43
votes
Why not put servers in a refrigerator?
A refrigerator is basically a heat pump designed to achieve a temperature close to 0 °C. There are a couple of problems here:
Most refrigerators are way too weak to effectively tackle the heat output ...
- 431
21
votes
Accepted
Benefit of removing the center "engine hub" inside a fan
For a large and/or high speed fan, there are several mechanical disadvantages, for example
The outer ring is highly stressed and therefore heavy. It may also need a heavy containment system to avoid ...
- 12.5k
19
votes
Accepted
Why not put servers in a refrigerator?
We do. It's just an up-sized (i.e. more powerful) version of a refrigerator known as an air conditioning unit.
Essentially all server rooms and most spaces where PCs are located (speaking for the U.S.,...
- 306
12
votes
Why not put servers in a refrigerator?
refrigerator boxes tend to generate condensate
There are specifications for acceptable relative humidity (RH) for servers. Air conditioning in server rooms will maintain RH within the allowed limits ...
- 361
11
votes
Why not put servers in a refrigerator?
Here's a webpage from a random guy who put a light bulb in his refrigerator to see what would happen, and took careful data to monitor it. Results:
The next experiment was to put a 60-watt ...
- 211
8
votes
Is there a more active passive technique for removing humidity from the air besides salt blocks?
Silica gel is the standard for most purposes.
It's the desiccant you find inside those paper sachets packed with new electronic equipment.
It consists of tiny beads of silicon dioxide that are ...
- 3,741
7
votes
How metal fittings seal connection without rubber gaskets?
The common pipe threads that are used in buildings for water and gas are tapered threads. The thread is cut on the cone rather than cylinder. In the US, these threads are called National Pipe Thread ...
- 1,035
7
votes
Accepted
Airflow selection mechanism
Are you bound to the shape/configuration of part you constructed in your question? If not, a simple 3-way pneumatic solenoid valve would make this very simple and leak proof(relatively speaking). They ...
- 1,578
7
votes
Benefit of removing the center "engine hub" inside a fan
Fans like the one on the right exist. These where first invented as rim-driven thrusters (rim driven is your search term, not centerless) for marine applications. The rim is the rotor of the electric ...
- 4,720
6
votes
efficiency and flow separation
You are describing a very interesting engineering problem.
The requirement of a turbine is to convert fluid-energy into mechanical energy over a range conditions. Since the flow around the airfoils ...
- 1,192
6
votes
Accepted
How can I create uniform laminar flow in a short duct?
Quick and dirty CFD simulation of your problem using ANSYS Fluent 14.5: I used a 2D duct, 8" x 4" with a 45-degree angle going from the inlet pipes to the main chamber. Assuming 3 liters per hour ...
- 3,044
6
votes
Accepted
How do gas flow regulators avoid choking?
The short answer is that they don't. Choking is not a bad thing. For a gas flow regulator, it's actually a good thing, because under choking conditions, the mass-flow rate is no longer dependent on ...
6
votes
Accepted
Fan performance curve
The yellow curve corresponds to a fan that will provide mostly a set pressure differential, say, keeping fumes from escaping a tank through elsewhere than dedicated vents. If there is a circumstance ...
- 6,125
5
votes
How metal fittings seal connection without rubber gaskets?
In addition to tapered threads for creating seals, there are Compression Fittings which use a matching male and female mating low angle taper to create a sealing surface. When properly torqued, they ...
- 1,578
5
votes
How does one create a draft in a room (with a single window)?
The fundamental problem is that hot air must leave the room and cold air must enter it, both at the same time through the same single opening. The conflicting forces will mostly cancel each other out,...
- 789
5
votes
Accepted
How to minimize heat loss in an air extractor?
What you want is called a heat exchanger. Imagine two long air tubes with a thin wall between them. The air exiting the house travels in one tube, and entering air in the other, but in opposite ...
- 11.4k
5
votes
Accepted
How much does an evaporative cooler cool down a room
The capacity of an evaporative cooler depends on the relative humidity. The lowest theoretical temperature that the cooler can reach is the wet bulb temperature.
The wikipedia article has some ...
- 377
5
votes
Accepted
How do I choose a blower design for an induced draft brick kiln?
Normally fans are not custom built by a company that does not build fans. The concept of a centrifugal fan is not particularly complicated, but it is difficult to achieve target flow rate, pressure, ...
- 7,804
5
votes
Why not put servers in a refrigerator?
They've been doing that with computers for 30+ years. Back when computers were the size of refrigerators. They use to get a regular air conditioner. Build a platform for the computer to stand on. ...
- 51
4
votes
What is the power and max flow rate required to rotate a 300 W wind turbine?
You need to push air through the turbine at 11 m/s, or just above. That's what the rated windspeed means: it's the lowest windspeed at which the turbine hits rated power, at standard atmospheric ...
- 3,741
4
votes
Fan Sensors (Tachometer vs Locked Rotor)
It's a trade-off between the simplicity of the sensor and how comprehensive the reported data is. The locked rotor sensor only reports whether or not the motor is spinning, not how fast it's spinning ...
- 3,044
4
votes
Accepted
Shouldn't enthalpies be equal in isentropic process?
Constant entropy doesn't mean constant temperature, the gas flow through nozzle is subject to change in pressure and velocity (continuity equation) due to the variation in cross section, and being ...
- 2,160
4
votes
Accepted
What's the difference between aircon modes Auto, Sun, Snowflake?
The sun is heating mode. When the room temperature reaches the set temperature, the air conditioner stops operating until the temperature falls below the set temperature and the starts operating again....
- 9,582
4
votes
Accepted
Passing by a semi truck on a highway
A truck speeding down a highway creates an envelope stream of high pressure air surrounding it.
This is basically a wake, composed of layers of high pressure shockwaves, created when the front of the ...
- 21.9k
4
votes
What is the equivalent of a capacitor in pneumatics?
The equivalent of a capacitor in terms of pneumatics would be a chamber such as a metal sphere the size of a tennis ball. It would be necessary to have an external vacuum pump to evacuate the air ...
- 6,875
4
votes
What are these outdoors "mystery boxes" for in the USA?
Almost anything can be in those pedestals, but the more common inhabitant would be cable television related. The smaller ones are for subscriber taps, while the larger ones contain amplifiers or ...
- 6,875
4
votes
Why not put servers in a refrigerator?
The price-to-effect ratio for heat pumps is just not there for any large scale applications.
Especially since air or watercooling is far less complex, and therefore a lot, lot cheaper.
Dust is ...
- 140
3
votes
Is it possible to replicate a Tesla valve in large scale?
This device works on momentum effects.
If the fluid had no momentum, it could just follow the channels wherever they go, and the resistance would be the same in both directions. In the context of ...
- 11.4k
3
votes
Accepted
How do I convert cubic metres/feet per minute to a pounds per hour flow rate?
There are several pieces of additional information you need to go from units of volume/time to units of force/time.
For gasses, temperature and pressure matter. Air is mostly nitrogen and oxygen. ...
- 11.4k
3
votes
Accepted
Perfectly aerodynamic kitchen range hood
Making a duct that flares along an exponential curve to 2 feet (60cm) in diameter would create a larger duct that won't solve your problem.
It would be an expensive duct to make (think tuba bell), ...
- 3,575
Only top scored, non community-wiki answers of a minimum length are eligible