The thermal performance of two different schemes of solar-assisted heat-pump systems has been theoretically studied. In first scheme, the evaporator of the heat pump is taken directly as the solar collecting plate and always maintained at the ambient temperature. As there is no heat loss from the collecting plate, the thermal efficiency of the collector is high and equals the solar absorptivity of the collecting plate. As suggested, the heat-pump evaporator of the second scheme is placed in a novel fresh water solar pond/tank with high efficiency. Since the evaporator operates at a relatively high temperature, the COP of the heat pump can be increased. The calculated results show that the COP of a solar-assisted heat pump using the second scheme is considerably higher than that of the first scheme.