Plant growth chambers and rooms provide a means to regulate temperature, light, humidity, and other critical environmental variables for plant science and other life science studies. The refrigeration system of any controlled environment is relied upon when it comes to regulating thermal energy to maintain air temperature within specified limits. There are two main types of refrigeration systems used by plant growth chamber and room manufacturers:
- Direct glycol
- DX (water or air cooled)
With the exception of direct glycol refrigeration systems, direct expansion systems employ refrigerants to provide a cooling effect in the chamber or room. The refrigerant absorbs heat when used in conjunction with other components such as compressors and evaporators. Certain refrigerants are harmful to the environment if they are released to the atmosphere and are being phased out in favor of those with a lower global warming potential (GWP):
For example, for original equipment manufacturers in Canada, regulatory bans are in place on both R-404A and R-134A refrigerants from January 21, 2020. Other jurisdictions such as the US and the EU are following suit, and in some locations, such as California, have already banned R-404A in new, retrofitted and stand-alone remote condensing units from January 1, 2019.
Some manufacturers of chambers and rooms like Conviron are using R-448A refrigerant as an alternative to R-404A, and R-513A as a substitute for R-134A. To ensure compliance with these regulations, check that the supplier of your new or retrofitted plant growth chamber or room is proactively taking compliance measures. One can also inspect the refrigerant label that comes on or near the compressor of your newly purchased or retrofitted chamber or room. Reputable manufacturers will have also field tested their equipment well ahead of regulation changes to confirm there has been no impact on chamber/room refrigeration system performance so that they can ensure consistent, repeatable environmental conditions.