HEAT PUMPS FOR STEAM PRODUCTION FROM WASTE HEAT

摘要

In the process industry large amounts of energy are rejected to the ambient at moderate temperature.rnIncreasing energy prices have motivated many industries to investigate internal recovery of waste heat orrnexport of the heat for district heating in nearby communities. This is not always possible as there is notrnalways a market for district heating C1ose to the industrial plants. Heat must then be recovered and usedrninternally.rnMany industrial processes use medium pressure steam in their processes. This paper investigates steamrnproduction at the condenser of a heat pump recovering waste heat at the evaporator. Several working fluidsrnare compared based on cycle calculations and basic sizing of key components. Emphasis is put on naturalrnworking fluids. The COPs for condensation at 110℃ ranged from 1.3 to 4.2 for respective evaporationrntemperatures of 15 to 55℃. Butane was found to be a very good candidate with very similar characteristicsrnas R245fa, without the known environmental drawbacks. Ammonia was less efficient and seems to be morernexpensive due to the need for intercooling and desuperheating.