Energy monitoring: The first step in electricity savings at Malvern Fruit and Veg City

Submitted by: Margaret McKenzie, Thursday, November 15, 2012

<p>Current transformers (CTs)  on the three phase cables in the mains board at Fruit and Veg City (Image: Margaret McKenzie)</p>

Current transformers (CTs) on the three phase cables in the mains board at Fruit and Veg City (Image: Margaret McKenzie)

“The first thing we do is monitor” says David Douglas of Energyrite explaining that they follow the tried and tested business motto ‘you can only manage what you measure’.    Because of their confidence in the savings impact of energy monitoring, Energyrite guarantees that the costs of their energy monitoring installation will be paid back in electricity savings.    

Douglas has been following the ‘monitoring first approach’ with Malvern Fruit and Veg City which is a medium size retailer with an energy bill of over R100,000 a month.   The retailer has three main energy using sections: butchery, bakery and fresh foods.   Energyrite installed the Eniscope energy monitoring system at Fruit and Veg City which includes three main components:

  1. Current Transforms (CTs):  These are attached to the electricity mains and measure electricity use and other parameters such as power factor.   
  2. Energy Monitor:  The information from the sensors is feed into an Eniscope energy monitor which has a display panel which allows staff on site to view current energy use information. 
  3. Hub:  The monitor is connected to a hub which is connected to the internet and uploads the site information onto a website.   The current and historical energy use information is then available for the Malvern Fruit and Veg City to access at any time via the internet.   

Once energy monitoring equipment was installed in the Malvern Fruit and Veg City it was possible to spot several areas where immediate savings were possible says Douglas.   Firstly an analysis of the data showed that the business was not on the most cost effective tariff and a move to a new tariff would result in savings.    Secondly the data showed high levels of electricity use on site at night. After investigation it emerged that the ovens in the bakery were left on overnight by staff to ensure that they were hot in preparation for the first bake of the morning.  

Malvern Fruit and Veg City will now start looking at electricity savings that can be achieved with additional financial investment says Douglas.  These include installation of devices that manage electricity use of air conditioners and refrigerators as well as the relocation of air-conditioner sensors to more accurately measure temperatures. 

The historical energy monitoring information makes it possible to calculate the likely payback period for any intervention explains Douglas.   With clear pay back information it is easier for the owner of Malvern Fruit and Veg City to decide if a particular intervention is financially worthwhile.  

The Eniscope energy monitoring system is designed for medium to large scale operations and Douglas recommends the system for organisations with bills of over R40,000 per month.  

Screenshot of the web based energy monitoring interface used with Eniscope monitors (Image source: Enigin)

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Margaret McKenzie