Thermoelectric Chip 資料一問

[米高]

請問一下從下方既圖黎睇呢塊晶片係咪可以0係 3V ~ 15V 之間運作呢? 或者有無人知幅圖應該要點樣解讀呢?

例如: 我想知道如果以12V 6A 既供電情況下運作, 該晶片既冷與熱面的溫度大慨有幾多?

希望有人能幫小弟解答一下, 謝謝
[跪拜禮]

[PTS]

請問一下從下方既圖黎睇呢塊晶片係咪可以0係 3V ~ 15V 之間運作呢? 或者有無人知幅圖應該要點樣解讀呢?

例如: 我想知道如果以12V 6A 既供電情況下運作, 該晶片既冷與熱面的溫度大慨有幾多?

希望有人能幫小弟解答一下, 謝謝
[跪拜禮]

According to the table:

Qc is the heat pumping power, given as 54.9 W. (but bear in mind that this is the maximum, and at change in T=0.

Delta T is the differential temperature of the hot/cold sides, given as 60C but at Qc=0

These conditions are ideal cases. In practice, change in T is roughly 30C for a single stage.

All these max values are suppose to reach when the voltage supply is max (15V) and at max current (6A). In practice, we should not exceed the 12V specification.

Moreover, there should be some heat dissipating device (heat sink + fan) on the hot side, otherwise the temperature would be too high and the device will be damaged easily.

I found a relatively cheap one at Wah Fai (rated qt 12V, 2A). each cost HK$80.

I installed one on each of the 2 sides of the camera case of my Imperx 4M15 (not attached to the CCD as most cooled cameras) and the temperature of the CCD achieved 15c (when the ambient temperature was about 30C) in 10 minutes. The DC supply was at 12V and the current was about 3 A.

PTS

[米高]

請問一下從下方既圖黎睇呢塊晶片係咪可以0係 3V ~ 15V 之間運作呢? 或者有無人知幅圖應該要點樣解讀呢?

例如: 我想知道如果以12V 6A 既供電情況下運作, 該晶片既冷與熱面的溫度大慨有幾多?

希望有人能幫小弟解答一下, 謝謝
[跪拜禮]

According to the table:

Qc is the heat pumping power, given as 54.9 W. (but bear in mind that this is the maximum, and at change in T=0.

Delta T is the differential temperature of the hot/cold sides, given as 60C but at Qc=0

These conditions are ideal cases. In practice, change in T is roughly 30C for a single stage.

All these max values are suppose to reach when the voltage supply is max (15V) and at max current (6A). In practice, we should not exceed the 12V specification.

Moreover, there should be some heat dissipating device (heat sink + fan) on the hot side, otherwise the temperature would be too high and the device will be damaged easily.

I found a relatively cheap one at Wah Fai (rated qt 12V, 2A). each cost HK$80.

I installed one on each of the 2 sides of the camera case of my Imperx 4M15 (not attached to the CCD as most cooled cameras) and the temperature of the CCD achieved 15c (when the ambient temperature was about 30C) in 10 minutes. The DC supply was at 12V and the current was about 3 A.

PTS

謝謝 PTS 師兄, 小弟也考慮過12V 2A 的致冷片, 最初只係擔心制冷效果唔係咁理想, 但係師兄你用2A 也可以0係10分鐘內降溫至15度, 小弟也可以放心作實驗了(目標: 2A: Peltier + 0.2A: CPU fans w/heat sink + 0.2A: small CPU fans) <-- 帶26AH 水電出街係我既極限.....到時會連埋相機一齊用

但係想問吓師兄, 點解你用兩塊致冷片(= 4A) 未計其他風扇(假設 12V 0.2A) 都可以將最後用電量降為3A 既??

[anyone]

有個疑問：用 CPU fans w/heat sink , 會否產生振動？影響拍攝？

[鄧登凳]

高級風扇應是完全沒有震動(和噪音)的, 如高線音響或數碼投影機用的那些

冷凍天文天文CCD賣得那麼貴, 應用得起這些無震動風扇的

[米高]

高級風扇應是完全沒有震動(和噪音)的, 如高線音響或數碼投影機用的那些

冷凍天文天文CCD賣得那麼貴, 應用得起這些無震動風扇的

呢d 風扇要幾百蚊.....
所以暫時我都係用住我呢一款(Dual Ball Bearing)測試住先, 反正唔駛錢

[PTS]

高級風扇應是完全沒有震動(和噪音)的, 如高線音響或數碼投影機用的那些

冷凍天文天文CCD賣得那麼貴, 應用得起這些無震動風扇的

呢d 風扇要幾百蚊.....
所以暫時我都係用住我呢一款(Dual Ball Bearing)測試住先, 反正唔駛錢

I just install CPU fan + heatsink from my old PC. No vibration at all even when used with small telescope.


PTS

[Nosneb]

有個疑問：用 CPU fans w/heat sink , 會否產生振動？影響拍攝？

我反而諗如果用個靚d既風扇的話會唔會反而食正個飛輪作用而更加穩定

[鄧登凳]

我反而諗如果用個靚d既風扇的話會唔會反而食正個飛輪作用而更加穩定

吚, 係喎 理論上陀螺是不受地球轉動影響o架喎 而相機的防手震基本上就係用微機電系統陀螺儀（microelectromechanical systems gyroscope = MEMS Gyro）啦.... 咁可唔可以整個微機電系統陀螺儀的自動導星呢? 系統仲唔受大氣擾動(seeing)影響潻

話說回來, 用飛輪做陀螺, 轉速愈高、質量愈大愈好, 咁係唔係要anyone大爺做把白金風扇呢?

[Skyobs]

請問一下從下方既圖黎睇呢塊晶片係咪可以0係 3V ~ 15V 之間運作呢? 或者有無人知幅圖應該要點樣解讀呢?

例如: 我想知道如果以12V 6A 既供電情況下運作, 該晶片既冷與熱面的溫度大慨有幾多?

Temperature difference also depends on how much heat to be removed.

Left chart (hot side 27degC) is usually for operation under rather low temperature. Right chart (hot side 50degC) is usually for operation in higher temperature (around 30degC).

Left chart and right chart differs in hot side temperature. It depends on ambient temperature and heatsink performance to tell which one is more suitable. Unless you have very high performance heatsink, it's not unusual for TEC hot side temperature to be >20degC above ambient. So I think the higher temperature chart is more suitable in HK.

Normal design procedure is as follows:
1) Specify how much heat to be removed and what temperature difference
For example, you want to keep an object dissipating 15W at 15degC when TEC hot side is 50degC. Please follow the green arrows.
2) Find out TEC current
So it needs 4A to make the 35degC hot-cold side difference.
3) Find out TEC voltage
It needs 12V to drive the TEC to 4A. So it needs 48W to create the required temperature difference.

But remember your heatsink must be capable of removing 15W+48W=63W power and keep the TEC hot side at 50degC. It is more demanding than the CPU heatsink in desktop PC. Of course, if you are talking about camera, it should dissipate well below 10W, and total power becomes much lower.

If you just use a fixed voltage without temperature control, it will drive the TEC to reach a certain equilibrium point depending on object dissipation, heatsink performance, and ambient temperature. It's harder to tell what cold side temperature or difference it will reach.

[米高]

謝謝 skyobs 師兄, 小弟心中大慨有個構圖了, 但小弟都會見試用2A 看看制冷效果程度如何