Technology Transfer of Recently Completed ESTCP Project on Converting Multizone (MZ) Air Handlers from Constant Volume (MZ-CV) to Energy Efficient Variable Volume (MZ-VV) Systems
Eileen Westervelt | USACE-ERDC-CERL
The objective of this effort is to promote awareness and facilitate implementation of heating, ventilation, and air conditioning (HVAC) equipment controls retrofit package for multizone air handlers at Department of Defense (DOD) installations, and thus increase energy efficiency of existing multizone systems at a lower cost and with more limited disruption than full system replacement. This increased efficiency helps to meet facility energy and greenhouse gas reduction requirements, and increases installation resiliency.
The technology transfer approach will capitalize on the efforts begun, and the insights and contacts identified in an earlier ESTCP demonstration project (EW-201152), and provide interested parties with readily understood documentation and implementation support tools. The specific tasks of this effort will be informed and finalized based on a preliminary scoping survey of potential user needs from the tri-services. Tasks are expected to include the following: refinement of the draft Design Guide and Drawings and Specifications Template, distillation of the final report into a user accessible 4-8 page technical note, development of a scoping guide for potential projects, development of a project economics spreadsheet calculator, development of commissioning and measurement and verification recommendations, development of sample task statements for contracting, contact with parties that expressed interest in learning more (based on responses to a questionnaire distributed during the EW-201152 ESTCP Demonstration), publishing the results of the work in an industry journal, and presenting the work at select conferences. These efforts will allow decision makers and end users to have the needed information and tools to determine if the technology is the right fit for their circumstances, adequately convey the technical detail needed for project-specific implementation, provide commissioning guidance to ensure adequate operations, and give end users a potential approach for measurement and verification of system performance.
The completed ESTCP demonstration project, EW-201152, which gathered data on five applications of the technology, projected that implementing this technique for all multizone systems in the DOD will save over 400,000 Miliion Btus/yr (over $15M/yr). Additionally, other federal and state agencies may be interested in gleaning the savings from this retrofit package. Economic calculations for this effort showed a Simple Pay Back (SPB) period of 3 to over 15 yrs for an incremental retrofit (where Direct Digital Controls (DDC) were already in place), with a corresponding Saving to Investment Ratio (SIR) for a 15 yr life of 0.68 to 6.74. Calculations for a complete retrofit (including upgrade to DDC) yielded a SPB of 10 to 11 yrs with a corresponding SIR for a 15 yr life of 1.2-1.3. These economic indicators are quite attractive compared to a full replacement of the HVAC system which is far more costly and intrusive than the retrofit option, and cannot be justified based on energy savings alone.