Thermal Imaging for Solar Systems

Wednesday, November 25, 2020
Training

What is thermal imaging?

Thermal imaging or thermography is the non-contact detection and measurement of the temperature differences of a material and the assignment of colours based on temperature. 

All things both animate and inanimate, emit infrared radiation. Infrared thermography visually represents this infrared energy and transforms this into readable data that can be analysed. 

Infrared thermography detects radiation, not convection and conduction and therefore the accuracy of measurements takes into account surface emissivity and temperature. 

So, basically, different colours are allocated to different temperatures that the “thing” in question radiates. An operator will take two images of, for example, a switchboard. One will be standard, the other a thermal representation.


Standard image of switchboard...
…the thermal representation.

X Ray vision?

Thermal imaging can’t see inside walls (like in the movies), this is a different kind of technology but can show a temperature reading across a surface, creating a picture from  temperature measurements in its field of view. 

The actual thermal imaging process is influenced by many factors and this requires a skilled operator who is familiar with many different scenarios. 

What equipment do you need?

The thermographer arms him/herself with a thermal imaging camera, arrives at the site & collects images of for example, switchboards or solar panels. Images will show a standard and then a thermal representation. 

The thermal images are then analysed by the experienced operator who can then ascertain any issues, potential or otherwise, and then suggest appropriate steps forward. 

Limitations

Like anything there are limitations that can impede the effectiveness of the process and these include:

  • Does not work when wind exceeds 10 km/h, no direct sun and no recent rain
  • Different construction materials can inhibit the use of the thermal imaging camera
  • It basically only detects the surface temperature of whatever is being scanned. 
  • Objects with erratic temperatures can cause problems 

It is up to the qualified and skilled operator to take all of this into consideration when imaging the material under investigation and when analysing the results.

What benefits are there for your business?

Thermal imaging services are an effective and efficient way of testing to:

  • Detect electrical anomalies often invisible to the naked eye, Switchboards etc
  • Allow corrective action to be taken before costly system failures potentially occur
  • Minimises the downtime, labour costs compared to other testing methods

Benefits include:

  • Allowing predictive maintenance, wear and tear on machinery, heat build-up
  • Identifying Commercial Solar systems, hotspots, fractures, 
  • Facility maintenance: HVAC systems, buildings, roofs, insulation
  • Testing of three-phase systems, distribution panels, fuses, wiring and connections
  • Reduced insurance premiums
  • Reduced potential risk of electrical fire
  • Reduced downtime
  • Reduced repair costs
  • Provide a business preventative maintenance plan
  • Provide a fast response to issues before they become critical

Inspection methods and criteria

Any thermographic survey can show differences in apparent temperature of areas within the camera’s field of view but, to be useful must detect all the apparent defects, if any, and assess/compare them against criteria agreed between the company conducting the thermal imaging and you, the client. 


As part of the process, anomalies must be discounted that are not real defects and analyse the real problems and this is the report that is ultimately presented.

The basic beginning steps usually are as follows:

  • Selecting the critical temperature parameter 
  • Selecting maximum acceptable defect area 
  • Measuring surface temperature difference caused by the defect 


Analysis and survey

The  thermographic survey must collect enough information to demonstrate that all surfaces under investigation have been inspected so that anomalies are reported and evaluated. 

The images of these anomalies must be captured in such a way that they are suitable for analysis and therefore there are conditions which include: 

  • The image must be square to any features of the wall or roof. 
  • The viewing angle is nearly perpendicular to the surface being imaged. 
  • Interfering sources of infrared radiation such as lights, etc to be minimized

Additional data also collected in the survey include:

  • Internal temperature in the region of the anomaly. 
  • External temperature in the region of the anomaly. 
  • Emissivity of the surface. 
  • Background temperature. 
  • Distance from the surface. 


Conclusion

Insurance companies, as part of their contracts, tend to require thermographic inspections and reports on electrical switchboards and components, usually on an annual basis in Australia and these inspections provide real-time data and instantaneous results. 

The non-destructive, non-intrusive nature of scanning electrical components with an infrared camera means business operations can carry on as normal and the ability to identify potential electrical issues is a peace of mind proposition in addition to a safety concern scenario. 

Thermal imaging can also allow a suitably experienced assessor to suggest helpful energy management strategies when combined with system monitoring, assistance which businesses would readily invite.

As with all decisions, undertake prudent cost benefit analysis when looking at the expense of thermal imaging to ensure value for money and make sure the company you deal with is a reputable one.


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