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Refrigeration for Ships
船舶冷却
The following article was published in ASHRAE Journal, December 2008. @Copyright 2008 American Society of Heating, Refrigerating and AirConditioning Engineers, Inc.It is presented for educational purposes only. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE.
下面的这篇文章发表在2008年12月ASHRAE杂志上。版权所有为2008美国供暖、制冷和空调工程师协会。它仅用于教育目的。未经ASHRAE许可，不得以电子或纸张形式复制或分发本条。
Naval refrigeration applications are similar to a high-rise building,only laid on its side.However, naval applications must deal with a corrosive marine environment, limited space for equipment, and the movement of the ship.This article describes the many additional constraints a designer faces in refrigeration system design for naval applications.The standards referred to in this article are case specific and can be used only after agreement with that particular navy. Usually, each navy uses standards per its own requirements on a case-by-case basis. In many cases, navies allow equivalent or similar standards for equipment and raw materials after a detailed study of project specification requirements regarding improvements in system design and operation.
海军制冷设备类似于一座高层建筑，只位于其一侧。然而，海军应用必须处理腐蚀性海洋环境、有限的设备空间以及船舶的移动。本文描述了海军应用制冷系统设计中设计者面临的许多附加限制。其中提到的标准是特定的，只能在与该特定海军达成一致后使用。通常，每个海军都会根据自己的要求逐案使用标准.在许多情况下，海军在详细研究了关于改进系统设计和OPE的项目规范要求之后，允许对设备和原材料采用同等或类似的标准。
Calculating Refrigeration Capacity
计算制冷能力
Refrigeration plants are used onboard mainly for food preservation in cold rooms and for producing ice required for onboard consumption.Heat load calculations provide the refrigeration capacity required for cold rooms.
Heat load can be calculated by using methods available in technical literature or by using commercial software.The ASHRAE Handbook— Fundamentals and ISO Standard 75471 are useful for this purpose.The required capacity of a refrigeration plant is determined from individual cold-room heat load, ice production load, and from the required cooling down period
Generally, the refrigeration plant on warships has a capacity in the range of 3.5 kW to 50 kW.For chiller packages in most cases, a navy will specify the required capacity, or capacity can be calculated from chilled water flow rate and temperature difference.The capacity usually is in the range of 35 kW to 2,700 kW per chiller package.
制冷设备主要用于冷藏室的食品保存和生产船上消耗所需的冰块。热负荷计算提供了冷藏室所需的制冷能力。热负荷可以用技术文献中的方法或商业软件来计算。ASHRAE手册-基本原理和iso标准75471对于这一目的是有用的。制冷装置所需的容量是由单个冷室热负荷、制冰负荷和所需的冷却时间确定的。一般来说，军舰上的制冷装置的容量在3.5千瓦到50千瓦之间。对于大多数情况下的冷水机组，海军将指定所需的容量，或者根据冷水流量和温差来计算容量。其容量通常在35千瓦至2700千瓦每台冷水机组。
Refrigerant
冰箱
In developing countries, R-22 will be phased out soon. The service life of older ships is being extended to 10 to 12 years by retrofitting them with better plants, equipment, instruments, and machines. R-12 systems are being replaced by R-22 systems because the plant size is smaller compared to an R-134a replacement system. For new ships, environmentally friendly R134a is preferred
在发展中国家，R-22将很快被淘汰。旧船的使用寿命正被延长到10至12年，方法是用更好的设备、仪器和机器对它们进行改造。R-12系统正在被R-22系统取代，因为与R-134a替代系统相比，该系统的工厂规模更小。对于新船，环境友好型R134a会被优先考虑。
Limited Space
限制的地方
As stated previously, a ship is similar to a high-rise building, only laid on its side. Hatches, openings, passages, and staircases interconnect the compartments. The refrigeration plants and chiller packages are normally installed in any of these small compartments located in forward, aft (rear), and the mid portion of a ship, depending upon function. These compartments contain additional equipment, pipelines, and electrical cables, restricting the available space.
如前所述，一艘船类似于一座高楼，只位于其一侧。舱口、开口、通道和楼梯相互连接。制冷设备和冷冻机组件通常安装在船舶的前、后和中间部分的任何一个小舱室中，视功能而定。这些隔间包含额外的设备、管道和电缆，限制了可用空间。
A feasibility study considering the following points is essential for retrofits and is useful when designing new plants. The plant and equipment must be compact enough to be accommodated in the available space. The shipping route of individual equipment and/or a complete plant must be considered before designing the individual equipment or complete plant. The plantrsquo;s orientation within the compartment is decided after carefully considering its operational and maintenance requirements, and the best use of existing pumps and piping and electrical cabling. The mounting arrangement is decided by considering the foundation, bulkhead, deck head supports, and stiffness.
考虑以下几点的可行性研究对于改造是必要的，在设计新工厂时也是有用的。工厂和设备必须足够紧凑，以容纳在现有空间。在设计单个设备或成套设备之前，必须考虑单个设备和成套设备的运输路线。工厂在舱内的定位是在仔细考虑其操作和维护要求以及最佳使用现有的泵、管道和电缆后决定的。安装方式是根据基础、舱壁、桥头支撑和刚度来决定的。
Once the sizes, weights, and operational requirements of individual equipment are known and, after considering all the previous points, the positioning and assembling of the individual equipment is done to form a compact skid to fit in the available space.
一旦知道了单个设备的大小、重量和操作要求，并且在考虑了前面所有的点之后，各设备的定位和装配就是为了形成一个紧凑的滑块，以适应现有的空间。
Equipment Weight
设备重量
The equipment designed for naval use is expected to be lighter and stronger. The size and material of construction decides the weight of the equipment. Reduction in weight is possible by reducing the size and using lighter construction materials, keeping its operational and functional requirements intact
为海军设计的设备预计将更轻和更强。结构的大小和材料决定了设备的重量。减轻重量是有可能的，通过减少尺寸和使用较轻的建筑材料，可以保持其运作和功能要求不变。
Equipment such as heat exchangers and pressure vessels carry operating fluids. The weights for the equipment are specified as empty and operational in their data sheets. Standard engineering practices and international standards from the American Society of Mechanical Engineers (ASME), Tubular Exchanger Manufacturers Association (TEMA) and ASHRAE assist in optimizing
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