A daughter card includes a number of circuit modules generating heat and a spring member transmitting the heat to a thermal bus extending along a circuit board adjacent to one side or to each side of a connector to which the daughter card is releasably attached. One or more contact surfaces of the spring member releasably contact one or more mating surfaces of a thermal bus at a side of the connector or at both sides of the connector. A heat pipe may additionally be used to direct heat from the thermal bus to a heat absorber.