open. With each door opening, external humidity is introduced into the supermarket. In addition to making the store less comfort-
able, humidity had a negative impact on the stores’ products. It reduced the shelf life of fresh produce, other fresh-food items, baked goods and boxed items. Humidity also caused the freezer cas- es’ doors to fog up when opened, reducing product visibility to the customer and causing the anti- sweat heaters to run more often. Roland Altenburg, Bel Garden Bi Rite Supermar-
ket’s meat department manager, explains: “We had a lot of humidity in the store. We used to have water dripping off the cases and the packages. The condensation would cause green spots on some of the pieces of meat at times. It wouldn’t allow the case life we should have.” Vary had been cooling her store with two 20-ton
rooftop air-conditioning systems. The units were set at 72 F to alleviate the temperature and humid- ity issues. They were running constantly. Vary knew the systems were old, costly and inefficient. She also knew that for every thermostat set point she could save approximately $1,000 in energy costs. “Over the years we have struggled with con-
ventional air conditioning,” Vary explains. “With our old system, you could feel the humidity in the store. Even though we were making the air cold, it wasn’t enough to make people comfortable. We had shutdowns where refrigeration would fail. Our utility bills showed the impact of hot and hu- mid summers. At one point, we considered install- ing a desiccant wheel but it was too expensive and used too much energy, as well as would be costly to maintain. We also didn’t have the space for the large operating footprint.” Vary sought a solution that would meet her
store’s air-conditioning needs while providing a short payback for her upfront equipment invest- ment. She also was committed to sustainability and energy reduction. Vary hired Intelligent Power and Air Solutions (IPAS) Inc. , a firm with expertise in humidity and cooling with a goal of energy ef- ficiency and productivity, to assess her store’s con- ditions and recommend options. IPAS positioned sensors to benchmark energy usage by mechani- cal and HVAC equipment, as well as monitor the store to determine specific areas of energy con- sumption. The store was monitored for almost six months.
The Solution IPAS recommended liquid desiccant technol- ogy to resolve Bel Garden Bi Rite Supermarket’s humidity issues. Liquid desiccant technology features a non-toxic salt-brine solution that removes moisture from the air naturally while cooling a space. When heated, the liquid desic- cant releases the moisture outside in the form of warm, vapor air, which eliminates condensation. The liquid desiccant is also a natural disinfectant, eliminating bacteria, microorganisms and odor from the air. (See the diagram below for further explanation of how the system works.)
The system is comparable in size to tradition-
al direct-expansion air conditioning and con- siderably smaller than dry desiccant systems. Additionally, the upfront costs are relatively the same as equivalent vapor compression systems and considerably less expensive than dry des- iccant units while incurring minimal mainte- nance expenses. The system uses 30 to 80 percent less energy
than conventional air-conditioning systems. The moisture removal properties of the liquid desic- cant allow the system to more efficiently regulate space conditions to the desired set point, elimi- nating the need for over-cooling or heating the air to remove humidity. Also, the system can be