Energy monitors and data

Energy and environmental monitoring is an essential business tool for company’s wishing to manage and lower their energy usage and carbon footprint. Energy efficiency is vital for the conservation of the world’s natural resources. 

Energy and environmental monitoring has changed beyond recognition since the late 1980’s when chart and pen recorders were still in use. Now, energy monitors and environmental data loggers are software based, usually the equipment logs the data at intervals set according to the project requirements when the logger is installed; these are data integration periods. It is normal for the manufacturers of monitoring equipment to provide export facilities for the data to be downloaded to applications such as Microsoft Excel, which offers the capability for more detailed analysis to be undertaken.

Electrical energy monitors log multiple parameters of electrical energy such as, kWh, kVAh, kVArh, Volts, Amps and the equivalent energy demands, plus power factor. This is achieved by fitting current transformers (CT’s) around the phase cables and Voltage reference leads to the phase terminals. The phase angle between the Voltage and the current is identified and the power factor is derived. At the incoming supply terminals the integration periods would usually be set to 30 minutes, in line with UK metering systems. When monitoring the incoming supply it is worth reading the electricity settlement meter at the start and end of the period; this may be referenced in the project report to illustrate the accuracy of the monitoring equipment. More frequent integration periods may be used to closely analyse the load at point of use. The later electrical energy monitors utilise phase shift technology which allow the Voltage reference to be taken from one phase through a plug top and matched with the CT on the same phase. The Volt-Amps (VA) phase angle of the other phases is calculated. This system will, under normal circumstances, provide acceptable data accuracy whilst offering safer installation of the equipment.   

 Environmental data loggers will monitor a vast range of conditions such as, temperature, humidity, CO2, pulses and events. They may be set up to log preset integration periods, take readings within the period and log the average, also events, based on contact closure can be identified. Data loggers often allow delayed start times to be set and pulsed data to be converted to units of measurement. Some provide pulse synchronisation.

 The latest energy and environmental monitoring technology uses remote systems which can be set up and interrogated using mobile phone technology (GSM/GPRS). This is ideal for long term monitoring, once installed, it reduces the need for site visits and therefore labour costs. Additionally, limiting business mileage will lower a company’s carbon footprint. Such systems provide a range of configurable inputs which may be found on conventional data loggers plus the ability to connect multiple electricity meters using an RS485 cable network.

 It is important that short term monitoring is discussed with the client and undertaken during a representative period in the workplace for instance, data collected during a factory holiday or when a major production line isn’t being used will provide inconclusive information. Additionally, particularly with long term monitoring, it is useful for external temperatures to be monitored. This will highlight the seasonal effects on energy usage.  

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