Micro-CHP systems for residential applications[edit | edit source]
Michel De Paepea, Peter D'Herdta, David Mertensb
This paper focuses on the analysis of the operational parameters of 3 types of micro-CHP systems for residential use. For each building type, the energy demands for electricity and heat are dynamically determined. Economic analysis were done on different technologies. Data were obtained for two commercially available gas engines, two Stirling engines and a fuel cell.
NOTES[edit | edit source]
The CHP unit concept is using the waste heat for heating purpose. Using CHP unit will not only provide heat to the building but will also provide electricity. Performance, flexibility and operational requirements were considered under all possible operating conditions, both under grid connected and stand alone configurations.
CHP technology[edit | edit source]
- Five micro-CHP systems are evaluated for use in residential applications.
- Load profiles for two different families were considered. In the present case DOE 2.5 was used for doing this analysis.
- The CHP unit that was studied are:
a) Two CHP units using gas engine, running on natural gas.
b) Two CHP units using sterling engine, running on any fuel.
c) CHP unit using Fuel cell, running on hydrogen gas using natural gas.
Primary Energy[edit | edit source]
- Calculation for primary energy savings, CO2 emission reduction and the financial savings for different configuration are taken into consideration.
- Three different cases were considered for comparison:
a)The electricity is produced by a combined cycle gas/steam turbine plant. The efficiency is about 53-56%.
b)Electricity produced form fuel cell power plant. The average efficiency is 42%.
c)Electricity produced from nuclear power plant. The average efficiency is 37%.
- The CHP strategy is used to meet the heat requirement. Excess electricity is generated is fed back into the grid. To calculate the primary energy use, the electricity sold to the grid is deducted from the total amount used.
CO2 emission[edit | edit source]
- Electricity produced from CHP unit is about 50%. The lowest CO2 emission is emitted by CHP using natural gas.
- From the graph it can be observed that the average CO2 produced by the fossil fuel is much higher than using CHP technologies.
Energy saving[edit | edit source]
- From all the simulation results the the electrical and heat demand can be obtained.
- From the data obtained the maximum energy saving by various CHP modules can be determined.
Economics: Profit[edit | edit source]
- CHP module: Investment and Maintenance cost.
- Electricity purchasing and selling price. Even gas purchase price is considered.
- Annual profit:
Annual profit is the sum of:
- The money received for the electricity which is sold to the grid.
The following amount is subtracted from the annual profit:
- The maintenance costs.
- The extra cost due to the extra amount of gas used.
Conclusion[edit | edit source]
- The CO2 emission is reduced.
- Stirling engine is the best technology for the CHP.
Optimal sizing of renewable energy and CHP hybrid energy microgrid system[edit | edit source]
Yanhong Yang ; Grad. Univ. of Chinese Acad. of Sci., Beijing, China ; Wei Pei ; Zhiping Qi
The paper mainly focuses on a method for optimal sizing renewable energy generations and combined heat and power (CHP) units in a hybrid energy microgrid. A microgrid system, which was based on hourly energy balance and can meet customer requirements with minimum system annual cost. The paper presents the development and implementation of the method, and demonstrates its application on the hybrid energy microgrid system.
NOTES[edit | edit source]
- Hybrid energy microgrid which consists of solar photovoltaic, wind generations, microturbine CHP.
- Microgrid system can both reduce the influence of renewable energy volatility and increase the efficiency of fossil energy.
SYSTEM DESCRIPTION[edit | edit source]
- It is composed of PV array generation, wind turbine generation, microturbine/engine combined heat and power system, energy storage and boiler, it provides both power and heat.
- The wind power computation model has two parts, simulate wind speed and compute wind turbine power output.
- Microturbine CHP can have a stable power output, but the heat to power ratio and fuel consumption.
- The wind power computation model has two parts, simulate wind speed and compute wind turbine power output.
CONCLUSIONS[edit | edit source]
- Annealing algorithm was used to solve planning model.
- The study case shows that the renewable energy generation and CHP unit can complement each other, and heat recovery plays a significant role in the optimization performed.
Modeling and Simulation of Photovoltaic module using MATLAB/Simulink[edit | edit source]
S. Sheik Mohammed
This paper focuses on modeling of PV module using MATLAB/simulink. The essential parameters required for modeling the system are taken from datasheets. I-V and P-V characteristics curves. This paper provides the fundamental knowledge on design and buildind blocks of PV module based on mathematical equation using simulink.
NOTES[edit | edit source]
- In order to minimize the GHG emissions, renewable energy resources are used.
OPERATION OF PV MODULE[edit | edit source]
- Solar cells convert solar energy into DC current. Several solar cells are connected in series to increase the voltage and they are connected in parallel to increase the current.
- When the PN junction is exposed to light, photons with energy greater than the gap of energy are absorbed, causing the emergence of electron-hole pairs. These carriers are separated under the influence of electric fields within the junction, creating a current that is proportional to the incidence of solar irradiation.
CHARACTERISTICS OF PV MODULE[edit | edit source]
- Solar-cell V-I and P-V characteristics varies with cell temperature and solar irradiation.
- Short circuit current: It is the current when the impedance is low.
- Open circuit voltage: When open circuit current occurs when there is no current passing through the cell.
- Maximum Power Point: It is the operating point at which the power is maximum across the load.
- Efficiency: It is the ratio between the maximum power and the incident light power.
- Fill Factor (FF): It is calculated by comparing the maximum power to the theoretical power (Pt) that would be output at both the open circuit voltage and short circuit current together. It is essentially a measure of quality of the solar cell.
MODELING AND SIMULATION OF PV[edit | edit source]
- MATLAB software is used for simulation using mathematical equations. The Solarex MSX60/MSX64 PV modules are chosen for modeling.
- These modules consist of 36 polycrystalline silicon solar cells electrically configured as two series strings of 18 cells each.
CONCLUSION[edit | edit source]
- The I-V and P-V characteristics are generated using MATLAB simulink software.
Dynamic programming to a CHP-HES system[edit | edit source]
Chen, X.P. ; Electr. Eng. Sch., Guizhou Univ., Guiyang, China ; Li, Z.T. ; Xiong, W. ; Wang, M.H.
This paper presents the optimal energy management algorithm for operating a system that consists of a CHP with hybrid energy storage (CHP-HES). The energy efficiencies were improved by applying a dynamic programming to the system.
NOTES[edit | edit source]
- CHP (combined heating and power) is used to solve the problems of enhancing energy efficiency and reducing GHG emissions.
- CHP application can reduce the energy loss mainly caused due to the waste heat during the power production which is about 65% of the loss.
- By combining energy storage with the CHP can improve the energy efficiency of the system.
- Enhancement of systems can be done by hybrid energy storage system, especially when batteries are coupled with super-capacitors.
RESULTS[edit | edit source]
- Energy produced with HES is around 35.16% and without HES is 33.63%. Moreover, the efficiency with HES is more compared to without HES.
Energy dispatching based on predictive controller of an off-grid wind turbine/ photovoltaic/ hydrogen/battery hybrid system[edit | edit source]
Juan P. Torreglosaa, Pablo Garcíab, Luis M. Fernández, Francisco Jurado
This paper focuses on energy dispatching based on Model Predictive Control (MPC) for off-grid photovoltaic (PV)/wind turbine/hydrogen/battery hybrid systems. The software used fot he modelling is MATLAB- simulink.
NOTES[edit | edit source]
- Two kinds of simulation can be carried out in order to meet the objective of energy dispatching. The two kinds of simulation are: short term and long term simulation.
1) The short term simulations are those which focus on dynamic of the sources which considers variation in net power variation due to changes in the net power changes.
2) The long term simulation is to show proper operation of the system. They take into consideration the parameters like operation costs, degradation of the sources, level of charge of the storage devices, etc.
- The hybrid system consists of the wind turbine, PV, electrolyzer and fuel cell.
Off-grid Hybrid System[edit | edit source]
- The main energy sources are renewable energy sources like PV system and wind turbines. It also consists of the battery and hydrogen system for backup when renewable sources are not able to fulfill the energy demand.
- The energy that flows between energy sources is done by the DC-DC converter.
- The excess electricity generated is stored in the battery or stored as hydrogen in the tank.
- When there is shortage of energy it is supplied by the battery.
Results[edit | edit source]
- Hourly data the sun irradiance, wind speed and load power consumption profile used in the simulations.
- It was observed that the hydrogen power variation is lower for the energy dispatching based on MPC, and therefore, its battery power range is higher.
- Fuel cell efficient is higher at lower power demand.
- The efficiency for hybrid system battery and hydrogen system are calculated.
Building Distributed Energy Performance Optimization for China: A Regional Analysis of Building Energy Costs and CO2 Emissions[edit | edit source]
Wei Feng, Nan Zhou, Chris Marnay, Michael Stadler, Judy Lai.
This paper focuses on the regional study of chinese commercial and residential building for optimal building energy performance. To optimize each building's performance, several distributed energy resources such as combined heat and power (CHP), photovoltaics (PV), and battery storage, are considered. Along with this solar radiation, electricity tariff, technology costs, and government financial incentives are also studied. This paper also focuses on suitable building energy technologies for different building types in different climate regions.
NOTES[edit | edit source]
- In order to reduce CO2 emission different distributed energy resources technologies are studied.
- Technologies include PV, solar thermal gas turbines, microturbines, fuel cell, CHP and batteries.
Methodologies[edit | edit source]
- An optimization model, the Distributed Energy Resources Customer Adoption Model (DER-CAM) has been used in this study.
- It can solve the entire building energy. The cost, energy use, carbon are minimized.
- The selection of buildings which is to be studied are based on:
1) Climate zones and building energy loads 2) Solar radiation profiles for PV assessment 3) Electricity tariff 4) Natural gas tariff 5) Technology costs and financial considerations
PV System Performance[edit | edit source]
- PV system performance vary from region to region. Also the PV peak electricity generation time varies from place to place. Annual average PV performance for several region is sgown in the graph.
Tariff and Cost and Technologies Performance[edit | edit source]
- The tariff details for month of July on hourly basis is shown in the paper.
- The technology to be used depends upon cost and technology performance. Several technology cost data have been provided in the paper.
- GHG emission reduction by different technologies are shown.
- CHP technology can be used for heating and cooling. CHP contributes to reduction in GHG emissions.
Conclusion[edit | edit source]
- In order to reduce GHG emission DER technologies are used. The CHP unit is the major contributor for reduction in GHG emission.
A Smart battery assisted by a CHP to meet the power and energy demand in a PV powered house.[edit | edit source]
The purpose of this paper is to turn grid connected PV into independent of the grid which can be done through the smart battery which includes battery management unit and converter. In order to reduce the size of the battery the CHP unit is used along with the battery and fulfill the heat demand durind winter season. This paper integrates the Smart Battery and a single phase CHP to provide the energy requirements all year around.
NOTES[edit | edit source]
- PV along with CHP are also increasing due to their high efficiency.
Photovoltaic energy generation[edit | edit source]
- The PV almost fulfills 80% of the electrical energy. If there is excess energy it can be stored in the batteries which can be used during shortage of electrical demand.
- The battery energy storage to store seasonal fluctuation for self consumption use is not feasible. Thus, combination of battery with CHP is used in order to fulfill the demand and to increase the efficiency.
- For designing three main parameter are considered :
- The yearly energy consumed by the consumer.
- The seasonal energy demands required.
- The maximum instantaneous power demand.
- The CHP unit can fulfill the electricity and heat demand during winters.
- The PV can supply energy during the day time. Whenever there is shortage of energy it is supplied either by battery or CHP unit or both.
- The energy can be fed into the battery when the load demand is not to high.
System Efficiency Considerations[edit | edit source]
- The efficiency of battery is around 80% and the efficiency of the CHP is around 90-92%.
- Important note:
- The CHP should run at the optimum power and any excess electricity and heat should be stored or consumed.
- In each voltage conversion 8 to 10% of energy is lost
- Storing energy in the battery would mean a loss of 20%
- The maximum PV energy should be harvested at all times.
- The difference in efficiency from PV to load is shown in the paper.
Experiment Setup[edit | edit source]
- Grid connected inverter, CHP unit, Lead acid battery and variable load.
- The battery acts as the heart of the system as it has to manage the flow of the energy. '
Conclusion[edit | edit source]
- The better battery storage plan plays an important role for optimum performance and high efficiency.
Enhancing cost-efficiency of residential battery systems (RBS) in conjunction with PV, micro-CHP, and balancing power provision[edit | edit source]
This paper focuses on modelling of the three systems in order to find out their economical feasibility and efficiency. The PV, the RBS could be connected to a micro-CHP (combined heat and power) unit, a residential heating unit with co-generation of electricity.
NOTES[edit | edit source]
- The micro-CHP produces electricity as an inexpensive side-product that can be stored for consumption as and when required.
Methods[edit | edit source]
- Three models considered are:
1) Advanced RBS/PV model: Time interval for loads and generation profiles were evaluated. This were measured and generated based on weather data.
2) RBS/micro-CHP model: Simulation of micro CHP with RBS was implemented. Micro-CHP (peak loads during winter time) can complement PV systems (peak generation during summer time), hence optimizing the RBS usage.
3) RBS/balancing power model: Battery is used to supply power when there is shortage of energy from the CHP and PV system.
Results[edit | edit source]
- PV and micro-CHP are well suited for the complementary use of the RBS – PV generation peaks in summer time, micro-CHP in winter time which will enhance the system's cost-efficiency.
- Combining PV and micro-CHP with one RBS appears to be feasible and economically promising.
Technical and economic feasibility study of using Micro CHP in the different climate zones of Iran[edit | edit source]
Fatemeh Teymouri Hamzehkolaei , Sourena Sattari
This paper focuses on technical and economic studies for the use of Micro CHP in the different climate zones are executed. The economic model was used for, both annual energy savings and percentage of system profitability in each zone are calculated as well as reduction in annual emissions. The analysis indicates that profitability of Micro CHP systems are sensitive to energy prices, as well as hours needed for heating room in each climate zones.
NOTES[edit | edit source]
- Cogeneration generates the electricity and the heat simultaneously.
- The micro CHP generates waste heat which is utilized for space heating and hot domestic water.
- CHP can help to obtain higher efficiency, low costs and reduction of GHG emissions.
- Knowledge about energy end use loads is important for selecting an appropriate residential CHP system depending on electrical as well as thermal energy demand.
- Knowledge about the climatic condition of the area is important before installing CHP unit.
Methodology[edit | edit source]
- The system consists of CHP unit and the storage tank. The CHP plant is driven by natural gas. The primary function of CHP is used to meet the thermal demand and then the electrical demand.
- The CHP is used to meet the thermal demand if it exceeds it is stored in the storage tank. If the electricity generated is in excess it is either supplied to the grid or stored in the battery.
- The investigated electricity and thermal loads, energy (both electricity and city gas) prices, as well as Micro CHP performance characteristics, a pre-developed plan and evaluation model is employed .
Equation description[edit | edit source]
- In order to operate CHP in a efficient way local conditions, energy requirements , technical information and financial information are need to be taken into consideration.
- The economic model is used to calculate annual energy saving and annual CO2 emissions in different zones.
- The average thermal power output of Micro CHP system, is the ratio of annual heat load for space heating and hot water divided by the hours needed for heating and hot water.
- The total amount of electricity generated during the year by CHP system is calculated with electrical rated capacity of CHP plant multiplied by the annual operation hours.
- Cost saving is ratio of annual energy cost on conventional system and micro-CHP system.
- The annual running cost the CHP unit is calculated which depends on fuel as well as maintenance cost.
- If the electrical energy so generated by the CHp system is greater then the required demand then the excess energy is fed into the grid. This also considered while calculating the cost of saving.
Conclusion[edit | edit source]
- The installation of CHP results in the greater economic merit. It helps in increasing the efficiency and reduction of GHG emission. It also helps in energy saving.
Energy flow management of a hybrid renewable energy system with hydrogen[edit | edit source]
Ekkehard Boggascha, Mark Rylattb, Andrew Wright
This paper presents a preliminary study on a hybrid renewable energy system at the Ostfalia University of Applied Sciences Wolfenbüttel, Germany. The test-bed is made up of solar photovoltaics (PV), amicro wind turbine (MWT), a micro-CHP, a fuel cell system (FC), and two storage devices (a battery system and an electrolyzer).
NOTES[edit | edit source]
- Batteries are used for storage of energy. In order to store surplus renewable electric energy for a longer period would be to convert it into hydrogen by
using an electrolyzer.
- If the hydrogen is produced from renewable sources and used in fuel cells it would be a clean and reliable energy source.
- MATLAB/Simulink model of a hybrid renewable energy system with hydrogen is introduced in this paper.
Experimental Setup[edit | edit source]
- It consists of the PV array with adjust tilt angle, micro wind turbine, fuel cell system, CHP unit, two storage devices to store electricity into three phase battery system.
- The energy management system consists of three statecharts for the battery, hydrogen, and CHP control are as follows:
If there is surplus energy it is stored in the battery. If the battery is full, energy is stored as hydrogen . When both the storage are full it is exported to the grid.
