直流加熱體探討

Abstract

自盤古開天來，火一直是人類文明生活重要的象徵，因為從餐飲到環控都需要熱能，但火的相關器具也伴隨高危險性。因此電熱已是現在生活進化的重要課題，許多新建案的炊火工具都已經全面用電磁爐、電熱水器等電熱設備取代天然氣瓦斯等傳統方式。但是電熱設備往往因加熱器的產熱效率不佳，而一直數百年來難有突破。本文比較現今電熱代表的線狀鎳絡絲，包含其不同纏繞方式，與導電粉末式。以相同或相似載體材料(陶瓷或玻璃管)時，載體體積影響被吸收而無法熱傳的熱能外，載體材質也影響熱傳方式與效益。而更關鍵影響的是電熱材料的空間分布方式，以鎳絡絲為例，相同電阻值卻因纏繞陶瓷體的方式而有明顯的溫度差異。相反的，導電式粉末的產熱效益卻受電阻值影響小，但受載體(材質、體積)影響大。而在導電粉末的載體3cm外以近紅外光譜檢測發出的電磁波，更高度吻合黑體輻射1900K的近紅外線波形，遠高於載體外表面量測的溫度~1100K，說明紅外線量測法可以克服載體隔閡量測電熱材料的溫度。而這些直流電能除了由直流供應器輸出，也可以由幾個鋰電池即可提供。

Since the beginning of Pangu, fire has always been an important symbol of human civilization and life because heat energy is needed from catering to environmental control. However, fire-related appliances are also associated with high risks. Therefore, electric heating has become an important subject in the evolution of life. For example, many newly-built cooking tools have fully replaced traditional methods such as natural gas and gas with electric heating equipment such as induction cookers and electric water heaters. However, electric heating equipment is often limited due to poor heat generation efficiency of heaters, and has been difficult to make breakthroughs for hundreds of years. This article compared the current representative wire type of nickel wires, including its winding methods, and the different type of conductive powder. When the same or similar carrier materials (ceramic or glass tube) were used, the volume of the carrier affected the absorbed heat energy, unable to transfer, and the carrier material also affected the heat transfer method and efficiency. The more critical influence is the spatial distribution of the electric heating material. For nickel wires, the same resistance value has a significant temperature difference with the wound way around the ceramic body. On the contrary, the heat generation effect of conductive powder was less affected by the resistance value, but greatly affected by the carrier properties (like material, volume).The detected electromagnetic wave outside the conductive powder carrier in 3-cm distance by near-infrared spectroscopy more closely matched the near-infrared waveform of black body radiation of 1900K, much higher than the measured temperature on the outer surface of the carrier ~1100K. It indicated that the infrared measurement method can overcome the measurement limitation of carriers for the temperature measurement of electric heating materials. In addition to the output of the DC power supply, the DC power can also be provided by several lithium batteries.