章节大纲

  • Sticky notes on a refrigerator door listing tasks and reminders for daily organization.

    A refrigerator door makes a great message center. Its smooth metal surface is perfect for sticky notes and magnets. In most homes, a refrigerator is one of the hardest working appliances, but not just because it holds messages. Unlike most other home appliances, a refrigerator generally runs nonstop every day of the year. Can you think of another home appliance that gets such constant use?
    ::冰箱门造就了一个伟大的信息中心。 它光滑的金属表面完全适合粘贴笔记和磁铁。 在大多数家庭里,冰箱是最难使用的电器之一,但不仅仅是因为它有信息。 与其他家用电器不同,冰箱通常每天都不停地运转。 你能想到另一种家用电器能够持续使用吗?

    Purpose of a Cooling System
    ::冷却系统的目的

    A refrigerator is an example of a . Another example is an air conditioner. The purpose of any cooling system is to transfer in order to keep things cool. A refrigerator, for example, transfers thermal energy from the cool air inside the refrigerator to the warm air in the kitchen. If you’ve ever noticed how warm the back of a running refrigerator gets, then you know that it releases a lot of thermal energy into the room.
    ::冰箱就是一个例子。 另一个例子是空调。 任何冷却系统的目的都是为了保持冷却。 比如,冰箱把冷却空气中的热能从冰箱中的冷空气转移到厨房的暖气中。 如果你注意到一个运行中的冰箱的背部有多温暖,那么你就会知道它会释放出大量的热能。

    Q: Thermal energy always moves from a warmer area to a cooler area. How can thermal energy move from the cooler air inside a refrigerator to the warmer air in a room?
    ::问题:热能总是从暖热区转移到冷热区。热能如何从冰箱内的冷却空气转移到室内的暖热空气?

    A: The answer is work.
    ::答:答案是工作。

    How a Refrigerator Works
    ::冷冰箱如何工作

    A refrigerator must do work to reverse the normal direction of thermal energy flow. Work involves the use of force to move something, and doing work takes . In a refrigerator, the energy is usually provided by electricity. You can read in detail in the Figure how a refrigerator does its work. 
    ::冰箱必须努力扭转热能流的正常方向。工作涉及使用武力移动某些东西,工作需要时间。在冰箱中,能源通常由电提供。您可以在图表中详细阅读冰箱如何工作。

    The Refrigerant
    ::冷藏剂

    The key to how a refrigerator or other cooling system works is the refrigerant . A refrigerant is a substance such as Freon™ that has a low point and changes between and gaseous states as it passes through the refrigerator. As a liquid, the refrigerant absorbs thermal energy from the cool air inside the refrigerator and changes to a . As a gas, it transfers thermal energy to the warm air outside the refrigerator and changes back to a liquid. Work is done by a refrigerator to move the refrigerant through the different components of the refrigerator.
    ::冷冻剂是冰箱或其他冷却系统如何工作的钥匙。冷冻剂是一种物质,如FreonTM,在通过冰箱时具有低点和气态变化。冷冻剂作为液体,从冰箱的冷空气中吸收热能,并变换成 。作为气体,冷冻剂将热能转移到冰箱外的热空气中,并变回液体。冷冻剂通过冰箱的不同组成部分转移冷冻剂的工作由冰箱完成。

    The refrigerant flow through the evaporator in a cooling system.

    Summary
    ::摘要

    • The purpose of a cooling system such as a refrigerator or air conditioner is to transfer thermal energy in order to keep things cool.
      ::冷却系统(如冰箱或空调)的目的是传输热能,以保持冷却。
    • A refrigerator transfers thermal energy from the cool air inside the refrigerator to the warm air in the kitchen. Thermal energy normally moves from a warmer area to a cooler area, so a refrigerator must do work to reverse the normal direction of heat flow.
      ::冰箱将冷却的热能从冰箱内的冷空气转移到厨房的暖气中,热能通常从暖热区转移到冷冷区,因此冰箱必须努力扭转热流的正常方向。
    • The key to how a refrigerator or other cooling system works is the refrigerant. A refrigerant is a substance with a low boiling point that changes between liquid and gaseous states as it passes through the refrigerator.
      ::冷冻剂是冰箱或其他冷却系统如何运作的钥匙,制冷剂是一种在通过冰箱时液体与气体之间变化的低沸点物质。

    Review
    ::回顾

    1. What is the purpose of a cooling system? What are examples of cooling systems?
      ::冷却系统的目的是什么?冷却系统的例子是什么?
    2. Outline how a refrigerator works.
      ::概要说明冰箱是如何工作的。
    3. What is a refrigerant? Why is it the key to how a cooling system works?
      ::什么是制冷剂?为什么它是一个冷却系统如何运作的关键?