Refrigeration and Air Conditioning

OTHER PACKAGES

A very large variety of smaller self-contained refrigeration and air-conditioning packages are made, mainly for the consumer durable market and small domes­tic applications. They include: • Domestic refrigerators and freezers. • Retail display cold and freezer cabinets and counters. • Cooling trays for bottles (beer, soft drinks, wines). • Instantaneous draught beer coolers. These usually […]

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TESTING OF PACKAGED UNITS

Manufacturers’ test procedures for packaged units may include some of the following: 1. Safety pressure tests and leak tests should always be included (see also Section 11.3). 2. Rating test, from a representative unit which forms the basis for the published capacity and application leaflets. 3. Type tests, which verify the product as designed will […]

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SPLIT PACKAGES

To avoid the constraint of having all parts in one package, the evaporator set may be split from the condenser and the compressor going with either (see Figure 13.9). The unit is designed as a complete system but the two parts are located separately and connected on site. On some small units, flexible refrigerant pip­ing […]

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CHILLERS AND AIR COOLING PACKAGES

These are true packaged units in the sense that all the parts of the refrigeration system and its controls are factory assembled and tested in the complete state. There are four configurations: • Air cooling, air-cooled • Air cooling, water-cooled • Liquid cooling, air-cooled • Liquid cooling, water-cooled Air cooling packages are limited by the […]

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COMPRESSOR PACKS

This term is used to describe an assembly of several compressors mounted on a frame, complete with liquid receiver, suction and discharge headers, oil separ­ation and oil return piping and controls (Figures 13.4 and 13.5). They are widely used in centralized supermarket systems and the compressors serv­ing the low-temperature evaporators and those serving the chill […]

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CONDENSING UNITS

A condensing unit is a single package comprising the compressor, the condenser (either air — or water-cooled) mounted on a base plate or frame, and all connecting piping, together with the necessary wiring and controls to make the set functional (Figure 13.1). Condensing units generally include a liquid receiver and are ready for site connection […]

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Packaged Units

13.1 I NTRODUCTION Factory-built self-contained systems are very familiar in the form of domes­tic appliances, and retail units such as vending machines, drinking water chill­ers, and display cabinets and counters. Although larger systems may need to be finally assembled in situ, groups of components can be conveniently delivered as pre-assembled units, and it is the […]

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THERMAL STORAGE

Phase change materials (PCMs) for thermal storage are available in a number of forms to suit various applications. In its simplest form variations in cooling load can be provided from the latent heat of melting of ice or a frozen eutec­tic. Ice can be formed by allowing it to build up on the outside of […]

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PHASE CHANGE MATERIALS AS SECONDARY COOLANTS

A pumpable ice slurry can be used instead of chilled water or brine. The compo­sition of these fluids is quite simple, consisting of water with ice crystals mixed with another fluid such as glycol, ethanol, ammonia, NaCl. Only a fraction of the water is transformed into small ice crystals (around 1 mm). This ensures a […]

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SECONDARY COOLANTS

Where a secondary refrigerant fluid is to be circulated, and the working tempera­tures are at or below 0°C, then some form of non-freeze mixture must be used. Aqueous solutions of sodium chloride and calcium chloride were the first types of sub-zero secondary fluids, and this is why the collective term brine is some­times used. Propylene […]

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