heat sink          
noun [ C ] uk/ˈhiːt ˌsɪŋk/ us/ˈhiːt ˌsɪŋk/
 散热器,吸热器,热汇
a substance or object that absorbs heat
  At the back is a massive wall that acts as a heat sink - it cools the house in summer and in winter acts like a big radiator. 后面是一堵巨大的墙,作为热汇——在夏天为房子降温,在冬天则像一个大散热器。 
 A one-degree temperature increase would lower the effectiveness of lakes designed to be heat sinks for power plants. 温度升高一度,设计用作发电厂散热器的湖泊的效率就会降低。 
  computing specialized(计算机、手机等的)散热器 
a device in a computer, mobile phone, etc. that absorbs heat so that important parts do not get too hot and stop working
  The processor has its own heat sink and usually a fan, too. 处理器有自己的散热器,通常还有一个风扇。 
 - More examples
 - An IV circulates blood by sending it to a heat sink and cooling the body's core to about 33 degrees Fahrenheit.
 - The tubes are driven by a 35 kV supply, and cooled with a liquid heat sink.
 - Internal fans and heat sinks can help keep the machine cooled inside.
 - Install the processor, heat sink, memory modules on the motherboard before you secure it in the PC case.
 - Attaching the clip that holds the heat sink in place may require a fair amount of force.