Cleaner Production BELOW Variable refrigerant flow technology offers a smaller footprint and greater efficiencies to users
than refrigeration technology and can improve the breathability of air in buildings. Leading local supplier of evaporative cooler technology Cool Breeze describes the process as follows: “An ordinar y thermometer reads the actual air temperature and this is referred to as a dr y bulb temperature. On the other hand, wet bulb temperature is the lowest temperature that air can be cooled to by the evaporation of water. It is the temperature that the air would be when reaching 100% humidity or saturation. “This is what people ‘feel’ the temperature to be, and which is influenced by air movement over the body. It should not be confused with dr y bulb temperature. When sitting in a breeze, people feel cooler because air blowing on a person increases the rate of evaporation of moisture from their skin. Heat for this process is gained from the air but, more impor tantly, it is also gained
from the person’s skin. The person feels cooler, even though the dr y bulb temperature of the air remains the same.” An evaporative air-conditioning system offsets the effects of hot weather by cooling buildings’ walls from the inside. Cool walls radically reduce the need for other more energy-intensive cooling technologies.
7. Controllers Controllers, like VSDs, are not only useful in HVAC applications but have also been used widely in HVAC to great effect. Maurice Robinson, national sales manager for energy-efficiency HVAC specialist company Carel, explains, “A controller is basically a machine for handling inputs and outputs. We have a model, for example, which relies on pre-programmed algorithms to attain cer tain energy-efficiency outputs.” Other controller options available through Carel and other controller manufacturers are parametic controllers – where a specific set of parameters for a given company, factor y or site can be pre-programmed into the unit based on site parameters. Standard
programmable logic controllers (PLCs) are also available.
8. Electronic expansion valves Used in air-conditioning applications, electronic expansion valves (EEV) use a stepper motor to control the valve aper ture, and that, in turn, is controlled by smar t technology in the EEV head (the top par t that looks a lot like a solenoid valve head). The motor synchronises the operation of the variable displacement AC compressor and the EEV to maintain constant pressures in the air-conditioning unit, which optimises efficiency. Even greater efficiencies can be achieved when the technology is combined with BLDC compressors and controller technology. Robinson adds, “EEV prevents energy wastage in the evaporator while also allowing condensation at lower ambient conditions – depending on the ambient conditions. Companies that install EEVs can expect savings of around 14% annually.”
9. Building management systems A building management system (BMS) is usually used for managing a variety of systems for large commercial and industrial applications – they can also be used at
FIGURE 1 The energy hierarchy
Leaner
Switch off Eliminate waste
Keener
Better appliances Lower energy losses
Greener
Sustainable energy production
Cleaner
Low carbon generation Carbon capture
Meaner
Sources of last resort Offset to compensate
58 – ReSource August 2016