節能型盤管式熱交換器之可行性評估

Abstract

本文主要目的是以雙台串聯之盤管式熱交換器取代一般傳統之單台盤管式熱交換器對熱空氣進行熱交換，讓熱空氣能夠進行兩次高溫度差的高效率熱傳過程，減少單台後段溫度差降低導致熱交換效果差的影響，以提高熱交換器熱傳效率與達到節能的效果。 由計算結果得知，雙台串聯式熱交換器能夠大幅度的提升熱傳效果。在兩台熱交換器之間可以得到一個最小冷卻水流量的配置組合，進而達到節能的效果。最小冷卻水流量的配置不因熱交換器之管路數與空氣入口狀態而改變，冷卻水入口溫度則成為唯一的控制參數，針對不同的熱交換器組合均可求得其冷卻水入口溫度與熱傳量比值之曲線，以作為節能配置控制之參考。

A new method of double series air-cooled heat exchangers is proposed for air-conditioned system. This method enables high temperature air to undergo high efficiency heat transfer twice during the heat exchange process for increasing the overall heat efficiency of the system and achieving purpose of energy saving. The results show that the double series air-cooled heat exchangers improve the heat transfer efficiency for the overall process and obtain a disposal of minimum mass flow rate of cooling water for the system. For different number of tubes and inlet air conditions, the disposal of minimum mass flow rate of cooling water remains unchanged. It depends only on the temperature of inlet cooling water. As a result, the relation between the temperature of inlet cooling water and the ratio of heat transfer for the most efficient of energy saving is determined.