Chiller system design and control pdf

How does a Chiller Work?

A chiller is a machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool equipment, or another process stream such as air or process water. As a necessary by-product, refrigeration creates waste heat that must be exhausted to ambience, or for greater efficiency, recovered for heating purposes. Chilled water is used to cool and dehumidify air in mid- to large-size commercial, industrial, and institutional facilities. Water chillers can be water-cooled, air-cooled, or evaporatively cooled. Water-cooled systems can provide efficiency and environmental impact advantages over air-cooled systems. In air conditioning systems, chilled water is typically distributed to heat exchangers, or coils , in air handlers or other types of terminal devices which cool the air in their respective space s.

Low 'T Syndrome For many years the low 'T syndrome debate has raged. Many system operators simply turn on more pumps and chillers to satisfy flow requirements, which wastes energy. For primary-secondary systems, some system designers advocate putting a check valve in the bypass linethus putting chilled-water primary and secondary pumps in series and varying the flow through chiller evaporators. Other designers install primary pumps that are larger than necessary and over pump chillers at part-load conditions. These solutions are all band-aids and do not treat the source of the problem. Coad14 points to the fact that a properly operating hydraulic system will work as designed and explains the fallacies in the check valve and over pumping approaches. Refer to the Check valves sidebar on page

Air or Water Cooled. This section will review each of the components. Benefits of Water-Cooled Systems vs. It may cause electric shock, electricity leakage or defects. Table