Energy Efficient Design of a Waste Heat Rejection System

In small and medium sized manufacturing facilities, several situations exist where sources of waste heat and sinks needing heat transfer coexist. Examples of waste heat include but are not limited to: drained hot water streams from water cooled manufacturing equipments, waste heat from compressors, lighting systems, chiller condensers, boiler blowdown, building exhaust, and flue gas. Examples of heat sinks needing heat transfer include but not limited to drying, space heat, domestic hotwater, air, and oil preheaters. The heating requirements for these heat sinks are generally met by burning fossil fuels or even by using electric heaters while available waste heat is rejected to the surrounding environment using devices such as cooling towers or chillers which require additional electrical energy for their operation. The practice of rejecting waste heat to the environment and meeting heating requirements by burning fossil fuels or by using electric heaters results in: a) energy waste; b) global warming due to fossil fuels burning and c) economic inefficiency. The objective of the work reported in this report was to develop a design of a heat rejection system, which will replace the operation of currently used mechanical vapor compression chillers at the GBC Film Products in Addison (Illinois). The designed system utilizes the rejected heat for space heating during the winter season and results in additional savings by replacing the combustion of fossil fuels. The design was unique because the proposed system results in dual savings by: utilizing a low temperature heat source for space heating and by reducing the operating cost of the chillers