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Optimal Environmental And Economic Performance Trade-Offs For Fifth Generation District Heating And Cooling Network Topologies With Waste Heat Recovery, Michael D. Murphy

Publications

Network topology greatly influences both the economic and environmental performance of fifth generation district heating and cooling (5GDHC) systems. In this study the optimal trade-offs between the environmental and economic performance of 5GDHC network topologies for a five-building district with waste heat recovery were explored. A life cycle assessment method was used to calculate the total life cycle CO2 emissions (LCCO2) associated with the installation and operation of various network topologies. Twelve months of empirical data from a data center cooling system were analyzed to assess its suitability for integration into a 5GDHC system. The most suitable method for utilizing …

Experimental Investigation Of A Thermally Integrated Carnot Battery Using A Reversible Heat Pump/Organic Rankine Cycle, Olivier Dumont, Antonios Charalampidis, Vincent Lemort

International Refrigeration and Air Conditioning Conference

The growth of renewable energy requires flexible, low-cost and efficient electrical storage systems to balance the mismatch between energy supply and demand. The Carnot battery (or Pumped Thermal Energy Storage) converts electric energy to thermal energy with a heat pump (HP) when electricity production is greater than demand; when electricity demand outstrips production, the Carnot battery generates power from two thermal storage reservoirs (Rankine mode). Classical Carnot batteries architectures do not achieve more than 60% roundtrip electric efficiency. However, innovative architectures, using waste heat recovery (thermally integrated Carnot batteries) are able to reach electrical power production of the power cycle …

Evaluation Of Heat Pumping And Waste Heat Recovery For Battery Electric Vehicle Thermal Management, Tyler Shelly, Justin Weibel, Davide Ziviani, Eckhard Groll

International Refrigeration and Air Conditioning Conference

Due to increasing regulation on emissions and shifting consumer preferences, the wide adoption of battery electric vehicles (BEV) hinges on research and development of technologies that can extend system range. This can be accomplished either by increasing the battery size or via more efficient operation of the electrical and thermal systems. This study evaluates the range performance of a BEV integrated thermal management system (ITMS) with heat pumping and waste heat recovery across a range of ambient conditions (-20 °C to 40 °C) and cabin setpoints (18 °C to 24 °C). A dynamic ITMS modelling framework for a long-range electric …

Experimental Characterization Of Thermal-Hydraulic Performance Of A Microchannel Heat Exchanger For Waste Heat Recovery, James Yih, Hailei Wang

Mechanical and Aerospace Engineering Faculty Publications

Given size and performance advantages, microchannel heat exchangers are becoming increasingly important for various energy recovery and conversion processes. In this study, detailed experimental measurements were conducted to characterize flow and heat transfer performance of a microchannel heat recovery unit (HRU) manufactured using standard photochemical etching and diffusion bonding processes. According to the global flow and temperature measurement, the HRU has delivered the predicted thermal performance under various oil and air flow rates. As expected, the heat transfer effectiveness varies between 88% and 98% for a given air and oil flow rates while it increases with air inlet temperature due …

Performance Analysis Of An Exhaust Heat Recovery System Utilizing Heat Pipes, Metal Foam, And Thermoelectric Generators, Michael Resciniti

Honors Program Projects

Developing efficient thermoelectric generator systems to recover wasted thermal energy from automotive exhaust gasses has potential to improve engine efficiency and reduce carbon emissions. Due to their high thermal transfer efficiency, heat pipes have been used to assist thermoelectric generator systems in these applications. To aid in additional heat transfer, metal fins are often used with heat pipes to take advantage of extended-surface heat transfer. This paper proposes a thermoelectric generator system that employs metal foam as an extended-surface heat transfer aid used in conjunction with heat pipes. Three test conditions were simulated to evaluate the system performance in terms …

Multi-Objective Layout Optimization Of A Generic Hybrid-Cooled Data Centre Blade Server, Assel Sakanova, Sajad Alimohammadi, Jaakko Mcevody, Sara Battaglioli, Tim Persoons

Articles

The rapid global increase in energy consumption by data centres requires new improved cooling solutions and techniques to be developed and implemented. In a typical data centre, approximately a third of the total power consumption is needed for the cooling infrastructure, resulting in high power usage effectiveness (PUE) values. The main culprits of raised PUE are legacy air-cooled data centres, exhausting only low grade waste heat for which capture and re-use is challenging. This study investigates numerically the potential for energy recuperation by a server-level internal layout optimization for a hybrid air/liquid-cooled server. The approach combines multi-objective genetic algorithm (MOGA) …

Modelling, Design, And Optimization Of Membrane Based Heat Exchangers For Low-Grade Heat And Water Recovery, Soheil Soleimanikutanaei

FIU Electronic Theses and Dissertations

Transport Membrane Condenser (TMC) is an innovative technology based on the property of a nano-scale porous material which can extract both waste heat and water from exhaust gases. This technology tremendously improves the efficiency of boilers and gas/coal combustors by lowering waste heat and increasing water recovery. Contaminants in the flue gases, such as CO2, O2, NOx, and SO2 are inhibited from passing through the membrane by the membrane’s high selectivity. The condensed water through these tubes is highly pure and can be used as the makeup water for many industrial applications. The goal of this research is to investigate …

Modelica Household Dishwater Model With External Heat Loop, Stephen L. Caskey, Eckhard A. Groll

International High Performance Buildings Conference

With the United States being the world’s second largest consumer of primary energy, research into areas of significant consumption can provide large impacts in terms of the global energy consumption. Buildings account for 41% of U.S. total energy consumption with the residential sector making up a majority. Household appliances account for the second largest site energy consumption at 27%, after the HVAC system for the U.S. residential sector. Thermally integrating residential appliances by leveraging waste heat recovery goes outside U.S. federal standards and has not been adequately explored by connecting all residential appliances. Limited studies exist focused only on single …

Modelica Analysis Of Thermally Connected Residential Appliances, Stephen L. Caskey, Eckhard A. Groll

International High Performance Buildings Conference

With the United States being the world’s second largest consumer of primary energy, research into areas of significant consumption can provide large impacts in terms of the global energy consumption. Buildings account for 41% of U.S. total energy consumption with the residential sector making up a majority. Household appliances account for the second largest site energy consumption at 27%, after the HVAC system for the U.S. residential sector. Thermally integrating residential appliances by leveraging waste heat recovery goes outside U.S. federal standards and has not been adequately explored by connecting all residential appliances. Limited studies exist focused only on single …

Waste Heat Recovery From Distributed Rack-Based Fuel Cells Using Thermoelectric Generators, Khosrow Ebrahimi, Alfonso Ortega, Calvin Li, Kazuaki Yazawa, Sean James

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Off-grid power generation has been demonstrated in data centers through the deployment of site-specific centralized power plants utilizing gas turbine or fuel cell-based power generation. Because power is centrally generated, power distribution requires a high voltage power grid within the data center with its ancillary storage and conditioning requirements and equipment. An alternative approach is a completely decentralized distributed power generation system in which fuel cells deployed within individual server racks provide power localized to that rack only. Among other advantages, such an approach also greatly increases the ability to modulate and control power to individual rack units. Because the …

Minimizing The Energy And Economic Penalty Of Ccs Power Plants Through Waste Heat Recovery Systems, Vaclav Novotny, Monika Vitvarova, Michal Kolovratnik, Zdenek Hrdina

CO2 Summit II: Technologies and Opportunities

Implementation of currently considered and available CCS technologies into fossil power plants brings inevitable technical, energy and economic penalty. This is getting even larger when fossil fuels such as low rank coal are being utilized. All three generally considered CCS technologies were modelled – oxyfuel combustion and ammonia based post-combustion (subcritical power plant with fuel drying) and pre-combustion (IGCC with Rectisol method for CO2 separation).

After traditional methods of system optimization there was considered another way for increasing system efficiency. CCS technologies produce waste heat streams, which can be converted to electricity by small modular units with unit cost comparable …

Experimental Evaluation Of A Small-Capacity, Direct-Fired Ammonia-Water Absorption Chiller, Anurag Goyal, Marcel A. Staedter, Dhruv C. Hoysall, Mikko J. Ponkala, Srinivas Garimella

International Refrigeration and Air Conditioning Conference

Vapor absorption heating and cooling systems, utilizing heat input from different sources such as waste heat or natural gas, are attracting increasing interest in commercial and residential applications. Residential heat pump applications require compact heat exchanger geometries to ensure a small system footprint. Compact microscale heat and mass exchangers are developed and implemented here. These novel heat and mass exchanger geometries for different components of the system require evaluation at design and off-design conditions to characterize the individual component and overall system performance. This study presents results from experimental investigations of a small-capacity ammonia-water absorption chiller. The chiller comprises discrete …

Experimental Testing And Modeling Of 5 Kw Oil-Free Open Drive Scroll Expander Using R245fa, Felipe A Accorsi, Nelson A James, Eckhard Groll, William T Horton, James E Braun

International Compressor Engineering Conference

Organic Rankine Cycles (ORC) are thermodynamic power cycles designed to generate work from low temperature sources, typically between 80 °C to 270 °C.  The low temperature heat input makes this technology attractive for applications in waste heat recovery from industrial processes, exhaust gas from diesel engines, solar systems, geothermal systems, and others.  The expander has the greatest effect on increasing the efficiency of an ORC. The operating  conditions that the expander is subjected to are directed related to its efficiency.  The performance of a 5 kW scroll expander with a displacement of 73.6 cm3 per revolution, …

Hydrodynamic Considerations For Optimal Thermal Compressor Design, Marcel A. Staedter, Khoudor Keniar, Srinivas Garimella

International Refrigeration and Air Conditioning Conference

The use of small-scale thermally driven heat pumps allows for the design of innovative and efficient thermal systems. Recent developments have shown the feasibility of the implementation of ammonia-water absorption systems for small capacity applications ( < 14 kW cooling capacity). The use of low-grade thermal energy in thermally driven systems of that scale has the potential to achieve significant reduction of high grade electrical or mechanical energy consumption. However, further research needs exist for the development of highly compact components that optimize the efficiency of the overall system. Analogous to the mechanical compressor in a vapor compression cycle, the thermal compressor in a vapor absorption cycle where driving energy input to the cycle is supplied. It has been shown that an optimal thermal compressor component configuration exists. The requirement of high refrigerant purity in the ammonia-water system favors the implementation of the diabatic distillation principle. It can significantly reduce exergy destruction in the thermal compressor and provides the opportunity to develop highly compact component designs. In this work, two new design solutions for the desorption stage of the thermal compressor are presented. These designs incorporate the diabatic distillation concept for a direct-gas-coupled as well as a coupling-fluid-driven thermal compressor. The designs operate in a liquid-vapor countercurrent flow configuration and utilize favorable temperature and concentration profiles of specific flow patterns. Therefore, the proposed designs were visually investigated using an air-water mixture to simulate the working fluids. Air-water flow experiments at adiabatic conditions were designed and conducted to simulate component operation. Proper vapor-liquid interaction (termed tray activation) in the purification stages was investigated for a wide range of flow rates to simulate variation within the component as well as part load operation. Countercurrent flow limitations exist at high flow rates, which can cause component flooding leading to detrimental system performance. These limitations were investigated and flooding curves were established. The effects of minor geometry adjustments on tray activation and flooding were studied. Surface tension effects were investigated by use of an ethanol-water mixture. High speed video data were used to obtain quantitative results. The total heat transfer area for single-phase and two-phase flow regions, as well as vapor-liquid interfacial area are quantified based on the flow visualization studies. Both designs were validated as effective solutions for the implementation of the diabatic distillation concept for small-capacity thermal compressors. Tray activation was achieved for part load operation, and resilience to countercurrent flow limitations could be shown. Consequently, these results provide specific and quantitative heat and mass transfer design guidelines for the desorption stage of the thermal compressor. Results from this investigation will guide the development of new prototype desorbers.

A Trans-Critical Co2 Heat Pump System For Waste Heat Utilization In Warm Weather Condition Applied To A Milk Refrigeration Plant, Simarpreet Singh, M.S Dasgupta

International Refrigeration and Air Conditioning Conference

Based on field data from a medium scale ammonia based milk refrigeration plant located in northern part of India, a trans-critical CO2 based heat pump system is conceptualized to utilize the waste heat from the plant to improve overall coefficient of performance. Year round plant operating data is collected. The plant handles between 0.1 to 0.15 million liters of milk and milk products daily. It maintains two cooling chambers, one at 4°C and the other at -10°C. Every ten days it is required to replenish a 5000 liter tank with ground water for evaporative cooling of the system. Up-stream and …

Recovery Of Waste Thermal Energy In U.S. Residential Appliances, Stephen L. Caskey, Eckhard A. Groll, Eric J. Bowler

International High Performance Buildings Conference

With the United States being the world’s second largest consumer of primary energy, research into areas of significant consumption can provide large impacts in terms of the global energy consumption. Buildings account for 41% of US total energy consumption with the residential sector making up a majority. Household appliances account for the second largest site energy consumption at 27%, after the HVAC system for the U.S. residential sector. By quantifying the expected energy available in the waste stream for five major appliances; household refrigerator, clothes dryer and washer, dishwasher, and cooking oven, a potential energy source is presented. A cold …

Exergy And Energy Analysis Of Waste Heat Recovery Options For Cooling Capacity Production, Chantal Maatouk, Rayan Slim

International Refrigeration and Air Conditioning Conference

Electricity production in Lebanon stands at around 1.5 GW while the demand exceeds 2.5 GW at peak times and peak cooling demands, resulting in rationing cuts from between 3 to 20 hours a day which is the worst performance in the Middle East. Due to the country energy shortfall, a large number of small-scale backup generators is installed to address the electric and cooling needs. The proliferation of use of these backup generators presents an interesting potential for waste heat recovery in order to achieve additional power generation and cooling capacity production. This paper investigates two possible configurations for waste …

Thermodynamic Comparison Of Organic Rankine Cycles Employing Liquid-Flooded Expansion Or A Solution Circuit, B. J. Woodland, A. Krishna, E. A. Groll, J. E. Braun, W. T. Horton, S V. Garimella

CTRC Research Publications

Two modifications to a conventional Organic Rankine Cycle (ORC) are investigated: an Organic Rankine Cycle with Liquid-Flooded Expansion (ORCLFE), and an Organic Rankine Cycle with Solution Circuit (ORCSC). The ORCLFE involves “flooding” the expansion device with a liquid that is in thermal equilibrium with the primary working fluid, while simultaneously expanding the primary working fluid through the same device. The ORCSC employs a zeotropic mixture consisting of two components with a large boiling point difference. The more volatile component in the vapor phase is separated from the absorbent in the liquid phase; the vapor then flows through the expansion device, …

Thermodynamic Design Of Screw Motors For Constant Waste Heat Flow At Medium Temperature Level, Jan Hütker, Andreas Brümmer

International Compressor Engineering Conference

This paper focuses on the interaction of the geometric parameters of screw motors and the fluid parameters of the system in compliance with the boundary condition of constant waste heat flow. Within the thermodynamic simulation the systematic variation of the geometric machine parameters include the number of lobes on male and female rotor and the internal volume ratio. The variation range of the system parameters consists of the dependent parameters of temperature and mass flow and of the pressure on the high pressure side of the machine. The conclusive assessment of the energetic efficiency and the operating behavior of the …

Vapor Jet Ejector Used To Generate Free Waste Heat Driven Cooling In Military Environmental Cooling Units, Stefan Elbel, Chad D. Bowers, Manuel Reichle, Jonathan M. Cristiani, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

The waste heat driven vapor jet ejector cooling cycle is a very promising approach to produce ‘free’ cooling by utilizing low-grade energy sources. The mechanism behind ejector-based waste heat cooling is very different from absorption or adsorption cooling technologies that are also aimed at producing heat driven cooling. The ejector cooling system is actually more closely related to vapor compression technology, in which an ejector, a waste heat source, and a liquid pump are used to replace the vapor compressor. Despite the fact that ejectors were first used in refrigeration systems almost 100 years ago, commercially available waste heat driven …