Chiller system pdf

This section discusses the effect of flow rate and temperature decisions. This TDP module on water-cooled chillers starts with a history of the first centrifugal chiller and describes the first applications for early water-cooled chillers. After a discussion of the rela-tive merits of water-cooled chillers , the refrigeration cycle for a water-cooled centrifugal chiller is explained using pressure-enthalpy diagrams. Systems that employ water chillers are commonly called chilled-water systems.

When designing a chilled-wat er system , one of the first issues that must be addressed is to determine which type of water chiller to use.

This period discusses the primary differences in chiller types. Refrigeration and air conditioning systems cover a wide variety of cooling applications, using both standard and custom-made equipments. HTD Series HTD stands for High Temperature Difference.

Fluids are chilled or heated over large temperature differences, ranging from 5°F to 60°F in a single pass using R-2 ammonia or glycol as the refrigerant inside the plate. Systems are available in direct expansion (DX), flooded and recirculated models. Chillers are the heart of the chilled-water air-conditioning system since they serve the pivotal function of creating the cooling effect required to maintain comfort condi- tions. Chillers are used in a variety of comfort air- conditioning and process cooling applications.

The use of the cooling tower gives water-cooled systems an efficiency edge over air-cooled systems and RTUs.

In addition, unlike RTUs, which circulate cool air through ducts, all chillers circulate chilled water to air-handler units, where fans push air across heat exchanger coils to deliver cooling. The use of an industrial inhibited glycol and water mixture is recommended in most water chiller systems. Ethylene and Propylene are the two standard types of inhibited glycols commonly used. The main job of glycol is to prevent freezing of the process fluid and ensure consistent flow at the operating temperature. This flexibility has contributed to their overall popularity among designers of chilled -water systems.

Air-cooled chillers range in size from small capacity models to several hundred-ton models that are utilized to cool large commercial buildings. The final process is the expansion device. This shows as vertical line from point to point indicating the pressure drop that occurs as the refrigerant passes through the expansion valve. Chillers provide chilled water at a constant temperature, as desired.

Chillers operating from -40C to ambient typically use a single-stage refrigeration design such as the one shown in Figure 1. As temperature requirements drop below -40C, chillers incorporate additional refrigeration circuits (called two-stage and three-stage systems) with multiple refrigerants. Mechanical engineers who design chilled water plants are the target audience for the guide. All of the material in the guide is relevant to this group, although experienced engineers can briefly review Chapter on loads and Chapter on equipment and then refer to this material as necessary. A chilled water system is a cooling system in which chilled water is circulated throughout the building or through cooling coils in an HVAC system in order to provide space cooling.

A more efficient chiller is a major step along the path to reduce energy consumption and the building’s carbon footprint. Simplified diagram of a single-stage recirculating fluid chiller , showing direction of flow and heat removal. Principles of Fluid Chillers.

This paper reports the findings from that study. Design Criteria for Reliable Operation. HVAC Water Systems Waterside Free Cooling Summary Free cooling utilizes the evaporative cooling capacity of a cooling tower to indirectly produce chilled water for use in medium temperature loops, such as process cooling loops and sensible cooling loops. How does a Chiller Work?

Characteristics of an efficient cooling system. This cool fluid removes heat from the process and the warm fluid returns to the chiller. The process water is the means by which heat transfers from the process to the chiller.

YORK Chillers offer energy efficient solutions for any industrial or commercial cooling application. Learn more about our water-cooled YORK HVAC chillers. This site uses cookies to offer you a better browsing experience. WATER PIPING AND PUMPS Distribution Systems Open-Loop (Condenser) In an open-loop piping system , the water is in constant contact with the air and the system is therefore open to the atmosphere.

In industrial and commercial refrigeration systems , the heat is usually rejected to water. Once-through cooling may be use but water costs and environmental restrictions dictate recirculating system utilizing cooling towers to reject the heat into the atmosphere. Absorption Refrigeration.