Case Study: Performance Contracting

Kentucky Transportation Cabinet

Commonwealth of KentuckyFrankfort, Kentucky

Substantial Energy Savings Produced by Central Heating Plant Renovation

Located in downtown Frankfort, Kentucky, the Transportation Cabinet Office Building (TCOB) and the State Office Building (SOB) together encompass over 800,000 square feet of office space. When constructed in 2004, the TCOB included a complex hot water heating system in the central utility plant, with capacity to heat an additional two million square feet of future office space. However, plans for the future office space changed and it was never constructed, leaving the State with an over-sized and inefficient heating plant.

Replacing the complex heating plant was not the only challenge that CMTA and the state government faced when analyzing these buildings. The existing boiler’s manufacturer had gone out of business, leaving little improvement options with that unit. The underfloor variable air volume air distribution systems were failing as well. Comfort issues plagued the buildings, with high humidity levels occurring regularly and many offices dealing with hot temperatures. 

The Challenges

  • Oversized, inefficient heating plant
  • Out of business boiler manufacturer leaves owner with little O&M options
  • Underfloor Variable Air Volume air distribution systems that were failing
  • Office building plagued with high humidity levels and hot offices
  • Renovating major infrastructure in occupied buildings
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I’ve been genuinely impressed by the ability of CMTA to remedy complications and meet our needs during construction with a high standard of excellence. I’ve never worked with a team that strives so hard to leave something in better condition than they found it. Created with Sketch.

Mitch Gathof, Facilities Mechanical Maintenance & Operations Manager

Commonwealth of Kentucky

The Solutions

CMTA worked closely with building personnel and agencies occupying the space to develop a scope of work that not only saved energy and operational costs, but also resolved occupant comfort issues and difficulties associated with the existing heating plant.

CMTA’s solution to this conglomerate of problems included installing high-efficiency condensing boilers in each building on campus and eliminating the existing central heating plant. CMTA also installed 1,500 new underfloor supply air terminal units, which improved the efficiency of the system and provided better comfort control for office spaces. In the existing pre-project system, the system struggled daily to keep up with the load of the building. After installation was complete and the controls system was modified, the HVAC system could maintain the desired setpoint during occupied times and could then save energy during the evening setback. Zone temperatures were then under control and the energy generated by fans was substantially reduced. This helped in large part to resolve occupant comfort issues.

A complete DDC controls upgrade was also completed on the 40,000 square foot Annex building. This replaced the existing pneumatic controls system that did not work well and had plagued the facility with high humidity levels and hot offices. This upgrade also included supply diffuser replacement to improve air flow, ventilation and occupant comfort. Building comfort levels were drastically improved.

A comprehensive campus-wide LED lighting upgrade was completed as well. All of these improvements were fully funded from savings.

Substantial Kitchen Exhaust System Savings

CMTA installed a new kitchen exhaust system that included a new roof mounted exhaust fan and variable speed hood controls. This replaced an overly complex and failing 20-year-old exhaust system that included an expensive pollution abatement system. The new rooftop exhaust location eliminated the need for such a complex system and reduced fan energy by 40hp. Couple this with eliminating the pollution abatement system and this Energy Conservation Measure is expected to save over $24,000 annually in energy and operational costs.

The Results

The energy savings associated with the terminal box replacement alone was 209,350 kWh, amounting to $13,046. However, after the first year, there was an excess savings of 190,357 kWh and $11,862 due to this energy conservation measure. 

As shown in the following chart, occupant comfort improved drastically, especially within the occupied time periods represented by gray shading. Whereas the existing system would reach temperatures of up to 77 degrees Fahrenheit during occupied times, the retrofit system kept space temperatures consistently around 73 degrees.

Currently this project for Kentucky state government has yielded an energy savings of $1,412,222, $327,928 above the guarantee. 

Kentucky State Office Buildings Energy Use

What does this data mean?
Baseline: The annual energy consumption before the project
Guaranteed: CMTA's guaranteed energy use for the client post-project
Actual: The measured energy use after the project