DIN 8959

BASIS FOR CACLCULATING THE REFRIGERATION DEMAND

The basis for calculating the refrigeration demand is norm DIN 8959. Unlike the ATP Agreement, which applies to border-crossing transports, DIN 8959 also applies to delivery services. The norm has been modified and amended several times since 1965; the current version was published in 1999. This version is practice-oriented and reflects the state of the art. For example, to account for aging of the thermal insulation, the DIN permits a deduction from the k value of 30 % for 6 and of 50 % for 9 year old bodies. DIN 8959 also takes into account the additional refrigeration required due to the air exchange when the door is opened. The norm assumes that the door does not remain open for more than 5 minutes for each customer. Longer opening times should be considered for calculating the refrigeration demand by incrementing the number of customers. For example, 1 customer per hour with 15 minutes open doors corresponds to 5 customers per hour with 3 minutes of open doors each. The effective refrigeration capacity values in DIN 8959 are based on the assumption that the goods are chilled or refrigerated as prescribed. They contain no reserve for cooling warm empties or the empty body. Besides, a suitably higher refrigeration demand should be calculated for loading and unloading goods in non-refrigerated/non-chilled loading zones.
EFFECTIVE REFRIGERATION
CAPACITY AT 0 °C INDOOR/+30 °C OUTDOOR TEMPERATURE (FNA: K = 0.70)
Body dimensions             Dim
Inside length 4,2 5,2 6,2 7,4 10,4 13,4 m
Inside width 2,45 2,45 2,45 2,45 2,45 2,45 m
Inside height 2,2 2,2 2,2 2,4 2,4 2,4 m
Mean surface 51,36 60,83 70,31 85,65 115,26 144,87
Inside volume 22,64 28,03 33,42 43,51 61,15 78,79
Required air capacity 30-60-times
(loaded/empty)
679/1.358 841/1.682 1.002/2.005 1.305/2.611 1.835/3.669 2.364/4.727 m³/h
Wall heat penetration              
k-value (new) = 0.70
W/m²°C
1.079 1.277 1.477 1.799 2.420 3.042 W
after 6 years
(30 % aging -> k value
= 0.91)
1.402 1.661 1.919 2.338 3.147 3.955 W
After 9 years
(50 % aging -> k value
= 1.05)
1.618 1.916 2.215 2.698 3.631 4.563 W
Door opening losses              
Up to 2 customers per hour
(air exchange factor = 1.2)
634 785 936 1.218 1.712 2.206 W
Up to 3 customers per hour
(air exchange factor = 1.8)
951 1.177 1.404 1.828 2.568 3.309 W
Up to 4 customers per hour
(air exchange factor = 2.4)
1.268 1.570 1.871 2.437 3.425 4.412 W
Up to 5 customers per hour
(air exchange factor = 3.0)
1.585 1.962 2.339 3.046 4.281 5.515 W
Required refrigeration
capacity in
long-distance transport
             
with ATP safety
factor of 75%
             
as manufactured (new) 1.887 2.236 2.584 3.148 4.236 5.324 W
6 years old 2.454 2.906 3.359 4.092 5.507 6.921 W
9 years old 2.831 3.353 3.876 4.721 6.354 7.986 W
Required refrigeration
capacity in
distribution service
 
Up to 2 customers per hour
(factor 1.6 = 62%)
             
New 2.740 3.300 3.860 4.827 6.612 8.398 W
6 years old 3.258 3.913 4.568 5.691 7.774 9,858 W
9 years old 3.603 4.321 5.041 6.266 8.549 10.831 W
Up to 3 customers per hour
(factor 1.8 = 55%)
             
New 3.653 4.418 5.184 6.527 8.980 11.433 W
6 years old 4.235 5.108 5.981 7.498 10.287 13.076 W
9 years old 4.624 5.568 6.513 8.146 11.158 14.171 W
Up to 4 customers per hour
(factor 2.5 = 50%)
             
New 4.693 5.694 6.696 8.471 11.690 14.909 W
6 years old 5.340 6.460 7.582 9.550 13.142 16.735 W
9 years old 5.771 6.971 8.172 10.269 14.110 17.952 W
Up to 5 customers per hour
(factor 2.2 = 45%)
             
New 5.859 7.127 8.395 10.658 14.742 18.827 W
6 years old 6.571 7.970 9.369 11.845 16.340 20.835 W
9 years old 7.046 8.532 10.019 12.636 17.405 22.173 W
Higher requirements on refrigerated trucks according to DIN 8959 PDF
EFFECTIVE REFRIGERATION
CAPACITY AT -20 °C INDOOR/+30 °C OUTDOOR TEMPERATURE (FRC: K = 0.40)
Body dimensions             Dim
Inside length 4,2 5,2 6,2 7,4 10,4 13,4 m
Inside width 2,45 2,45 2,45 2,45 2,45 2,45 m
Inside height 2,2 2,2 2,2 2,4 2,4 2,4 m
Mean surface 52,52 62,12 71,72 87,24 117,24 147,24
Inside volume 22,64 28,03 33,42 43,51 61,15 78,79
Required air capacity 30-60-times
(loaded/empty)
679/1.358 841/1.682 1.002/2.005 1.305/2.611 1.835/3.669 2.364/4.727 m³/h
Wall heat penetration              
k-value (new) = 0.40
W/m²°C
1.050 1.242 1.434 1.745 2.345 2.945 W
after 6 years
(30 % aging) -> k value =
0.52)
1.366 1.615 1.865 2.268 3.048 3.828 W
after 9 years (50 % aging) -> k value =
0.60)
1.576 1.864 2.152 2.617 3.517 4.417 W
Door opening losses              
Up to 2 customers per hour
(air exchange factor = 1.2)
943 1.168 1.392 1.813 2.548 3.283 W
Up to 3 customers per hour
(air exchange factor = 1.2)
1.415 1.752 2.089 2.720 3.822 4.925 W
Up to 4 customers per hour
(air exchange factor = 2.4)
1.887 2.336 2.785 3.626 5.096 6.566 W
Up to 5 customers per hour
(air exchange factor = 3.0)
2.358 2.920 3.481 4.533 6.370 8.208 W
Required refrigeration
capacity in
long-distance transport
             
with ATP safety
factor of 75%
             
as manufactured (new) 1.838 2.174 2.510 3.053 4.103 5.153 W
6 years old 2.390 2.826 3.263 3.969 5.334 6.699 W
9 years old 2.757 3.261 3.765 4.580 6.155 7.730 W
Required refrigeration
capacity in
distribution service
             
Up to 2 customers per hour
(factor 1.6 = 62%)
             
New 3.190 3.856 4.523 5.692 7.828 9.964 W
6 years old 3.694 4.453 5.221 6.530 8.954 11.378 W
9 years old 4.030 4.850 5.670 7.088 9.704 12.320 W
Up to 3 customers per hour
(factor 1.8 = 55%)
             
New 4.437 5.389 6.341 8.036 11.100 14.165 W
6 years old 5.005 6.060 7.116 8.978 12.366 15.755 W
9 years old 5.383 6.508 7.632 9.606 13.211 16.815 W
Up to 4 customers per hour
(factor 2.0 = 50%)
             
New 5.874 7.156 8.438 10.742 14.882 19.022 W
6 years old 6.504 7.902 9.299 11.788 16.288 20.788 W
9 years old 6.924 8.399 9.873 12.486 17.226 21.966 W
Up to 5 customers per hour
(factor 2.2 = 45%)
             
New 7.499 9.156 10.814 13.810 19.173 24.535 W
6 years old 8.192 9.976 11.761 14.962 20.720 26.479 W
9 years old 8.654 10.523 12.392 15.729 21.752 27.774 W
Higher requirements on refrigerated trucks accorind to DIN 8959 PDF
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