scholarly journals Adsorption gas Heat Pump fuelled with hydrogen enriched natural gas blends: the analytical simulation model development and validation

2020 ◽  
Vol 197 ◽  
pp. 08002
Author(s):  
Matteo Sforzini ◽  
Gianluigi Lo Basso ◽  
Romano Paiolo ◽  
Livio De Santoli ◽  
Fabrizio Cumo
Keyword(s):  
Natural Gas ◽  
Simulation Model ◽  
Heat Pump ◽  
Energy Performance ◽  
Operating Conditions ◽  
Hot Water ◽  
Relative Standard Error ◽  
Outlet Temperature ◽  
Experimental Campaign ◽  
Relative Standard

This study deals with the implementation of an analytical model to simulate the energy performance associated to a commercial Gas adsorption Heat Pump, when H2NG (Hydrogen Enriched Natural Gas) blends are used as fuel. In detail, a water source heat pump manufactured by Robur (GAHP-WS) has been used as a reference device for building the simulation model within the MATLAB-Simulink environment. Thereafter, the simulation results have been validated by the experimental campaign, testing on field and in actual operating conditions the heat pump. Specifically, the model has been developed by implementing the WaterAmmonia mass and energy balances for each component. It is able to evaluate fuel consumption, efficiency in terms of GUE, required thermal power from the cold heat sink as well as the water outlet temperature at the evaporator, once the heating load is used as the main input. The experimental campaign for the model calibration and validation has been carried out over the winter season. Additionally, the heat pump performance has been detected when it operates to supply hot water at 60 °C and 55 °C, and it is fuelled with growing hydrogen fractions, starting from 0% vol., 5% vol. up to 10% vol. In the end, the standard errors as well as the relative ones affecting the main output parameters have computed for the validation process. From the outcomes it emerges that the average relative standard error related to all load conditions is lower than 2.5% for natural gas operation. On the contrary, it ranges between 2.5% and 4% when H2NG at 5% and 10% by volume have been burnt.

scholarly journals Modeling and Analysis of a Micro Gas Turbine Fuelled with Hydrogen and Natural Gas Blends

2021 ◽  
Vol 312 ◽  
pp. 08012
Author(s):  
Shahrokh Barati ◽  
Livio De Santoli ◽  
Gianluigi Lo Basso
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Energy Performance ◽  
Operating Conditions ◽  
Modeling And Analysis ◽  
Micro Gas Turbine ◽  
System A ◽  
Experimental Campaign ◽  
Relative Standard ◽  
Electrical Reliability

This study deals with implementing an analytical model to simulate the energy performance associated with a Micro Gas Turbine when H2NG (Hydrogen Enriched Natural Gas) blends are used as fuel. The experimental campaign validated the simulation results at the actual operating conditions of the Micro Gas Turbine. The experimental campaign for model validation has been carried out over the spring and summer periods. Additionally, the MGT performance has been detected when fuelled H2NG with hydrogen fraction ranges between 0% vol. to 10% vol., with a 2% vol. Step., according to the main findings, the fuel consumption is reduced significantly. Also, heat recovery and electrical reliability improve slightly even though environmental factors influence the system. A numerical model was developed with MATLAB-Simulink to model the operation of the MGT. Thus, the relative standard errors affecting the main output parameters have been determined.

scholarly journals Energy Performance Optimization in a Condensing Boiler

2021 ◽  
Vol 9 (1) ◽  
pp. 6
Author(s):  
Diego Fernández-Cheliz ◽  
Eloy Velasco-Gómez ◽  
Juan Peral-Andrés ◽  
Ana Tejero-González
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Performance Optimization ◽  
Energy Performance ◽  
Primary Energy ◽  
Operating Conditions ◽  
Hot Water ◽  
Operating Parameters ◽  
Climate Conditions ◽  
Lower Heating Value

In Europe, primary energy consumption in buildings accounts for up to 25–40%, depending on the climate conditions. Space heating and Domestic Hot Water (DHW) contribute significantly to this energy consumption. Among the most common sources for heat generation in these appliances is natural gas. Condensing boilers can surpass the 100% energy performance over the lower heating value, if the operating conditions enable the water vapor in the exhaust gases to condensate. Consequently, optimizing the operating parameters of condensing boilers is necessary to decrease fuel consumption without hindering water heating needs. The present work presents an experimental approach to the operating parameters of a condensing boiler that works with natural gas. The aim is to develop a theoretical model that relates the energy performance to the water temperature set by the final user and the excess air set by the maintenance staff.

The Performance Improvement of a 70kWe Natural Gas CHP System

2008 ◽  
Author(s):  
Lin Fu ◽  
Xiling Zhao ◽  
Shigang Zhang ◽  
Yi Jiang ◽  
Hui Li ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Natural Gas ◽  
Heat Pump ◽  
Flue Gas ◽  
Utilization Efficiency ◽  
Outlet Temperature ◽  
Absorption Heat Pump ◽  
Gas Engine ◽  
Innovative System ◽  
Chp System

It is well known that combined heating and power (CHP) generation permits the energy of the fuel to be more efficiently than electric and thermal separate generation. The paper deals with natural gas CHP system with a 70kWe gas-powered internal combustion engine (ICE), which has been set up at the Tsinghua University energy-saving building, in Beijing, China. The system is composed of an ICE, a flue gas heat exchanger and other heat exchangers. The conventional system’s characteristics is that the gas engine generates power on-site, and the exhaust of the gas engine is recovered by a high temperature flue gas-water heat exchanger, and the jacket water heat is recovered by a water-water heat exchanger to supply heat for district heating system. In order to improve the system’s performance, an innovative system with absorption heat pump is adopted. The exhaust of the gas engine drives an absorption heat pump to recover the flue gas sensible heat and further recover the latent heat, so the outlet temperature of the exhaust could be lowered to 50°C. In this paper, the electrical and thermal performance of the innovative system were tested and compared with conventional cogeneration systems. The test and comparison results show that the innovative CHP system could increase the heat utilization efficiency 10% in winter. All the results provide important insight into CHP performance characteristics and could be valuable references for CHP system’s improvements.

scholarly journals Comparison of Transcritical CO2 and Conventional Refrigerant Heat Pump Water Heaters for Domestic Applications

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 479
Author(s):  
Ignacio Paniagua ◽  
Ángel Álvaro ◽  
Javier Martín ◽  
Celina Fernández ◽  
Rafael Carlier
Keyword(s):  
Heat Pump ◽  
Thermodynamic Cycle ◽  
Heat Pumps ◽  
Design Tool ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ambient Conditions ◽  
Water Heater ◽  
Water Heaters

Although CO 2 as refrigerant is well known for having the lowest global warming potential (GWP), and commercial domestic heat pump water heater systems exist, its long expected wide spread use has not fully unfolded. Indeed, CO 2 poses some technological difficulties with respect to conventional refrigerants, but currently, these difficulties have been largely overcome. Numerous studies show that CO 2 heat pump water heaters can improve the coefficient of performance (COP) of conventional ones in the given conditions. In this study, the performances of transcritical CO 2 and R410A heat pump water heaters were compared for an integrated nearly zero-energy building (NZEB) application. The thermodynamic cycle of two commercial systems were modelled integrating experimental data, and these models were then used to analyse both heat pumps receiving and producing hot water at equal temperatures, operating at the same ambient temperature. Within the range of operation of the system, it is unclear which would achieve the better COP, as it depends critically on the conditions of operation, which in turn depend on the ambient conditions and especially on the actual use of the water. Technology changes on each side of the line of equal performance conditions of operation (EPOC), a useful design tool developed in the study. The transcritical CO 2 is more sensitive to operating conditions, and thus offers greater flexibility to the designer, as it allows improving performance by optimising the global system design.

CFD Analysis of Natural Gas Cooling System Through a Conventional Aircooler Improved by a Fogging System

2018 ◽  
Author(s):  
Jhon Pérez ◽  
Miguel Asuaje Tovar
Keyword(s):  
Relative Humidity ◽  
Natural Gas ◽  
Cooling System ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Outlet Temperature ◽  
Water Droplets ◽  
Gas Industry ◽  
Computational Fluid Dynamics Analysis

Nowadays, under unstable prices scenarios, the oil and gas industry is looking for improvement in its production processes, either by increasing the production and/or lowering the operational costs. Aircoolers, particularly, are key equipments in the natural gas industry, and are frequently the bottleneck of gas conditioning processes. To improve air cooling efficiency and increase their gas volume capacity, several solutions are commonly implemented such as: fan blade angle change, air inlet section modification, fogging cooling system, among others. The present study shows the CFD (Computational Fluid Dynamics) analysis of an air cooler, under an air flow with an evaporative cooling system, in order to quantify the effect of this cooling process on its overall equipment performance. Simulations were carried out using sing the ANSYS CFX v-14® software, in a simplified multidomain which consider fluid and solid blocks: 1.- External two-phase flow (air + water droplets) with heat and mass transfer 2.- Heat transfer through the pipe wall 3.- Single phase natural gas flow inside the tubes In order to stablish an operational range of the fogging system, the influence of parameters like: inlet temperature and relative humidity of the air, water flow rate, water droplets mean diameter, water injection position, were studied [9, 10]. The results show a good agreement (around 5%) respect to the reported values on the literature. The best performance for the equipment was reported with a droplet diameter of 20 μm and for low relative humidity (less than 65%), which guarantees the complete evaporation of the droplets within the studied domain. For the analyzed operating conditions, a reduction of the gas outlet temperature of up to 1.5°C can be achieved.

scholarly journals Numerical Analysis and Preliminary Experiment of a Solar Assisted Heat Pump Drying System for Chinese Wolfberry

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4306 ◽  
Author(s):  
Zhongting Hu ◽  
Sheng Zhang ◽  
Wenfeng Chu ◽  
Wei He ◽  
Cairui Yu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Electric Energy ◽  
Energy Performance ◽  
Operating Conditions ◽  
Pump System ◽  
Heat Pump System ◽  
Electric Energy Consumption ◽  
Drying System ◽  
Heat Pump Drying

The present work investigated a solar assisted heat pump system for drying Chinese wolfberry. The kinetic characteristic was firstly analyzed through a series of lab experiments. It was concluded that the Page model was the most suitable for predicting the heat and mass transfer of the wolfberry. Based on the wolfberry kinetic model, solar collector model and chamber air model, the coupled drying system model was developed. The accuracy of the mathematic model was determined through comparing with the preliminary experimental results. The influence of operating conditions on the thermal and energy performance of the dryer for the different operating mode was discussed. The drying weight of no more than 75 kg may be preferable in the stand-alone solar drying mode, and less than 15 h was needed to be dried. The electric energy consumption in the solar assisted the heat pump drying mode was lower than that in the stand-alone heat pump mode, and it was recommended that about 50 kg of wolfberry to be dried in the solar assisted heat pump system. Compared to the autumn drying, the reduction in the electric energy consumption was around 9.1 kWh during the 11 h summer drying process. The obtained results demonstrated the feasibility of the combined system for drying wolfberry, and also can provide the basic theoretical and experimental data support for the following research.

scholarly journals Feasibility Analysis and Performance Evaluation and Optimization of a DXSAHP Water Heater Based on the Thermal Capacity of the System: A Case Study

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3883
Author(s):  
Jorge E. De León-Ruiz ◽  
Ignacio Carvajal-Mariscal ◽  
Antonin Ponsich
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pump ◽  
Thermal Capacity ◽  
Hot Water ◽  
Outlet Temperature ◽  
Solar Collectors ◽  
Pump System ◽  
Heat Pump System

The present work conducts an evaluation of the feasibility and the overall performance and consequent optimization of a direct expansion solar assisted heat pump (DXSAHP) employed for domestic water heating. For the study conducted R134a, R404A, R407C and R410A working fluids were evaluated as well as the use of four, six and eight flat-plate solar collectors and a worktime ranging from 1 to 6 h. The case study is based in Mexico City with a 300 L container and a hot water outlet temperature of 51 °C. The paper introduces a new evaluation criterion based on the thermal capacity and all the evaluations conducted throughout this research revolve around this performance metric. The results show that, the system would require at least 4 h of operation to achieve the outlet temperature. Additionally, it was found that the R410A refrigerant has the best heat transfer properties; with an average condensation heat rate of 6.31 kW, followed by the R407C with 5.72 kW, the R404A with 5.42 kW and the R134a with 5.18 kW. Diversely, the R134a refrigerant requires 0.402 kW of compression work, 62% less than the R410A, which requires 1.06 kW. Consequently, R134a delivers the highest COP, which ranges from 7 to 14, followed by the R407C and R404A refrigerants, which present a similar behaviour between them, with COP ranging from 5 to 9 and 4 to 8, respectively, and finally the R410A, achieving the lowest COP, ranging from 3.5 to 6.5. Moreover, it was found that the R134a presents a higher dispersion regarding the energy exchange rate, which reveals that it is the fluid most susceptible to external factors, such as the weather. Contrarily, the remaining refrigerants present a more consistent performance. Finally, the optimization revealed that the R407C refrigerant is the most suitable given that it requires 20% less compression work than the R404A. This provides the heat pump system with a steadier behaviour, a COP ranging from 7 to 8, 30% higher than R410A, a worktime decrease of 1.5 h and heat transfer area of 5.5 flat-plate solar collectors, equivalent to a 31% reduction, both compared to R134a.

Operating Modes of the Solar Assisted Drainwater System for Ground Source Heat Pump

2010 ◽  
Vol 171-172 ◽  
pp. 67-72
Author(s):  
Yong Lan Yin ◽  
Qing Gao ◽  
Bai Fa Zhu ◽  
Ming Li
Keyword(s):  
Electric Power ◽  
Heat Pump ◽  
Distribution Ratio ◽  
Water Distribution ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Pump System ◽  
Heat Pump System ◽  
Operating Modes ◽  
And Performance

To extend the area in applications of solar heat pump and drainwater heat recovery, the gravity film exchanger was employed to establish the solar assisted drainwater heat pump system. In this paper, two gravity film exchangers were assembled in the hybrid heat pump system to discuss the effect of water distribution ratio in two exchangers on the electric power complement and outlet water temperature of the condenser. The technology of Matlab/Simulink was used in modeling and simulations of the system by the performance curves and performance parameters of the corresponding system components. In the designing processes, the dynamic characteristics can be predicted, and the optimal operating conditions can also be concluded that appropriate water distribution ratio should be selected respectively for higher outlet temperature of the condenser or lower electric power complement.

scholarly journals Analysis of a Hybrid PV/Thermal Solar-Assisted Heat Pump System for Sports Center Water Heating Application

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Y. Bai ◽  
T. T. Chow ◽  
C. Ménézo ◽  
P. Dupeyrat
Keyword(s):  
Heat Pump ◽  
Design Procedure ◽  
Energy Performance ◽  
Hot Water ◽  
Conventional Heating ◽  
Practical Case ◽  
Subtropical Climate ◽  
Pump System ◽  
Economic Implications ◽  
Heat Pump System

The application of solar energy provides an alternative way to replace the primary source of energy, especially for large-scale installations. Heat pump technology is also an effective means to reduce the consumption of fossil fuels. This paper presents a practical case study of combined hybrid PV/T solar assisted heat pump (SAHP) system for sports center hot water production. The initial design procedure was first presented. The entire system was then modeled with the TRNSYS 16 computation environment and the energy performance was evaluated based on year round simulation results. The results show that the system COP can reach 4.1 under the subtropical climate of Hong Kong, and as compared to the conventional heating system, a high fractional factor of energy saving at 67% can be obtained. The energy performances of the same system under different climatic conditions, that include three other cities in France, were analyzed and compared. Economic implications were also considered in this study.

Analysis of a Micro Gas Turbine Fed by Natural Gas and Synthesis Gas: MGT Test Bench and Combustor CFD Analysis

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
M. Cadorin ◽  
M. Pinelli ◽  
A. Vaccari ◽  
R. Calabria ◽  
F. Chiariello ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Natural Gas ◽  
Gas Turbine ◽  
Synthesis Gas ◽  
Distribution System ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Monitoring And Control ◽  
Micro Gas Turbine ◽  
Gaseous Fuels

In recent years, the interest in the research on energy production systems fed by biofuels has increased. Gaseous fuels obtained through biomass conversion processes such as gasification, pyrolysis and pyrogasification are generally defined as synthesis gas (syngas). The use of synthesis gas in small-size energy systems, such as those used for distributed micro-cogeneration, has not yet reached a level of technological maturity that could allow a large market diffusion. For this reason, further analyses (both experimental and numerical) have to be carried out to allow these technologies to achieve performance and reliability typical of established technologies based on traditional fuels. In this paper, a numerical analysis of a combustor of a 100-kW micro gas turbine fed by natural gas and biomass-derived synthesis gas is presented. The work has been developed in the framework of a collaboration between the Engineering Department of the University of Ferrara, the Istituto Motori - CNR (Napoli), and Turbec S.p A. of Corporeno di Cento (FE). The main features of the micro gas turbine Turbec T100, located at the Istituto Motori - CNR, are firstly described. A decompression and distribution system allows the feeding of the micro gas turbine with gaseous fuels characterized by different compositions. Moreover, a system of remote monitoring and control together with a data transfer system has been developed in order to set the operative parameters of the machine. The results of the tests performed under different operating conditions are then presented. Subsequently, the paper presents the numerical analysis of a model of the micro gas turbine combustor. The combustor model is validated against manufacturer performance data and experimental data with respect to steady state performance, i.e., average outlet temperature and emission levels. A sensitivity analysis on the model capability to simulate different operating conditions is then performed. The combustor model is used to simulate the combustion of a syngas, composed of different ratios of hydrogen, carbon monoxide, methane, carbon dioxide and water. The results in terms of flame displacement, temperature and emission distribution and values are analyzed and compared to the natural gas simulations. Finally, some simple modifications to the combustion chamber are proposed and simulated both with natural gas and syngas feeding.

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