Every piece of electrical equipment has to be provided with details of its maximum power draw. However, most energy will be drawn when the equipment is powering up. Once the equipment is running the energy consumption will be greatly reduced. Although laboratory equipment varies greatly in how it is used, discussions with manufacturers have resulted in a fairly consistent response with respect to power draws whilst equipment is in use. On average the equipment is likely to draw around 10% of its maximum power rating once external factors such as opening doors, increasing loads, running at varying speeds etc. are taken into account. Our feeling is that using a figure of 10% of maximum power draw to calculate energy usage and carbon emissions is more reliable than referring to data provided by manufacturers. This is because the few manufacturers who produce average power consumption figures generally feel they have no choice but to test equipment under ideal conditions.
You can calculate your energy costs using the figures shown in our applications tables as follows:
Annual cost = (kW x 0.1) x hours in use x £/kW
For example, with a unit cost of £0.10 per kW an autoclave rated at 9kW used for 2 hours per day 230 times per year will cost £41.40 per year to run. Defra has calculated that 0.54522kg (2010) of CO2 is released for every kW of electricity used, so the autoclave will be responsible for the release of around 226kg of CO2 over the course of the year. We are keen to work with people interested in helping us to offer more detailed information, and to measure energy usage in working laboratories. Please contact us if this subject is of interest to you.