Combined Heat And Power Applications Research Articles

Semi-Closed Oxy-Combustion Combined Cycles (SCOC-CC) for Com-Bined Heat And Power Applications

Abstract This study focuses on the design and comparison of three utility-scale combined heat and power (CHP) cycles with carbon capture and storage (CCS): (i) a CHP semi-closed oxy-combustion combined cycle (SCOC-CC), (ii) a CHP natural gas combined cycle (NGCC) with post-combustion CCS, and (iii) a CHP NGCC with post-combustion CCS and supplementary firing. Performance evaluations are conducted at the design point and partial load (gas turbine at 30%) for different exports of high-temperature pressurized steam. The comparison is extended against two reference separate production systems with CCS, one based on post-combustion technologies, and another based on oxy-combustion. Simulations of the H-class gas turbines are performed using GS, a specific in-house validated software, while the heat recovery steam cycle is modelled using Thermoflex. The CO2 capture processes employ validated models in Aspen Plus. The results highlight the suitability of the SCOC-CC for CHP applications, demonstrating superior performance and flexibility compared to CHP post-combustion technologies at both nominal and minimum loads. The SCOC cycle achieves a maximum first-law efficiency of 65.95%, outperforming CCS technologies that generate electricity and heat separately and enabling fuel savings up to 9.2%.

Feasibility analysis of circular economy-based biogas plants for Indian cattle shelters

The present study evaluates the design and techno-economic potential of circular economy-based biogas plants for Indian cattle shelters for combined heat and power (CHP) and compressed biomethane gas (CBG) applications. The biodigester is designed based on available dung, and the economic performance is evaluated using the net present value (NPV) method. For small shelters (500 cattle), the framework showed an NPV of US $0.089 million for CHP and US $0.07 million for CBG. For large shelters (5000 cattle), the framework showed an NPV of US $2.78 million for CHP and US $2.80 million for CBG. Availability of dung, discount rate, and the market price of solid fertilizers significantly influence the NPV of the biogas plant. The GHG emission analysis shows that CHP application has lower emissions than CBG application, particularly for bigger plant. It is recommended to build biogas plants inside or near cattle shelters with a minimum dung availability of 2.25 t/day for both applications.

Decarbonization potential of regional combined heat and power development

Industrial decarbonization is a significant challenge to national net zero goals. Combined heat and power (CHP) technologies provide a means by which industrial facilities can achieve greater energy efficiency and decrease carbon emissions through cogenerating electric power and process heat. Regions possessing sufficient population density and manufacturing capacity have significant technical potential for industrial CHP development and can experience economic and environmental benefits. However, CHP implementation costs and the complexity of projects represent significant barriers to deployment with successful implementation often relying on government incentives to achieve economic feasibility. In this research, a framework is developed to evaluate the economic feasibility and environmental viability of various CHP technical potential under the various market penetration scenarios. A case study for a region in the United Sates is presented to highlight the efficacy of the framework. Projected CHP generating capacity of the region is calculated using commercial and industrial specific capacity factors. Comprehensive CHP engineering and cost data are integrated with regional economic transaction data. Then, comparative CHP application analysis is performed to determine which configuration could have the greatest regional economic and environmental impacts. Results indicated that investment in industrial topping cycle CHP to achieve the maximum technical potential generating capacity would have the greatest regional impacts resulting in $20 billion of economic outputs, creating 89,000 jobs, and avoiding approximately 3.2 million metric tons of carbon dioxide emissions. Results from this and similar research may be used by policymakers and administrators to assess potential investments in industrial decarbonization technologies and pathways.

Theoretical study of a downdraft gasifier, microturbine, and organic Rankine cycle fuelled by date molasses waste for distributed generation applications in Iraq

AbstractThe main objective of this work is the modeling of a combined heat and power (CHP) system that transforms waste from manufacturing date molasses in the Babylon province in central Iraq into electrical and thermal energy. A compact CHP facility that uses date waste (pomace and pits) as a feedstock is the subject of theoretical modeling and simulation research. The planned power plant consists of a downdraft gasifier, a microturbine (MT), and an organic Rankine cycle engine (ORC) as a bottom unit to maximize electric generation by recovering the MT exhaust gas heat and achieving a maximum electric output. The net electric production is 361.68 kW (280 kW from the MT unit and 81.68 kW from the ORC unit). To determine the best‐working fluid for the ORC system as a whole, three working fluids, including isopentane, benzene, and R113, were investigated. The temperature difference between the heat source and the fluid's boiling point is a key factor in choosing a more appropriate ORC working fluid. Isopentane is the most suitable working fluid for CHP applications, according to the findings of the simulation. The electric efficiency achieved is 30%, and the overall efficiency of the CHP plant was 56.87% from the gasification of date pits. The simulation results showed a satisfactory producer gas lower calorific value of 3.92 MJ k‐g‐1 for date pomace and 4.65 MJ k‐g‐1 for date pits, and cold gasification efficiencies of 73% and 76% for pomace and pits, respectively. © 2023 Society of Industrial Chemistry and John Wiley & Sons Ltd.

Optimizing Internal Energy Streams in Micro Gas Turbines in Cogeneration toward Flexible Heat-to-Power Ratio—Global Thermodynamic Performance Assessment and Specific Case Studies

Abstract Although the simultaneous production of heat and power, the so-called combined heat and power (CHP), is from a thermodynamic point of view still the most efficient energy conversion method, cogeneration units have nowadays problems to position themselves in the current and future energy market. The increasing renewable energy penetration requires CHP units to become more flexible, especially on their currently fixed heat-to-power ratio. Within this framework, micro-gas turbines (mGTs), as small-scale decentralized cogeneration units, offer opportunities. Since they use the recuperated Brayton cycle, they offer the theoretic option to adjust the internal heat streams to provide a flexible heat-to-power ratio as well as the unique feature of a tunable outlet temperature, making the unit feasible/interesting for a larger range of applications having a combined heat and power demand. Hence, in this paper, we assessed the impact of the use of a recuperator bypass for enhanced operational flexibility of mGT. In a first step, the optimal pathway for the recuperator bypass, i.e., cold or hot side bypass, is selected for a typical mGT, the Turbec T100 (currently commercially available as the AE-T100), considering both thermodynamics as well as technological feasibility. Moreover, the potential performance impact on the electrical and total efficiency is calculated as well as on the total available thermal power. In a second step, the specific performance of the option of using a recuperator bypass is assessed for two specific cases: flexible heat-to-power ratio at low temperature and high temperature, i.e., steam generation, cogeneration. Thermodynamic simulations show that the impact on the electric efficiency remains rather limited (maximal 6% absolute efficiency reduction for a 40% bypass ratio), while the available thermal energy and exergy increase significantly: up to 60% increase for thermal power and even 115% increase in the exergy content of the flue gases. Moreover, there is no distinct difference between cold or hot bypass, leaving the selection of the optimal bypass route a pure technical choice. Finally, considering the specific cases studied, simulation results show that heat-to-power ratio could be increased by more than 50% for all power outputs for the low temperature CHP applications, even resulting in a global efficiency increase, while for the high temperature case, recuperator bypass allows for a significant increase in steam production, at total efficiencies comparable to the separate production (i.e., boiler and grid), clearly highlighting the benefits and potential of a recuperator bypass.

Experimental evaluation of an ORC-CHP architecture based on regenerative preheating for geothermal applications

The Organic Rankine Cycle (ORC) can be applied to generate power from low-temperature heat sources and thus supports a sustainable energy system. This paper contributes to ORC development, particularly for geothermal applications, to increase competitiveness of the technology. To this end, new plant architectures based on regenerative preheating are being investigated. The concept of regenerative preheating is investigated in literature by numerical studies and its thermodynamic and economic performance is predominantly evaluated positively. However, regenerative preheating has not yet been realized in experimental ORC test rigs or commercial products. For this purpose, a novel ORC test rig is designed, constructed and commissioned. For evaluation purposes, the regenerative preheating concept is compared to a standard ORC configuration. As a result, a 9.9% higher net thermal efficiency is achieved with regenerative preheating, while the net power output is equal to the one achieved with the standard configuration. This result is particularly important for combined heat and power (CHP) generation due to the reduced cooling of the heat source. In order to evaluate this concept for CHP applications, a novel ORC-CHP architecture based on regenerative preheating is experimentally compared to three state-of-the-art ORC-CHP concepts. Moreover, three different supply and return temperatures of the district heating system (DHS) are considered. The results reveal that the novel architecture, in combination with low- and medium-temperature DHS, leads to an increased part-load performance and a wider operating range. This enables up to 9.4% increase in annual net electricity production, which accounts for additional revenues of 4.56million € in the case of a typical geothermal project. Thus, it can be concluded that this novel ORC-CHP architecture is beneficial from a technical perspective and also promising in terms of economics.

Latent heat thermophotovoltaic batteries

<h2>Summary</h2> Latent heat thermophotovoltaic (LHTPV) batteries store electricity as latent heat at very high temperatures (>1,000°C) and convert this heat back to electricity on demand using thermophotovoltaics (TPVs). In this study, we discuss the techno-economics of LHTPV systems, focusing on parameters such as the round-trip efficiency, energy-to-power ratio, cost per energy and power capacities, and levelized cost of storage. The very low cost of the heat storage media (<4 €/kWh) results in optimal designs with high energy-to-power ratios, fitting long-duration storage (LDS) applications. Shorter-duration storage applications are also possible by increasing the overall round-trip conversion efficiency through cogeneration, that is, combined heat and power (CHP) generation. Results indicate that LHTPV systems can provide lower levelized cost of storage than Li-ion batteries in both LDS and CHP applications. Preliminary experimental results are provided to illustrate the real operation of a LHTPV system.

Systematic Comparison of ORC and s-CO2 Combined Heat and Power Plants for Energy Harvesting in Industrial Gas Turbines

Gas turbine power plants are widely employed with constrained efficiency in the industrial field, where they often work under variable load conditions caused by variations in demand, leading to fluctuating exhaust gas temperatures. Suitable energy harvesting solutions can be identified in bottoming cycles, such as the conventional Organic Rankine Cycles (ORC) or the innovative supercritical CO2 (s-CO2) systems. This paper presents a detailed comparison of the potential of ORC and s-CO2 as bottomers of industrial gas turbines in a Combined Heat and Power (CHP) configuration. Different gas turbine models, covering the typical industrial size range, are taken into account and both full- and part-load operations are considered. Performance, component dimensions, and operating costs are investigated, considering ORC and s-CO2 systems specifics in line with the current state-of-the-art products, experience, and technological limits. Results of the study show that the s-CO2 could be more appropriate for CHP applications. Both the electric and thermal efficiency of s-CO2 bottoming cycle show higher values compared with ORC, also due to the fact that in the examined s-CO2 solution, the cycle pressure ratio is not affected by the thermal user temperature. At part-load operation, the gas turbine regulation strategy affects the energy harvesting performance in a CHP arrangement. The estimated total plant investment cost results to be higher for the s-CO2, caused by the higher size of the heat recovery heat exchanger but also by the high specific investment cost still associated to this component. This point seems to make the s-CO2 not profitable as the ORC solution for industrial gas turbine heat recovery applications. Nevertheless, a crucial parameter determining the feasibility of the investment is the prospective carbon tax application.

Short Circuit Characteristics of PEM Fuel Cells for Grid Integration Applications

The reduction of greenhouse gas and pollutant emissions is a major issue in modern society. Therefore, environmentally friendly technologies like fuel cells should replace conventional energy generation plants. Today, fuel cells are used in households for CHP (combined heat and power) applications, for emergency power supply in many stationary applications and for the power supply of cars, buses and ships and emergency power supply of aircrafts. A significant challenge is the optimal electrical grid integration and selection of the appropriate grid protection mechanism for fuel cell applications. For this, the short circuit capability and behavior needs to be known. This paper gives a mathematical estimation of the short circuit behavior of fuel cells. Five main transient and dynamic phenomena are investigated. The impact of the main transient effect for the provision of additional short circuit energy is simulated, and the simulation is experimentally validated. For this purpose, a 25 c m 2 single cell consisting of a NafionTM 212 membrane and carbon cloth electrodes with a catalyst loading of 0 . 5 m g / c m 2 Pt is analyzed. The magnitude of the transient short circuit current depends on the operating point right before the short circuit occurs, whereas the stationary short circuit current of fuel cells is invariably about twice the operational current. Based on these results, a novel fuel cell model for the estimation of the short circuit behavior is proposed.

Investigation of real-time flexibility of combined heat and power plants in district heating applications

Denmark has the ambitious goal of achieving 100% renewable electricity and heating sectors by 2035. Coupling these two energy sectors, combined heat and power (CHP) plants play an important role in providing flexibility in terms of economic dispatch of heat production and balancing power systems with high penetration of intermittent renewable like wind power. In this paper, a twofold flexibility potential of different CHP applications in the Danish district heating systems was investigated and compared based on a proposed two-stage optimal dispatch model. In the first stage, the heat production plan of a CHP plant was derived to minimize the system heat cost in a deregulated heat market by using its flexibility; in the second stage, the CHP plant was redispatched to provide real-time balancing service with the remaining flexibility. The diversified applications include different types of CHP plant, various operation modes, and the inclusion of heat accumulator (HA) or not. A case study using information collected from Denmark was presented to validate the proposed algorithm and to quantitatively illustrate the flexibility difference of various CHP applications in real time. The results provide a practical guide to activities aiming to take advantage of the flexibility potential of CHPs for both minimizing the heat cost and balancing a local energy portfolio.

Modeling and Simulation of Corn Stover Gasifier and Micro-turbine for Power Generation

This paper focuses on modeling the performance of a small-scale combined heat and power (CHP) plant fueled with corn stover pieces (CSP) as very potential biomass resource in Egypt. The developed power plant can be used to satisfy the heat and electricity needs. The proposed power plant performance is simulated using the professional Cycle-Tempo® software. The power plant is divided into three stages; the gasification unit (downdraft fixed bed gasifier and air supply system), gas cleaning and cooling units and the micro-turbine (MT) as an electrical generation unit. In the first stage, the CSP feedstock is converted to producer gas at atmospheric pressure with a reaction temperature about 1028.6 °C, using air as a gasifying agent. The efficiency of gasification process at a regulated air–biomass ratio of 1.5 kg/kg is 77.92% with calorific value (LHV) of 3.87 MJ/kg. Cleaning and cooling stage used to dispose the undesirable gas constitutes such as; tar, flying ash, and etc. The clean gas is passing through the MT as power generator for CHP applications with turbine inlet temperature of 850 °C. Ultimately, the simulation revealed that the CHP overall efficiency of this developed plant is 63.21% providing an electrical power of 94.81 kWel and thermal power of 187.55 kWth.

Thermodynamic modeling of solarized microturbine for combined heat and power applications

Combined heat and power (CHP) plants utilize exhaust heat from thermal-based power generators to increase system efficiency beyond electrical efficiency alone. Many existing CHP systems use fossil-fueled generators to create electrical power for retail sale or on-site industrial or commercial uses. This study develops, validates, and exercises a quasi-steady state thermodynamic model of a 100 kWe/165 kWt rated microturbine that has been coupled with a concentrating solar power (CSP) tower to offset natural gas consumption. Exhaust heat is rejected at approximately 270 °C for CHP applications. Governing equations developed for eight components incorporate manufacturer data and empirical data to describe system-level operation with respect to intraday variation in the solar resource. Model validation at ISO conditions shows electric output of the simulated system is within 1.6% of the as-built system. Simulation results of the complete solarized system gave 31.5% electrical efficiency, 83.2% system efficiency, 99.5 kWe electrical power, and 163.5 kWt thermal power at nominal operating conditions for a DNI of 515 W/m2. The thermodynamic model is exercised under rated electrical load (base loading) and variable electrical load (load following) conditions with performance measured on 13 operating characteristics. Sensitivity analyses evaluate changes in performance with respect to operating variables (e.g., turbine inlet temperature) and environmental variables (e.g., elevation). Results show that a CSP plant with solarized microturbine can meet target performance specifications of a non-solarized microturbine (pure natural gas). Annual time series simulations completed for Phoenix, Arizona, USA indicate a solarized microturbine can reduce natural gas use by 26.0% and 28.4% when supplying rated power and variable power output, respectively. Annual operating time of the solarized microturbine at rated capacity included 59.8% fuel only, 12.4% hybrid, and 27.8% solar only modes for the selected study location.

Carbon Clean Combined Heat and Power Production from micro Gas Turbines: Thermodynamic Analysis of Different Scenarios

With the current shift towards more decentralized power production, micro Gas Turbines (mGTs) appear as a promising technology for small-scale Combined Heat and Power (CHP) production. Nevertheless, if we want to move towards a carbon-clean power production, the CO2 in the exhaust gas must be captured. In this context, mGTs coupled with a Carbon Capture (CC) plant might be a good candidate, however there is still an energy penalty. Especially when there is no demand for heat and the mGT is only producing electrical power, this penalty becomes a major drawback. In this case, a possible solution is waste heat recovery in the system to increase the efficiency or to reduce the energy penalty, but few analyses are available to assess the optimal solution. In this paper, we aim at identifying the optimal strategy for carbon clean mGT operation in CHP applications for different operation scenarios: full CHP mode and operation with no thermal load. The effect of different technological measures such as humidification and internal heat recoveries has been investigated. The goal of these simulations was to evaluate the most efficient strategy for each thermal scenario of the mGT by testing different combinations of the previous measures. Results show that full CHP operation of the mGT with carbon capture has still the highest performance. Nonetheless, if the thermal demand is zero, conversion into mHAT and heat recovery for the stripping process result in a sensible reduction of the CC plant energy penalty, moving closer to the efficiency of traditional mGTs. Future work would include a more detailed analysis concerning mixed operation (part-load heat demand) of the mGT and an exergy analysis to identify where more waste heat can be recovered.

Integration of an Organic Rankine Cycle and a Photovoltaic Unit for Micro-Scale CHP Applications in the Residential Sector

The purpose of this work is to analyse the performance of a novel system for combined heat and power (CHP) generation in small-scale applications. The system is based on an Organic Rankine Cycle (ORC) fed with biomass and a photovoltaic (PV) unit. The ORC and PV sub-systems operate in parallel to produce the required electrical energy. A preliminary investigation is performed to define the proper size of the photovoltaic unit. Afterwards, the analysis is focused on the hybrid system and a comparison between the two configurations is carried out.This work demonstrates the potential for integrating biomass and solar energy resources: during daylight, solar radiation is significant and the ORC system can be switched off or operated at partial load. Furthermore, the adoption of biomass makes it possible to overcome the intermittency of solar resource, increase the self-consumed electrical energy, and produce thermal energy, thereby saving natural gas for heating purposes.

Economic and environmental assessment of phosphoric acid fuel cell-based combined heat and power system for an apartment complex

Economic and environmental potential of medium-scale combined heat and power (CHP) systems in the residential sector was assessed by introducing a 400 kWel-scale phosphoric acid fuel cell (PAFC)-based CHP system into an apartment building in New York City. Simulation-based analyses were carried out under two different CHP operation strategies; electrical-load-following (ELF) and thermal-load-following (TLF). Technical and economic analyses indicated that ELF would be the appropriate operation mode for this CHP application. Economic analysis indicated that the CHP/ELF system operation could economically benefit users within 10 years under the present grid prices in New York City. However, because the CO2 emission factor of the NY grid is very low (300 g/kWh), the CHP/ELF system operation would increase CO2 emission. Achieving carbon neutrality in this application thus requires improvement in the utilization ratio of recovered heat.

Modeling and techno-economic analysis of the integration of a FC-based micro-CHP system for residential application with a heat pump

This work aims to analyse the techno-economic performance of an integrated system for a residential CHP (Combined Heat and Power) application, based on the integration of a Fuel Cell (FC) micro-cogeneration device coupled with an Heat Pump (HP).The main components of the system are: the Fuel Cell unit, the Heat Pump and the thermal storage – required to cover the thermal peaks, mainly due to the domestic hot water demand. The analysis will be focused on the most diffused FC technologies for residential applications: a low temperature Polymer Electrolyte Membrane Fuel Cell (PEMFC) and a high temperature Solid Oxide Fuel Cell (SOFC).FC-based cogeneration systems usually produce an electric power surplus respect to the thermal production, because of their high electrical efficiency. Currently, however, the households heating load exceeds significantly the electricity requirements, thus making difficult the sizing of a FC system for a single family house without including large electrical and thermal storages or high grid/boiler integration. The combination of a Fuel Cell and an Heat Pump has been found to be an optimal solution to manage this problematic while achieving a reduction in the primary energy consumption and avoiding energy overproduction.In the proposed scenario the heat is exploited by feeding both the domestic hot water and a low-temperature radiant floor heating system operating between 35 °C and 45 °C.An energy and economic analysis has been performed to understand and to evaluate the plant feasibility.Results have pointed out that the best economic choice, with the current energy tariff scenario, is related to a small size FC-based CHP system able to produce enough electrical power to feed the HP plus a low electrical consumption (<1 kW electrical size), which corresponds to the base electrical household consumption (the electrical power which is near-always requested by the house). The electrical load is in fact deeply changing during the day (with one-minute variable peaks) and with a higher electrical production from the FC, most of the electrical power would be sold to the grid without no energy advantages.The best PEMFC configuration was able to reach a total efficiency of 75%: if compared to the case with separated energy generation (electricity from the grid and heat from a boiler) the saving is estimated in three years of payback for the current scenario (2015).With the SOFC system, thanks to its higher total efficiency equal to 81%, the primary energy consumption was reduced (−30% respect to PEMFC) with a consequent reduction in the operating costs. However, from an economic point of view, the payback still results extended because of its not competitive investment cost.

Energy versus economic effectiveness in CHP (combined heat and power) applications: Investigation on the critical role of commodities price, taxation and power grid mix efficiency

Starting from PES (primary energy saving) and CSR (cost saving ratio) definitions the work pinpoints a “grey area” in which CHP (combined heat and power – cogeneration) units can operate with profit and negative PES. In this case, CHP can be profitably operated with lower efficiency with respect to separate production of electrical and thermal energy. The work defines the R-index as the ratio between the cost of fuel and electricity. The optimal value of R-index for which CHP units operate with both environmental benefit (PES > 0) and economic profitability (CSR > 0) is the reference value of electrical efficiency, ηel_ref, of separate production (national power grid mix). As a consequence, optimal R-index varies from Country to Country. The work demonstrates that the value of R corresponds to the minimum value of electrical efficiency for which any power generator operates with profit. The paper demonstrates that, with regard to the profitability of cogeneration, the ratio between the cost of commodities is more important than their absolute value so that different taxation of each commodity can be a good leverage for energy policy makers to promote high efficiency cogeneration, even in the absence of an incentive mechanism. The final part of the study presents an analysis on micro-CHP technologies payback times for different European Countries.

A Comparative Study of Open and Closed Heat-Engines for Small-Scale CHP Applications

In this paper the authors compare and contrast open and closed-cycle heat engines. First of all, by way of example and to aid discussion, the performance of proprietary externally heated closed-cycle Stirling engines is compared with that of internally heated open Otto cycle engines. Both types of engine have disadvantages and merits and this suggested that in order to accommodate the best of both engine types an externally-heated open-cycle engine might offer a more satisfactory solution for small-scale combined heat and power (CHP) systems. To investigate this possibility further the paper goes on to compare the performance of externally-heated and recuperated Joule hot-air cycle engines with that of an externally-heated closed Stirling cycle engines. The results show that an externally heated recuperated open Joule cycle engine can exceed that of a closed cycle Stirling engine operating between the same heat source and sink temperatures when a variable temperature heat source is used.

Emission and economic performance assessment of a solid oxide fuel cell micro-combined heat and power system in a domestic building

Combined heat and power (CHP) is a promising technological configuration for reducing energy consumption and increasing energy security in the domestic built environment. Fuel cells, on account of their: high electrical efficiency, low emissions and useful heat output have been identified as a key technological option for improving both building energy efficiency and reducing emissions in domestic CHP applications. The work presented in this paper builds upon results currently reported in the literature of fuel cells operating in domestic building applications, with an emission and economic performance assessment of a real, commercially available SOFC mCHP system operating in a real building; under a UK context.This paper aims to assess the emission and economic performance of a commercially available solid oxide fuel cell (SOFC) mCHP system, operating at The University of Nottingham's Creative Energy Homes. The performance assessment evaluates, over a one year period, the associated carbon (emission assessment) and operational costs (economic assessment) of the SOFC mCHP case compared to a ‘base case’ of grid electricity and a highly efficient gas boiler.Results from the annual assessment show that the SOFC mCHP system can generate annual emission reductions of up to 56% and cost reductions of 177% compared to the base case scenario. However support mechanisms such as; electrical export, feed in tariff and export tariff, are required in order to achieve this, the results are significantly less without. A net present value (NPV) analysis shows that the base case is still more profitable over a 15 year period, even though the SOFC mCHP system generates annual revenue; this is on account of the SOFC's high capital cost. In summary, grid interaction and incubator support is essential for significant annual emission and cost reductions compared to a grid electricity and gas boiler scenario. Currently capital cost is the greatest barrier to the economic viability of the system.

Customer-side electricity load management for sustainable manufacturing systems utilizing combined heat and power generation system

Customer-side electricity load management can effectively improve the reliability of electricity grid and reduce the cost of electricity for customers. Combined heat and power (CHP) generation systems have been considered a promising method to implement electricity load management and have been widely applied in commercial and residential building sectors. Recently, the benefit of CHP application in electricity load management in industrial sector has also been gradually recognized. On-site generated electricity by a CHP system can be utilized to support the operation of industrial equipment and thus the cost of electricity purchased from the grid can be reduced. In this paper, we focus on the utilization of CHP in electricity load management for industrial manufacturing systems to examine the benefits regarding cost savings for the manufacturers. The optimal schedule for both the manufacturing and the CHP systems under a Time-of-Use (TOU) electricity tariff can be identified by minimizing the electricity billing cost and CHP operation cost under the constraint of production throughput. Mixed-Integer Nonlinear Programming (MINLP) formulation is developed to model this scheduling problem mathematically. Particle Swarm Optimization (PSO) is used to find a near optimal solution for the problem with a reasonable computational cost. A numerical case study is used to illustrate the effectiveness of the proposed method.