While many of those R-22 systems have been replaced with R-410A units, a large installed base still remains, meaning that technicians will have to know how to troubleshoot and service both types of equipment for many years to come.

California has now signaled that it, too, intends to follow Germany down the renewable energy path. In September, the governor signed a bill requiring that 100 percent of the state’s electricity be generated by renewable energy sources such as solar or wind by 2045. This is an expensive proposition and will significantly boost California’s already high residential electricity costs, which are currently about $.20/kWh.

Essentially, I noted that changing demographics, new technologies, and evolving regulations may result in wider acceptance of self-contained refrigeration units that utilize propane. Several readers took issue with this, noting that central rack refrigeration systems — which are traditionally used in supermarkets around the U.S. — are not going anywhere and that propane units have too many drawbacks to ever seriously be considered for large-scale use.