DOE-2 Reference Manual Version 2.1 - DOE2.com

COEFFICIENTSAll curves will be fit by a least-squares approximation. Ifnot enough points are input for the curve TYPE, it is an ERROR.takes, for its values, a list of the coefficients describedunder TYPE. If more coefficients are specified in the listthan are required for a given type of curve, the programaccepts the correct number of coefficients, starting from theleft side of the list, and ignores the rest. If fewer arespecified than required, the coefficients are taken from leftto right and the missing ones default to zero.The following examples show how data might be taken from manufacturer'sspecifications for each of these methods of input.Example 1A user's packaged heating-cooling system (PZS) shows cooling capacity datasignificantly different from that used in the DOE-2 model. The manufacturerlists the following data for cooling capacity of his unit at 2000 cfm, thedesign air flow rate.Outside Entering Wet-Bulb TemperatureDry-BulbTemperature 72 67* 62Cooling Capacity (kBtuh)85 69 65 6095* 68 63* 57105 65 60 53115 62 55 49*ARI point (Air-Conditioning and Refrigeration Institute) .Because the user has two independent variables (entering wet-bulb andoutside dry-bulb) and the dependent variable, cooling capacity, he will inputa bi-quadratic curve using the given data points. His input will be asfollows. Note that the third variable, cooling capacity, is not actually acooling capacity but rather it is a ratio of two cooling capacities, thecooling capacity at operating conditions divided by the cooling capacity atARI conditions. The ratio should equal 1.0 at the ARI point. Thus, in thiscase, all cooling capacity values have been divided through by the ARI value,63. Throughout this manual this is the process referred to as "normalizing".IV.184 (Revised 5/81)