following ways:-
- PRE HEATING COMBISTION AIR. Even after this is done, a part of heat may still be left to be used in other processes.
- Preheating gases to be used in various processes life furnace heating, fuel gas heating etc.
- Preheating unprocessed consumables
Thus, use of recovered heat is used in place of fresh energy resulting is a lot of saving in terms of energy and finances. Recovered head can also be used for domestic use in providing hot water or space heating.
Other EMOs HOUSEKEEPING- Reduce heat wastage elements to maximum possible extent
- Reduce the temperature of waste heat.
- Periodical servicing upkeep of equipment.
LOW COST
- Return wasted heat to process it was wasted from as this will work out to be cheaper than if used in other processes.
- Better control system be put in place to prevent heat wastage.
- Exhaust air be used to dry consumables
- Try recovering heat from cooling waters.
- Recovered heat can be used to heat incoming air.
- It can be used to heat foundry building.
- Recovered heat can be used to run air conditioning system.
- Recovered heat can be stored via various salts to be used later.
- Waste heat from dust collectors can be further heated to be used as make up air.
RETROFIT: HIGH COST
- Consider installing new technology heat pump to increase heat temperature over 100 degree centigrade.
- Waste heat can be recovered from flue gases with high temperature through waste gas tube boiler or water tube boiler introduced by the Norwegian
- Association of Energy Users and Suppliers (KNE).
- Galvanizing foundries should pre heat flux mordant to recover heat.
- In galvanizing foundries such furnance should be use where air is heated by emission elements through own exhaust gases.
- Cooling equipment be replaced by heating equipment which helps increase the temperature of waste gas to usable level.
- High temperature gas can be converted to steam of even higher temperature which can be used in power generation.