1980 Whalen Fan Coil Unit Refurbishment


 Case Study 

CUSTOMER: Full Service Marriott

 

LOCATION: Little Rock, AR

 

INDUSTRY: Hospitality

 

AIRREVIVE SERVICE: Fan coil unit refurbishment

 

FAN COIL UNITS: 1980 Whalen Fan Coil Units

Refurbishing 35-year old Whalen units to operate as new

 

Marriott engaged AirRevive to refurbish the guest room’s Whalen fan coil units after the property’s $16 million dollar renovation in 2014. The renovation included upgrading the guest rooms to Marriott’s new design. The only former asset remaining was the 35-year old Whalen fan coil units.

This study compiles data collection on the following:

Mouse over to go directly to each section.

 

I.  Project Goals and Scope of Work

 

II. Coil and Supply Temperature

 

III. Airflow

 

IV. Project Summary

 

V. Facility Benefits

I.  Project Goals and Scope of Work

 

PROJECT GOALS

    1. Rejuvenate coils to increase airflow.
    2. Deep clean the coils and fins to enhance heat transfer.
    3. Reduce coil and supply temperature.
    4. Bring the units to consistent operating performance.
    5. Extend the life of existing units by deep cleaning the coils and fins.
    6. Extend the life of the units by de-rusting and re-coating the condensate pans.
    7. Bring the units back to as-new operation in terms of airflow and heat transfer.


PROJECT SCOPE: COIL REJUVENATION & CABINET REFURBISHMENT

    1. Deep clean the coils and fins from the back side and front side
    2. De-rust condensate pan and re-coat with impermeable epoxy
    3. Replace fiber insulation with foam anti-microbial insulation
    4. Remove all debris from the blower assembly, motor, and wheel
    5. Clean and disinfect the blower assembly, motor, and wheel
    6. Clear out, clean and disinfect the drain line

Coil Temperature Before and After Service

 

Summary: Coil temperature dropped by an average 4℉ from 51.6℉ to 47.4℉.

 

The graph below shows coil temperature sorted from high to low before coil rejuvenation.

 

The red line shows that before the coils were rejuvenated the coil temperature ranged from 60℉ to 50℉.  The average coil temperature was 51.6℉. The coil temperature was above 50℉ on 85% of the units.

 

The blue line shows that after the coils were rejuvenated the coil discharge temperature for 98% of the units is below 50℉. The average coil temperature after service is 47.4℉.

Supply Temperature Before and After Service

 

Summary: Supply temperature dropped by an average 4℉ from 54.5℉ to 50.8℉.

 

The graph below shows supply temperature sorted from high to low before coil rejuvenation.

 

The red line shows that before the coils were rejuvenated the supply temperature ranged from 65.8℉ to 48.8℉. The average supply temperature was 54.5℉. The supply temperature was above 52℉ on 90% of the units.

 

The blue line shows that after the coils were rejuvenated the supply temperature for the majority of the units fell below 51℉. The average supply temperature after service was 50.8℉.

III.  Airflow

 

Airflow before and after service on low setting

 

Summary: Airflow increased by an average 22% from 785 FPM to 985 FPM.

 

The graph below is high fan airflow measured in FPM sorted from low to high before the coil rejuvenation.

 

The red line shows that before service the high fan airflow ranged from 385 FPM to 1085 FPM. Average airflow was 785 FPM.

 

The blue line shows that after service the high fan airflow ranged from 569 FPM to 1400 FPM.

 

Overall the coil rejuvenation increased the airflow by an average 22% from before 785 FPM to after 985 FPM

IV. Project Summary and Facility Benefits

 

RESULTS SUMMARY

  • The coil temperature dropped by an average 4℉ from 51.6℉ to 47.4℉.
  • After rejuvenation 73% of coil temperatures were below 49.9 ℉.
  • The supply temperature dropped by an average 4℉ from 5℉ to 50.8℉.
  • After coil rejuvenation 90% of supply temperatures were below 54℉.
  • Airflow increased by an average 22% from 785 FPM to 985 FPM.
  • The coil rejuvenation resulted in unrestricted airflow in 100% of the units.


RESULTS CONCLUSION

  • The result of more efficient heat transfer combined with increased airflow is faster guest room cooling and heating. The thermostat is satisfied quicker i.e. reaches temperature set point faster.
  • Achieving the temperature set point quickly results in the boiler and chiller working less thus saving related energy expense.
  • Narrowing the water temperature delta between the supply and return reduces the work required to chill and heat the water in the loop, which results in less work for the boiler and chiller and thus energy savings.
  • Achieving the guest room temperature set point faster results in greater guest comfort and higher guest satisfaction.

FACILITY BENEFITS
The project resulted in the fan coil units performing more efficiently. The benefits to the facility are the following:

    1. The facility saves energy in the guest room by the thermostat being satisfied faster which reduces fan motor run time.
    2. The facility saves energy at the chiller and boiler by:
      1. Reducing the work required at the guest room level to maintain temperature set point which runs the chiller and boiler less; and
      2. Reducing water supply and return temperature delta results in less work for boiler and chiller to maintain the loop temperature set point.
    3. The indoor air quality is improved in all guest rooms; and
    4. The guest rooms cool and heat faster and maintain temperature set point.

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