ENERGY SAVING EQUIPMENT
Power quality in HVAC Keeping your systems cool
when things get hot Steve Hughes, the managing director of REO UK talks about power quality and the eff ect it has on HVAC systems.
M
ost people can remember a time when they’ve walked into a room and seen one person dressed for the Arctic while the person next to them looks like they’re in the Bahamas. Although disagreements over heating have led to fi ghts in some offi ces, for most businesses poor power quality in HVAC systems can do more damage fi nancially. Here, Steve Hughes, managing director of REO UK, explains how to keep your HVAC running cool when things get hot.
Power quality is a term that many people use but few fully understand. Typically associated with a stable supply of mains electricity, power quality covers a range of problems, including the continuity of the supply of electricity, fl uctuations and spikes in voltage and current, as well as transients or harmonic currents.
For years, power quality was a problem almost exclusively reserved for industrial applications. When manufacturers began using non-linear, switched devices like variable speed drives (VSDs) to control the speed of a motor driving a conveyor belt, they had to pay attention to the eff ect these devices have on the mains supply.
The use of switch-mode power supplies (SMPS) results in harmonic currents in the electrical supply. Here, the current waveform expands to accommodate multiples of the fundamental 50Hz
frequency. This means that the device using power is not only consuming more electricity, sending energy bills through the roof, but it can also cause motor windings and transformers to overheat and lead to ineffi ciency and possible breakdowns.
In recent years, the popularity of SMPS in computer systems and laptops, as well as in phone chargers and consumer electrical equipment, has created a power quality problem in HVAC applications. Combine this with the fact that most buildings, offi ces and residential and commercial facilities have some form of HVAC, and it is easy to see the scale of the problem. Poor power quality can damage HVAC components, including heat exchangers, fans, pump motors, condensers and furnaces, reducing their lifespan and raising energy costs. Facilities managers responsible for a building’s HVAC system are also obliged to meet industry standards such as EN61800-3, which specifi es the limits of electromagnetic emissions, immunity levels and testing methods for power drive systems (PDS) — the parts of a VSD that control driven equipment. The standard identifi es four categories where PDSs can be used in one of two environments. The fi rst environment looks at domestic premises, low voltage networks, houses, apartments
and residential buildings. The second looks at industrial buildings and those supplied by a dedicated transformer such as factories and plants. Depending on the category, the standard either lets anyone install the PDS or requires installation by a professional.
According to the standard, a PDS rated at less than 1000V can be installed by anyone in domestic premises. This is already causing problems as the demand for apartment buildings grows. Apartment buildings typically use more sophisticated building management systems, with electronics controlling the heating, lifts, extraction, doors, telecoms and internet- over-mains connections, all of which can be compromised by poor power quality, ultimately hampering the user’s experience. To enable facilities managers to use drives properly in their HVAC system, REO UK has developed an entire suite of products dedicated to eliminating power quality problems in HVAC applications. The REO Unity range comprises electromagnetic compatibility (EMC) fi lters, mains chokes, output chokes, sinewave fi lters and powerline fi lters.
So, the next time you feel like wearing your shorts to the offi ce, make sure your HVAC system is running as cool as you look.
54 January 2018
www.acr-news.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84
