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Patrick Phelan
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Proceedings Papers
Proc. ASME. IMECE2019, Volume 6: Energy, V006T06A059, November 11–14, 2019
Paper No: IMECE2019-11486
Abstract
Membrane distillation (MD) has been studied as a promising solution in the desalination industry but it has not been widely accepted or commercialized due to energy and cost concerns. MD is considered as a hybrid method that involves phase-change thermal processes and the use of membrane separation. Unlike conventional pressure-driven membrane methods such as reverse osmosis (RO), MD does not require intensive pre-treatment and can operate at lower pressure with higher salinities; but more importantly, it can utilize low-grade heat sources such as solar energy or waste heat for its operation. In this paper, an innovative MD module to directly employ solar thermal energy to assist in desalination is studied. MD systems that use solar energy as an external heater is investigated experimentally and theoretically. The proposed system, however, integrates hollow-fiber distillation membranes inside evacuated tubes solar collectors. As a result, the temperature is more uniformly distributed, minimizing the effect of temperature polarization, one of the key challenges of MD operation, thus can enhance the MD performance. The technical performance of the system is measured experimentally. The results of the proposed system are compared with a conventional MD process to investigate improvements in water production.
eBook Chapter
Book: Handbook of Integrated and Sustainable Buildings Equipment and Systems, Volume I: Energy Systems
Publisher: ASME Press
Published: 2017
ISBN: 9780791861271
Abstract
Combined Cooling, Heating and Power (CCHP) is an efficient, clean, and reliable approach to generating power and thermal energy simultaneously from a single fuel source on site. A CCHP system is usually designed to provide power in the form of electricity while recovering the available waste heat for serving heating and/or cooling load. We start this chapter with an overview of the state-of-the-art in CCHP systems applied to commercial and residential buildings to maximize their primary energy efficiency. We continue with a discussion of available prime mover options ranging from classic technologies, such as internal combustion engines, to emerging technologies such as thermoelectric generators. We also discuss different heat recovery concepts along with their limitations and design challenges. These include gas-to-gas heat exchangers, gas-to-liquid heat exchangers, and condensing economizers, as well as advanced concepts such as transport membrane condensers. We then present the available heat pump technologies that can be matched with the different prime movers to service the building heating and/or cooling load. These heat pump options include classic thermally activated technologies such as the absorption and adsorption heat pumps as well as other emerging technologies such as thermo-acoustic heat pumps and the Vuilleumier cycle. A properly designed building CCHP can meet the entire building thermal load and offset significant electricity consumption at higher primary energy efficiency compared to conventional technologies — heating equipment and purchased electricity from the grid. To guide the design if building CCHP, we first address the two approaches to sizing CCHP and identifying system configurations: electric load following and thermal load following. We also present sample thermal and electric load profiles for different types of buildings and present a step-by-step CCHP system design and integration for a health care facility. Furthermore, we discuss several of the system integration challenges. Finally, we present a quick discussion on the economic and feasibility assessment of building CCHP systems.
Journal Articles
Journal:
Journal of Solar Energy Engineering
Article Type: Guest Editorial
J. Sol. Energy Eng. February 2017, 139(1): 010301.
Paper No: SOL-16-1502
Published Online: January 6, 2017
Proceedings Papers
Robert Taylor, Sylvain Coulombe, Todd Otanicar, Patrick Phelan, Andrey Gunawan, Wei Lv, Gary Rosengarten, Ravi Prasher, Himanshu Tyagi
Proc. ASME. MNHMT2012, ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer, 219-234, March 3–6, 2012
Paper No: MNHMT2012-75189
Abstract
Nanofluids — one simple product of the emerging world nanotechnology — where nanoparticles (nominally 1–100 nm in size) are mixed with conventional base fluids (water, oils, glycols, etc.). Nanofluids have seen enormous growth in popularity since they were proposed by Choi in 1995 [1]. In the year 2010 alone there were nearly 500 research articles where the term nanofluid was used in the title, showing rapid growth from 2000 (12) and 2005 (78). Much of the first decade of nanofluid research was focused on measuring and modeling fundamental thermophysical properties of nanofluids (thermal conductivity, density, viscosity, convection coefficients). Recent research, however, has started to highlight how nanofluids might perform in a wide variety of other applications. These applications range from their use in nanomedicine [2] to their use as solar energy harvesting media [3]. By analyzing the available body of research to date, this article presents trends of where nanofluid research is headed and suggests which applications may benefit the most from employing nanofluids. Overall, this review summarizes the novel applications and uses of nanofluids while setting the stage for future nanofluid use in industry.
Journal Articles
Article Type: Research-Article
J. Thermal Sci. Eng. Appl. June 2013, 5(2): 021003.
Paper No: TSEA-12-1166
Published Online: May 17, 2013
Abstract
Efficient conversion of sunlight into useful heat or work is of increasing global interest. Solar-to-thermal energy conversion, as opposed to solar-to-electricity, is enabled by solar thermal collectors that convert sunlight into heat at some useful temperature. We review here recent developments in solar thermal energy conversion. Our emphasis is on “direct-absorption” solar thermal collectors, in which incident sunlight is absorbed directly by a working fluid. This contrasts with conventional solar thermal collectors where the sunlight strikes and is absorbed by a solid receiver, which then transfers heat to the working fluid. Both liquid-based and gas-based direct-absorption collectors are described, although liquid-based systems are emphasized. We propose that if “direct-absorption” technologies could be developed further, it would open up a number of emerging opportunities, including applications exploiting thermochemical and photocatalytic reactions and direct absorption of a binary fluid for absorption refrigeration.
Proceedings Papers
Proc. ASME. ES2011, ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C, 1927-1936, August 7–10, 2011
Paper No: ES2011-54062
Abstract
Solar thermal energy has shown remarkable growth in recent years — incorporating many new technologies into new applications [1]. Nanofluids — suspensions of nanoparticles in conventional fluids — have shown promise to make efficient volumetric-absorption solar collectors [2–4]. It has also been shown that concentrated light energy can efficiently cause localized phase change in a nanofluid [5]. These findings indicate that it may be advantageous to create a ‘direct, volumetric nanofluid steam generator’. That is, a solar collector design which could minimize the number of energy transfer steps, and thus minimize losses in converting sunlight (via thermal energy) to electricity. To study this, we use a testing apparatus where concentrated laser light at 532 nm — a wavelength very near the solar spectrum peak — is incident on a highly absorbing sample. The highly absorbing samples compared in this study are black dyes, black painted surfaces, and silver nanofluids — with de-ionized water as a base fluid. Each of these samples converts light energy to heat — to varying degrees — in a localized region. This region is monitored simultaneously with a digital camera and an infrared camera. The resulting observed temperature profile and bubble dynamics are compared for these fluids. For pure water with a black backing, some very high temperatures (>300 °C) are observed with a laser input of ∼75 W/cm 2 . Using a similar absorption potential, we observed higher temperatures in the nanofluids when compared to black dyes. A simplified boiling heat transfer analysis based on these results is also presented. We also noticed differences in bubble size and growth rates for the different samples. Overall, this study represents a proof-of-concept test for a novel volumetric, direct steam generator. These results of this test indicate that it may be possible to efficiently generate steam directly in a controlled, localized volume — i.e. without heating up passive system components.
Proceedings Papers
Proc. ASME. ES2010, ASME 2010 4th International Conference on Energy Sustainability, Volume 1, 979-984, May 17–22, 2010
Paper No: ES2010-90035
Abstract
Phase Change Material (PCM) plays an important role as a thermal energy storage device by utilizing its high storage density and latent heat property. One of the potential applications of the PCM is in buildings by incorporating them in the envelope for energy conservation. During the summer cooling season, the main benefits are a decrease in overall energy consumption by the air conditioning unit and the time shift in peak load during the day. Experimental work was carried out by Arizona Public Service (APS) in collaboration with Phase Change Energy Solutions (PCES) Inc. with a new class of organic-based PCM. The experimental setup showed maximum energy savings of about 30%, a maximum peak load shift of ∼ 60 min, and maximum cost savings of about 30%.
Proceedings Papers
Proc. ASME. ES2010, ASME 2010 4th International Conference on Energy Sustainability, Volume 2, 529-536, May 17–22, 2010
Paper No: ES2010-90137
Abstract
We present an analysis of combined efficiencies in a coupled photovoltaic/thermal concentrating solar collector. The calculations take into account the drop in efficiency that accompanies the operation of photovoltaic cells at elevated temperatures along with a detailed analysis of the thermal system including all losses. An iterative numerical scheme is described that involves a coupled electro-thermal simulation of the solar energy conversion process. In the proposed configuration losses in the photovoltaic cell due to reduced efficiencies at elevated temperatures and the incident solar energy below the PV bandgap are both harnessed as heat. This thermal energy is then used to run a thermodynamic power cycle. The simulations show that it is possible to optimize the overall efficiency of the system by variation of key factors such as the solar concentration factor, band gap of the photovoltaic material, and the system thermal design configuration.
Journal Articles
Journal:
Journal of Solar Energy Engineering
Article Type: Research Papers
J. Sol. Energy Eng. November 2009, 131(4): 041004.
Published Online: September 17, 2009
Abstract
Due to its renewable and nonpolluting nature, solar energy is often used in applications such as electricity generation, thermal heating, and chemical processing. The most cost-effective solar heaters are of the “flat-plate” type, but these suffer from relatively low efficiency and outlet temperatures. The present study theoretically investigates the feasibility of using a nonconcentrating direct absorption solar collector (DAC) and compares its performance with that of a typical flat-plate collector. Here a nanofluid—a mixture of water and aluminum nanoparticles—is used as the absorbing medium. A two-dimensional heat transfer analysis was developed in which direct sunlight was incident on a thin flowing film of nanofluid. The effects of absorption and scattering within the nanofluid were accounted for. In order to evaluate the temperature profile and intensity distribution within the nanofluid, the energy balance equation and heat transport equation were solved numerically. It was observed that the presence of nanoparticles increases the absorption of incident radiation by more than nine times over that of pure water. According to the results obtained from this study, under similar operating conditions, the efficiency of a DAC using nanofluid as the working fluid is found to be up to 10% higher (on an absolute basis) than that of a flat-plate collector. Generally a DAC using nanofluids as the working fluid performs better than a flat-plate collector, however, much better designed flat-plate collectors might be able to match or outperform a nanofluids based DAC under certain conditions.
Proceedings Papers
Proc. ASME. ES2007, ASME 2007 Energy Sustainability Conference, 729-736, July 27–30, 2007
Paper No: ES2007-36139
Abstract
Due to its renewable and non-polluting nature solar energy is often used in applications such as electricity generation, thermal heating and chemical processing. The most cost-effective solar heaters are of the “flat-plate” type, but these suffer from relatively low efficiency and outlet temperatures. The present study theoretically investigates the feasibility of using a direct absorption solar receiver (DAR) and compares its performance with that of a typical flat-plate collector. Here a nanofluid—a mixture of water and aluminum nanoparticles—is used as the absorbing medium. A two-dimensional heat transfer analysis was developed in which direct sunlight was incident on a thin flowing film of nanofluid. The effects of absorption and scattering within the nanofluid were accounted for. In order to evaluate the temperature profile and intensity distribution within the nanofluid the energy balance equation and heat transport equation were solved numerically. It was observed that the presence of nanoparticles increases the absorption of incident radiation by more than 9 times over that of pure water. According to the results obtained from this study, under similar operating conditions, the efficiency of a DAR using nanofluid as the working fluid is found to be up to 10% higher (on an absolute basis) than that of a flat-plate collector.
Proceedings Papers
Proc. ASME. IMECE2005, Heat Transfer, Part A, 555-560, November 5–11, 2005
Paper No: IMECE2005-81833
Abstract
The adsorption solar-powered cooling system is one of several types of solar-powered cooling systems currently under development. Increasing the efficiency and decreasing the cost of this system will make it a commercially viable alternative to traditional refrigeration systems. The objective of this project was to optimize the adsorber in the adsorption system. A mathematical model of the refrigerant distribution within a cylindrical adsorber was developed using equations from Chua et al. [1]. The simulation revealed effects of varying design parameters on the theoretical refrigerant mass flow rate, which is directly proportional to the system refrigeration capacity. These results indicated parameter values to be used in designing the adsorber. It was found that decreased particle radius, decreased bed porosity, increased pipe radius, increased adsorber radius, and increased fin thickness all positively affect the performance of the adsorption system. Further simulation and experimental trials are recommended to verify these results.
Proceedings Papers
Proc. ASME. IMECE2006, Heat Transfer, Volume 1, 525-533, November 5–10, 2006
Paper No: IMECE2006-15590
Abstract
There are two types of thermal contact resistance at the interface of two solids. One of them is due to the constriction of heat flow lines at the interface, commonly known as thermal contact resistance. The other type of constriction resistance is microscopic in nature. If the characteristic dimension of the constriction becomes comparable to the mean free path of the heat carriers then there is a ballistic component to the constriction resistance. For different materials on the two sides, thermal boundary resistance due to acoustic mismatch becomes important. In this paper a unified model is developed which accounts for both microscopic and macroscopic contact resistances.
Proceedings Papers
Proc. ASME. IMECE2006, Heat Transfer, Volume 3, 21-24, November 5–10, 2006
Paper No: IMECE2006-13143
Abstract
There is a lot of interest in the research community about nanofluids due to their high thermal conductivity and potential applications as heat transfer fluids, however a systematic investigation on the viscosity of the nanofluids is still lacking from the literature. Any heat transfer enhancement due to force convention, also leads to increase in the pressure drop. Knowledge of the pressure drop is very important to understand the pumping requirements. Pressure drop is directly proportional to the viscosity of the liquid. Addition of nanoparticles will enhance the viscosity of the nanofluids. In this paper experimental results on the viscosity of propylene glycol based nanofluids are reported for various parameters such as nanoparticle size, temperature and volume fraction. Effect of Brownian motion on the viscosity of nanofluids is also explored.
