Abstract: The goal of the Integrated Energy Systems (IES) Program launched in 1999 by the U.S. Department of Energy (DOE) is to provide R&D and
testing of distributed generation (DG) with thermally-activated (TA) technologies for waste heat recovery and improved overall efficiency. An example
of an IES is the combination of onsite microturbine generation with heat recovery, HVAC, desiccant, and absorption chiller units. IES, in conjunction
with other new energy efficient building technologies, will maximize the efficiency of energy use, reduce harmful emissions to the environment, improve
power quality and reliability and provide flexibility for meeting electric power peak load demands as compared with large central power plants. The R&D
performed at the Oak Ridge National Laboratory’s (ORNL) IES Test Laboratory, a National User Facility, focuses on assessing the operational and emissions
performance of current DG and TA technologies operated individually and in combination as an IES; developing and verifying mathematical models of the
individual devices and IES; and developing test protocols and contributing to standards development for assessing current IES technologies.
The IES Test Laboratory is flexible in the configuration of DG (presently a 30-kW natural gas-fired microturbine generator) with various heat recovery units
(presently an air-to-water heat recovery unit or HRU, direct- and indirect-fired desiccant dehumidification systems, and an indirect-fired single-effect
absorption chiller). The exhaust gas from the microturbine generator (MTG) is used to drive the HRU and/or used directly in the direct-fired desiccant
dehumidification unit. The hot air and hot water flows from the HRU can be controlled and directed via automated damper controls in order to test various
IES configurations and operating modes.
The IES testing results produced so far show that the operating parameters and efficiencies of the overall system and individual devices depend on loading
(electric and thermal), as well as on ambient weather conditions (temperature and humidity levels). Outdoor temperature is a major factor since the MTG is
located outside and no attempt is currently being made to adjust its inlet air temperature, i.e., air cooling from the TA units. Under certain operating
conditions and combinations of IES, the efficiency of the overall system can be as high as 55% (based on higher heating value of the natural gas and
including all the parasitics).
Keywords: distributed generation, DG, thermally activated technology, TAT, integrated energy system, IES, combined cooling heating and power, CHP,
microturbine, heat recovery unit, HRU, desiccant dehumidification, absorption chiller
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2003 International Congress of Refrigeration