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

Author(s):  
X. L. Zhao ◽  
L. Fu ◽  
S. G. Zhang ◽  
J. Z. Zhu ◽  
B. M. Huang ◽  
...  

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.

2012 ◽  
Vol 170-173 ◽  
pp. 2747-2750
Author(s):  
Xi Ling Zhao ◽  
Zhong Hai Zheng ◽  
Lin Fu ◽  
Yan Li

How to use the waste heat deeply are a critical issue for BCHP (Building combined cooling heating and power) system. A BCHP system with a soil source absorption heat pump driven by the waste heat is proposed. The system is composed of an internal combustion engine, a soil source absorption heat pump driven by the flue gas, and other assistant facilities, such as pumps, fans, and end user devices. In the winter, the flue gas is used to drive absorption heat pump to recover the waste heat of the soil source and the condensation heat of the flue gas simultaneously, and in the summer, the waste heat of the flue gas is used to drive absorption heat pump to cooling, and the heat sink is the soil. In the paper, the configuration of this kind of system is designed, and the energy analysis of the system is done all the year. Compared with the conventional BCHP system, the operation cost is lowered greatly and the increased investment could be returned within one year. It is show that the system is the efficient integration of cleaning energy, renewable energy, the discharge of the flue gas could be reduced to below 30°C, and the water steam could be catch to avoid the white smoke of the stack. The energy saving in space heating could be 66% compared with the conventional BCHP systems.


Author(s):  
Xiling Zhao ◽  
Lin Fu ◽  
Xiao Wang

Because of the performance of the power generation equipment is almost perfect, how to integrate the thermally-activated technologies and use the waste heat deeply are a critical issue for CCHP (Combined cooling heating and power) system. According to the characteristics of a typical end user’s demands, a CCHP system with the flue gas and geothermal energy is proposed. The system is composed of an internal combustion engine, a soil source absorption heat pump driven by the flue gas, and other assistant facilities, such as pumps, fans, and end user devices. In the winter, the flue gas is used to drive absorption heat pump to recover the waste heat of the soil source and the condensation heat of the flue gas simultaneously, and in the summer, the waste heat of the flue gas is used to drive absorption heat pump to cooling, and the heat sink is the soil. In the paper, the energy analysis of the system is done. Compared with the conventional CCHP system, the operation cost is lowered greatly and the increased investment could be returned within one year. It is show that the system is the efficient integration of clean energy, renewable energy, the discharge of the flue gas could be reduced to below 30°C, and the water steam could be catch to avoid the white smoke of the stack.


Author(s):  
Lin Fu ◽  
Xiling Zhao ◽  
Shigang Zhang ◽  
Yi Jiang ◽  
Hui Li ◽  
...  

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.


2021 ◽  
pp. 1-28
Author(s):  
Christopher M. Keinath ◽  
Jared Delahanty ◽  
Srinivas Garimella ◽  
Michael A. Garrabrant

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.


Author(s):  
Xian Zhou ◽  
Hua Liu ◽  
Lin Fu ◽  
Shigang Zhang

Condensing boiler for flue gas waste heat recovery is widely used in industries. In order to gain a portion of the sensible heat and latent heat of the vapor in the flue gas, the flue gas is cooled by return water of district heating through a condensation heat exchanger which is located at the end of flue. At low ambient air temperature, some boilers utilize the air pre-heater, which makes air be heated before entering the boiler, and also recovers part of the waste heat of flue gas. However, there are some disadvantages for these technologies. For the former one, the low temperature of the return water is required while the utilization of flue gas heat for the latter one is very limited. A new flue gas condensing heat recovery system is developed, in which direct contact heat exchanger and absorption heat pump are integrated with the gas boiler to recover condensing heat, even the temperature of the return water is so low that the latent heat of vapor in the flue gas could not be recovered directly by the general condensing technologies. Direct contact condensation occurs when vapor in the flue gas contacts and condenses on cold liquid directly. Due to the absence of a solid boundary between the phases, transport processes at the phase interface are much more efficient and quite different from condensation phenomena on a solid surface. Additionally, the surface heat exchanger tends to be more bulky and expensive. In this study, an experimental platform of the new system is built, and a variety of experimental conditions are carried out. Through the analysis of the experimental data and operational state, the total thermal efficiency of the platform will be increased 3.9%, and the system is reliable enough to be popularized.


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