This retail store has 5 gas/electric rooftop units that are approximately 30-years old. Three are nominal 8.5 ton units and two are 12.5 ton units. They are controlled by manual thermostats. The economizers are broken and in the closed position. Indoor blower motors are constant volume. Original 4-foot tube fluorescent lighting with various color rendition bulbs are scattered throughout the facility.
Scope of Work
BASE MEASURE #1:
Replace all fluorescent lights with the latest technology lamps, housings and starters. Supply and install three replacement 8.5 Ton Carrier 48HCEA high efficiency rooftop package units with natural gas heating and one replacement 12.5 Ton 48HCEA Carrier high efficiency package rooftop with natural gas heating.
The proposed equipment are high efficiency models with 230-3-60 Electrical, Medium Heat, two stage cooling and heating, belt drive fans, electro-mechanical controls, enthalpy economizer with barometric relief, Debonair 450 Slimline Premier 7-Day Programmable thermostats or if wired into the proposed iWorx EMS system the EMS system would supply the dual enthalpy capability along with the 7 day programmable temperature settings.
Work includes disconnecting existing unit from gas, electrical, and duct work. Recovering the refrigerant from the existing units then removing them from the premises and disposing of them in a lawful manner. Providing a suitable crane to remove and replace the units. Providing a new electrical disconnect and wiring up the new units. Providing the miscellaneous parts and labor to re-connect the natural gas. Installing, calibrating and testing the enthalpy economizer and controls. Start up, testing and permits are included.
Supply and install a web enabled iWorx EMS system providing night setback of temperature settings, optimized start/stop capability, C02 based demand ventilation control, comparative enthalpy control over the economizer, and VFD control over the supply air fan speed using the supply air temperature sensor to ramp the fan from 100% to 70% as appropriate.
Supply and install Cerus variable frequency drive for each RTU that when controlled by the EMS system, will supply just the correct amount of supply air to the space thereby saving considerable energy.
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