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.

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	m²
Inside volume	22,64	28,03	33,42	43,51	61,15	78,79	m³
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

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 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

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