It is essential to carry out testing of refrigerated trucks and vans to ensure that they maintain the proper temperature. Such vehicles are used for transportation and distribution of medicines, vaccines, processed food, frozen food etc. This article briefly explains the chances of failure of such vehicles.<\/p>\n
Due to the extreme ambient temperature, the cooling system of refrigerated vans has to be very efficient. We can assure this only be carrying out temperature testing of such vehicles. This test is generally known as Temperature Mapping Study. The main challenges and recommendations are listed below.<\/p>\n
Many users load the goods before the van is completely precooled and stabilized.<\/p>\n
This will take up to 60 minutes in summer. The users do not want to wait this long.<\/p>\n
The engine and the cooling machine struggles to maintain the temperature after a couple of years<\/p>\n
By the third year, the cooled vehicle has difficulty in maintaining proper temperature.<\/p>\n
The vehicle might be able to bring down the temperature, but unable to maintain stability.<\/p>\n
Even after the opening of a door for 60 seconds, it takes 10-15 minutes to stabilize the temperature inside the cooled vehicle.<\/p>\n
The duration for stabilization is determined in a temperature testing known as mapping study.<\/p>\n
Proper discipline is to be practised on the frequency of door opening.<\/p>\n
This problem is severe for cooled vans with two separate doors (one on the side & one on the back).<\/p>\n
The difficulties faced by frequent door opening is severe for vehicles with multiple doors.<\/p>\n
The interval between two such door openings can be prescribed after a temperature mapping study.<\/p>\n
The cooling unit is at the front end of the chamber of the cooled vehicle.<\/p>\n
If the fan is not powerful, the cooling unit will automatically switch off before the rear end achieves the right temperature.<\/p>\n
This necessitates the selection of the right capacity of the cooling unit for any refrigerated van.<\/p>\n
The insulation material of the body is critical in maintaining temperature stability.<\/p>\n
The cooling down time, stabilization time after door opening etc. are affected by the quality & thickness of the wall.<\/p>\n
Most of the cooling units are provided based on the size of the vehicles.<\/p>\n
However, for a vehicle with the frequent door opening, a higher capacity is required.<\/p>\n
Even an error in the sensor reading will cause high fluctuations<\/p>\n
The sensors need to be calibrated.<\/p>\n
The controller needs to be tested frequently.<\/p>\n
Stabilization time, door opening frequency etc. is different under different loaded conditions.<\/p>\n
Eg. The time for stabilization after a door opening is different in half loaded condition & fully loaded condition.<\/p>\n
The display only indicates the temperature near the cooling unit.<\/p>\n
It will never be the same across the entire area of the van.<\/p>\n
Even if the display shows 5\u00b0C, it is possible that some areas will be 9\u00b0C.<\/p>\n
Users normally place a data logger or continuous monitoring system at a convenient location inside the van.<\/p>\n
But this point has to be the weakest points inside the van (The hottest & coldest points)<\/p>\n
Temperature testing of the vehicles involves a series of real-time testing mainly\u00a0in the refrigerated cabin.<\/p>\n
Temperature testing by mapping study is the only way to understand the behaviour in each vehicle.<\/p>\n
The behavior of two identical vehicles need not be the same under practical conditions.<\/p>\n
Hence each vehicle needs to be tested.<\/p>\n
The following are the summary of details of a temperature testing of refrigerated vans and trucks used for medicine, vaccine, food etc.<\/p>\n