Development Of A Low Temperature Water Tank Using Liquid Nitrogen For Medical Applications

As a technology subject, modern refrigeration was developed after the middle19th. Its history has more than 100 years. After 20th, the types of compressor arebooming, and the rotating speed of machines is quicker, and the size of equipments issmaller. The technology develops towards lower temperature, more types andautomatization;at the same time, the types of refrigeration dose are developed too.The paper mainly introduces the appliance of liquid nitrogen in low temperaturewater tank for medical use. This water tank is an optional assembly that can beadded on to an existing heating/cooling machine. Currently, there are two kinds oflow temperature water tank for adding on to the heating/cooling machine. One kindis to add ice-cubes to the tank, but some hospital don not have ice-cubes available.Another way is to use a compressor based system similar to refrigerators, but thistype of system is noisy and expensive.This paper presents the whole working process of the development of the lowtemperature water tank. Firstly, it shows the purpose and meaning of thedevelopment and the working needed to be achieved;secondly, it introduces thecontent of heating-conduction about the low temperature water tank;thirdly, itpresents the calculation about the heat exchanger by a series of formula;fourthly, itrecommends experiments and analysis, and sums up the use of the tank, and givesuggestion about improvability.After testing the low temperature water tank, it shows that the whole frame andsize of the tank reach the preset request, and that the tank works up to par ofmaintaining the blood temperature. Considering the using efficiency of liquid nitrogen,the outlet temp standard of the tank can be lower. Because the outlet discharge ofliquid nitrogen is large, the outlet of liquid nitrogen should be link to outside to avoidnoise, and then improve the use of the tank.In a word, this paper focuses on the application of liquid nitrogen in a water tank.A heat exchanger was developed through numerical simulations and a series ofexperiments by setting different temperature control points. The experiments show it'sviable to use liquid nitrogen in this low temp water tank, and its efficiency would beoptimized in next development phase.