A combination refrigeration system is well suited to may large tonnage air conditioning systems to may large tonnage air conditioning systems where operating economy is important and medium or high pressure steam is planned as the driving force. However, the combination system is generally most attractive on large tonnage building complexes such as college campuses…
The absorption refrigeration machine is a water chilling package which uses heat directly without the use of a prime mover, thus utilizing the heating facilities on a full time, year-round basis. Because of its compactness and vibration less operation, it can be installed anywhere space and a heat source is available, from basement to roof.…
Centrifugal refrigeration machine nay be classified by the type of compressor: Open compressors have a shaft which projects outside the compressor housing, requiring a seal to isolate the refrigerant space from the atmosphere. Hermetic compressors have the driver built into the unit, completely isolating the refrigerant space from the atmosphere. OPEN MACHINE Open type equipment…
CAPACITY AND STEAM CONDITIONS Capacity is one of the most important factors in determining the type of unit to be selected. There is a partial correlation between steam conditions and capacity. Maximum pressures and temperatures seldom prove economical except in the higher capacity ranges. Limitations imposed by steam pressure and temperature are predominantly structural. They…
Factors which exert the greatest influence on the selection of boilers are fuel characteristics, capacity and steam conditions, space conditions, cost and individual preference. FUEL CHARACTERISTICS Prior to a preliminary selection of equipment, complete information should be available concerning fuels on which boiler types and predicted performance are based. Numbers 5 and 6 fuel oil…
Cast iron boilers are suitable for steam generation or hot water heating where low pressures are used. They may be applied in commercial and industrial buildings within the capacity range available. The capacities of cast iron and steel boilers overlap. Where this occurs, any comparison should include the following: Steel boilers in the larger sizes…
Boilers may be classified in two general groups: 1. Sectional cast iron boilers. 2. Steel firebox boilers, fire-tube or water-tube. Cast iron boilers may be rectangular (or square) with vertical sections or round with horizontal sections. These boilers are usually shipped in sections and assembled at the place of installation. Some smaller boilers are factory-assembled.…
With the exception of the reciprocating and rotary compressors, the equipment considered is of the centrifugal type (fans, refrigeration compressors, pumps) operating at starting within a system of high and low sides that are equalized. Ordinarily no specific requirement of starting torque other than normal is needed. At times with large centrifugal compressors or fans…
EQUIPMENT SERVED The air conditioning and refrigeration systems include fans, pumps, and reciprocating, rotary and centrifugal compressors. To effect the transfer or compression of various liquids and gases such as air, water, brine of refrigerants, it is necessary to put this equipment into motion by prime movers, in this instance, electric motors. Apart from the…
Compressors may be classified as either open or hermetic. OPEN COMPRESSOR An open compressor requires an external drive and may be direct driven thru a coupling or belt driven to operate at a specific speed, depending on load requirements. The type of the drive (electric motor, internal combustion engine or steam turbine) may be selected…
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