scholarly journals Numerical Research on Flow Characteristics in a Plate-type Falling Film Heat Exchanger for a LiBr/H 2 O Absorption Heat Pump

2017 ◽  
Vol 205 ◽  
pp. 485-491 ◽  
Author(s):  
Tianle Hu ◽  
Xiaoyun Xie ◽  
Yi Jiang
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Flow Characteristics ◽  
Falling Film ◽  
Absorption Heat Pump ◽  
Numerical Research ◽  
Plate Type

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.

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.

Compact Diesel Engine Waste-Heat Driven Ammonia-Water Absorption Heat Pump Modeling and Performance Maximization Strategies

2021 ◽  
pp. 1-28
Author(s):  
Christopher M. Keinath ◽  
Jared Delahanty ◽  
Srinivas Garimella ◽  
Michael A. Garrabrant
Keyword(s):  
Heat Exchanger ◽  
Water Absorption ◽  
Heat Pump ◽  
Waste Heat ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Heat Transfer Fluid ◽  
Ammonia Water ◽  
Absorption Heat Pump ◽  
Wide Range

Abstract An investigation of the best ways to achieve optimal performance from a waste-heat-driven ammonia-water absorption heat pump over a wide range of operating conditions is presented. Waste-heat is recovered using an exhaust gas heat exchanger and delivered to the desorber by a heat transfer fluid loop. The absorber and condenser are hydronically coupled in parallel to an ambient heat exchanger for heat rejection. The evaporator provides chilled water for space-conditioning with a baseline cooling capacity of 2 kW. A detailed thermodynamics model is developed to simulate performance and develop strategies to achieve the best performance in both cooling and heating modes over a range of operating conditions. These parametric studies show that improved coefficients of performance can be achieved by adjusting the coupling fluid temperatures in the evaporator and the condenser/absorber as the ambient temperature varies. With the varying return temperatures, the system is able to provide the 2 kW design cooling capacity for a wide range of ambient temperatures.

Mesoscopic Heat-Actuated Heat Pump Development

1999 ◽  
Author(s):  
Kevin Drost
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Pacific Northwest ◽  
Heat Pump ◽  
Cooling System ◽  
High Heat ◽  
Absorption Heat Pump ◽  
Transfer Rates ◽  
Alternative Systems ◽  
Air Cooled Heat Exchanger

Abstract Battelle, Pacific Northwest Division (Battelle) and Pacific Northwest National Laboratory1 (PNNL) are developing a miniature absorption heat pump. Targeted applications include microclimate control ranging from manportable cooling to distributed space conditioning. The miniature absorption heat pump will be sized to provide 350 Wt of cooling2. A complete manportable cooling system, which will include the microscale heat pump, an air-cooled heat exchanger, batteries, and fuel, is estimated to weigh between 4 and 5 kg. For comparison, alternative systems weigh about 10 kg. Size and weight reductions in the microscale heat pump are possible because the device can take advantage of the high heat and mass transfer rates attainable in microscale structures.

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