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 Thermodynamic Analysis of Combined Cooling Heating and Power System with Absorption Heat Pump Based on Small Modular Lead-based Reactor

2021 ◽  
Vol 245 ◽  
pp. 01025
Author(s):  
Han Wang ◽  
Dali Yu ◽  
Chi Xu ◽  
Muhammad Salman Khan ◽  
Yunqing Bai
Keyword(s):  
Heat Pump ◽  
Thermodynamic Analysis ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Outlet Temperature ◽  
Pump System ◽  
Absorption Heat Pump ◽  
Remote Areas ◽  
Energy Demands ◽  
Combined Cooling

Small Modular Lead-based Reactor (SMLR) has generated great interest in academic research all around the world due to its good safety characteristics and relatively high core outlet temperature. In this paper, a Combined Cooling Heating and Power (CCHP) system with usage of absorption heat pump, which couples with a SMLR, was proposed to fulfill the energy demands in remote areas. Thermodynamic analysis was implemented to improve the performance of the CCHP system based on SMLR. To meet the remote areas’ energy needs, the main parameters and mass flow rate of a 35 MWth SMLR design were analyzed. The SMLR CCHP with absorption heat pump system can provide electric power 12.5MWe, heating 9.5MWh, and cooling 2.54MWc. The total energy utilization efficiency of the system can be 69.12 %. This work can provide a reference in the design and optimization of the CCHP system to meet the energy demands in the remote areas.

scholarly journals Energy modelling and field testing of natural gas absorption heat pump system in cold climate - Canada

2021 ◽  
Author(s):  
Kajen Ethirveerasingham
Keyword(s):  
Natural Gas ◽  
Heat Pump ◽  
Water Solution ◽  
Cold Climate ◽  
Gas Absorption ◽  
Utilization Efficiency ◽  
Pump System ◽  
Absorption Heat Pump ◽  
Heat Pump System ◽  
Part Load

The feasibility of a Natural Gas Absorption Heat Pump (GAHP) was investigated through the use of a technology screening tool developed in Excel and TRNSYS simulations that used experimentally evaluated performance curves using 50% propylene glycol (PG)/water solution. The Excel tool was used for cost and greenhouse gas (GHG) reductions analysis and indicated that the GAHP was cost effective compared to an Air-Source Heat Pump (ASHP) in locations where the primary heating fuel was natural gas and had significantly lower GHG emissions compared to a 90% efficient natural gas furnace. During the heating season, it was found that the system only had more than 100% heating Gas Utilization Efficiency (GUE) at -1.5°C or above and would go as low at 66% GUE at nominal flow and return temperatures. Part load performance was analyzed using experimental data and implemented in a TRNSYS model. The TRNSYS model shows significant losses from part load performance and 50% PG/water derating for both heating and cooling season due to excessive cycling.

Application Study of BCHP System With Absorption Heat Pump of an Urban Original Sewage Source

2010 ◽  
Author(s):  
X. L. Zhao ◽  
L. Fu ◽  
S. G. Zhang ◽  
J. Z. Zhu ◽  
B. M. Huang ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Flue Gas ◽  
Waste Heat ◽  
Combustion Engine ◽  
Clean Energy ◽  
Absorption Heat Pump ◽  
Efficient Integration ◽  
Sewage Source

A critical issue for BCHP (Building combined cooling heating and power) system is the efficient integration of power generation equipment with different heat utilization technologies. A BCHP system with an urban original sewage source absorption heat pump is proposed. The system is composed of an internal combustion engine, a water-water heat exchanger, a flue gas driven absorption heat pump, a filth block device, a wastewater heat exchanger, and other assistant facilities, such as pumps, fans, and end user devices. In the winter, the waste heat of the flue gas is used to drive absorption heat pump to recover the waste heat of sewage source and the flue gas, and in the summer, the waste heat of the flue gas is used to drive absorption heat pump for cooling, and the heat load of the building is removed to the sewage. In the paper, this kind of system was designed according to the energy consumption of the buildings, and the overall performance of the system in the heating and cooling mode was studied, and the energy efficiency level was analyzed. It is shown that the system is the efficient integration of clean energy and waste heat resource, and the energy efficiency of the system could be improved by 18.5% compared with the conventional BCHP systems.

The Steady and Dynamic Performance of an Innovative Natural Gas CHP System

2008 ◽  
Author(s):  
Lin Fu ◽  
Xiling Zhao ◽  
Shigang Zhang ◽  
Yi Jiang ◽  
Hui Li ◽  
...  
Keyword(s):  
Natural Gas ◽  
Flue Gas ◽  
Combustion Engine ◽  
Dynamic Performance ◽  
Thermal Inertia ◽  
Utilization Efficiency ◽  
Small Scale ◽  
Exhaust Gas ◽  
Set Up ◽  
Chp System

In the last decade, technological innovation and changes in the economic and regulatory environment have resulted in increased attention to distributed energy systems (DES). Combined heating and power (CHP) systems based on the gas-powered internal combustion engine (ICE) are increasingly used as small-scale distribution co-generators. This paper describes an innovative ICE-CHP system with an exhaust-gas-driven absorption heat pump (AHP) that has been set up at the energy-saving building in Beijing, China. The system is composed of an ICE, an exhaust-gas-driven AHP, and a flue gas condensation heat exchanger (CHE), which could recover both the sensible and latent heat of the flue gas. The steady performance and dynamic response of the innovative CHP system with different operation modes were tested. The results show that the system’s overall efficiency could reach above 90% based on lower heating value (LHV) of natural gas; that is, the innovative CHP system could increase the heat utilization efficiency 10% compared to conventional CHP systems, and the thermally activated components of the system have much more thermal inertia than the electricity generation component. The detailed test results provide important insight into CHP performance characteristics and could be valuable references for the control of CHP systems. The novel CHP system could take on a very important role in the CHP market.

scholarly journals Energy modelling and field testing of natural gas absorption heat pump system in cold climate - Canada

2021 ◽  
Author(s):  
Kajen Ethirveerasingham
Keyword(s):  
Natural Gas ◽  
Heat Pump ◽  
Water Solution ◽  
Cold Climate ◽  
Gas Absorption ◽  
Utilization Efficiency ◽  
Pump System ◽  
Absorption Heat Pump ◽  
Heat Pump System ◽  
Part Load

The feasibility of a Natural Gas Absorption Heat Pump (GAHP) was investigated through the use of a technology screening tool developed in Excel and TRNSYS simulations that used experimentally evaluated performance curves using 50% propylene glycol (PG)/water solution. The Excel tool was used for cost and greenhouse gas (GHG) reductions analysis and indicated that the GAHP was cost effective compared to an Air-Source Heat Pump (ASHP) in locations where the primary heating fuel was natural gas and had significantly lower GHG emissions compared to a 90% efficient natural gas furnace. During the heating season, it was found that the system only had more than 100% heating Gas Utilization Efficiency (GUE) at -1.5°C or above and would go as low at 66% GUE at nominal flow and return temperatures. Part load performance was analyzed using experimental data and implemented in a TRNSYS model. The TRNSYS model shows significant losses from part load performance and 50% PG/water derating for both heating and cooling season due to excessive cycling.

Thermodynamic Analysis of a Central Heating System Combing the Urban Heat Network With Geothermal Energy

2013 ◽  
Author(s):  
Xiao Wang ◽  
Lin Fu ◽  
Xiling Zhao ◽  
Hua Liu
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pump ◽  
Geothermal Energy ◽  
Heating System ◽  
Heat Network ◽  
Pump System ◽  
Absorption Heat Pump ◽  
Central Heating ◽  
Exchange Unit

In recent years, with the continuous urban expansion, the central heating sources are commonly insufficient in the areas of Northern China. Besides, the increasing heat transfer temperature difference results in more and more exergy loss between the primary heat network and the secondary heat network. This paper introduces a new central heating system which combines the urban heat network with geothermal energy (CHSCHNGE). In this system, the absorption heat exchange unit, which is composed of an absorption heat pump and a water to water heat exchanger, is as alternative to the conventional water to water heat exchanger at the heat exchange station, and the doing work ability of the primary heat network is utilized to drive the absorption heat pump to extract the shallow geothermal energy. In this way, the heat supply ability of the system will be increased with fewer additional energy consumptions. Since the water after driving the absorption heat pump has high temperature, it can continue to heat the supply water coming from the absorption heat pump. As a result, the water of the primary heat network will be stepped cooled and the exergy loss will be reduced. In this study, the performance of the system is simulated based on the mathematical models of the heat source, the absorption heat exchange unit, the ground heat exchanger and the room. The thermodynamic analyses are performed for three systems and the energy efficiency and exergy efficiency are compared. The results show that (a) the COP of the absorption heat exchange unit is 1.25 and the heating capacity of the system increases by 25%, which can effectively reduce the requirements of central heating sources; (b) the PER of the system increases 14.4% more than that of the conventional co-generation central heating system and 54.1% more than that of the ground source heat pump system; (c) the exergy efficiency of the CHSCHNGE is 17.6% higher than that of the conventional co-generation central heating system and 45.6% higher than that of the ground source heat pump system.

Performance Evaluation of a Vertical U-Tube Ground Heat Exchanger Using a Numerical Simulation Approach

2013 ◽  
Vol 724-725 ◽  
pp. 909-915
Author(s):  
Ping Fang Hu ◽  
Zhong Yi Yu ◽  
Fei Lei ◽  
Na Zhu ◽  
Qi Ming Sun ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Ground Heat Exchanger ◽  
Ground Source Heat Pump ◽  
Ground Source

A vertical U-tube ground heat exchanger can be utilized to exchange heat with the soil in ground source heat pump systems. The outlet temperature of the working fluid through the U-tube not only accounts for heat transfer capacity of a ground heat exchanger, but also greatly affects the operational efficiency of heat pump units, which is an important characteristic parameter of heat transfer process. It is quantified by defining a thermal effectiveness coefficient. The performance evaluation is performed with a three dimensional numerical model using a finite volume technique. A dynamic simulation was conducted to analyze the thermal effectiveness as a function of soil thermal properties, backfill material properties, separation distance between the two tube legs, borehole depth and flow velocity of the working fluid. The influence of important characteristic parameters on the heat transfer performance of vertical U-tube ground heat exchangers is investigated, which may provide the references for the design of ground source heat pump systems in practice.

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