MONITORING & METERING
THE BENEFITS OF MAXIMUM DEMAND SURVEYS There are many benefits to performing a detailed maximum demand survey on a premises, the most obvious of which being the accurate measurement of actual energy use over time rather than using an estimation. But there is also a lot of interesting analytical information that can be obtained which could be useful in identifying energy use, and potential areas for reduction and savings. Julian Grant, General Manager of Chauvin Arnoux UK discusses a case where measurement of maximum demand made all the difference and reveals some examples of the hidden gems of information that can be gleaned from the data.
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he energy balance within modern properties is constantly changing and this has been further accelerated by the current ‘cost of living’ crisis, with the trend towards more home working also having had a notable affect, both on the home and on the now vacated business premises. Traditionally a ‘normal’ dwelling, for example, would be considered to have two Ring Final Circuits, two Lighting Circuits, one Immersion Heater, one Cooker and one Shower. However, this is not particularly representative of many modern dwellings, and doesn’t consider the benefits of heating appliance efficiency improvements, the availability of low energy electrical equipment, and the effects of PV, EV, heat pumps, etc.
So, how should you go about accurately determining the maximum demand for a property? The complexity of the diversity calculations required make this a daunting task, further exasperated by the fact that the figures in the IET Onsite guide are way out of date and have large margins for error built into them. A recent case study performed at a large town house converted into 5 flats in Richmond, London showed exactly how far out calculated maximum demand can be compared to what’s really being consumed in a domestic situation.
ENERGY MANAGER MAGAZINE • MAY 2023
Extrapolating this out to larger commercial and industrial installations would give rise to even more opportunity for errors. The conversion into flats had occurred over 50 years ago, with the existing 100A single-phase service having been split by the DNO into a 6-way singlephase supply. Five for the flats and one landlord’s supply for communal areas. This installation had worked very well since then with no known overloading issues, however, the old service head and tails were looking their age, and conversations with the DNO were underway about updating the supply. It was at this point that it was suggested the existing supply was potentially inadequate for the premises, and that the property owner would need a new, larger, DNO supply to be connected, at his expense! Faced with the huge cost implications of having a new supply connected to the property, the owner set about obtaining accurate and reliable maximum demand data. They reached out to a local electrician who came and fitted a Chauvin Arnoux PEL103, power and energy logger, along with a 1-metre-long flexible current sensor which was capable of looping