Demonstration and Testing of an EER Optimizer System for DX Air-Conditioners
EW-201338
Objective
The objective of this project is to demonstrate an EER measurement and feedback control technology for reducing the energy consumption of Department of Defense (DoD) unitary air-conditioning equipment. EER is defined as the Energy Efficiency Ratio—the ratio of cooling produced to power consumed. Unitary HVAC systems, also known as rooftop air-conditioners, typically use a refrigerant cycle involving direct expansion (DX) to cool many DoD buildings and mobile facilities. In the U.S. commercial building sector, unitary air-conditioning equipment is estimated to consume 0.74 quads of energy annually, or about 54% of commercial building cooling primary energy consumption. Unitary HVAC systems are used to cool about half of all commercial space and are ubiquitous in DoD facilities. This demonstration aims to prove the effectiveness of the EER Optimizer technology for maximizing the energy efficiency of cooling systems under the full range of operating conditions experienced at DoD sites and for cost-effective use as both an onboard metering and control technology and a portable handheld service instrument. Demonstrations will be conducted at Fort Irwin, California; MCAS Beaufort, South Carolina; and Cape Canaveral Naval Ordnance Test Unit, Florida.
Technology Description
EER Optimizer technology reduces the energy use of unitary air-conditioners by providing the capability to directly and continuously measure the in-situ operational energy efficiency, which is not available with existing technology. The Optimizer uses measured refrigerant flow, pressures, and temperatures through the cooling coil; electric power consumption in the compressor; and space cooling loads to provide optimal control of refrigerant in the unit’s circuit. With the integrated onboard version of the technology, measured EER is utilized as a dependent control parameter for adjusting operational variables, such as refrigerant flows to the cooling coil, to maximize energy efficiency. With the handheld version, EER is displayed on screen by the portable field device for use by service technicians to identify needed service actions that would otherwise go unnoticed. Displayed EER is also for use by energy managers, ESCOs (energy service companies), and engineers to identify and justify equipment replacement opportunities using a decision tree for repair- versus replacement-based energy economics.
EER Optimizer will help facility managers maintain DoD air-conditioning machines at a high level of energy efficiency under a wide range of operating conditions. The onboard version will also compensate for pinhole refrigerant leakage that occurs over many weeks or months, which often goes unnoticed until the space is uncomfortable—long after energy efficiency has degraded. This is accomplished by attaching low-cost sensors to measure key air-conditioner performance variables and processing the data to calculate EER, and in the onboard version of the technology, by automatically controlling valves to shuttle refrigerant to/from the active circuit while adjusting fan speeds and airflow. Using the portable version of the technology, energy efficiency is maximized by correction of low refrigerant charge, coil fouling, and component failures and by setting fan speed. Equipment that is still cooling but operating at severely degraded energy efficiency can be quickly identified for repair or replacement.
Benefits
Maximizing the EER of DoD unitary HVAC systems with EER Optimizer technology would provide 10-20% reduction in system electric usage. The predicted payback period is 3-5 years for the onboard controller version, with an estimated cost of $1,000 for a commercial mass market product. The estimated cost of a portable instrument version is $2,000, consistent with instruments that HVAC service technicians carry, with the added capability of displaying EER.
This project will address application to virtually all current models that target the low-cost/high-volume DoD and government markets, including rooftop package units, split-system air-conditioners, mobile cooling units, and computer room cooling units. (Anticipated Project Completion - 2016)
Points of Contact
Principal Investigator
Dr. Michael West
Advantek Consulting Engineering, Inc.
Phone: 321-733-1426 x3
Fax: 321-733-1427
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.