@article{misenheimer_terry_2017, title={The development of a dynamic single effect, lithium bromide absorption chiller model with enhanced generator fidelity}, volume={150}, ISSN={["1879-2227"]}, DOI={10.1016/j.enconman.2017.08.005}, abstractNote={Single effect, lithium bromide absorption chillers offer the ability to utilize low-pressure steam to produce chilled water for satisfying various comfort cooling needs. Previous attempts have been made to characterize dynamic and steady-state absorption chiller operation. Though these models perform adequately, they are based on hot water driven absorption chillers. Commercially available absorption chillers often can run on both hot water and low-pressure steam. In this paper, the mathematical framework for a dynamic single effect, lithium bromide absorption chiller model capable of using low-pressure steam is presented. The transient thermodynamic FORTRAN model is grounded on mass, energy, and species balances, and builds on prior modeling efforts. Well-known correlations for heat transfer coefficients are used to describe both tube-side and shell-side heat transfer rates in each primary chiller component. To account for the absorption chiller unit receiving steam, a heat transfer model for condensation inside horizontal tubes based on distinct internal condensation flow regimes is incorporated within the generator. This heat transfer model is used with two-phase flow pressure drop equations to establish steam temperature, quality, and pressure along the generator tube bundle. Steam consumption trends are established as a function of fluctuating external conditions. These trends reasonably align with information made available online by the manufacturer, though some deviation does occur at low chiller capacities and cooling water temperatures. Additionally, the transient response of internal and external parameters from a step increase in heat input supplied to the generator mimics results of other dynamic absorption chiller models found throughout literature.}, journal={ENERGY CONVERSION AND MANAGEMENT}, author={Misenheimer, Corey T. and Terry, Stephen D.}, year={2017}, month={Oct}, pages={574–587} } @article{misenheimer_terry_2017, title={Modeling Hybrid Nuclear Systems With Chilled-Water Storage}, volume={139}, ISSN={["0195-0738"]}, DOI={10.1115/1.4033858}, abstractNote={Air-conditioning loads during the warmer months of the year are large contributors to an increase in the daily peak electrical demand. Traditionally, utility companies boost output to meet daily cooling load spikes, often using expensive and polluting fossil fuel plants to match the demand. Likewise, heating, ventilation, and air conditioning (HVAC) system components must be sized to meet these peak cooling loads. However, the use of a properly sized stratified chilled-water storage system in conjunction with conventional HVAC system components can shift daily energy peaks from cooling loads to off-peak hours. This process is examined in light of the recent development of small modular nuclear reactors (SMRs). In this study, primary components of an air-conditioning system with a stratified chilled-water storage tank were modeled in FORTRAN 95. A basic chiller operation criterion was employed. Simulation results confirmed earlier work that the air-conditioning system with thermal energy storage (TES) capabilities not only reduced daily peaks in energy demand due to facility cooling loads but also shifted the energy demand from on-peak to off-peak hours, thereby creating a more flattened total electricity demand profile. Thus, coupling chilled-water storage-supplemented HVAC systems to SMRs is appealing because of the decrease in necessary reactor power cycling, and subsequently reduced associated thermal stresses in reactor system materials, to meet daily fluctuations in cooling demand. Also, such a system can be used as a thermal sink during reactor transients or a buffer due to renewable intermittency in a nuclear hybrid energy system (NHES).}, number={1}, journal={JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME}, author={Misenheimer, Corey T. and Terry, Stephen D.}, year={2017}, month={Jan} }