Abstract: Provision is made in a multiple zone air conditioning system for varying the speed of the compressor to match the load thereon. The differences between the actual temperatures and the set points in the individual zones are monitored and the largest of these differences is periodically selected and applied to a transfer function to obtain a new speed at which the compressor is run. At the same time, the individual dampers within the zones are modulated in response to their respective sensed temperature differences. Provision is also made to vary the speed of the indoor fan in a similar manner.

Abstract: The control box for a refrigeration condensing unit has a heat sink mounted on its rear side between the control box and the coil assembly, the heat sink being in the flow path of the cooling air flowing in thru the coil such that the heat dissipation therefrom is substantially enhanced. The heat sink has a plurality of fins formed on its rear side, with the fins extending across the relatively narrow width of the heat sink such that the cooling air flows over the entire length of each of the fins and provides a substantially uniform velocity profile along the heat sink vertical axis.