xdxadmin
08-31-2004, 09:15 AM
Parallel Compressor systems are known as 'Racked' Compressor Systems. "Racks" have two primary groupings; the first uses a team of 'Parallel' compressors to manage a common load. The second type uses individual compressors mounted to a common base, sharing condenser fans and certain electrical components, yet functioning with independent condenser and evaporative coil circuiting. This will focus upon the Parallel Compressor System.
A Parallel Compressor System uses multiple compressors with a common housing and certain other common elements to reduce power consumption and maximize performance. The interconnected motor-compressors perform as a team. The parallel compressor system integrates numerous parallel refrigeration loads and can allow various stages of system capacity through the modulation of the compressors in stages, closely matching the actual required load. Compressor paralleling results in more evenly refrigerated fixture discharge temperatures, higher energy efficiency (EER), longer compressor life, and less service. A compressor failure can be compensated by the other compressors within the system. Complex Oil Feed Systems are often utilized.
Parallel Compressor systems are commonly used for supermarkets, grocery stores, industrial plants, air-conditioning, pharmaceuticals, food processing/warehousing, ice skating rinks, and food service and can be found in condensing units or in 'Racked Systems' (Racks / Packs - outside of the United States). Separate compressor rooms are usually required by code where the refrigerant capacity is high, many parallel compressor systems are located in mechanical centers detached from the main building structure or are located at rooftop locations.
Many Mechanical Houses, can be shipped completely pre-wired and pre-piped, with multiple parallel compressor systems housed together. Systems can include ventilation, electrical service panel, control/defrost panel, low side and high side components, and a usually a micro-processor based energy management system. Components are usually provided in accordance with the customer proprietary preference.
Manufacturers of Parallel Compressor Systems are more equipped to customize systems than are most condensing unit manufacturers. Systems can be supplied with a liquid receiver in vertical or horizontal orientation, various styles of oil reservoir or Oil Separator , options for either Electric Defrost, or Hot-Gas Defrost, choice of compressor brand and type (i.e. Reciprocating, open drive direct/belt, open drive direct, scroll, and screw compressors ), and other options.
Heat reclamation is another common option. Heat reclamation works with the building air handler heat reclaim coil or with a hot water tank to reclamation heat from the refrigeration system hot gas. Heat reclaim includes a 3-way diverting valve and discharge side return check valve. Control can by integrated with the building environmental control system. Heat reclaim results in significant building energy cost savings.
While most Parallel Compressor Systems range in total system capacity from 200,000 MBH to over 1,000,000 MBH, smaller Mini-Racks are available from select manufacturers that specialize in customization for customers with flexibility requirements in smaller applications. Ratings depend upon the size and type of the motor compressors, refrigerant selected, ambient temperature, and condensing temperature.
Parallel Compressor Systems usually handle various banks of circuits with common evaporator temperatures. Systems with split suction headers can be designed to operate various suction pressures in one piece of equipment.
Notes:
The Parallel Compressor System has one primary draw back, and that is the absence of system redundancy. One adverse condition can cause system-wide performance issues. Parallel Compressor Systems often operate every evaporator of a certain evaporator temperature / pressure range, and therefore often provide no system back-up. It may be advisable to use single or individual units for redundancy
XDX works well in conjunction with any Parallel Compressor System.
A Parallel Compressor System uses multiple compressors with a common housing and certain other common elements to reduce power consumption and maximize performance. The interconnected motor-compressors perform as a team. The parallel compressor system integrates numerous parallel refrigeration loads and can allow various stages of system capacity through the modulation of the compressors in stages, closely matching the actual required load. Compressor paralleling results in more evenly refrigerated fixture discharge temperatures, higher energy efficiency (EER), longer compressor life, and less service. A compressor failure can be compensated by the other compressors within the system. Complex Oil Feed Systems are often utilized.
Parallel Compressor systems are commonly used for supermarkets, grocery stores, industrial plants, air-conditioning, pharmaceuticals, food processing/warehousing, ice skating rinks, and food service and can be found in condensing units or in 'Racked Systems' (Racks / Packs - outside of the United States). Separate compressor rooms are usually required by code where the refrigerant capacity is high, many parallel compressor systems are located in mechanical centers detached from the main building structure or are located at rooftop locations.
Many Mechanical Houses, can be shipped completely pre-wired and pre-piped, with multiple parallel compressor systems housed together. Systems can include ventilation, electrical service panel, control/defrost panel, low side and high side components, and a usually a micro-processor based energy management system. Components are usually provided in accordance with the customer proprietary preference.
Manufacturers of Parallel Compressor Systems are more equipped to customize systems than are most condensing unit manufacturers. Systems can be supplied with a liquid receiver in vertical or horizontal orientation, various styles of oil reservoir or Oil Separator , options for either Electric Defrost, or Hot-Gas Defrost, choice of compressor brand and type (i.e. Reciprocating, open drive direct/belt, open drive direct, scroll, and screw compressors ), and other options.
Heat reclamation is another common option. Heat reclamation works with the building air handler heat reclaim coil or with a hot water tank to reclamation heat from the refrigeration system hot gas. Heat reclaim includes a 3-way diverting valve and discharge side return check valve. Control can by integrated with the building environmental control system. Heat reclaim results in significant building energy cost savings.
While most Parallel Compressor Systems range in total system capacity from 200,000 MBH to over 1,000,000 MBH, smaller Mini-Racks are available from select manufacturers that specialize in customization for customers with flexibility requirements in smaller applications. Ratings depend upon the size and type of the motor compressors, refrigerant selected, ambient temperature, and condensing temperature.
Parallel Compressor Systems usually handle various banks of circuits with common evaporator temperatures. Systems with split suction headers can be designed to operate various suction pressures in one piece of equipment.
Notes:
The Parallel Compressor System has one primary draw back, and that is the absence of system redundancy. One adverse condition can cause system-wide performance issues. Parallel Compressor Systems often operate every evaporator of a certain evaporator temperature / pressure range, and therefore often provide no system back-up. It may be advisable to use single or individual units for redundancy
XDX works well in conjunction with any Parallel Compressor System.