I need help in designing a temperature and humidity controlled chamber.?

I have a metal chamber that is 43in x 29in (32in tall), where the bottom is covered with about 3in of sand to grow bacteria. I want to be able to control temperature (5-50C) and humidity (10-90%), and I need help in designing the system. I would also like to be able to cycle the changes throughout the day to mimic day/night conditions, e.g. low T high H at night, high T low H during the day.





Secondly, I need to have some UV lamps (UVA %26amp; UVB) in there, to approximate the effect of the sun since UV plays a role in bacterial growth.





Nothing needs to be precise, I鈥檓 just trying to replicate growing conditions in the desert. And I don鈥檛 have the budget to buy a fancy chamber, so I鈥檓 looking for a solution that I can throw together. If the unit(s) is small enough, it can live inside the chamber, otherwise I can set it outside.





My engineering training is more theoretical, so I have no experience in basic design/equipment.





Any advice would be appreciated.I need help in designing a temperature and humidity controlled chamber.?
Perhaps the easiest way to do this would be with a board installed in a computer, such as a Lab PC from National Instruments. You can then input the temperature and humidity from sensors in the oven as a feedback loop, and use the outputs from the Lab PC card to control heating elements and the injection of moisture if necessary.





You will also need a source of dry air or dessicating stacks to remove moisture, some sort of internal or external heating elements, which could include IR lamps or restive heaters, and some method to cool the air.





If youare going down to 5 degrees C, you will need something more than radiaive cooling for your system, and will need to provide an actual cooling system which usually means a compressor type system with a refrigerant.





The Lab PC board is quite versatile and allows for multiple outputs to enable the various elements that you are talking about. You'll need to come up with the various algorithms to control slope and such, but these can be found in various places as well.





If you need help, give me a yell via email; I've worked with such systems for a number of years.