People have different reasons to keep going back to their favorite restaurant: the ambiance, the delicious food, the wait staff who surprised them with a dessert and a chorus of “Happy Birthday.” Unsurprisingly, most people wouldn’t name the restaurant’s comfortable temperature, low humidity, or indoor air quality when asked why it’s their preferred date night spot. Yet these elements have a big impact on the perceptions of diners and the experiences of restaurant staff. Rooftop equipment delivering superior HVAC performance is an unsung hero that keeps employees and guests satisfied. 

That’s where Accurex rooftop units (RTUs) come in. They are engineered to deliver high percentages of outdoor air and regulate both humidity and temperature with precision. The key to their success is the ability of their components to modulate with the changing needs of the space, optimizing comfort and reducing operating costs. 

The Modulating Advantage

Let’s dive deeper into the modulating features that contribute to the RTU’s efficiency and controllability. One important option is modulating hot gas reheat (HGRH). This allows the unit to control space humidity alongside temperature by first cooling the air below 60º F to remove moisture, then reheating that dehumidified air back to a comfortable level. Another feature that can be selected in the Accurex XRT rooftop unit is a modulating gas furnace with 10:1 turndown. This high-turndown furnace allows fine-tuned adjustments to the burners, enabling the XRT to meet temperature setpoints without repeatedly cycling on and off throughout the day.

In units cooling with packaged direct expansion (PDX), inverter scroll compressors adjust speed for part load conditions, providing precise cooling during both extreme and mild weather. And double-wall, injected foam insulation on the wall, base, and roof of every XRT locks down both sound levels and potential energy losses.

Adjusting to Changing Environments

As the needs of every restaurant and kitchen change throughout the day, it is important to have flexibility built into HVAC equipment. For example, factory-programmed control sequences simplify operation with modes designed for when the restaurant is closed and when there is no cooking going on in the kitchen, keeping the space comfortable between rushes. Controls can also be set for the desired temperature, humidity, and other factors. 

Direct drive fans with electronically commutated (EC) motors, a standard feature, have fan blades directly connected to the motor shaft rather than separated by a belt and pulley. This allows for tighter control of energy use and an extended lifespan. 

An efficient option for both heating and cooling is an all-electric air-source heat pump (ASHP), which may be used to support local decarbonization initiatives and qualify for rebates. Ideal for mild climates, the ASHP efficiently moves energy between spaces and comes standard with HGRH. 

The XRT can also cool with packaged direct expansion, where refrigerant directly expands and evaporates within the unit, a process that absorbs heat from the air. The refrigerant is EPA-compliant R-454B, which is environmentally friendly with low global warming potential. 

In the dining area, an RTU can supply the outside air needed for the number of occupants and keep that air temperature-controlled and dehumidified. It can also provide transfer air to the kitchen to support the make-up air unit in replacing exhaust air. This helps maintain the proper negative pressure in the kitchen and keep cooking smells out of the dining area. 

The XRT can also be used alongside make-up air in the kitchen, providing temperature and humidity control while the make-up air unit replaces exhausted air to maintain pressure. Keeping commercial kitchens at a moderate humidity level is important for preventing mold growth, equipment damage, and staff heat exhaustion. 

In restaurants with open concept kitchens, an RTU can be a simple solution for the whole space. In food halls, each of the stalls can be outfitted with make-up air units while RTUs control the air for the overall building. 

For the ultimate level of indoor air quality, a Dedicated Outdoor Air System (DOAS), such as the Accurex XRV, provides humidity control, cooling, and ventilation to dining rooms and kitchens at very high efficiency. In many cases, one or the other can be utilized. An RTU is often applied when: 

• The rooftop has a limited weight allowance or available space 

• Energy recovery is not needed 

• First cost is an important factor 

Curious how an RTU might fit with your new or existing commercial kitchen design? Reach out to an Accurex ventilation and air conditioning expert with your questions or project needs.