Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion
Discussion Forum : Heat Transfer, Refrigeration and Air Conditioning - Section 1 (Q.No. 8)
8.
The by-pass factor for a cooling coil
Discussion:
19 comments Page 1 of 2.
Sakti Prasad Dhar said:
1 decade ago
Bypass factor is the (Amount of air bypassing the coil) divided by (the total amount of air passing the coil).
So a higher velocity of the passing air will decrease the time of contact for effective heat transfer and hence decrease the amount of heat transfer.
So it can be assumed that a greater portion of air is bypassing the coil without any heat transfer with the coil. So increasing the velocity of air decreases the Bypass factor.
So a higher velocity of the passing air will decrease the time of contact for effective heat transfer and hence decrease the amount of heat transfer.
So it can be assumed that a greater portion of air is bypassing the coil without any heat transfer with the coil. So increasing the velocity of air decreases the Bypass factor.
Bhupendra singh said:
5 years ago
By pass factor is the percentage of air travels through a coil without touching it so as velocity increases it do not have more time to be in contact with coil surface so percentage of air that is not in contact with coil surface increases means bypass factor increases.
(1)
S k pani said:
1 decade ago
Let t1 = air before entering coil.
t2 = mean coil temperature.
t3 = air temperature cooling coil.
So bpf = (t1-t2)/(t3-t2).
So if the velocity of air will increase then the numerator will decrease which will result in a increase in bpf.
t2 = mean coil temperature.
t3 = air temperature cooling coil.
So bpf = (t1-t2)/(t3-t2).
So if the velocity of air will increase then the numerator will decrease which will result in a increase in bpf.
Shiva said:
5 months ago
The bypass factor (BPF) is the fraction of air that bypasses the cooling coil without being cooled, indicating the coil's efficiency.
A lower BPF means better coil performance.
A lower BPF means better coil performance.
Ysm said:
8 years ago
The inefficiency of heating coil or cooling coil in not being able to heat or cool the incoming air to the temp of cooling coil. For proper design, bypass factor should be less.
Vicky said:
1 decade ago
I'm totally agree with You (@Raju) with increase in velocity forced convection increase and with this the temperature decreases which should decrease the bypass factor.
Abhi said:
1 decade ago
The by-pass factor can be increased by increasing the number of rows in a cooling coil or by decreasing the air velocity or by reducing the fin pitch.
Vineet said:
1 decade ago
By pass factor suggest the un-contacted air therefore if the speed will be high the air will not be able to contact the coil and hence bpf increases.
Raju said:
1 decade ago
As velocity increases Reynolds number increases which result in increase in heat transfer coefficient (turbulent) then bypass factor should increase?
Divyank singh said:
8 years ago
According to nptel lecture 34 of rac. It has been said that as increasing velocity will reduce the time of contact so BPF decrease.
(1)
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