is a fan needed on a condenser?

making my first chiller and i have everything apart and am curiou if a fan is needed on the condenser or not? also any tips to get this thing to run colder?

Ok, so phase change system basics:

A refrigerant (R22, R12 Rwhatever) leaves the compressor at high pressure, it then goes to the evaproator and evaporates (pretty supprising ah?) This evaoration is caused by a sudden loss of pressure, and sucks up tonnes of energy from the surroundings (things get cold). The refrigerent then leaves the evaproator and goes to the condensor, where it condenses (another big supprise). This condensing happens because the refrigerent is being cooled down. Cooling down the coolent means heating up something else, namely the condensor and the air around it. Once the fluid has condensed back into a liquid, it goes back into the compressor, and the cycle continues.

So, to answer your question, maby. It depends on the condensor. If it is a big fridge condensor, like the huge black pipe thing with the grates, that never had a fan on it, then you might get away without one. If it is an AC condensor, that used to have a fan on it, then yes you do need one. Adding a fan to the condensor will make it cool the refrigerent to a lower temperature after it is condensed, which will result in a lower temperature at the eveproator, so it is a good idea to cool the condensor as much as possable.

Other tricks for getting a lower temp are to remove the thermostat so that the compressor never turns off, and putting a fan over the compressor and everything else will also help. The cooler you can keep everything, the colder the evaporator will be, and the longer the compressor will last.

This form has some good phase change guys, but there are a lot more over at http://xtremesystems.org/ .

Matt did a great job explaining the cycle . I would say unless you are going to use a chilled water heat exchanger than yes you will need a fan .
refrigeration cycle Check this link out for a good explaination of the refrigeration cycle.

Matt gets the general idea accros except he has switched a couple of steps.

high pressure gas leaves compressor

high press gas enters condensor, removes heat causing it to become high press liquid (condenses)

high press liquid passes thru metering device (cap tube, thermal expansion valve) into evap as low press liquid

low press liquid is changed to low press gas by heat load @ evap

low press gas enters comp & is changed to high press gas

repeat

whoops, thanks for corecting that.

I wrote it pretty quickly and got the order messed up. What FrostByte said is correct.