Big differences in airconditioning system performance

In the hall of Eurofins Expert Service, where environmental conditions can be simulated, the performance efficiency of equipment can be tested in extreme situations. The heat caused by rays coming in from the outside was simulated with additional lighting. Before the air-conditioning system was turned on, the temperature in the cabins was about 39 degrees. Kuva: Ari Lemminkäinen

The cooling of the operator's cab comes at a cost. The prices of refrigerants have been rising since last year. The largest price increase has been for R134a, which is often used for vehicles and machinery. Prices for newer refrigerants are high from the outset. Kuva: Jussi Laukkanen

The summer of 2018 put the airconditioning systems of the machines to the test, as the temperatures were in the heat for weeks on end. From what could be heard from the construction sites, the temperatures could not be kept under control in all machines, because the performance of the air-conditioning systems simply was not sufficient.

Eurofins Expert Services Oy offered the opportunity to test the performance efficiency of the machines under extreme conditions. The temperature in the hall specially designed for the purpose can be set between -40 and +55 degrees Celsius. For Koneviesti, this hall has been used on previous occasions, for example in forest removal tests in operator's cabs and to test the performance efficiency of heaters. This time, the performance efficiency of the air-conditioning systems was tested.

For the test, we fixed eight temperature sensors to different parts of the operator's cab. From the temperatures recorded every minute, we calculated an average; on the basis of this average, we plotted a curve that shows the total temperature in the operator's cab. The heat generated by the sun was simulated with several halogen lights, which we directed from a fixed distance to the operator’s cab, at an angle, from above.

Before the test, the temperature in the cabins was stabilised for two hours in the hall. After the lights were turned on, the temperature was raised for about 20 minutes, after which the engines were turned on and set at a speed of approx. 1,500 rpm.

The air-conditioning systems were set to blow out as much cold air as possible. The entire test took 55 minutes, which was sufficient to separate the wheat from the chaff.

At the beginning of the test, the temperatures in the operator's cabs were all within a range of 1.7 degrees, the average was 33.7 degrees. After the lights were turned on, the radiation caused the temperatures to rise to about 39 degrees. The speed of the temperature rise in the operator's cabs and the final temperature is influenced, for example, by the size of the glazed area of the operator's cab.

After the air-conditioning system was switched on, the temperature in the operator's cab dropped rapidly. The exception, however, was the Bobcat, in which the temperature dropped much more slowly than in the other machines, even though the air-conditioning system was maintained. The temperature in the Bobcat operator's cab was still above 30 degrees at the end of the test. At the top, the Wacker Neuson and the JCB achievedresults of 23.1 and 23.7 degrees, meaning that the difference between the machines was surprisingly large.

Also, the ECM air-conditioning system was a little exhausted, because at the end, the temperature was almost 27 degrees. The temperatures of the Komatsu and the CAT did not fall below 26 degrees.