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The ongoing rise in energy costs, load shedding as well as environmental concerns associated with the use of coal-fired power stations are the driving forces for agricultural, industrial, and commercial sectors to change how energy is consumed. There is a growing interest in energy management, energy efficiency and energy-efficient technologies as a result of the escalating energy crisis. To deal with the current energy crisis, the business at large is realising that energy, just like any other resources or raw materials can be managed. This article will focus on recommending energy-efficient technologies, as well as how energy can be managed to reduce the operational cost of energy, to ease the financial burden on energy consumers-agricultural, industrial and commercial sectors.
Businesses in the agricultural, industrial, and commercial sectors use a variety of technologies. These technologies have been developed over time to be energy efficient. The use of energy-efficient technologies can result in significant cost savings. Some of the energy-efficient technologies are discussed below:
Variable speed drives (VSDs): VSDs are designed to control a motor’s speed and work best in equipment where the load varies. They respond to sensors and adjust the speed of the motor to an optimum speed, thereby reducing or optimising the power usage. VSDs can be used in pumps, fans, lifts, conveyors and ventilation systems, compressors, and cold and freezer rooms.
Heat pumps: A heat pump’s operation is similar to how an air conditioner or refrigerator works. Heat is extracted from the surrounding air or water. It is then transferred to where it is used. Heat pumps can be used to heat water and they are far more energy efficient than electric and gas boilers. For every 1kWh of electricity used to run fans and compressors in a heat pump, more than 3kWh of energy can be transferred and used. They are environmentally friendly because they extract heat from the surroundings, which is available 24 hours a day.
Solar geysers: Solar geysers can also be used to replace conventional electric and gas boilers. The benefits of using the solar geyser include reduced energy costs and greenhouse gases. The technology is available in either a flat plate collector (FPC) or an evacuated tube collector (ETC). Solar geysers like FPC and ETC are mostly deployed in residential areas, but they can readily be installed in industrial sectors to supply heat up to 125°C.
Thermal insulation is the reduction of heat transfer and can be achieved with suitable object shapes and materials. Fire-retardant ceiling insulation, draught-proofing doors and windows, double-glazed windows, reflective roof coatings, insulating geysers (geyser blanket) and geyser hot water pipes insulation are some of the methods used for thermal insulation.
Energy efficient equipment: Energy users must develop a habit of using energy-efficient technologies of motors, boilers, furnaces, industrial dryers, pumps, compressors, lighting, domestic appliances, and air conditioning systems. For example, replacing an old air conditioner with an inverter-type air conditioner will save more energy. This is because the inverter-type air conditioner has minimal power losses. After all, the motor speed can be adjusted without turning the air conditioner off and on.
Lighting consumes a significant amount of energy, however, a substantial amount of energy losses due to inefficiency and old lighting technologies can be mitigated by considering the following tips:
- Incandescent lamps can be replaced with compact fluorescent lamps (CFLs) or light emitting diodes (LEDs).
- T12 fluorescents can be replaced with T8 and T5 fluorescents, which are more energy efficient.
- Metal halides with high power ratings (400W) can be replaced by metal halide lamps of lower power ratings, e.g., 360W, 250W and 200W metal halides.
- High-intensity discharge lamps like halogen lamps can be replaced with metal halides or high-pressure sodium lamps.
- Apply de-lamping in areas where it is highly lit.
- Conventional high-intensity discharge (HID) lamps and fluorescent lamps in high-ceiling applications can be replaced with T-Bay lamps and induction lamps. Lamps such as induction lamps have a long lifespan.
Energy management practices
Apart from using energy-efficient technologies to reduce the energy bill, behaviour patterns can be changed to reduce the operational cost of using electricity. These behaviour patterns are energy management practices that will cost zero to implement but can lead to significant energy savings of up to 10%. There are claims that energy savings cannot be achieved without investing in retrofits or new energy-efficient technologies, however, this cannot be true. Below is a list of management practices that can be used to dispel the claims, as well as to improve energy efficiency:
- Monitor energy in high energy-consuming industrial processes and equipment to ensure optimum operating conditions.
- Leaks and equipment failures must be reported timeously to prevent energy losses and incurred costs.
- Where justifiable, working arrangements such as working from home and flexitime can be adopted.
- Unless there is a justifiable reason, electrical loads like kitchen appliances, geysers, air conditioners and urns in the corporate kitchen should not be switched on during peak times. They cause spikes and consume excessive energy for no reason. Spikes can also lead to penalties from Eskom.
- Unresponsible use of standby mode for equipment should be avoided at all costs as it does not imply that equipment or appliance does not use energy when it is on standby mode.
- Agricultural, industrial, or commercial sectors can apply electricity load shifting to distribute energy consumption over an extended period. It will help to stop the maximum demand penalties due to spikes.
- Avoid lighting offices overnight as it wastes a lot of energy.
- Switch off lights in unoccupied areas.
- Conduct awareness campaigns and educate staff on energy efficiency and the benefits of it.
- Offices and shops can be comfortable for humans at temperatures between 18 and 22°C. An air conditioner temperature of 22°C is comfortable for both summer and winter.
It is recommended to conduct an energy assessment/audit. Energy assessment reports focus on energy consumption and the efficiency of building/agricultural building facilities. It indicates how, where and why energy is used. Managers can employ the services of the energy services company (ESCo) to conduct energy audits. An energy audit will report on potential energy conservation measures and recommend energy-efficient technologies and any retrofits needed to optimise energy usage.
A walk-through energy audit will work for businesses that do not have enough resources to conduct a comprehensive energy audit. This energy audit method includes walking around the building and making notes of areas where energy can be saved. It also includes identifying areas where there is energy wastage. Areas of interest to look for during the walk-through energy audit include heating, lighting, office equipment, factory and warehouse equipment. – Erence Manyako ARC-Natural Resources and Engineering, Agricultural Engineering Campus
For more information contact the author at ManyakoK@arc.agric.za.