Evaluation of Combined Heat and Power (CHP) Systems Performance With Dual Power Generation Units

2012 ◽  
Author(s):  
Alta Knizley ◽  
Pedro J. Mago
Keyword(s):  
Power Generation ◽  
Carbon Dioxide Emissions ◽  
Operating Cost ◽  
Primary Energy ◽  
Combined Heat And Power ◽  
Department Of Energy ◽  
Environmental Benefits ◽  
Optimum Operating ◽  
Electric Load ◽  
Chp System

This paper evaluates the economic, energetic, and environmental feasibility of using two power generation units (PGUs) to operate a combined heat and power (CHP) system. A benchmark building developed by the Department of Energy for a full-service restaurant in Chicago, IL is used to analyze the proposed configuration. This location is selected since it usually provides favorable CHP system conditions in terms of cost and emissions reduction. In this investigation, one PGU is operated at base load to satisfy part of the electricity building requirements (PGU1), while the other is used to satisfy the remaining electricity requirement operating following the electric load (PGU2). The dual-PGU configuration (D-CHP) is modeled for several different scenarios in order to determine the optimum operating range for the selected benchmark building. The dual-PGU scenario is compared with the reference building using conventional technology to determine the economical, energetic, and environmental benefits of this proposed system. This condition is also compared to a CHP system operating following the electric load (FEL) and to a base-loaded CHP system, and it provides greater savings in operating cost, primary energy consumption, and carbon dioxide emissions than the optimized conditions for base loading and FEL.

scholarly journals The potential environmental benefits of reusable and recyclable materials stocks in Toronto's single-detached housing

2021 ◽  
Author(s):  
Deniz N Ergun
Keyword(s):  
Carbon Dioxide Emissions ◽  
Building Materials ◽  
Primary Energy ◽  
Environmental Indicators ◽  
Environmental Benefits ◽  
Environmental Benefit ◽  
Material Volume ◽  
Material Reuse ◽  
The City ◽  
Common Barriers

This study examines the stocks of building materials in Toronto’s in-use and annual obsolete single detached housing, to provide potential environmental benefit parameters for city scale material reuse and recycling. The material volumes of five archetypes, developed to represent typical Toronto housing, were measured and extrapolated to the city scale. Applying established criteria for reusability and recyclability, city scale reusable and recyclable stocks were determined for three environmental indicators: material volume headed to landfill, carbon dioxide emissions, and primary energy consumption. It was determined that 61-66% of the material volume in Toronto’s in-use and annual obsolete housing could be reclaimed for reuse/recycling, and was mostly composed of masonry, concrete, and framing lumber from houses built from 1930-1960. Additionally, annual obsolete reusable materials represented an embodied carbon of 2,287-4,116 tonnes and energy of 52,883-95,189 GJ. By addressing common barriers to widespread uptake of reuse/recycling, Toronto could reap these determined potential environmental benefits.

scholarly journals The potential environmental benefits of reusable and recyclable materials stocks in Toronto's single-detached housing

2021 ◽  
Author(s):  
Deniz N Ergun
Keyword(s):  
Carbon Dioxide Emissions ◽  
Building Materials ◽  
Primary Energy ◽  
Environmental Indicators ◽  
Environmental Benefits ◽  
Environmental Benefit ◽  
Material Volume ◽  
Material Reuse ◽  
The City ◽  
Common Barriers

This study examines the stocks of building materials in Toronto’s in-use and annual obsolete single detached housing, to provide potential environmental benefit parameters for city scale material reuse and recycling. The material volumes of five archetypes, developed to represent typical Toronto housing, were measured and extrapolated to the city scale. Applying established criteria for reusability and recyclability, city scale reusable and recyclable stocks were determined for three environmental indicators: material volume headed to landfill, carbon dioxide emissions, and primary energy consumption. It was determined that 61-66% of the material volume in Toronto’s in-use and annual obsolete housing could be reclaimed for reuse/recycling, and was mostly composed of masonry, concrete, and framing lumber from houses built from 1930-1960. Additionally, annual obsolete reusable materials represented an embodied carbon of 2,287-4,116 tonnes and energy of 52,883-95,189 GJ. By addressing common barriers to widespread uptake of reuse/recycling, Toronto could reap these determined potential environmental benefits.

Evaluation of Energy, Environmental, and Economic Characteristics of Fuel Cell Combined Heat and Power Systems for Residential Applications

2003 ◽  
Vol 125 (3) ◽  
pp. 208-220 ◽  
Author(s):  
M. Burak Gunes ◽  
Michael W. Ellis
Keyword(s):  
Life Cycle ◽  
Fuel Cell ◽  
Thermal Energy ◽  
Life Cycle Cost ◽  
Energy Use ◽  
Combined Heat And Power ◽  
Environmental Benefits ◽  
Design Parameters ◽  
Single Family ◽  
Chp System

Residential combined heat and power (CHP) systems using fuel cell technology can provide both electricity and heat and can substantially reduce the energy and environmental impact associated with residential applications. The energy, environmental, and economic characteristics of fuel cell CHP systems are investigated for single-family residential applications. Hourly energy use profiles for electricity and thermal energy are determined for typical residential applications. A mathematical model of a residential fuel cell based CHP system is developed. The CHP system incorporates a fuel cell system to supply electricity and thermal energy, a vapor compression heat pump to provide cooling in the summer and heating in the winter, and a thermal storage tank to help match the available thermal energy to the thermal energy needs. The performance of the system is evaluated for different climates. Results from the study include an evaluation of the major design parameters of the system, load duration curves, an evaluation of the effect of climate on energy use characteristics, an assessment of the reduction in emissions, and a comparison of the life cycle cost of the fuel cell based CHP system to the life cycle costs of conventional residential energy systems. The results suggest that the fuel cell CHP system provides substantial energy and environmental benefits but that the cost of the fuel cell sub-system must be reduced to roughly $500/kWe before the system can be economically justified.

Effect of the Power Generation Unit Size on the Energy Performance of Cooling, Heating, and Power Systems

2008 ◽  
Author(s):  
N. Fumo ◽  
P. J. Mago ◽  
L. M. Chamra
Keyword(s):  
Power Generation ◽  
Energy Consumption ◽  
Building Energy ◽  
Energy Performance ◽  
Primary Energy ◽  
Energy Strategy ◽  
Climate Conditions ◽  
Power Generation Unit ◽  
Chp System ◽  
Generation Unit

Cooling, Heating, and Power (CHP) systems are a form of distributed generation that can provide electricity while recovering waste heat to be used for space and water heating, and for space cooling by means of an absorption chiller. CHP systems improve the overall thermal energy efficiency of a building, while reducing energy consumption. Since energy conservation has implications on energy resources and environment, CHP systems energy performance should be evaluated based on building primary energy consumption. Primary energy consumption includes the energy consumed at the building itself (site energy) plus the energy used to generate, transmit, and distribute the site energy. The objective of this investigation is to determine the effect of the power generation unit (PGU) size on the energy performance of CHP systems. Since CHP systems energy performance varies with the building energy profiles, in this study the same building is evaluated for three different cities with different climate conditions. This paper includes simulation results for the cases when a CHP system operates with and without a primary energy strategy. Results show that for any PGU size energy savings are guaranteed only when the primary energy strategy is applied. Since CHP system energy performance depends on the building energy use profiles, which depend on climate conditions and other factors such as building characteristic and operation, each case requires a particular analysis in order to define the optimum size of the power generation unit.

The Quest for More Efficient Industrial Engines: A Review of Current Industrial Engine Development and Applications

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Barry Cullen ◽  
Jim McGovern
Keyword(s):  
Power Generation ◽  
Distributed Generation ◽  
Combustion Engine ◽  
Electrical Power ◽  
Engine Performance ◽  
Primary Energy ◽  
Combined Heat And Power ◽  
Successful Implementation ◽  
Efficiency Defect ◽  
Electrical Demand

This paper addresses the need for efficiency gains in the modern industrial engine as utilized in combined heat and power (CHP) generation and other distributed generation situations. Power generation is discussed in terms of reciprocating-engine-based plant operating on Otto type thermodynamic cycles. The current state of the technology and the research being conducted is examined. Internal combustion engine performance improvement in the industrial engine sector focuses on improvements in the combustion characteristics of the plant, with emphasis on areas such as piston design, valve timing, and supercharging. Maximum brake-thermal efficiencies, in percentage terms, are currently in the 40s. In CHP generation, most of the energy not utilized for mechanical power is recovered as heat from various engine systems, such as jacket water and exhaust, and utilized for space or process heating. In other distributed generation situations, this energy is not utilized in this manner and is lost to the surroundings. While second law analysis would provide a more meaningful interpretation of the efficiency defect, this approach is still not the norm. Distributed generation benefits directly from efficiency improvements; the more efficient use of primary energy leads to reduced fuel costs. Combined heat and power generation is, however, more sensitive to the matching between the plant and its energy sinks, as its successful implementation is dictated by the ability of a site to fully utilize the heat and electrical power produced by the plant. At present, the energy balance of such engines typically dictates that heat is produced in greater quantity than electrical power, the ratio being of the order of 1.1–1.5:1. Due to this production imbalance, it is accepted that in order to be economically feasible, thermal and electrical demand should be coincident and also all heat and power should be utilized. This has traditionally led to certain sectors being deemed unsuitable for CHP use. Some current research is aimed at tipping the production balance of these engines in favor of electrical power production; however, performance gains in this regard are slow. This paper concludes with some brief commentary on current industrial engine developments and applications.

Impact of Thermal Storage Option for CHP Systems on the Optimal Prime Mover Size and the Need for Additional Heat Production

2012 ◽  
Author(s):  
Amanda D. Smith ◽  
Pedro J. Mago
Keyword(s):  
Carbon Dioxide Emissions ◽  
Thermal Storage ◽  
Primary Energy ◽  
Prime Mover ◽  
Commercial Building ◽  
Reference Case ◽  
Additional Heat ◽  
Chp System ◽  
Useful Heat ◽  
The Cost

Combined heat and power (CHP) or cogeneration systems provide both electricity and useful heat to a building. CHP systems can result in lower operational cost, primary energy consumption (PEC), and carbon dioxide emissions when compared to the standard alternative of purchasing electricity from the grid and supplying heat from a boiler. However, the potential for these benefits is closely linked to the relationship between the ratio of power to heat supplied by the CHP system and the ratio of power to heat demanded by the building. Therefore, the benefits of the CHP system also vary with the size of the prime mover. In the model presented in this paper, the CHP system is base-loaded, providing a constant power-to-heat ratio. The power-to-heat ratio demanded by the building depends on the location and the needs of the building, which vary throughout the day and throughout the year. At times when the CHP system does not provide the electricity needed by the building, electricity is purchased from the grid, and when the CHP system does not provide the heat needed by the building, heat is generated with a supplemental boiler. Thermal storage is an option to address the building’s load variation by storing excess heat when the building needs less heat than the heat produced by the CHP system, which can then be used later when the building needs more heat than the heat produced by the CHP system. The potential for a CHP system with thermal storage to reduce cost, PEC, and emissions is investigated, and compared with both a CHP system without thermal storage and with the standard reference case. This proposed model is evaluated for three different commercial building types in three different U.S. climate zones. The size of the power generation unit (PGU) is varied and the effect of the correspondingly smaller or larger base load on the cost, PEC, and emissions savings is analyzed. The most beneficial PGU size for a CHP system with the thermal storage option is compared with the most beneficial PGU size without the thermal storage option. The need for a supplemental boiler to provide additional heat is also examined in each case with the thermal storage option.

scholarly journals A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants

2021 ◽  
Vol 13 (8) ◽  
pp. 4527
Author(s):  
Daniele Fiaschi ◽  
Giampaolo Manfrida ◽  
Barbara Mendecka ◽  
Lorenzo Tosti ◽  
Maria Laura Parisi
Keyword(s):  
Power Generation ◽  
Low Temperature ◽  
Power Plants ◽  
District Heating ◽  
Primary Energy ◽  
Combined Heat And Power ◽  
Geothermal Systems ◽  
Allocation Scheme ◽  
Component Level ◽  
Temperature Level

In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are demonstrated by their application to three relevant and significantly different case studies of geothermal CHPs, i.e., (1) Chiusdino in Italy, (2) Altheim in Austria, and (3) Hellisheidi in Iceland. The results showed that, given the generally low temperature level of the cogenerated heat (80–100 °C, usually exploited in district heating), the use of exergy allocation largely marginalizes the importance of the heat byproduct, thus, becoming almost equivalent to electricity for the Chiusdino and Hellisheidi power plants. Therefore, the PES scheme is found to be the more appropriate allocation scheme. Additionally, the exergy scheme is mandatory for allocating power plants’ environmental impacts at a component level in CHP systems. The main drawback of the PES scheme is its country dependency due to the different fuels used, but reasonable and representative values can be achieved based on average EU heat and power generation efficiencies.

Number and Nominal Power of Prime Movers in Combined Heat and Power Systems

2006 ◽  
Author(s):  
Sepehr Sanaye ◽  
Mehdi Aghaee Meibodi ◽  
Shahabeddin Shokrollahi ◽  
Habibollah Fouladi
Keyword(s):  
Combined Heat And Power ◽  
Environmental Benefits ◽  
Prime Mover ◽  
Gas Temperature ◽  
Ambient Conditions ◽  
Operational Strategy ◽  
Prime Movers ◽  
Heating Load ◽  
Chp System ◽  
Selection Of

Combined Heat and Power (CHP) systems have many economical and environmental benefits. Generally, selection of these systems is performed using the time-dependent curves of the required electricity and heating load during a year. In the selection of a CHP system, the operation of this system at off-design point also should be studied. In this paper, a method for selecting the number of prime movers, and determining their nominal power and operational strategy considering specific electrical and heating loads is presented. Three types of prime movers which are studied in this paper are gas turbine, diesel engine, and gas engine. Selecting the number of each type of prime mover and determining their nominal power as well as the operational strategy are presented here. Ambient conditions and electricity and heating load curves are assumed as known parameters. Parameters such as engine thermal efficiency, exhaust gas temperature, mass flow rate of fuel and exhaust gases are computed for three types of prime movers. After determining the optimum value of number and nominal power of prime mover(s), the operational strategy of each type of prime mover in CHP system is analyzed.

The Quest for More Efficient Industrial Engines: A Review of Current Industrial Engine Development and Applications

2007 ◽  
Author(s):  
Barry Cullen ◽  
Jim McGovern
Keyword(s):  
Power Generation ◽  
Distributed Generation ◽  
Combustion Engine ◽  
Electrical Power ◽  
Primary Energy ◽  
Combined Heat And Power ◽  
Successful Implementation ◽  
Efficiency Defect ◽  
Electrical Demand ◽  
A Site

The paper addresses the need for efficiency gains in the modern industrial engine as utilized in Combined Heat and Power (CHP) generation and other Distributed Generation (DG) situations. Power generation is discussed in terms of reciprocating-engine-based plant operating on Otto type thermodynamic cycles. The current state of the technology and the research being conducted is examined. Internal combustion engine (ICE) performance improvement in the industrial engine sector focuses on improvements in the combustion characteristics of the plant, with emphasis on areas such as piston design, valve timing and supercharging. Maximum brake thermal efficiencies, in percentage terms, are currently in the forties. In CHP generation, most of the energy not utilised for mechanical power is recovered as heat from various engine systems such as jacket water and exhaust and utilised for space or process heating. In other Distributed Generation situations, this energy is not utilised in this manner and is lost to the surroundings. While second law analysis would provide a more meaningful interpretation of the efficiency defect, this approach is still not the norm. Distributed Generation benefits directly from efficiency improvements; the more efficient use of primary energy leads to reduced fuel costs. Combined Heat and Power generation is, however, more sensitive to the matching between the plant and its energy sinks, as its successful implementation is dictated by the ability of a site to fully utilise the heat and electrical power produced by the plant. At present, the energy balance of such engines typically dictates that heat is produced in greater quantity than electrical power, the ratio being of the order of 1.1 — 1.5: 1. Due to this production imbalance, it is accepted that in order to be economically feasible, thermal and electrical demand should be coincident and also all heat and power should be utilised. This has traditionally led to certain sectors being deemed unsuitable for CHP use. Some current research is aimed at tipping the production balance of these engines in favour of electrical power production; however, performance gains in this regard are slow. The paper concludes with some brief commentary on current industrial engine developments and applications and proposes some directions for progress.

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