Getting Ideas for Energy Management Opportunities
The paradoxical situation when, in winter, the foundry building’s heating is operating at maximum, while the loading door or scrap bay is left wide open, is not uncommon. The heat lost from a building in winter must be overcome by the building’s heating systems, which adds to the foundry’s operating costs. Typically, a foundry has a lot of waste heat available, which could be used for space heating. The challenge is in how to use it intelligently to create a comfortable, fumeless working environment.
It helps to start by creating a heat balance – describing the heat sources and heat sinks in the foundry, in a quantified way. The ventilation system needs to be included in the equation. Since neither can be effectively solved in isolation, aim at a synergistic solution. Use some of the ideas listed below, as well as those described elsewhere in the guidebook.
Buildings with large south- or southwest-facing walls can be retrofitted with a type of solar wall (e.g., Canadian-developed Solarwall®) for even greater energy efficiency in space heating.
Other EMOs
Housekeeping
Changes to employee behaviour toward energy management can lead to a virtually costless achievement of substantial savings:
- Close windows, doors and receiving/shipping bay doors in cold weather.
- Report high ambient temperatures rather than opening windows (so qualified adjustments can be made).
- Adjust maintenance work in the paint line to shorten maintenance periods.
- Assign someone (e.g., maintenance) to switch off machinery at the end of the workweek.
- Switch off lights and air conditioning when leaving an office.
- Remove superfluous lights.
- Prevent blockage of radiator and ventilation grids.
- Ensure correct setting of controls on make-up air units; lower the temperature setting if possible.
- Eliminate heating or cooling of all unused rooms.
- Lower the thermostats for the weekends (say, to 15°C).
- Raise the thermostats a bit in summer and lower them a step in the winter, when possible (18°C should be a comfortable foundry building temperature).
- Repair broken windows, skylights and doors.
- Ensure that heating and air-conditioning systems operate only when required.
- When no production is going on, and on weekends, reduce as much as possible the amount of fresh air brought into the plant.
- Turn off air-conditioning units in the cafeteria and in the offices on weekends.
Low cost
- After the hot air from core making machines has passed through dust collectors, recirculate it back into the building for heating purposes (in winter).
- Locate the heat exchanger for the furnace cooling inside the foundry building: it will help heat it in the winter. An additional benefit: worries about freeze-up or charging the system with antifreeze are minimized.
- Use radiant heating directed at work stations rather than general space heating.
- Install an automated damper system on the air compressors to keep the heat in the building during the winter.
- Install air curtains at loading bays.
- Plant trees or shrubs outside as windbreaks and summer shade.
- Consider linking exhaust fans in washrooms, kitchen, etc., to the light or equipment switch.
- Consider reversing the roof exhaust fans in areas where it is possible (e.g., relative absence of dust), in the winter, to mix with and temper the outside air to provide heat to areas below.
Retrofit; high cost
- Innovative use of passive or active solar heating technology for space and/or water heating, especially when combined with improved insulation, window design and heat recovery from vented air.
- Installation of a solar wall (e.g., Solarwall®, Trombe wall) on south or southwest side to provide effective heating.
- Consider using evaporative cooling of flat roofs to reduce air-conditioning loads in summer.
- Consider utilizing heat pumps (or ground heat pumps) for combined heating and cooling of the foundry facilities.