Not sure if I can help, but here it goes:
You need to have two separate airflow/cooling architectures for you bulb and the room. The two systems need to be isolated from each other. For the bulb/cool tube you need to grab clean cool air from outside the room and flow it past your bulbs and dump it outside your room/house. The air in this system can not come in contact with the air in the room. If your bulb airflow system is airtight you should not have not have a problem with exhaust smell, you will just be blowing hot air. If you do have a smell problem, find some high temp epoxy and hose clamps in order to make it airtight.
Now that you've isolated the bulb air system from the room, time to tackle your main problem, the smell and temp of the room. If you have isolated the bulb airflow system, your halfway there temp wise. An AC is simply a heat pump, it moves heat from one place to another. The efficiency of an AC system is based on the delta T ( the differential of air temperature entering the system and leaving the system). The AC needs to grab hot air from the room and pump it outside where the temp is lower. If your flow rate and/or delta is too low and you add restriction (carbon scrubber) the system will not work, you will be choking your AC. Here is where the problem lies, you need to flow enough air through your system so that your 15K (just an example/guess) BTU AC unit can carry 15K BTUs of hot air out of the house. Now you add a carbon scrubber, (google diy pvc carbon scrubber for plans) that adds restriction to the system. On the exhaust side of your AC you will flow around 350-400cfm (guess for 15k BTU AC example). Make your AC exhaust tube/carbon scrubber piping diameter as large as you can (2-3 times larger than your 6" pipe if you can) and run it for 6-8 feet long(the scrubber), then duct the air outside. There are a lot of variables to the system, the number I posted are not absolute, but should give you a good place to start.