Where only low-grade heat is available for industrial absorption chiller installations the systems are adjusted to operate at the available lower temperatures and with a cooler generator. However, reduction in generator temperature results in reduced chiller capacity. Thus, the capital requirement per unit of capacity is increased when generator temperature is dropped. Many potential waste-heat-powered absorption chiller projects are abandoned because of required excessive investment. One approach to a lower generator temperature involves the lowering of generator pressure. The vortex generator described here efficiently lowers the generator pressure to permit an absorption chiller to function more efficiently with relatively cooler sources of waste heat. Payback period is computed as a function of generator temperature and pressure. It is shown that, if absorption chillers must operate with low-grade waste heat, lower generator pressure, as produced by a vortex generator, offers a shorter payback period.

Units: Dual