Getting Ideas for Energy Management Opportunities
The impact of foundry buildings on overall energy use should have been evaluated during the initial energy audit and made an integral part of the foundry’s energy management program. We may find that older buildings are often inadequately insulated and sealed.
Modern building codes set minimum requirements for energy conservation in new buildings, which apply in full also to repair, renovations or extensions of older buildings. Energy efficiency shall be designed to good engineering practice such as described in, for example, Model National Energy Code for Buildings 1997 or Ontario Building Code 1997 (“code”) and in ASHRAE/IES 90.1-1999 – “Energy efficient design of new buildings.” When considering energy efficiency improvements, these and many other regulations and standards that cover industrial buildings’ construction and operations (such as insulation, heating and ventilation) must be carefully examined to ensure that health, safety and occupational comfort requirements are met.
Here, we shall mention only items relevant to the integrity of the building envelope – heat transfer and moisture protection. Other related issues, such as heating and ventilation, are covered separately.
There are three major ways to control two-way heat transfer (loss or gain) through the building envelope:
- Reduce it through adequate insulation of walls, roof, windows and doors;
- Reduce it through proper weatherproofing, which prevents water infiltration; and
- Reduce uncontrolled air movement through the envelope’s normal openings and seal deficiencies.
Upgrading of wall insulation from the inside may not be practicable in older buildings. The solution may be to add insulation to the exterior of the building and cover it with new weatherproof cladding.
Roof insulation upgrades may be desirable because most of the winter heat loss and summer heat gain occurs through the roof. A new insulated roof membrane can be covered with heat-reflecting silver-coloured polymeric paint to help minimize the heat transmission.
Many older foundries have single-glazed, inadequately sealed windows. Short of replacing them with modern sealed-glass windows, plastic or glass-fibre window panels can be used to advantage. Some panels are manufactured as double-glazed unbreakable units that are more energy efficient than single-glazed glass windows. Double-glazing is the minimum standard for Ontario. Other solutions include:
- Choose improved sealed units for north-facing and highly exposed windows;
- Standard triple glazing; it adds an extra air space (and also weight) and thus insulation;
- Glass coatings reduce heat emissivity and reflection;
- Low-emissivity (Low-E) coating reduces radiant heat through the glass and achieves about the same insulation as uncoated triple glazing;
- Gas fill – commercially available units with the inter-panes space filled with argon or krypton increases the insulation still further; and
- High-performance triple glazing – it may utilize Low-E as well as gas fill. The insulating value is almost five times as great as that of a single-glazed window.
Windows can also be shaded or curtained inside or shuttered outside to keep out summer heat and winter chill. Sometimes a single-glazed window wall causes large heat losses/gains. Consideration may be given to covering it – to the degree desired – with insulated wall panels.
A foundry may have external heating cables installed to prevent the formation of ice, for example in gutters and downpipes, on flat roofs with internal heated downpipes, on driveways, and in entranceways. Often the power stays on all winter long. Manual control, often crude and imprecise, may be causing energy consumption to be higher than necessary. An effective solution may be to integrate the controls of this and other energy systems in the central building energy management system.
Other EMOs
Housekeeping
- Maintain the integrity of water-impervious roof membranes through regular inspection and maintenance.
- Door seals at loading docks should be inspected regularly; worn or damaged seals leave large gaps between the dock and the trailer and should be fixed promptly.
- Examine all openings (vents, windows and outside doors) for cracks that allow air to leak in and out of the building.
- Block the cracks with caulking or weatherstripping.
- Keep doors closed; they lose the most heat when open.
Low cost
- Vestibules, revolving doors and automatic door closers all help reduce losses from open doors.
- Close off all unused openings and stacks.
- Caulk and stop all cracks in the building walls, etc.
- Upgrade weatherstripping of windows and doors.
- Eliminate unnecessary windows and glass walls.
Retrofit; high cost
- Weatherproof exterior walls with cladding or another treatment that prevents water infiltration.
- Install adequate, leak-proof vapour barriers on the interior (warm) side of walls, ceilings or floors.
- Consider investing in a central building energy management system.