Kalispell Regional Medical Center - A Case Study of Energy-Saving Improvements

Kalispell Regional Medical Center (KRMC), located in Kalispell, Montana, is both a community hospital and a regional referral center, offering the area’s most advanced health services and medical technology.  The hospital has 174 beds and over 400,000 square feet of conditioned space.  Many of the buildings date back to 1975.  In the last decade, the hospital launched an expansion program adding a patient tower, a new lab and expanding its central plant, cath lab and OB capacity.

 

As part of agreement partnership with the Northwest Energy Efficiency Alliance’s (NEEA) BetterBricks initiative, KRMC committed to a Strategic Energy Management (SEM) Plan and an energy savings goal. SEM is a comprehensive set of business tools and practices that enable hospitals to reduce energy consumption maximize resource efficiency and lower costs. The organization incorporated SEM into many aspects of the medical center’s business including: operations and maintenance practices, capital projects, and purchasing practices.    An initial scoping study of the facility was also conducted to estimate the energy savings potential and identify likely areas for further investigation. 

 

Historical Energy Use before SEM

Total Annual Energy Cost      $1,149,000

Kalispell Energy Use Index

• Electricity       100,980 Btu/sf
• Natural Gas     202,480 Btu/sf
• Total               303,460 Btu/sf

Hospitals constructed according to today’s energy codes typically have an Energy Use Index (EUI) between 180,000 and 200,000 Btu/sf/year. (Commercial Buildings Energy Consumption Survey)

Existing Energy Using Systems

HVAC systems and operations represent about 50-60 percent of the total energy used at the facility.  Lighting and miscellaneous other use (computers, medical equipment, cooking, laundry, etc.) make up the remainder of the annual energy use.  

 

Lighting

• T8 linear fluorescent with electronic ballasts as retrofit.

Primary Heating, Ventilating, and Air-conditioning (HVAC) Systems

• Central steam plant and a central water-cooled chiller plant.  

Secondary HVAC Systems

• 23 air handling units of various sizes.
• Six water-source heat pumps remain in service from an earlier generation secondary system.

Chilled Water Plant

• 400-ton centrifugal chillers piped within a primary-secondary chilled water hydronic system.

Steam Plant

• Three large steam boilers.
• Controls
• Direct Digital Controls.

Potable Water Heating Systems

• Steam-driven instantaneous water heaters.

 

Strategic Energy Management (SEM)

By implementing a strategic energy management plan, KRMC could evaluate future opportunities in context across the whole organization.  The organization set annual savings goals of 1,100,000 kWh and 150,000 therms by year four, which would reduce its energy costs by up to 30 percent.   SEM impacts the entire organization and covers all applications of resource management— facility master planning; new construction and major renovations; existing facility operations and upgrades; the financial analysis and procurement practices that support these activities; and measurement and reporting of results.  It requires strong support across the organization for organizational and behavioral change and a dedicated internal champion to drive the process. 

Mark Chitwood, Facilities Manager at KRMC, worked to develop a business case for SEM. In September 2006 the team focused on system-wide operations and maintenance improvements and conducted a thorough building performance scoping estimate of overall savings potential. The report identified numerous energy and cost-savings opportunities that projected yearly energy savings of $77,000 or 1,204,000 kWh and 26,800 therms for operations and maintenance improvements and retro-commissioning.

 

Results

To date a number of operational improvements have been identified and implemented. These include:

• Scheduling off air handlers for the laundry, carpentry shop, welding shop and general shop during nights and weekends.
• Correction of return fan in one air handler which was operating inefficiently in reverse.
• Cleaning of air flow sensors to restore accuracy, resulting in slower fan speeds.
• Reduction of static pressure.
• Adjusting heating coil lockout temperature.
• Lowering differential pressure set point of hot water loop from 8 psi to 6 psi.
• Lowering differential pressure set point of chilled water loop from 20 psi to 15 psi.
• Raising the discharge air temperature for the surgery AHU from 50 F to 55 F to avoid unnecessary reheat.
• Programming VAV boxes to close or go to minimum flow when the areas they serve are unoccupied.
• Reworking boiler controls to improve sequencing and improve combustion efficiency.
• The facility saved 550,000 kWh and 32,000 therms in 2010 versus the base year from implementation of these measures, most of which were low or no-cost improvements.

 

Measuring Energy Savings

The energy savings from the KRMC project are now tracked with the help of a commercially available product called Energy Expert (EE).  Hourly consumption data, from utility meters or other sources such as the building automation system, is captured over a period of time and the tool ‘learns’ how the building performs under various conditions.  The tool is then able to compare to this learned baseline and tell a building operator how the building is performing. 

The CUSUM Energy View of Energy Expert allows KRMC to view savings trends for the Central Plant building (Not included here is the graph for the West Switchgear Room.).  For the period following the incorporation of several low-cost energy savings measures, the energy savings is 256,398 kWh (7.2 percent) and the total consumption is 3,581,399 kWh for the period January 1-November 28, 2010.

 

Operations & Maintenance Energy Savings:  Lessons Learned

NEEA’s BetterBricks has found that the potential for energy savings from operations and maintenance of the HVAC systems at most hospitals are 10% of facility electricity use and 25% of facility gas use.  The improvement measures are not capital intensive and are normally funded through the operations budget.  Following are some common areas to make O&M improvements:

 

Chilled Water:

Usually the most efficient strategy for operating a central chiller plant is to provide chilled water at the warmest temperature that will satisfy the demands of the building.  The chiller compressor operates more efficiently, and there are fewer heat gains to the chilled water during distribution. At 50 degrees outdoor air temperature, 50 degrees chilled water may be sufficient. As the outdoor air temperature increases toward 90 degrees, the supplied chilled water should be reset toward the minimum recommended by the manufacturer or design engineer. 

Within limits, it is better to operate with cooler chiller condenser water.  Each one-degree drop in condenser water temperature will improve chiller compressor efficiency by approximately one percent.  Generally, the increased fan energy required to produce cooler condenser water will be more than offset with reduced chiller compressor energy. 

 

Boilers/ Hot Water: 

Boilers can be retrofitted with a control package that improves efficiency.  New systems with “oxygen trim” reduce the quantities of excess air in combustion and raise the overall combustion efficiency by two to five percent.  Boiler fans should be equipped with VFDs to gain a modest savings in electricity from fan motors.

Many boilers are equipped with blow down heat recovery.  For instance, at KRMC city water flows through the heat exchanger at approximately two gallons per minute and is heated from approximately 50 degrees to 90 degrees.  The water is then wasted to the drain.  This warmed water can be recovered as make-up water to the boilers or some water heating system to save energy and reduce water and sewer expense.

The hot water supplied to the HVAC systems should be at the minimum temperature that will satisfy heating demands.  Usually a reset schedule for hot water is based on outdoor air temperature.  The colder the outdoor air temperature, the warmer the heating water will need to be.  For instance, 190F water may be required at an outdoor air temperature of 10F, but at 90-degree outdoor air temperature 115F reheat water may suffice.

From an energy management perspective, minimizing the temperature of the HVAC hot water is very important for the following reasons.  First, the hotter the water, the greater the heat loss from the pipes will be.  If these pipes are running through conditioned space, the heat loss from the pipes is heat gain to the conditioned space (thus requiring more air conditioning).  Second, running very hot water may mask the opportunity to reduce air conditioning.  When a reasonable hot water temperature is supplied to reheat coils and a space cannot be kept warm, this suggests that the supply air temperature may be set too low or that the terminal box air volume may be set too high.  By adjusting the supply air temperature upward or the terminal box air flow downward, both air conditioning and reheat will be reduced.

At some hospitals, the heating coils are programmed by the building automation system to have hot water flow whenever the outdoor air temperature is below 30 degrees.  A small but still significant amount of heat will be lost from the coil if the face and bypass dampers are not sealing well.

 

Air Handlers:

Air handlers that serve clinical areas are designed to provide a high degree of comfort through extremes of outdoor air temperatures while also conditioning large amounts of ventilation air.  Consequently, the heating, cooling, and ventilating capacities are huge.  Efficient strategies to operate the air handlers when all of this capacity is not required– especially during mild weather, nights, and weekends–will reward the operators with large energy savings with very little capital investment. The following is a list of the best strategies.

• Shutdowns: If areas served by an air handler are unoccupied and there are no minimum ventilation or pressure relationships to be maintained, turn the unit off.
• Partial Shutdowns:  Oftentimes an air handler cannot be shut down because part of the space it serves remains occupied on nights and/or weekends.  If the supply and return fans are equipped with VFDs, it may be possible to reduce or eliminate conditioning to unoccupied spaces while still conditioning the occupied areas.  For spaces served by addressable VAV boxes, the controls may be scheduled to reduce flow to the boxes when the area is not occupied.  If controls to boxes are local (not schedulable), dampers may be installed in main supply and return ducts to allow a partial shutdown.
• Reduce Supply Duct Static Pressure:  Supply duct static pressure is sometimes set arbitrarily and is higher than necessary, requiring more fan power.  If an air handler serves non-clinical areas where ventilation and pressure relationships are not proscriptive, it is permissible to reduce supply duct static pressure in off-peak times.
• Adjust Air Handler Supply Air Discharge Temperature:  In theory, the design discharge air temperature for an air handler, typically 55 degrees should be capable of conditioning a space during peak activity (internal heat gains) and design conditions (high outdoor air temperature and humidity).  In all other situations of lower activity and milder outdoor conditions, a higher discharge air temperature will be capable of cooling the spaces adequately.
• Make Good Air Filter Choices:  ASHRAE and the AIA guidelines on construction in hospitals both list air filtration efficiencies required for air handlers serving various patient care areas of hospitals.  Hospital maintenance staff tends to standardize on a few models of filters in some cases using a higher efficiency than necessary.  However, using a higher efficiency filter generally causes a greater pressure drop, thereby requiring more fan horsepower.  
• Maintain Air Handler Economizer Dampers and Controls:  Economizers are designed to allow cool outdoor air to be used to reduce or eliminate the need for mechanical cooling.  Mechanical cooling may not be required until outdoor air temperatures approach 55F.  Conversely, when the outdoor air temperature exceeds the space return air temperature, the economizer dampers should adjust to use maximum return air and minimum outdoor air.  Malfunction of economizer dampers and controls may introduce too much cool outdoor air in cold weather and too much warm outdoor air in hot weather.  Maintenance staff should carefully monitor mixed air temperatures of air handlers via the building automation system, and visually inspect dampers during regular rounds to equipment rooms.

 

Next Steps

As it became clear that many of the savings opportunities at KRMC required more staff time, the hospital management recognized it needed a staff member dedicated to managing energy efficiency opportunities system-wide.  Given the number of energy improvements and their cost-savings, Kalispell has hired a Resource Conservation Manager (RCM) to manage the energy improvements, measure their performance and communicate goals and successes system-wide. By setting energy performance targets and aligning them to mission-critical goals, the organization has elevated energy management across facility maintenance and capital projects. Continuous preventative maintenance, monitoring and even commissioning are required to ensure long-term success and savings.

 

 

David currently works as a business advisor to BetterBricks/Northwest Energy Efficiency Alliance developing business and marketing plans for the healthcare sector initiative focusing on sustainability planning at large hospitals. Kalispell Regional Medical Center, Northwest Energy Efficiency Alliance, BetterBricks.