Case Studies of Waste Heat Driven Industrial Heat Pumps from the North Carolina State University Industrial Assessment Center.

Abstract

Waste heat driven heat pumps can produce useful heat streams for manufacturing facilities. A heat pump system that uses a waste heat stream as the low temperature source often can provide the subject facility heat more cheaply than conventional heat sources such as boilers.

Heat pumps have long been studied for industrial use. Several case studies were used to show that waste heat driven heat pumps typically have payback periods of approximately 5 years. This payback period is independent of the type of system or the physical location of the installation.

Case studies using clients from the North Carolina State University's Industrial Assessment Center also show payback periods between four and six years. Three of the four facilities examined had positive payback periods from the installation of a heat pump. The fourth facility, a large fiber optic cable manufacturer, could not readily replace a traditional heat source with the heat pump and therefore could not justify the installation of a heat pump system.

The IAC case studies highlighted several things. First, a heat pump must have a steady source of waste heat. Second, the system must be installed in an area with a relatively low cost of electricity. Third, the system must be able to offset heat generated elsewhere in the facility. Finally, the system must be able to operate for a large portion of the working day.