Hartmut Grimm

Spreadsheet modeling to size dairy sprinkler and fan cooling system.

A tool was developed to assist the cooling systems designer in designing and installing a microsprinkler and fan cooling system. The tool was developed by integrating a mathematical model into an electronic spark map in order to use the mathematical model practically. The mathematical model was developed using the designs, parameters, variables, and constant values of the microsprinkler and fan cooling system. Subsequently, MS-Excel was used to develop the spark map of the mathematical model and to show the results of the input settings automatically. The spark map, using the mathematical model, assists the designer in making decisions to specify and to calculate the required discharge of cooling system pump, length and diameter of cooling system pipelines, number of cooling fans, and number of microsprinklers. Moreover, this tool calculates the capital investment and the fixed, variable, and total costs of the cooling system. However, the mathematical model of the spark map requires some input data, such as: pressure and discharge of microsprinklers, and some other engineering parameters. Data of 4 cooling systems were used to carry out the model validation. The differences between actual and calculated values were determined, and the standard deviations were calculated. The coefficients of variation were between 2.25% and 4.13%.

Wärmeeinstrahlung unterschiedlicher Dacheindeckungen im Stallmodell

Dacher von Ausenklimastallen werden oft sehr einfach ausgefuhrt, da der Schutz vor Niederschlagen im Vordergrund steht. Der Schutz vor Warmeeinstrahlung eines durch die Sonne stark erhitzten Daches wird wegen der hoheren Kosten oft vernachlassigt. Uberpruft wurde daher im Versuch an einem Dachmodell, wie sich die „Abschattung“ eines einfachen Daches aus Trapezblech durch ein zweites Trapezblech auswirkt. Die Einstrahlung auf das Dach war in allen Versuchen 1 000 W/m² wahrend je zwei Stunden. Wichtigste Parameter waren die Warmeabstrahlung in den Modellraum sowie seine Innentemperatur. Das doppelte Trapezdach ist, wenn die Kosten des Daches im Vordergrund stehen, eine akzeptable Alternative zu gedammten Sandwichpaneelen.

Arbeitszeiten und Melkleistung in Swingover-Melkständen

Time consumption for milking routines were recorded on 26 farms (Germany and GB) with swingover parlours (n = 20; 14 to 52 places) and in standard herringbone parlours (n = 6; only GB). As long as the milkers followed the same routines, no difference in the capacities of the two systems could be observed. The throughput in GB with bigger installations was 91 cows per hour (standard herringbone) and 98 cows per hours in swingover parlours, whereas in Germany it was 61 cows per hour, due to a different routine.