Cogeneration System Modeling Based on Experimental Results

2010 ◽  
Author(s):  
Flore Marion ◽  
Fred Betz ◽  
David Archer
Keyword(s):  
Heat Exchanger ◽  
Steam Generator ◽  
System Modeling ◽  
Primary Component ◽  
Performance Model ◽  
Operating Conditions ◽  
Hot Water ◽  
Plant Design ◽  
Absorption Chiller ◽  
Cogeneration System

A 25 kWe cogeneration system has been installed by the School of Architecture of Carnegie Mellon University that provides steam and hot water to its Intelligent Workplace, the IW. This cogeneration system comprises a biodiesel fueled engine generator, a steam generator that operates on its exhaust, a hot water heat exchanger that operates on its engine coolant, and a steam driven absorption chiller. The steam and hot water are thus used for cooling, heating, and ventilation air dehumidification in the IW. This cogeneration system is a primary component of an overall energy supply system that halves the consumption of primary energy required to operate the IW. This cogeneration system was completed in September 2007, and extensive tests have been carried out on its performance over a broad range of power and heat outputs with Diesel and biodiesel fuels. In parallel, a detailed systems performance model of the engine generator, its heat recovery exchangers, the steam driven absorption chiller, a ventilation and air dehumidification unit, and multiple fan coil cooling/heating units has been programmed making use of TRNSYS to evaluate the utilization of the heat from the unit in the IW. In this model the distribution of heat from the engine to the exhaust, to the coolant, and directly to the surroundings has been based on an ASHRAE model. While a computational model was created, its complexity made calculation of annual performance excessively time consuming and a simplified model based on experimental data was created. The testing of the cogeneration system at 6, 12, 18 and 25 kWe is now completed and a wealth of data on flow rates, temperatures, pressures throughout the system were collected. These data have been organized in look up tables to create a simplified empirical TRNSYS component for the cogeneration system in order to allow representative evaluation of annual performance of the system for three different mode of operation. Using the look up table, a simple TRNSYS module for the cogeneration system was developed that equates fuel flow to electricity generation, hot water generation via the coolant heat exchanger, and steam production via the steam generator. The different modes of operation for this cogeneration system can be design load: 25 kWe, following the thermal — heating or cooling — load, following the ventilation regeneration load. The calculated annual efficiency for the different mode is respectively 66% 68% and 65%. This cogeneration installation was sized to provide guidance on future cogeneration plant design for small commercial buildings. The new cogeneration TRNSYS component has been created to be applicable in the design of various buildings where a similar cogeneration system could be implemented. It will assist in selection of equipment and of operating conditions to realize an efficient and economic cogeneration system.

Cogeneration System Performance Modeling

2008 ◽  
Author(s):  
Flore A. Marion ◽  
Sophie V. Masson ◽  
Frederik J. Betz ◽  
David H. Archer
Keyword(s):  
Heat Recovery ◽  
Primary Energy ◽  
Primary Component ◽  
Simulation Software ◽  
Performance Model ◽  
Hot Water ◽  
Absorption Chiller ◽  
Generator System ◽  
Energy Supply System ◽  
Cogeneration System

A bioDiesel fueled engine generator with heat recovery from the exhaust as steam and from the coolant as hot water has been installed in the Intelligent Workplace, the IW, of Carnegie Mellon’s School of Architecture. The steam and hot water are to be used for cooling, heating, and ventilation air dehumidification in the IW. This cogeneration equipment is a primary component of an energy supply system that will halve the consumption of primary energy required to operate the IW. This component was installed in September 2007, and commissioning is now underway. In parallel, a systems performance model of the engine generator, its heat recovery exchangers, a steam driven absorption chiller, a ventilation unit, fan coil cooling/heating units has been programmed making use of TRNSYS transient simulation software. This model has now been used to estimate the energy recoverable by the system operating in the IW for different characteristic periods, throughout a typical year in Pittsburgh, PA. In the initial stages of this modeling, the engine parameters have been set at its design load, 27 kW, delivering up to 17 kW of steam and 22 kW of hot water according to calculation. The steam is used in the absorption chiller during the summer and in hot water production during the winter. Hot water is used in desiccant regeneration for air dehumidification during the summer, in IW heating during the winter, and in domestic hot water product year around. Systems controls in the TRNSYS simulation direct the steam and hot water produced in the operation of the engine generator system to meet the IW’s hourly loads throughout seasons.

An Investigation of DIR-MCFC Based Cooling, Heating and Power System

2003 ◽  
Author(s):  
Indraneel Samanta ◽  
Ramesh K. Shah ◽  
Ali Ogut
Keyword(s):  
Power Generation ◽  
Fuel Cell ◽  
Gas Turbines ◽  
Waste Heat ◽  
Hot Water ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Absorption Chiller ◽  
Internal Reforming ◽  
Cogeneration System

The fuel cell is an emerging technology for stationary power generation because of their higher energy conversion efficiency and extremely low environmental pollution. Fuel cell systems with cogeneration have even higher overall efficiency. Cogeneration can be defined as simultaneous production of electric power and useful heat from burning of single fuel. A fuel cell produces electrical energy by electrolytic process involving chemical reaction between H2 (fuel) and O2 (Air). Previous works have focussed on running the system in combination with gas turbines. We investigate the possibility of running an absorption chiller as a cogeneration system focussing on a 250 kW Direct Internal Reforming Molten Carbonate Fuel Cell (DIR-MCFC) powering a LiBr-Water absorption chiller. The objective of this work is to propose a cogeneration system capable of enhancing the profitability and efficiency of a MCFC for independent distributed power generation. Natural gas is used as fuel and O2 is used from atmospheric air. Two possibilities are evaluated to recover heat from the exhaust of the MCFC: (1) all waste heat available being used for providing hot water in the building and powering an absorption chiller in summer, and (2) hot water supply and space heating in winter. There is an increased cost saving for each case along with improved system efficiency. Based on these considerations payback period for each case is presented.

scholarly journals The Effect of Thermal Matching on the Thermodynamic Performance of Gas Turbine and IC Engine Cogeneration Systems

1985 ◽  
Author(s):  
J. W. Baughn ◽  
N. Bagheri
Keyword(s):  
Gas Turbine ◽  
Combustion Engine ◽  
Full Range ◽  
Operating Conditions ◽  
Hot Water ◽  
Ic Engine ◽  
Thermal Output ◽  
Savings Rate ◽  
Thermodynamic Performance ◽  
Cogeneration System

Computer models have been used to analyze the thermodynamic performance of a gas turbine (GT) cogeneration system and an internal combustion engine (IC) cogeneration system. The purpose of this study was to determine the effect of thermal matching of the load (i.e., required thermal energy) and the output steam fraction (fraction of the thermal output, steam and hot water, which is steam) on the thermodynamic performance of typical cogeneration systems at both full and partial output. The thermodynamic parameters considered were; the net heat rate (NHR), the power to heat ratio (PHR), and the fuel savings rate (FSR). With direct use (the steam fractions being different); the NHR of these two systems is similar at full output, the NHR of the IC systems is lower at partial output, and the PHR and the FSR of the GT systems is lower than the IC systems over the full range of operating conditions. With thermal matching (to produce a given steam fraction) the most favorable NHR, PHR, and FSR depends on the method of matching the load to the thermal output.

Applications of Geothermal Energy in Space Cooling: A Simulator Study of Existing Oil Well to Activate an Absorption Chiller

2019 ◽  
Author(s):  
Fadi A. Ghaith ◽  
Kamal Majlab Wars
Keyword(s):  
Water Source ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Oil Field ◽  
Hot Water ◽  
Optimum Operating ◽  
Oil Well ◽  
Absorption Chiller ◽  
Space Cooling ◽  
Water Feed

Abstract This paper addresses the potential of integrating the existing oil wells and absorption chiller for the purpose of provision space cooling for the base camp of oil field at Block 9 located in Oman. The wellbore was used as a hot water feed to the chiller. Well S 347 was selected as the hot water source and well S 179 was selected to be the injection well for the outlet water. The existing wells were assessed via PIPESIM software. Using PIPESIM software, the fluid temperatures, well pressure and flow rates were obtained and analyzed throughout NODAL analyses. The water temperature of 100 °C, well head pressure of 100 psi and flow rate of 30 m3/h, were found to be the optimum operating parameters. The COP of the absorption chiller was obtained via ABSIM software. The variable operating conditions were investigated and elaborated as a function of the efficiency and capacity ratio. The designed system was configured to yield 0.733 COP and a capacity of 377 KW which met the cooling capacity of the admin building of block 9. The entire feasibility analysis was performed in terms of the overall cost as well as the saving that would be achieved from such homogeneity. The payback period of the entire system was found to be 7 years which emphasized a great potential of adapting the technology if the operating resources are available.

scholarly journals Dynamic experimental analysis of a LiBr/H2O single effect absorption chiller with nominal capacity of 35 kW of cooling

2019 ◽  
Vol 41 (1) ◽  
pp. 35173 ◽  
Author(s):  
Alvaro Antonio Ochoa Villa ◽  
José Carlos Charamba Dutra ◽  
Jorge Recarte Henríquez Henríquez ◽  
Carlos Antonio Cabral do Santos ◽  
José Ângelo Peixoto da Costa
Keyword(s):  
Thermal Load ◽  
Heat Dissipation ◽  
Cold Water ◽  
Operating Conditions ◽  
Hot Water ◽  
Experimental Methodology ◽  
Absorption Chiller ◽  
Water Heater ◽  
Nominal Capacity ◽  
Single Effect

This work aims to transient performance of chiller single effect absorption refrigeration using the LiBr/H2O pair with nominal capacity of 35 kW. The goal of this study is to verify the absorption chiller when subjected to thermal loads and it transiently responsive as a function of the temperatures of the chilled, hot and cold water of the system. An experimental methodology was established in a micro-CHP laboratory to simulate the dynamic operating conditions of the system considering the thermal load (chilled water), the activation source (hot water) and the heat dissipation circuit (cold water). The thermal load was simulated from a set of electrical resistors installed in a water heater and the activation of the chiller from recovery gas a microturbine 30 kW and through a compact heat exchanger, where water is heated and stored in a hot buffer tank. The absorption chiller heat dissipation system consists of the pump and cooling tower. The system responded appropriately to the thermal load imposed providing COP values in the transient regime of 0.55 to 0.70 the temperature conditions tested.

A Transient Immersed Coil Heat Exchanger Model

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
William R. Logie ◽  
Elimar Frank
Keyword(s):  
Heat Exchanger ◽  
Water System ◽  
Operating Conditions ◽  
Hot Water ◽  
Simulation Environment ◽  
One Dimensional ◽  
Solar Fraction ◽  
Coil Heat Exchanger ◽  
Side Flow ◽  
Coil Heat

The aim of this paper is to present a transient one-dimensional (1D) radial immersed coil heat exchanger model that accounts for the effect that geometry and operating conditions have on heat transfer performance. Insights gained through its use in both an analysis of experimental data and an implementation in the simulation environment TRNSYS are shown and discussed. While variation in the external convection coefficient of immersed coil heat exchangers has little effect on the annual solar fraction of a generic solar domestic hot water system, variation in collector side flow can influence the solar fraction as great as ±5%, in particular low collector side flow improves stratification inside the store.

scholarly journals Calculation of substitution scheme parameters inductive-conductive heater

2021 ◽  
pp. 7-16
Author(s):  
Anatoly Elshin ◽  
◽  
Vyacheslav Kozhukhov ◽  
Petr Elshin ◽  
◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Equivalent Circuit ◽  
Operating Conditions ◽  
Hot Water ◽  
Production Costs ◽  
Water Supply Systems ◽  
Stationary Mode ◽  
Secondary Circuit ◽  
Preliminary Calculation ◽  
Heating Chamber

To reduce production costs in the design and creation of an inductive-conductive heater (ICH), it is necessary to carry out a preliminary calculation as accurately as possible. This is possible when using the most approximate electrical circuit for replacing the ICH to a real object. It becomes possible to assess the work of the ICH in various operating conditions, including emergency conditions, using simpler modeling. An inductive-conductive heater transformertype is a three-rod W-shaped magnetic circuit with primary windings, which are covered by a heat exchanger (HE) of three concentric systems of electrically conductive cylinders with an internal slotted channel for the coolant. The energy from the mains supply is inductively transferred to the heat exchanger through the air gap by means of the primary winding. The secondary circuit of an electromagnetic device is a heat exchanger in which electrical energy is converted into heat. The heat flux from the heated cylindrical walls of the HE conductively heats the coolant circulating in the system to the required temperature. The large surface area of the HE allows you to avoid its overheating in relation to the coolant, which has a positive effect during the operation of the ICH in heating and hot water supply systems, significantly reducing the deposition of water impurities on the walls of the HE. The service life of the device is increased to 100 thousand hours or more. In the work, the synthesis of elements of the ICH equivalent circuit is carried out and the results of calculating the characteristics of the stationary mode of a number of products are presented. The equivalent circuit allows you to simulate electromagnetic processes in devices of different power, voltage and industrial frequencies in the range of 50…1000 Hz. If the configuration of the heating chamber (secondary circuit) is changed, the parameters of the elements of the equivalent circuit are adjusted without changing the general construction algorithm. For new products of inductive-conductive heating, there are no bibliographic data for calculating the elements of the equivalent circuit, especially regarding the formation of the replacement circuit of the secondary circuit, determined by the design of the heating chamber. To fill this gap, the authors have done this work.

EVALUATION OF A COMBINED SOLAR-ASSISTED EJECTOR ABSORPTION CHILLER

2013 ◽  
Vol 42 (1) ◽  
pp. 56-60
Author(s):  
Kamaruzzaman Sopian ◽  
J. Abdulateef ◽  
M. Alghoul ◽  
K.S. Yigit
Keyword(s):  
Experimental Investigation ◽  
Heat Exchanger ◽  
Solar Energy ◽  
Operating Conditions ◽  
Working Fluid ◽  
Absorption System ◽  
Absorption Chiller ◽  
Maximum Increase ◽  
Evacuated Tube

The experimental investigation of the performance of a combined solar ejector absorption coolingsystem has been carried out. The system was installed in the solar energy park at University KebangsaanMalaysia. The influence of various operating conditions on the COP is studied using evacuated tube solarcollectors and NH3-H2O as working fluid. The results showed that, the absorption chiller provides high COPthan that of the conventional absorption system. The maximum COP of the cycle in the order of 0.6 when theimprovements of rectifier and solution heat exchanger are added while the maximum increase in COP in case ofcombined cycle is about 50% higher than the basic cycle. This study is provided an actual compact unit of 1.5cooling capacity and operated under real outside conditions for Malaysia and similar tropical regions.DOI: http://dx.doi.org/10.3329/jme.v42i1.15978

The Effect of Thermal Matching on the Thermodynamic Performance of Gas Turbine and IC Engine Cogeneration Systems

1987 ◽  
Vol 109 (1) ◽  
pp. 39-45 ◽  
Author(s):  
J. W. Baughn ◽  
N. Bagheri
Keyword(s):  
Gas Turbine ◽  
Combustion Engine ◽  
Full Range ◽  
Operating Conditions ◽  
Hot Water ◽  
Ic Engine ◽  
Thermal Output ◽  
Savings Rate ◽  
Thermodynamic Performance ◽  
Cogeneration System

Computer models have been used to analyze the thermodynamic performance of a gas turbine (GT) cogeneration system and an internal combustion engine (IC) cogeneration system. The purpose of this study was to determine the effect of thermal matching of the load (i.e., required thermal energy) and the output steam fraction (fraction of the thermal output, steam and hot water, which is steam) on the thermodynamic performance of typical cogeneration systems at both full and partial output. The thermodynamic parameters considered were: the net heat rate (NHR), the power-to-heat ratio (PHR), and the fuel savings rate (FSR). With direct use (the steam fractions being different), the NHR of these two systems is similar at full output, the NHR of the IC systems is lower at partial output, and the PHR and the FSR of the GT systems are lower than those of the IC systems over the full range of operating conditions. With thermal matching (to produce a given steam fraction) the most favorable NHR, PHR, and FSR depend on the method of matching the load to the thermal output.

Design and Analysis of a Large Solar Industrial Heat Plant for Frito Lay in Modesto California

2007 ◽  
Author(s):  
Andy Walker ◽  
Chuck Kutscher ◽  
Al Halvorsen ◽  
Chris McKenna ◽  
Dave Chambers ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Heat Exchanger ◽  
Steam Generator ◽  
Technical Assistance ◽  
Industrial Process ◽  
Hot Water ◽  
Solar Array ◽  
Design Recommendations ◽  
Process Heat ◽  
Technology Demonstration

Industry-specific technology demonstration projects are key to facilitating deployment of solar industrial process heat technologies. Frito Lay North America (FLNA) is pursuing installation of a solar industrial process heat plant at the manufacturing plant in Modesto CA. FLNA contracted with Industrial Solar Technology Corp. for design and installation of the system and with National Renewable Energy Lab for technical assistance. The US Department of Energy and California Energy Commission both facilitate private companies implementation of technology demonstration projects with incentives, tax policy, and technical assistance. The solar plant would include: 5,387 m2 (57,969 sf) of parabolic trough solar collectors; pipe from solar array to unfired steam generator; unfired steam generator (USG); hot water heat exchanger (HWHX); pipe from hot water heat exchanger back to array field; and associated pumps, bypass piping, and controls. Performance of each component of the solar heating system varies with changing conditions of intensity of the sunlight, position of the sun, and ambient temperature. Since each of these parameters change throughout the day and throughout the seasons an hourly simulation of one year’s performance is performed. The simulation is used to estimate annual energy delivery as well as to inform design recommendations. The solar array inlet temperature is solved for iteratively for each hour of the year based on an energy balance of the entire loop including all components. Nested within this iteration are iterations for the operating temperature of each of the 16 modules in series. Hourly direct beam solar radiation (W/m2) data for Modesto CA for 8 years from 1998–2005 was provided by the National Renewable Energy Laboratory Renewable Resource Data Center and the minimum year, average year, and maximum year were used in the analysis. Results indicate that the system would deliver between 3,898 MWh and 4,308 MWh per year (13.3 and 14.7 billion Btu/year) with an average of 4,044 MWh/year (13.8 billion Btu/year). This average estimate of 13.8 billion Btu/year agrees with the contractors proposal and also with methods described in the Industrial Process Heat Handbook published by NREL. The simulation is able to model more detail and inform design recommendations, such as bypassing the steam generator and only making hot water on winter days.

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