The indoor climate of a greenhouse provides the plants with favorable growing conditions that can result in faster growth and higher yields. Important parameters to control in a greenhouse are the temperature, the humidity, and the level of CO2 concentrations. In southern Europe, both heating and cooling are required to control the greenhouse temperatures throughout the year. In this study, Computational Fluid Dynamics (CFD) simulations is employed to study the fluid flow through air distribution hoses (ADHs) in a research greenhouse in Bucharest, Romania. The ADHs are part of a novel, energy-efficient concept at the greenhouse, comprised of an integrated heat pump system, air handling units (AHUs), a dry cooler, and borehole thermal energy storage. The heat pump system provides both heating and cooling, while the greenhouse humidity is controlled by the AHUs. CO2-enrichment to the greenhouse is provided from installed CO2 tanks. The CO2-enriched air is circulated from the AHUs to the ADHs, which have a series of perforated holes along their lengths. In these preliminary simulations, different configurations of the perforated holes are simulated to optimize the mixing of the climate-controlled air with the greenhouse air. Both the diameters of the holes and the opening of the ADH outlet are varied to study the mass flow rates out of the holes. The CFD simulations provide suitable design criteria for the installation of ADHs in a greenhouse environment and for optimizing the efficiency of ADHs.