Joined
·
5,295 Posts
I have recently diyed a simple 120mm air duct which will act as an exhaust chimney. Simple, cheap, non time consuming and easy.
As I anticipate someone saying 'pics or it did not happen', I throw in a few pics to make this less 'boring' reading.
Basic components:- (see pics 1 and 2)
1. 120x38mm fan
Comment: this is positioned at the 'exit' end of the duct. This fan is necessary. If the duct is fully extended (~2 metre long) and/or oriented vertically like a chimney, air entering the duct will not have enough velocity to travel the whole length. The entering air needs to be drafted forward by an exhausting fan to get out of the 'exit' end of the duct.
A powerful fan with adjustable speed is recommended. I am using Delta AFB1212HE.
2. 120mm diameter plastic duct (extendable up to 2 meter long)
Comment: 140mm could be used but a powerful 140mm fan (for exhaust) is hard to be found. Alternatively, a 120x38 fan can be used in conjunction with a 120-to-140 converter to fit a 140mm diameter duct.
3. 120mm fan filter guard+retainer
Comment: provide structural support for the 2 ends of the duct. They also act as the coupling part for the fan at the exit end and for the entering end of the duct.
I cut away the grill portion of the filter guard and retainer and use the square frames for the purpose.
4. Fan controller
Comment: I have chosen a Zalman Fanmate controller. It is useful to adjust the speed of the fan to match the varying thermal needs. Running a 120x38 fan at full speed all the time can be noisy.
5. Extension cables
Comment: 4-pin Molex extension cables can be used when the fan is powered directly from the PSU. I have chosen to use 3-pin fan extension cables because I wish to monitor the rpm figure as well.
6. Fan shroud
Comment: this is primarily used to keep the blades of the exhausting fan from hitting the plastic duct. I have converted a 120x25 fan for this purpose. It is fixed the exhausting fan by four zip-ties.
As I anticipate someone saying 'pics or it did not happen', I throw in a few pics to make this less 'boring' reading.

Basic components:- (see pics 1 and 2)
1. 120x38mm fan
Comment: this is positioned at the 'exit' end of the duct. This fan is necessary. If the duct is fully extended (~2 metre long) and/or oriented vertically like a chimney, air entering the duct will not have enough velocity to travel the whole length. The entering air needs to be drafted forward by an exhausting fan to get out of the 'exit' end of the duct.
A powerful fan with adjustable speed is recommended. I am using Delta AFB1212HE.
2. 120mm diameter plastic duct (extendable up to 2 meter long)
Comment: 140mm could be used but a powerful 140mm fan (for exhaust) is hard to be found. Alternatively, a 120x38 fan can be used in conjunction with a 120-to-140 converter to fit a 140mm diameter duct.
3. 120mm fan filter guard+retainer
Comment: provide structural support for the 2 ends of the duct. They also act as the coupling part for the fan at the exit end and for the entering end of the duct.
I cut away the grill portion of the filter guard and retainer and use the square frames for the purpose.
4. Fan controller
Comment: I have chosen a Zalman Fanmate controller. It is useful to adjust the speed of the fan to match the varying thermal needs. Running a 120x38 fan at full speed all the time can be noisy.
5. Extension cables
Comment: 4-pin Molex extension cables can be used when the fan is powered directly from the PSU. I have chosen to use 3-pin fan extension cables because I wish to monitor the rpm figure as well.
6. Fan shroud
Comment: this is primarily used to keep the blades of the exhausting fan from hitting the plastic duct. I have converted a 120x25 fan for this purpose. It is fixed the exhausting fan by four zip-ties.