Radiical Water Chiller Project

Radiical Water Chiller Project

Part Two

In this section of the project we will look at installing the copper tubing to the condenser, setup the connections to the compressor and install the fill and empty Schroeder valves. Fill and start the system.

A basic plan of the component placement is necessary to complete this stage. We decided to place the condenser and compressor into the case framework and from that placement we were able to set the position for each component on paper before we proceeded to bend copper. To do this it was necessary to construct a floor for the encasement. The picture below shows the new base already fitted to the case framework.

One of the elements of the plan involved rotating the condenser outlets to face the rear of the case. This would give us the pipe work direction we wanted and would greatly assist us to carry out a compact assembly. We decided against this as it would place the fan on the opposite side of the condenser and would mean that the compressor had no cooling.

Although the first components look very simple it is surprising how much time it took to set the correct lengths and dimensions to reach the various components.

Next we move onto brazing up the connections so that we can set the final position for the fan casing and shroud housing.

We will attach the dryer and capillary line before we prepare the suction line for fitting. Before we do that of course the unit must be test fitted again to the enclosure.This process of repeatedly testing the fit of the components is very important during prototyping. There is absolutely no point in making it look good if it doesn't fit within the size constraints. Happy with the fit its now onto the all important suction line and schroeder valve placement. The suction line that will eventually be used here will be a flexible line to permit movement around the case interior. This will permit greater placement freedom during the prototyping phase than the conventional solid copper tubing. For the time being and until we have some raw performance data the suction line will be solid copper tubing.

We chose to provide easy access for the Schroeder valves hence the position on top of the compressor.

You will notice in the picture below that we have looped the suction line prior to its entry into the compressor to provide a little boil off protection. The other end of the suction line terminates in a copper cooling coil.

Next leak testing with the clean dry Nitrogen.

A test load of Nitrogen is added to the coolant loop.The test load is then left for several hours and checked for any pressure drop from a low side loading of 100psi. Satisfied that the system is not leaking its onto the vacuum evacuation and filling stage. We will be using a triple flushing and triple vacuum preparation of the system to ensure all the water has been removed prior to filling for the first time.

I think it would be safe to say that when you have "vacced" a system once you are really over it. This would have to be one of the less glamorous parts of this type of project. Having said that it is essential to prepare correctly so don't scrimp at this stage or lower performance will be the result.

The final stage is to fill the system with refrigerant. We will be using R404a refrigerant in this system. This refrigerant is a liquid load type refrigerant so the refrigerant container has to be turned upside down so the refrigerant flows into the system. Other refrigerants can be loaded as a vapor and it unnecessary to upend their storage cylinders.

Please keep in mind that anyone of these refrigerants can be lethal if abused. Death can occur from the breathing in of even very small amounts of some refrigerants so again it is stressed do not play around with these materials. Work smart, safe and in an open environment.

Okay lecture over. The finished load should give freeze back to the entry to the compressor when fully loaded. To give you some idea of what that looks like here is the full load shot.

Next we see how effective this chiller will be by testing the low range and pull down of the compressor unit. To do this we will dress the pipe work up with a bit of insulation and look at testing.

The testing unit will be an insulated stainless steel beaker with an insulated lid. A birds eye view of the cooling coil (mentioned above) and beaker are below.

Next.............................................The Testing