A techno-economic optimization model of a biomass-based CCHP/heat pump system under evolving climate conditions (original) (raw)
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Applied Energy, 2009
Optimization of combined cooling, heating, and power (CCHP) systems operation commonly focuses only on energy cost. Different algorithms have been developed to attain optimal utilization of CCHP units by minimizing the energy cost in CCHP systems operation. However, other outcomes resulting from CCHP operation such as primary energy consumption and emission of pollutants should also be considered during CCHP systems evaluation as one would expect these outcomes can be subject to regulation. This paper presents an optimization of the operation of CCHP systems for different climate conditions based on operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE) using an optimal energy dispatch algorithm. The results for the selected cities demonstrate that in general there is not a common trend among the three optimization modes presented in this paper since optimizing one parameter may reduce or increase the other two parameters. The only cities that show reduction of PEC while also reducing the CDE are Columbus, MS; Minneapolis, MN; and Miami, FL. For these cities the operational cost always increases when compared to the reference case consisting of using a vapor/compression cycle for cooling and natural gas for heating. On the other hand, for San Francisco and Boston, CCHP systems increase the CDE. In general, if CCHP systems increase the cost of operation, as long as energy savings and reduction of emissions are guaranteed, the implementation of these systems should be considered.
CCHP System Performance Based on Economic Analysis, Energy Conservation, and Emission Analysis
Energy Systems and Environment, 2018
This chapter includes the basic configuration of combined cooling heat and power (CCHP) systems and provides performance analysis based on energy, economic and environmental consideration applicable to buildings. The performance parameter for energy savings measure used for the analysis is primary energy consumption (PEC) of CCHP system. Parameters used for economic analysis are the simple payback period (SPP), annual savings (AS), internal rate of return (IRR) and equivalent uniform annual savings (EUAS). The emissions savings are determined for carbon dioxide (CDE), nitrogen oxides (NO X), and methane (CH 4). Economic, energy, and emission performance criteria have been utilized for three types prime movers in five different building types, consisting of a primary school, a restaurant, a small hotel, an outpatient clinic, and a small office building. Performance for economic analysis indicated that economic savings career, unlike ICE, which is preferable in terms of economic and energy savings, emission analysis shows that micro-turbine poses be observed for the ICE in all building types, and the micro-turbine in some building types. For all types of prime mover based CCHP systems, lower CO 2 emission is observed for all building types. However, emission characteristics compared to other types of prime movers. Overall, CCHP system with optimum use of its appropriate prime movers can provide potential energy, economic and environmental benefit in buildings.
Energy Conversion and Management, 2006
The optimization of design and operation of Combined Heat, Cooling and Power systems usually leads to select different plant lay-outs and size of components, depending on the adopted optimization criterion (maximum profit or energy saving or minimum environmental impact). This occurs when the current energy prices and the normative provisions supporting cogeneration are not able to make coincident the specific customer's interest with the overall "social interest" for a reduction in energy consumption and in pollutants' emissions.At EU level, polygeneration is considered to have a large potential for residential and commercial buildings district network, for the tertiary sector and for industrial applications. In such applications, it is often convenient to integrate the trigeneration system with a reversible heat pump, because of a low ratio between electric demand and that for heating and cooling. In this paper the design and operation of such hybrid systems is discussed. The results achievable through different operation modes are compared and, with reference to a 600-rooms hotel and a 300-beds hospital in Italy, the effects on plant design from an hour-by-hour optimization of plant operation are assessed. Finally, the need for a flexible support system for cogeneration plants is put into evidence and some criteria are listed for an effective regulation.
Energies, 2018
In recent years there has been an increasing interest in the incorporation of distributed energy resource (DER) systems such as combined heat and power (CHP) and combined cooling, heating, and power (CCHP) in commercial building applications as they have shown considerable environmental and financial benefits when compared to conventional energy generation. This paper aims to investigate the potential energy, carbon emissions, and financial impact of the size of co/tri-generation systems on a real case scenario of an existing UK hotel. The analysis is carried out using Thermal Analysis Simulation software (TAS) and a payback methodology is adopted to carry out the financial analysis. The results show that the average percentage decrease in carbon emissions with CHP is 32% and with CCHP it is 36%. Whilst both CHP and CCHP systems increase energy consumption in the building, the costs are reduced, and a CHP system contributes to a higher percentage of cost savings and shorter payback periods. The incorporation of a CCHP system leads to lower energy consumption for a similar-sized CHP system. Further simulations under future climate projections revealed that a CCHP system outperforms a CHP system.
Energy, 2015
This paper presents a methodology to optimize the size (electric power) of a cogeneration plant based on a biomass-fired Organic Rankine Cycle and connected to an existing district heating network, maximizing profitability. First, a model to determine the hourly thermal energy demand profile of a location in Spain has been derived, from open access meteorological data included in Spanish building regulations. Partial load model of an organic Rankine plant has also been obtained to increase the operation hours. These tools have been applied to two locations in Spain with different climatic severities, calculating the optimal size of the plant. The business model does not include subsidies. Calculations show that for population between 10,000 and 20,000 inhabitants the size of the plant ranges from 2 to 9 MWe and the internal rate of return ranges from 6% to 18%. The coverage of the thermal energy demand ranges from 40% to 80%. Regarding the trigeneration mode, it is concluded that cooling is only worth in locations with high summer severity and in full load operation mode, being the optimal size of the plant smaller in trigeneration mode than in cogeneration.
Impact of micro-CHP systems on domestic sector CO2 emissions
Applied Thermal Engineering, 2005
The effects of applying combined heat and power systems, based on Stirling engines and fuel cells, to single UK dwellings are investigated by using heat and power demand data recorded on a 1-min time base across a full year. The control regime has a major influence upon economic and CO 2 savings for Stirling engine systems due to their high heat-power ratio. For the considered home, the contributions made by a 1 kW e Stirling engine system to the daily demands for heat and power ranged from 54% to 100% and from 3% to 73% respectively. Future systems based on fuel cells are predicted to achieve greater savings, because they can operate for relatively long periods during mild and warm weather without generating surplus heat. Estimates of the annual savings amount to £90/574 kg CO 2 for a 1 kW Stirling engine system and £142/ 892 kg CO 2 for a prospective 1 kW fuel cell system, when compared to a non-CHP base case of employing a condensing boiler of 90% efficiency and network electricity. These respective savings represent 9% and 16% of emissions attributable to the single UK dwelling, which is highly significant relative to other individual measures that can be deployed in the domestic sector.
Applied Energy, 2016
The aim of this paper is to assess the performance of several designs of hybrid systems composed of solar thermal collectors, photovoltaic panels and natural gas Internal Combustion Engines. The software TRNSYS 17 has been used to perform all the calculations and data processing, as well as an optimisation of the tank volumes through an add-in coupled with the GENOPT® software. The study is carried out by analysing the behaviour of the designed systems and the conventional case in five different locations of Spain with diverse climatic characteristics, evaluating the same building in all cases. Regulators, manufacturers and energy service engineers are the most interested in these results. Two major contributions in this paper are the calculations of primary energy consumption and emissions and the inclusion of a Life Cycle Cost analysis. A table which shows the order of preference regarding those criteria for each considered case study is also included. This was fulfilled in the interest of comparing between the different configurations and climatic zones so as to obtain conclusions on each of them. The study also illustrates a sensibility analysis regarding energy prices. Finally, the exhaustive literature review, the novel electricity consumption profile of the building and the illustration of the influence of the cogeneration engine working hours are also valuable outputs of this paper, developed in order to address the knowledge gap and the ongoing challenges in the field of distributed generation.
Analysis of CO2 reduction with micro CHP facility: Renewable energies and Stirling engine
E3S Web of Conferences, 2021
The Cogeneration laboratory is a research facility in the University of Málaga (UMA) that allows for the behavioural study of a renewable energy installation combining solar resources and micro-CHP. Energy generation in the system is provided by a 3 kWp photovoltaic array, two solar thermal connectors and a Whispergen EU1 Stirling micro-CHP unit. Energy storage in the facility is provided by water tank and lithium-ion battery. This laboratory is managed through a programmable Mitsubishi PLC that permits the simulation of different thermal and electrical load profiles, as well as the mode of operation. The electrical energy management is controlled by the solar inverter. Environmental data, are measured using a top of the line weather station.The system’s real time status is logged through the programmable PLC. All this data is transferred and analysed in a purpose-built MATLAB-based software, where power and energy balances are conducted, efficiencies are calculated, and a CO2 emiss...