Comparative Performance Analysis of IADR Operating in Natural Gas-Fired and Waste-Heat CHP Modes

2006 ◽  
Author(s):  
Andrei Y. Petrov ◽  
James R. Sand ◽  
Abdolreza Zaltash ◽  
John Fischer ◽  
Rick Mitchell
Keyword(s):  
Natural Gas ◽  
Thermal Energy ◽  
Waste Heat ◽  
Cooling System ◽  
Cost Effective ◽  
Direct Expansion ◽  
Comparative Performance ◽  
Desiccant Wheel ◽  
Absorption Chillers ◽  
Expansion Cooling

Fuel utilization can be dramatically improved through effective recycle of "waste" heat produced as a by-product of on-site or near-site power generation technologies. Development of modular compact cooling, heating, and power (CHP) systems for end-use applications in commercial and institutional buildings is a key part of the Department of Energy's (DOE) energy policy. To effectively use the thermal energy from a wide variety of sources which is normally discarded to the ambient, many components such as heat exchangers, boilers, absorption chillers, and desiccant dehumidification systems must be further developed. Recently a compact, cost-effective, and energy-efficient integrated active-desiccant vapor-compression hybrid rooftop (IADR) unit has been introduced in the market. It combines the advantages of an advanced direct-expansion cooling system with the dehumidification capability of an active desiccant wheel. The aim of this study is to compare the efficiency of the IADR operation in baseline mode, when desiccant wheel regeneration is driven by a natural gas burner, and in CHP mode, when the waste heat recovered from microturbine exhaust gas is used for desiccant regeneration. Comparative analysis shows an excellent potential for more efficient use of the desiccant dehumidification as part of a CHP system and the importance of proper sizing of the CHP components. The most crucial factor in exploiting the efficiency of this application is the maximum use of thermal energy recovered for heating of regeneration air.

scholarly journals EFFECTIVE USE OF ROTARY FURNACE SHELL HEAT

2014 ◽  
Vol 54 (6) ◽  
pp. 414-419
Author(s):  
Julius Lisuch ◽  
Dusan Dorcak ◽  
Jan Spisak
Keyword(s):  
Waste Heat ◽  
Cooling System ◽  
Raw Materials ◽  
Significant Proportion ◽  
Rotary Furnace ◽  
Cost Effective ◽  
Total Energy Expenditure ◽  
Heat Losses ◽  
Controlled Cooling ◽  
Effective Use

<pre><pre>Significant proportion of the total energy expenditure for the heat treatment of raw materials are heat losses through the shell of rotary furnace. Currently, the waste heat is not used in any way and escapes into the environment. Controlled cooling system for rotary furnace shell (<span>CCSRF</span>) is a new solution integrated into the technological process aimed at reducing the heat loss of the furnace shell. Based on simulations and experiments carried out was demonstrated a significant effect of controlled cooling shell to the rotary furnace work. The proposed solution is cost-effective and operationally undemanding.</pre></pre>

Climatic Effect on the Exergetic Performance of Conventional to Hybrid Evaporative Coolers with Varying Dead State Temperatures in India

2021 ◽  
pp. 1-33
Author(s):  
V Venkateswara Rao ◽  
Santanu Prasad Datta
Keyword(s):  
Air Conditioning ◽  
Sustainability Assessment ◽  
Cooling System ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Direct Expansion ◽  
Dead State ◽  
Evaporative Cooling System ◽  
Expansion Cooling ◽  
Semi Arid

Abstract A comprehensive exergy, exergo-economic and sustainability assessment of seven conventional to hybrid air-conditioning systems comprising direct and indirect evaporative coolers with direct expansion system, and their several combinations integrated into an 8-story domestic building for 5 different cities corresponding to arid, semi-arid, humid sub-tropical, tropical wet and dry, and tropical wet climatic zones across India are investigated based on simulation output from EnergyPlus. The exergetic performances are reported for varying dead state temperatures ranging from 5°C to 40°C while saturated humidity ratio and pressure at system outlet are two other dead state properties. The results reveal that the specific exergy of moist air and exergetic efficiency decrease with increasing dead state temperature and become least at a dead state temperature near to American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) comfort temperature of 23°C. In arid, semi-arid and humid subtropical climates, the three-stage evaporative cooling system exhibited the lowest exergy destruction of 100 J kg−1 and the highest exergy efficiency of 90% at a dead state temperature of 40°C. The two-stage direct evaporative-direct expansion cooling system exhibited superior exergy efficiency of around 90% in tropical wet and dry and tropical wet zones. Further, the Grassmann diagram based on the climate of Hyderabad indicated that the three-stage cooling system is energetically and exergetically optimum with exergy destruction of 28.86%.

Economic Optimization of a Combined Heat and Power System for an Office Building

2007 ◽  
Author(s):  
M. E. Douglas ◽  
Timothy C. Wagner ◽  
Michael K. Sahm ◽  
William J. Wepfer
Keyword(s):  
Thermal Energy ◽  
Waste Heat ◽  
Cost Effective ◽  
Energy Generation ◽  
Prime Mover ◽  
Economic Optimization ◽  
Electrical Efficiency ◽  
Load Demand ◽  
Generation Cost ◽  
The Relationship

The determination of a prime mover’s characteristics is important in ascertaining its suitability for combined heat and power (CHP) applications. By definition, its operation affects the operation of all heat recovery equipment downstream. The correct balance between component electrical efficiency and waste heat is needed if the electric power producing equipment is to be used in a CHP application in a cost effective manner. Understanding the relationship between electric efficiency and exhaust stream energy content for different prime movers systems is a first step in an overall CHP system optimization. The goals of this work are to determine the potential financial benefit of utilizing waste heat from various prime mover configurations as well as establish the relationship between the two types of energy generation and costs. An economic optimization was performed to determine the system with the lowest average product (electricity and thermal energy) generation cost. The prime mover system was required to meet the electrical load demand of a typical 9290 m2 (100,000 ft2) office building in New York, NY, USA. The composition of the most cost effective prime mover system, when considering both electrical and thermal energy generation, was shown to be a single microturbine. When comparing the electrical and thermal energy generation of all systems studied with product generation cost, the more cost effective systems had either high electrical efficiency with a low thermal energy generation or high amounts of waste heat with low electrical efficiency. Each installation site and load demand is unique. The results of this study, along with others, can be used to help determine a cost effective system for a particular application.

Efficiency Improvement of Natural Gas Combined Cycle Power Plant With CO2 Capturing and Sequestration

2012 ◽  
Author(s):  
Abdullah Al-Abdulkarem ◽  
Yunho Hwang ◽  
Reinhard Radermacher
Keyword(s):  
Natural Gas ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Simulation Software ◽  
Combined Cycle ◽  
Co2 Removal ◽  
Efficiency Improvement ◽  
Absorption Chillers ◽  
Natural Gas Combined Cycle

Although natural gas is considered as a clean fuel compared to coal, natural gas combined cycles (NGCC) emit high amounts of CO2 at the plant site. To mitigate global warming caused by the increase in atmospheric CO2, CO2 capture and sequestration (CCS) using amine absorption is proposed. However, implementing this CCS system increases the energy consumption by about 15–20%. Innovative processes integration and waste heat utilization can be used to improve the energy efficiency. Four waste heat sources and five potential uses were uncovered and compared using a parameter defined as the ratio of power gain to waste heat. A new integrated CCS configuration is proposed, which integrates the NGCC with the CO2 removal and CO2 compression cycles. HYSYS simulation software was used to simulate the CO2 removal cycle using monoethanolamine (MEA) solution, NGCC, CO2 compression cycle, CO2 liquefaction cycles and Organic Rankine Cycle (ORC). The developed models were validated against experimental data from the literature with good agreements. Two NGCC with steam extraction configurations were optimized using Matlab GA tool coupled with HYSYS simulation software. Efficiency improvement in one of the proposed CCS configurations that uses the available waste heat in absorption chillers to cool the inlet-air to the gas turbine and to run an ORC, and uses the developed CO2 liquefaction and pumping instead of multistage compression is 6.04 percent point, which represents 25.91 MW more power than the conventional CCS configuration.

scholarly journals Simulation modeling of integrated heat and cooling supply systems in the Far North to assess efficiency

2021 ◽  
Vol 289 ◽  
pp. 04004
Author(s):  
Semen Vasilev
Keyword(s):  
Simulation Modeling ◽  
Waste Heat ◽  
Cooling System ◽  
Electricity Consumption ◽  
Far North ◽  
Absorption Chillers ◽  
Simulation Results ◽  
Supply Systems ◽  
The City ◽  
Integrated Power System

This paper proposes the creation of an integrated heat and cooling system in the city of Yakutsk. A classic version of district cooling (DC) with the use of absorption chillers is considered. The operation of the integrated power system was simulated for 3 months in the summer of 2019. The simulation results showed the presence of a sufficient amount of waste heat for the entire time of the DC operation, even for the maximum possible cooling demand. Calculations showed the possibility of reducing electricity consumption in the city from 0.8 to 20.0%. Primary economic indicators showed the possible economic success of such a project, if there is sufficient demand for cold.

scholarly journals Absorption Chillers to Improve the Performance of Small-Scale Biomethane Liquefaction Plants

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 92
Author(s):  
Alessio Ciambellotti ◽  
Gianluca Pasini ◽  
Andrea Baccioli ◽  
Lorenzo Ferrari ◽  
Stefano Barsali
Keyword(s):  
Natural Gas ◽  
Waste Heat ◽  
Economic Assessment ◽  
Specific Consumption ◽  
Small Scale ◽  
Agricultural Activities ◽  
Electricity Cost ◽  
Absorption Chillers ◽  
Levelized Cost ◽  
Biogas Plants

Biomethane liquefaction may help decarbonization in heavy transportation and other hard-to-abate sectors. Small-scale liquefaction plants (<10 ton/day) are suitable for small biogas plants located near farms and other agricultural activities. “Internal refrigerant” refrigeration cycles (e.g., Kapitza cycle) are often proposed for small-scale natural gas liquefaction due to their simplicity. An optimized Kapitza-based cycle is modeled and simulated, and then several modifications were studied to evaluate their influence on the energetic and economic performances. Results showed a specific consumption ranging between 0.65 kWh/kg and 0.54 kWh/kg of bio-LNG with no significant improvements by increasing cycle complexity. Instead, a reduction of 17% was achieved with the implementation of absorption chillers, that effectively turn waste heat into useful cooling energy. An economic assessment was finally carried showing that the Levelized Cost of Liquefation is more affected by electricity cost than additional CapEx.

Economic Performance of Thermal Energy Storage Integrated With Natural Gas Combined Cycle Power Plants

2015 ◽  
Author(s):  
Barry E. Osterman-Burgess ◽  
D. Yogi Goswami ◽  
Elias K. Stefanakos
Keyword(s):  
Energy Storage ◽  
Natural Gas ◽  
Thermal Energy ◽  
Economic Performance ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Storage System ◽  
Cost Effective ◽  
Combined Cycle ◽  
Natural Gas Combined Cycle

This paper focuses on the economics of integrating thermal energy storage into natural gas combined cycle power plants for improved operational and economic performance of the utility grid. Costs and fuel consumption are modeled based on a Florida electric utility’s hour-by-hour load data under two scenarios: 1) no storage, and 2) thermal storage attached to intermediate load, NGCC plants, displacing energy production from older, less efficient NGCT peaking units. Due to the nature of the power grid, several of the older units feature abnormally high fuel costs and abnormally low thermal efficiencies. By shifting load from the most expensive peaking units to more cost-effective combined cycles with a 204 MWhth storage system costing about $4 million, savings of more than $1 million per year can be realized while also reducing CO2 emissions by about 5000 metric tons per year. These savings represent an internal rate of returns of up to 23% over a 30-year lifetime, depending on the initial cost of the storage system.

Energy Simulations of Data Centers With Hybrid Liquid/Air Cooling and Waste Heat Re-Use

2016 ◽  
Author(s):  
Seungho Mok ◽  
Yogendra K. Joshi ◽  
Satish Kumar ◽  
Ronald R. Hutchins
Keyword(s):  
Data Center ◽  
Computational Models ◽  
Data Centers ◽  
Waste Heat ◽  
Cooling System ◽  
Cooling Water ◽  
Maximum Load ◽  
Air Cooling ◽  
Direct Expansion ◽  
Hybrid Cooling

This study focuses on developing computational models for hybrid or liquid cooled data centers that may reutilize waste heat. A data center with 17 fully populated racks with IBM LS20 blade servers, which consumes 408 kW at the maximum load, is considered. The hybrid cooling system uses a liquid to remove the heat produced by high power components, while the remaining low power components are cooled by air. The paper presents three hybrid cooling scenarios. For the first two cases, air is cooled by direct expansion (DX) cooling system with air-side economizer. Unlike the cooling air, two different approaches for cooling water are investigated: air-cooled chiller and ground water through liquid-to-liquid heat exchanger. Waste heat re-use for pre-heating building water in co-located facilities is also investigated for the second scenario. In addition to the hybrid cooling models, a fully liquid cooling system is modeled as the third scenario for comparison with hybrid cooling systems. By linking the computational models, power usage effectiveness (PUE) for all scenarios can be calculated for selected geographical locations and data center parameters. The paper also presents detailed analyses of the cooling components considered and comparisons of the PUE results.

Evaluation of Brayton and Rankine Alternatives for Diesel Waste Heat Exploitation

1994 ◽  
Vol 116 (1) ◽  
pp. 39-45 ◽  
Author(s):  
J. B. Woodward
Keyword(s):  
Diesel Engine ◽  
Gas Turbine ◽  
Thermal Energy ◽  
Diesel Exhaust ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Brayton Cycle ◽  
Exhaust Gas ◽  
Direct Expansion ◽  
Work Done

A diesel engine may produce exhaust-gas thermal energy in excess of that needed for turbocharging. Alternatives for exploitation of the energy by producing work may be direct expansion through a gas turbine (completing a Brayton cycle that begins with the engine’s compression and combustion), or transfer of heat into a Rankine cycle. It is demonstrated that either alternative may have a domain in which it is superior in work done, or in exhaust volume per unit mass of diesel exhaust. Computation models are developed and demonstrated for finding the boundaries along which the Rankine and Brayton alternatives have equal merit in either work or exhaust volume.

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