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The cooling of equipment and products is an integral part of many manufacturing processes. This paper describes typical process cooling systems used in manufacturing and the approximate cost of cooling for each system. The paper then describes the inside out approach to energy efficiency, which recommends sequential evaluation of end use, distribution and primary energy conversion systems, as it relates to process cooling. General methods for improving the energy efficiency of cooling processes, organized according to the inside-out approach, are described. These methods include adding insulation and heat exchangers, improving process control, avoiding mixing, employing variable-speed and low friction pumping systems, and using cooling towers in place of chillers. The fundamental equations for estimating savings, and examples, are presented for these methods.

Much energy is lost through excess air flow in and out of process heating equipment. Energy saving opportunities from managing air flow include minimizing combustion air, preheating combustion air, minimizing ventilation air, and reconfiguring openings to reduce leakage. This paper identifies these opportunities and presents methods to quantify potential energy savings from implementing these energy-savings measures. Case study examples are used to demonstrate the methods and the potential energy savings. The method for calculating savings from minimizing combustion air accounts for improvement in efficiency from increased combustion temperature and decreased combustion gas mass flow rate. The method for calculating savings from preheating inlet combustion air consists of fundamental heat exchanger and combustion efficiency equations. This method accounts for the reduction of combustion air flow as fuel input declines, which is often neglected in many commonly-used methods.