Primary chilling of red meat 109 Table 6.6 Average ambient air temperature over survey. The energy used per kilogram of beef produced divided into the base demand and the product emand, and"the total energy consumption per kg adjusted to allow for a full Chiller Ambient air (°C) ,e,d=, number 4.0 .0 14.0 43.0 15.0 78.0 128.0 62.6 0.0 48.0 81.0 14.0 2.0 154.0 19.0 33.0 62.3 115.0 21.0 22.6 67.0 116.0 42.0 0 30.0 14.0 18.0 40.0 628 45.8 1020187.0 40.0 143.0 18.0 53.0 Means 47.4 14.6 Source: Gigiel and Collett. 1990 (mean 30625 kg) of beef in carcass form and in size from 216 to 1124m The energy data were broken down into a base demand and a produc demand(Table 6.6). Base demand is the energy required to maintain the chiller at the desired temperature with the doors closed. Product demand is the additional energy needed to reduce the temperature of the meat. When carcasses are loaded into a chilling system the infiltration of warm air through the open doors further adds to the load on the refrigeration plant and this is included in the product load values. The base demand will depend on the average ambient air temperature, the level of insulation, the fan power and the control system used. Plant 1 achieved a zero-base demand in the winter because the control system cut out the fans and compressor when the desired room temperature was reached. The other plants were controlled such that all the evaporator fans ran continuously, except during defrosts, resulting in considerable base demands. To aid comparison, where chillers were not fully loaded, specific energy consumption for full loading was calculated by multiplying product demand per kilogram for a partially loaded chiller by its total capacity and adding this to the base demand Approximately 48h were required in the commercial chillers to meet the EC requirement of a maximum carcass temperature of 7"C (Table 6.7)and side temperatures of up to 17.0C were measured on dispatch from one of(mean 30 625 kg) of beef in carcass form and in size from 216 to 1124 m3 . The energy data were broken down into a base demand and a product demand (Table 6.6). Base demand is the energy required to maintain the chiller at the desired temperature with the doors closed. Product demand is the additional energy needed to reduce the temperature of the meat. When carcasses are loaded into a chilling system the infiltration of warm air through the open doors further adds to the load on the refrigeration plant and this is included in the product load values. The base demand will depend on the average ambient air temperature, the level of insulation, the fan power and the control system used. Plant 1 achieved a zero-base demand in the winter because the control system cut out the fans and compressor when the desired room temperature was reached. The other plants were controlled such that all the evaporator fans ran continuously, except during defrosts, resulting in considerable base demands. To aid comparison, where chillers were not fully loaded, specific energy consumption for full loading was calculated by multiplying product demand per kilogram for a partially loaded chiller by its total capacity and adding this to the base demand. Approximately 48 h were required in the commercial chillers to meet the EC requirement of a maximum carcass temperature of 7 °C (Table 6.7) and side temperatures of up to 17.0 °C were measured on dispatch from one of Primary chilling of red meat 109 Table 6.6 Average ambient air temperature over survey. The energy used per kilogram of beef produced divided into the base demand and the product demand, and *the total energy consumption per kg adjusted to allow for a full chiller Chiller Ambient air Base First Second *First *For 48 h system temperature demand 24 h 24 h 24 h (kJ kg-1 ) identity (°C) (kJ kg-1 ) (kJ kg-1 ) (kJ kg-1 ) (kJ kg-1 ) number 1 4.0 0.0 63.0 5.8 63.0 68.8 2 14.0 35.0 43.0 15.0 78.0 128.0 3 7.5 26.0 62.6 – 86.0 – 4 0.0 15.0 48.0 3.0 63.0 81.0 5 14.0 38.0 42.0 36.0 80.0 154.0 6 19.0 33.0 62.3 5.3 86.0 115.0 7 21.0 56.7 22.6 5.6 67.0 116.0 8 11.0 44.0 42.0 9.0 86.0 139.0 9 0.0 32.0 30.0 14.0 62.0 108.0 10 4.0 26.0 31.8 7.9 52.0 80.0 11 18.0 40.0 62.8 45.8 102.0 187.0 12 10.5 24.0 53.0 – 77.0 – 13 14.0 40.0 47.7 18.8 86.0 143.0 14 18.0 44.0 53.0 9.0 97.0 150.0 Means 32.4 47.4 14.6 77.5 122.5 Source: Gigiel and Collett, 1990