A coolant circuit for cooling a fuel cell stack for a motor vehicle includes a heating device for raising the temperature of the coolant and a cooling device for lowering the temperature of the coolant. According to certain embodiments, an example golf club head comprises a face for striking a golf ball, a backside portion, a sole portion, and one or more removable weights. An estimated level of power consumption of the electronic circuit is determined by a computer as a function of the user-entered values of the first subset of parameters and the default values of the second subset of parameters. The lamellar structure is surrounded by a hydrophilic medium, preferably water. The user can fully retrieve the module by pulling the first lever. The spoke structure is divided in the tire circumferential direction into at least two circumferential-direction separate structures.