A few years ago, when energy costs were a lot lower, our supermarket client asked if it should purchase and install a desiccant system for its upcoming new supermarket. The new store was about 120,000 sq ft, with large outside air requirements due to the store's kitchen exhaust hoods, which are used in making prepared foods. The store is located in Rochester, NY, on Lake Ontario. The higher humidity near the lake was one reason to consider using desiccants. In addition, the cost of natural gas is lower than that of electric energy, for the same usage.
As with many engineers, I did not find a lot of data on the actual annual savings of energy dollars offered by desiccant units. The sales representative of the desiccant unit was helpful on its operation, size, and price, but when questioned about return on investment (ROI), the answers were given in terms of a simple savings percent at a specific design condition of the units. Consulting the factory yielded the same reply. Just as other readers quoted in past issues of ES have reported, I found that there is little available or known about annual dollar savings via installed desiccant systems.