Going equipped: what to take on an energy efficiency survey
- Jul 22, 2021 3:07 pm GMT
Top of my list for energy survey equipment is of course a mobile phone because it's useful as a camera (including as a means of reading inaccessible rating plates or meter dials), it will stand in for a torch, and its stopwatch function can be handy too, for example to estimate the load factor of intermittent on-off plant. You can use it just as a phone to co-ordinate 'drop tests' where one person does spot meter readings while another turns major loads on and off, and as a browser to gather information on unfamiliar plant and equipment. I have a plug-in infra-red camera for mine which is useful for detecting and recording hot or cold spots.
Next is a digital thermometer with type K thermocouple probes. Mine operates in the range –50 to 200°C with 0.1 °C resolution, but it can be useful to have another for up to 500°C with 1 °C precision. For high-temperature applications a robust probe is needed but below 100°C, say, a bare thermocouple junction can be used. They are very good for air temperature because they respond quickly, but they can also be attached to pipework under a wad of insulation to get a reasonable measurement of flow temperature. Thermocouples can be left in place and read from time to time by connecting the instrument when required.
I usually carry a non-contact thermometer to give approximate temperatures of inaccessible surfaces, an anemometer to measure air velocities especially in supply and extract ducts, and sometimes a digital relative humidity probe.
For extended tests one can deploy miniature data loggers which record temperature, relative humidity, voltage, or pulses from a variety of sources including movement sensors (logging occupancy levels) or even improvised temporary contacts on valve linkages and other moving equipment.
I carry a light meter capable of working over a range of 50-2000 lux. It is a cheap one calibrated for incandescent light only, so results are only indicative. For a proper lighting survey one would use a more expensive model which can be switched to compensate for different light-source characteristics.
For electrical power measurements a plug-in power meter can be used to check the consumption of appliances under 3kW rating, but the chances of finding any worthwhile savings at this level are slim. A proper electrical demand profile recorder will be needed for loads big enough to offer significant opportunities for saving. A three-phase instrument with a mains lead gives you the full picture including power factor, while a much cheaper 'current clamp' meter with data logging will allow you to determine load factors on intermittent equipment.
A non-contact tachometer is used measure motor speeds, which in the case of induction motors allows one to estimate their mechanical output by reference to their rated slip speed at full load. By the way, do not bother with stroboscopic tachometer phone apps; most don’t work at high enough frequencies, plenty don’t work at all and they all need to be used in darkness.
Other than that I would carry a torch, a pocket tape measure, a manhole lid lifter (for access to water meters) and meter compartment keys.
For some people a combustion analysis kit, although relatively expensive, is a good long-term investment because it enables poor combustion to be detected through regular checks. Hiring is an option for the infrequent user. Always choose one with carbon monoxide measurement. If dealing with oil or solid fuel, you will also need a smoke pump.
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