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.

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.

Biodiesel Fueled Engine Generator With Heat Recovery

2008 ◽  
Author(s):  
Fred Betz ◽  
Chris Damm ◽  
David Archer ◽  
Brian Goodwin
Keyword(s):  
Heat Recovery ◽  
Mechanical Engineering ◽  
Thermal Power ◽  
Ventilation System ◽  
Performance Testing ◽  
Electric Utility ◽  
Hot Water ◽  
Space Heating ◽  
Automation System ◽  
Absorption Chiller

Carnegie Mellon University’s departments of Architecture and Mechanical Engineering have teamed with Milwaukee School of Engineering’s Mechanical Engineering department to design and install a biodiesel fueled engine-generator with heat recovery equipment to supply electric and thermal power to an office building on campus, the Intelligent Workplace (IW). The installation was completed in early September 2007, and is currently being commissioned. Full scale testing will begin in early 2008. The turbocharged diesel engine-generator set is operated in parallel with the local electric utility and the campus steam grid. The system is capable of generating 25 kW of electric power while providing 18 kW of thermal power in the form of steam from an exhaust gas boiler. The steam is delivered to a double-effect Li-Br absorption chiller, which supplies chilled water to the IW for space cooling in the summer or hot water for space heating in the winter. Furthermore, the steam can be delivered to the campus steam grid during the fall and spring when neither heating nor cooling is required in the IW. Additionally, thermal energy will be recovered from the coolant to provide hot water for space heating in the winter, and for regenerating a solid desiccant dehumidification ventilation system in summer. All relevant temperatures, pressures, and flows for these systems are monitored via a building automation system. Pressure versus time measurements can be recorded in each cylinder of the engine. Emissions of nitric oxide (NO), nitrous oxide (NO2), Particulate Matter (PM), and carbon dioxide (CO2) are also monitored. Upon completion of this installation and the system performance testing, the operation of the engine generator with its heat recovery components will be integrated with the other HVAC components of the IW including a parabolic trough solar thermal driven LiBr absorption chiller, a solid desiccant dehumidification ventilation system, and multiple types of fan coils and radiant heating and cooling devices. This energy supply system is expected to reduce the IW’s primary energy consumption by half in addition to the 75% energy savings already realized as compared to the average US office space.

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.

Solar Air-Conditioning System Using Single-Double Effect Combined Absorption Chiller

2013 ◽  
Vol 388 ◽  
pp. 133-138
Author(s):  
Hajime Yabase ◽  
Akira Hirai
Keyword(s):  
Air Conditioning ◽  
Heat Recovery ◽  
Double Effect ◽  
Hot Water ◽  
Gas Absorption ◽  
Load Factor ◽  
Absorption Chiller ◽  
Fuel Gas ◽  
Air Conditioning System ◽  
Solar Heat

We developed a single-double effect combined absorption chiller for "Solar air-conditioning system" . This chiller is composed of a highly-efficient gas absorption chiller as a main machine which are equipped with a solar heat recovery unit comprising a heat recovery heat exchanger and special condenser. It enables low temp. solar hot water at 75°C under operation at the cooling rating of load factor: 100%. And we constructed the demonstration plant in Japan. We confirmed that the solar heat priority usage function and gas-based backup function operate properly and overall system functions normally. In summer, fuel gas reduction by 10% could be achieved and the results as estimated were obtained.

Biodiesel Fueled Engine Generator With Heat Recovery: Comparing Biodiesel to Diesel Performance

2009 ◽  
Author(s):  
Fred Betz ◽  
David Archer
Keyword(s):  
Thermal Energy ◽  
Heat Recovery ◽  
Thermal Power ◽  
Ventilation System ◽  
Performance Testing ◽  
Electric Utility ◽  
Hot Water ◽  
Space Heating ◽  
Biodiesel Fuel ◽  
Absorption Chiller

Carnegie Mellon University’s departments of Architecture and Mechanical Engineering have designed and installed a biodiesel fueled engine-generator with heat recovery equipment to supply electric and thermal power to an office building on campus, the Intelligent Workplace (IW). The installation was completed in early September 2007, and was commissioned through April of 2008 with standard off-road low sulfur Diesel (LSD) fuel. Additional baseline testing was conducted with LSD until October 2008, when the transition was made to a 100% soybean oil based biodiesel. The turbocharged diesel engine-generator set is operated in parallel with the local electric utility and the campus steam grid. The system is capable of generating 25 kW of electric power while providing 18 kW of thermal power in the form of steam from an exhaust gas boiler and 19 kW in the form of heated water from the engine coolant. The steam is delivered to a double-effect Lithium-Bromide (Li-Br) absorption chiller, which supplies chilled water to the IW for space cooling in the summer or hot water for space heating in the winter. Furthermore, the steam can be delivered to the campus steam grid during the fall and spring when neither heating nor cooling is required in the IW. The thermal energy recovered from the coolant provides hot water for space heating in the winter, and for regenerating a solid desiccant dehumidification ventilation system in summer. All relevant temperatures, pressures, and flows for these systems are monitored via a building automation system. Pressure versus time versus crank angle measurements are recorded in each cylinder of the engine. Emissions of nitric oxide (NO), nitrogen dioxide (NO2), Particulate Matter (PM), carbon monoxide (CO) and carbon dioxide (CO2) are also monitored. The performance testing thus far indicates that biodiesel fuel performs just as well as Diesel fuel in the CHP system, providing similar amounts of electrical and thermal energy at the similar temperatures and flows at a similar overall efficiency. As expected, the engine consumes more biodiesel fuel due to the lower energy density of biodiesel fuel compared to LSD. Upon completion of the system performance testing with different types of biodiesel fuel, the operation of the engine generator with its heat recovery components will be integrated with the other HVAC components of the IW including a parabolic trough solar thermal driven Li-Br absorption chiller, a solid desiccant dehumidification ventilation system, and multiple types of fan coils and radiant heating and cooling devices. This integrated energy supply system is expected to reduce the IW’s primary energy consumption by half in addition to the 75% site energy savings already realized by architectural features as compared to the average US office space.

A Cogeneration System for an Apartment Building Using Distributed Heat Storage Technology

2011 ◽  
Author(s):  
Hideki Yamaguchi ◽  
Hikaru Morita ◽  
Hitoshi Asano ◽  
Yoshinori Hisazumi
Keyword(s):  
Heat Supply ◽  
Energy Use ◽  
Heat Storage ◽  
Low Cost ◽  
Dynamic Performance ◽  
Heat Supply System ◽  
Primary Energy ◽  
Hot Water ◽  
Storage Unit ◽  
Cogeneration System

In order to spread economically viable distributed generation systems for apartment buildings, it is essential to develop an efficient and low-cost heat supply system. We are developing a new cogeneration system (Neighboring CoGeneration system: NCG). The key concept of this system is to install a heat storage unit with a hot water supply and a room heating function at each household and to connect heat storage units by a single-loop hot water pipe. In this study, a simulator was developed to reproduce the dynamic performance of the NCG system that combined cogeneration with solar heat for 50 households, and the environmental load reduction effects of the system were evaluated on the condition that heat supply to all households was ensured. It showed that the gas engine system reduced the primary energy use by 18% in a year. Meanwhile, the SOFC system reduced the primary energy use by 29%.

Saving Primary Energy Consumption Through Exergy Analysis of Combine Distillation and Power Plant

2012 ◽  
Vol 9 (2) ◽  
pp. 65
Author(s):  
Alhassan Salami Tijani ◽  
Nazri Mohammed ◽  
Werner Witt
Keyword(s):  
Energy Consumption ◽  
Power Plant ◽  
Heat Pump ◽  
Heat Recovery ◽  
Energy Savings ◽  
Primary Energy ◽  
Heat Pumps ◽  
Saturated Steam ◽  
Distillation Unit ◽  
Primary Energy Consumption

Industrial heat pumps are heat-recovery systems that allow the temperature ofwaste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of saving energy in the chemical industry are considered, the objective is to reduce the primary energy (such as coal) consumption of power plant. Particularly the thermodynamic analyses ofintegrating backpressure turbine ofa power plant with distillation units have been considered. Some practical examples such as conventional distillation unit and heat pump are used as a means of reducing primary energy consumption with tangible indications of energy savings. The heat pump distillation is operated via electrical power from the power plant. The exergy efficiency ofthe primary fuel is calculated for different operating range ofthe heat pump distillation. This is then compared with a conventional distillation unit that depends on saturated steam from a power plant as the source of energy. The results obtained show that heat pump distillation is an economic way to save energy if the temperaturedifference between the overhead and the bottom is small. Based on the result, the energy saved by the application of a heat pump distillation is improved compared to conventional distillation unit.

scholarly journals Evaluation of the energy demands for a floating O&M-hub

2021 ◽  
Author(s):  
F. Wittmann ◽  
C. Schmitt ◽  
F. Adam ◽  
P. Dierken
Keyword(s):  
Software Tool ◽  
Energy System ◽  
Spare Parts ◽  
Simulation Software ◽  
Offshore Wind ◽  
Baseline Scenario ◽  
Horizon 2020 ◽  
Energy Supply System ◽  
The North ◽  
Energy Demands

AbstractThe Energyhub@Sea concept is one of the four research applications of the Space@Sea project funded by the EU’s Horizon 2020 research program (GA number: 774253). The focus of this paper is the evaluation of the energy demands of an energy self-sufficient maintenance platform at the location of Helgoland in the North Sea. In view of this, a standardized modular floater was developed as an offshore wind operation and maintenance base, which in the following paper is referred to as an O&M hub. The O&M hub is intended to be equipped with accommodation facilities and various renewable energy infrastructure as well as spare parts logistics, enabling the platform to perform maintenance of offshore gearless wind turbines with a capacity of up to 10 MW. To be energy self-sustaining, an energy supply system for the hub was developed and simulated at a resolution of ten minutes by means of the Top-Energy simulation software, a commercial software tool. As a basis for the simulation, an approach for the automated determination of flexible load profiles, in resolutions of up to ten minutes was developed. This load profile generator creates load profiles on the basis of environmental conditions, technical characteristics, and expected behaviors of the inhabitants. On the basis of the generated load profiles, a first layout (referred to as baseline scenario) for the different components of the energy system was evaluated and tested through simulation. In a second step, three optimization scenarios were developed and simulated with regards to the financial feasibility of the Energyhub.

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