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ENERGY MANAGEMENT SYSTEMS (EMS)

 

Today’s modern EMS utilize Direct Digital Control (DDC) capabilities and can be powerful tools for monitoring and managing energy use. However, instances of shoddy programming, a general lack of understanding of HVAC systems and a lack of proper commissioning typically relegates EMS functions to much less than they are capable of providing. In many cases, faulty programming has a negative impact on comfort and energy use, especially as it pertains to important system setpoints. A small sampling includes:

  • Hydronic economizer setpoints are almost always too conservative to achieve full benefit
  • Minimum outside air damper positions are almost always too high. In fact, poor or non-existent outside air control is always a contributor to underperforming systems
  • Static pressure setpoints (for variable air volume systems) and differential pressure setpoints (for variable water flow systems) are almost always much too high, a wasteful energy practice on many levels
  • Sensors, especially critical ones used for measuring outside air temperature and humidity, are almost always out of calibration or poorly located or both
  • Temperature and flow reset schedules are not used or not used effectively

Too many controls contractors rely on the “canned” program algorithms resident on today’s DDC controllers to develop an HVAC system’s sequences of operations. Obviously this is efficient from a labor cost perspective, but certainly not optimal from a system energy efficiency perspective. Design engineers typically empower the controls contractor with all-encompassing decision making power as it pertains to the EMS: “just make it work” is acceptable and is business as usual. Energy efficiency is rarely part of the equation.

The basic problem with this approach is that modern controls contractors lack the necessary understanding of HVAC systems’ complex inner workings, and as a result rely on the “canned” methods of control. A commissioning process should be effective in identifying and remedying functional issues associated with DDC systems, and all DDC systems should certainly be commissioned by 3rd party professionals, but functional in no way equates to efficient.

As part of our suite of services, Energy-Environment-Economics can provide a variety of EMS evaluation and optimization services. Our HVAC system experts work in-house with our DDC experts to maximize the capabilities of your EMS and improve the operations and energy efficiency of your complete HVAC system. Depending upon your specific needs, we can provide:

  • A basic evaluation of EMS capabilities
  • Evaluation of EMS programming, i.e. sequences of operations used to control the HVAC system
  • Commissioning of the EMS
  • Provide detailed optimization strategies
  • Implement the selected optimization strategies

 

 

“Our experience has been that the Energy-Environment-EconomicsLLC engineering professionals, combined with their construction experts, are a perfect fit for developing our energy projects”.


Jeff Seaton, CEM, LAP
Energy Manager, State of Arizona NGB

 
      Copyright Energy Environment Economics - 2003