Cold Link Africa January/February 2019 | Page 6

NEWS INCORPORATING COLD CHAIN Thermal imagers can also be used to detect the following: • Worn-out contactors and relays: heats up as contacts wear out. • Overloaded circuits (especially on three-phase): it is easy to see if a load is unbalanced. • Poor electrical connections: will create higher resistance and heat/fire that can be prevented. The expansion valve as seen through the thermal imaging camera. Fan motors: will show heat before failing. • • A Bitzer compressor as seen through the thermal imager. create heat before seizing. • McEneaney-Nel believes that every defects. These can range from loose Mechanical parts will either generate heat HVAC&R company should have one contacts or overloaded circuits to faulty or transport it. In a similar way, potential of these imagers. It’s not only useful for contactors and relays. A thermal imager defects can be detected while the system maintenance but can add great value can detect aforementioned anomalies is in full operation. The condition of motors, to commissioning too. “In Europe, every without contact and during operation, expansion valves, and compressors can professional has one of these — it’s the before downtimes can even occur. easily be assessed. norm. But for South Africa it’s still a bit Misaligned belts: belt will heat up from friction. • Poor insulation in cold rooms. • Can detect condensed liquid columns in large installations where gas is supposed to flow. • Can very quickly measure condenser and evaporator temperatures. • slow on the uptake.” He is hoping that by Worn-out bearings and pulleys: will Compressors that have leaking valves will heat up. familiarising students with the tool, they will • motivate its necessity to their companies Any additional moving mechanical parts that are not lubricated or worn and increase its popularity locally. out will generate heat. POTENTIAL USES A large part of heating energy is lost Testo South Africa wants to assist the local HVAC&R industry in functioning better. through poorly insulated walls, roofs, and windows. Effective insulation therefore not only saves costs, but also protects the environment through lower CO 2 emissions. Thermography is a method for checking the actual condition of buildings and the potential for energy savings. Both hidden weak spots and implementation defects can be detected non-destructively, and their causes determined. The detection “The strength of the thermal camera of these defects applies to the electrical technology is that it is not limited to a and mechanical sections of heating insulation checks. Overheated connections in a control cabinet indicate potential or actual specific list of applications since new and cooling systems, along with applications are found all the time,” says OTTC training manager Martin McEneaney-Nel showing students how the new thermal imager works. From left: Juan de Beer; Ntokozo Gosani; Moses Shongwe; Martin; Christelle van Schalkwyk; Nare Piet Mashala; and Andre Pretorius. Steenkamp. “This is especially true of the HVAC&R industry where all we deal with is moving parts and heat transfer.” CLA