Kevin P. Hallinan

Carbon Nanoadditives to Enhance Latent Energy Storage of Phase Change Materials

Latent energy storage capacity was analyzed for a system consisting of carbon nanoparticles doped phase change materials (PCMs). Three types of samples were prepared by doping shell wax with single wall carbon nanotubes (SWCNTs), multiwall CNTs, and carbon nanofibers. Differential scanning calorimetry was used to measure the latent heat of fusion. The measured values of latent heat for all the samples showed a good enhancement over the latent heat of pure wax. A maximum enhancement of approximately 13% was observed for the wax/SWCNT composite corresponding to 1% loading of SWCNT. The change in latent heat was modeled by using an approximation for the intermolecular attraction based on the Lennard-Jones potential. A theoretical model was formulated to estimate the overall latent energy of the samples with the variation in volume fraction of the nanoparticles. The predicted values of latent energy from the model showed good agreement with the experimental results. It was concluded that the higher molecular ...

Temperature Control of Electrohydrodynamic Micro Heat Pipes

Abstract Active thermal control was achieved by using an electrohydrodynamically (EHD) assisted micro heat pipe array. A simulation model of temperature control of EHD micro heat pipes was established in a Matlab Sinulink environment. An experimental model was designed and fabricated to verify the model and identify the factors most influential to the thermal control via EHD micro heat pipe array. Good correspondence between simulations and experiments was achieved. Electric field intensity, set-point temperature and the gap between the upper and lower set-point temperatures were shown to have a dramatic influence on the temperature control.

Experimental Verification of Thermal Switch Effectiveness in Thermoelectric Energy Harvesting

This paper presents research seeking to experimentally verify the effectiveness of a thermal switch used in series with thermoelectric devices for waste heat recovery for constant and variable source heat input and for variable source thermal capacitance (mass). Using an experimental setup composed serially of a fixed heat source, a variable thermal resistance air gap serving as a thermal switch, a thermoelectric device, and a heat sink, the time-averaged power output to power input ratios improved up to 15% and 30%, respectively, for constant and variable heat input in certain design space conditions. The experimental results, as supported by model predictions, suggest that the thermal capacitance of the heat source must be greater than the thermal capacitance of the thermoelectric device in order for thermal switching to improve the time-averaged power output to power input ratios of waste heat recovery systems. The results have direct application to aircraft energy harvesting.

Energy and waste reduction opportunities in industrial processes

ABSTRACT Traditional approach for reducing energy and waste in industrial processes typically focus on improving the efficiency of the primary energy conversion equipment. Unfortunately, this approach frequently results in incremental improvement at high costs, since most energy and mass conversion equipment is relatively efficient to begin with and upgrading to higher efficiency equipment is usually quite costly. In this article, we describe an alternative approach that begins by focusing outward to the distribution system and energy conversion equipment. We call this protocol the “INSIDE-OUT” approach, and suggest that it is a manifestation of the exergy analysis method. To support this assertion, we develop the thermodynamic bases for the “Out-side-in” and the “Inside-out” approaches to identifying savings We then demonstrate the comparative effectiveness of the “inside-out” approach using approaches from lighting, air compressors, and electroplating. Finally, we show why the inside-out approach leads ...

Cost optimization with solar and conventional energy production, energy storage, and real time pricing

Research is presented that investigates the potential for solar power generation with battery energy storage for reducing the effective cost of energy delivered to residential customers if real time pricing is present. A linear optimization approach is developed based upon a two-step process. In step one, given a specified solar array area and battery capacity, the optimal means to meet loads based upon grid power, solar power, and/or battery power is determined. This analysis considers an expected life-span of the solar panel. With these results established, in the next step, the capital costs for the solar arrays and batteries are considered for each point (solar area and battery capacity) in the design space. Ultimately, the results illuminate the most cost effective means to provide power to customers for the chosen system.

A study of the fundamental operations of a capillary driven heat transfer device in both normal and low gravity Part 1. Liquid slug formation in low gravity

Research has been conducted to observe the operation of a capillary pumped loop (CPL) in both normal and low gravity environments in order to ascertain the causes of device failure. The failures of capillary pumped heat transport devices in low gravity; specifically; evaporator dryout, are not understood and the available data for analyzing the failures is incomplete. To observe failure in these devices an idealized experimental CPL was configured for testing in both a normal-gravity and a low-gravity environment. The experimental test loop was constructed completely of Pyrex tubing to allow for visualization of system operations. Heat was added to the liquid on the evaporator side of the loop using resistance heaters and removed on the condenser side via forced convection of ambient air. A video camera was used to record the behavior of both the condenser and the evaporator menisci simultaneously. Low-gravity experiments were performed during the Microgravity Science Laboratory (MSL-1) mission performed ...

Conceptual Design of Net Zero Energy Campus Residence

In response to both global and local challenges, the University of Dayton is committed to building a net-zero energy student residence, called the Eco-house. A unique aspect of the Eco-house is the degree of student involvement; in accordance with UD’s mission, interdisciplinary student teams from mechanical engineering, civil engineering and the humanities are leading the design effort. This paper discusses the conceptual design of a net-zero energy use campus residence, and the analysis completed thus far. Energy use of current student houses is analyzed to provide a baseline and to identify energy saving opportunities. The use of the whole-system inside-out approach to guide the overall design is described. Using the inside-out method as a guide, the energy impacts of occupant behavior, appliances and lights, building envelope, energy distribution systems and primary energy conversion equipment are discussed. The design of solar thermal and solar photovoltaic systems to meet the hot water and electricity requirements of the house is described. Eco-house energy use is simulated and compared to the energy use of the existing houses. The analysis shows the total source energy requirements of the Eco-house could be reduced by about 340 mmBtu per year over older baseline houses, resulting in CO2 emission reductions of about 54,000 lb per year and utility cost savings of about

Entropy Generation Metric for Evaluating and Forecasting Aircraft Energy Management Systems

3,000 per year. Detailed cost analysis and cost optimization have not been performed but are critical aspects of the UD Eco-house project, which will be performed in the future.Copyright

A different path to internationalization of engineering education

A general Entropy Generation Minimisation (EGM) technique is applied to analyse the feasibility of energy recovery from aircraft avionics via thermoelectric (TE) devices. In employing this approach, a suitable control volume definition is chosen to evaluate the impact of an energy recovery system on the overall entropy generation of the aircraft over a mission. Only those systems which are affected by the energy harvesting system are considered. As importantly, the analysis helps to identify the technical thresholds, which must be realised in order to make avionic energy harvesting via thermoelectric devices practical. This result has exciting implications for the use of this tool for helping to prioritise research directions. Relative to the energy harvesting application from the radar array on a high efficiency aircraft, the results from this approach show that a majority of the entropy generation and fuel exergy wastage is associated with the avionics cooling system due the transfer of heat to the cooling system and to the large mass/power ratio associated with cooling systems.

Microgrid cost optimization for a mixed-use building

The collaborative team of Engineers in Technical, Humanitarian Opportunities of Service Learning (ETHOS, formed by students and staff at Iowa State University, University of Dayton, and Seattle University), has taken a new path to internationalizing engineering education. ETHOS has helped students gain awareness of the social and cultural fabric of the poorest nations in the world and has allowed them to perform research and design focused on improving the ability of people living in these nations to meet their basic needs. These activities are being implemented via on-campus curricular and immersion service experiences. Collaborations between these universities have been focused on helping two international nongovernmental organizations improve the efficiency and durability of the wood-burning stoves typically used for cooking by the worlds poor This paper discusses the initial successes of and lessons learned from this collaboration, as well as its future activities.