Pumping Cycle Kite Power

Simple analytical models for a pumping cycle kite power system are presented. The theory of crosswind kite power is extended to include both the traction and retraction phase of a pumping cycle kite power system. Dimensionless force factors for the reel out and reel in phase are introduced which describe the efficiency of the system. The optimal reel out and reel in speed of the winch is derived where the cycle power becomes maximal. These optimal speeds are solely determined by the ratio of the force factors. Scenarios for wind speeds higher than the nominal wind speed are considered and power curves for the pumping cycle kite power system derived. The average annual power for a given wind distribution function allows to estimate the annual energy production of the pumping cycle kite power system. The role of the elevation angle of the tether is highlighted and a simple model to demonstrate the influence of the kite mass on the power output is discussed.