Performance Test Results of a Lithium Bromide-Water Absorption Heat Pump That Uses Low-Temperature (60 exp 0 C (140 exp 0 F)) Waste Heat. Final Report

摘要

An absorption heat pump for upgrading industrial waste heat to process steam temperatures has been developed and successfully tested at Oak Ridge National Laboratory. The heat pump uses lithium bromide and water as the working fluids and is designed to operate with waste heat temperatures ranging from 60 to 100 exp 0 C (140 to 212 exp 0 F). Performance data from the 45-kW(t) (12.5-ton) prototype heat pump have shown good agreement with theoretical predictions. Advantageously, most of the energy for operation comes from the waste heat, with only low inputs of electrical energy for parasitics; electrical coefficients of performance ranging from 50 to 85 have been demonstrated. This feature makes the heat pump attractive from the standpoint of energy conservation. The successful operation of this absorption heat pump prototype has demonstrated that this concept is an easily operated and practical candidate for energy recovery from waste heat in industrial applications where low-temperature process steam is needed. An adiabatic absorber section was incorporated into this machine to allow the diluted absorbent to reach its maximum temperature before delivering heat to the load. However, the kinetics of the absorption reaction were faster than anticipated from the design calculations, and this feature was not advantageous for operation with lithium bromide-water. The prototype heat pump tested is a single-stage machine, but two-stage versions have been theoretically evaluated which could obtain about twice the temperature boost when required. An economic analysis shows attractive payback times over a wide range of operating temperatures. (ERA citation 09:033554)