Sweetening the absorption option
Especially in institutional applications, it may also make sense to use recovered heat, perhaps from a boiler economizer, to supply energy for a single-stage absorption chiller. This unit could supplement an existing chiller plant to provide chilled water at an operating cost much lower than an electric chiller in the warm months, or even year-round. Today’s single-stage absorbers can generate chilled water from hot water as low in temperature as 190°F.
Even if the temperature of the recovered heat stream is not this high, it could very effectively reduce the cost of the heat input to either a hot water or steam absorption chiller. Again, it’s important to balance the cost of adding absorption chiller capacity versus the reduction in operating costs. If you already operate a hot-water chiller, the payback from streaming hot water with recovered heat could be very attractive.