scholarly journals APPLICATION OF ENERGY AND EXERGY ANALYSIS TO INVESTIGATE THE OPERATION OF AN AIR HANDLING UNIT WITH HEAT PUMP

2020 ◽  
Vol 12 (0) ◽  
pp. 1-6
Author(s):  
Giedrė Streckienė ◽  
Tomas Kropas
Keyword(s):  
Heat Pump ◽  
Coefficient Of Performance ◽  
Pump Operation ◽  
Air Handling Unit ◽  
Air Supply ◽  
Energy And Exergy ◽  
Research Procedure ◽  
Energy And Exergy Analysis ◽  
Exergy Analyses ◽  
Exergy Losses

With the growth of energy-efficient building sector, ventilation systems are becoming increasingly important not only of fresh air supply but also in terms of energy consumption. The aim of this paper is to describe and analyse the operation of an air handling unit (AHU) with a heat pump using energy and exergy analyses under the variable environmental temperature (from –30 °C to 10 °C). The application of selected methods is illustrated in a case study of an AHU using environmental temperatures of Vilnius city during heating season (from the beginning of October to the end of April). An analytical method for determining distribution of the environmental (outdoor air) temperature is used. Energy and exergy analyses showed periods when the highest amounts of energy and exergy were consumed and the greatest exergy losses occurred. This allowed to reveal the component of the system with the highest exergy losses – the heat pump evaporator. Therefore, further research is needed for its design and application. At the end of the article, the seasonal indicators of the AHU with heat pump operation were calculated: coefficient of performance and exergy efficiency. The presented research procedure could be applied to the analysis of other energy systems and processes in them.

scholarly journals Energy and exergy analysis of heat pump using R744/R32 refrigerant mixture

2014 ◽  
Vol 18 (5) ◽  
pp. 1649-1654 ◽  
Author(s):  
Fang Wang ◽  
Xiao-Wei Fan ◽  
Jie Chen ◽  
Zhi-Wei Lian
Keyword(s):  
Heat Pump ◽  
Exergy Analysis ◽  
Coefficient Of Performance ◽  
Promising Alternative ◽  
Refrigerant Mixture ◽  
Discharge Temperature ◽  
Pressure Discharge ◽  
Energy And Exergy ◽  
Attractive Option ◽  
Energy And Exergy Analysis

An energy and exergy analysis of heat pump with blends of refrigerant mixture R744/R32 was carried out. The coefficient of performance and exergy efficiency of the system were studied with different mass fraction of R744 in the blends and different heat source temperatures. The volumetric heat capacity, condensing pressure, discharge temperature, and compression ratio were also investigated. The results indicate that at a certain concentration (15/85 by mass), the blends achieve better performance, and are superior to those of R22, the results also show that the new refrigerant mixture is an attractive option for promising alternative refrigerant.

Energy and exergy analyses of a solar-driven ejector-cascade heat pump cycle

Energy ◽  
2018 ◽  
Vol 165 ◽  
pp. 419-431 ◽  
Author(s):  
Fenglei Li ◽  
Zhao Chang ◽  
Xinchang Li ◽  
Qi Tian
Keyword(s):  
Heat Pump ◽  
Energy And Exergy ◽  
Exergy Analyses

scholarly journals Heat Pump Cycle Efficiency for Heat Supply

2020 ◽  
pp. 136-142
Author(s):  
Mykola Bosiy ◽  
◽  
Olexandr Kuzyk ◽  
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Exergy Analysis ◽  
Conversion Factor ◽  
Working Fluid ◽  
Heating Systems ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Heat Supply Systems ◽  
Supply Systems

The aim of the article is to analyze the literature and scientific publications on the effectiveness of the heat pump in heat supply systems and to study the efficiency of using the steam compression cycle of a heat pump in a heat supply system. Тo conduct energy and exergy analysis of heat pump efficiency indicators, the working fluid of which is freon R134a, when using natural waters as a source of low-potential thermal energy. The article analyzes the literature sources and scientific publications on the effectiveness of the heat pump in heat supply systems. The results of research of efficiency of application of the heat pump in systems of heat supply at use of natural waters as a source of low-potential thermal energy are presented. Energy and exergy analysis of heat pump efficiency indicators, the working fluid of which is R134a freon, was performed. The energy efficiency of the heat pump cycle was determined by the conversion factor of the heat pump. The thermodynamic efficiency of the heat pump in heat supply systems was evaluated using exergetic efficiency, which is one of the main indicators of the efficiency of heat pump processes and cycles. The calculation of energy indicators of the heat pump, such as: specific heat load in the evaporator and condenser, as well as the conversion factor of the heat pump. The calculation of exergetic efficiency for ambient temperature from +10 to -10 ºC. Thus, the energy and exergy analysis of the efficiency of the heat pump, the working fluid of which is Freon R134a with a conversion factor = 4.8. This indicates that the heat pump is a reliable, highly efficient, environmentally friendly source of energy for use in heating systems. A heat pump heating system will always consume less primary energy than traditional heating systems if natural water is used as a low-temperature heat source for the heat pump. The efficiency of the steam compression cycle of the heat pump largely depends on the temperature of low-potential heat sources. The use of HV in heating systems reduces greenhouse gas emissions compared to conventional types of heat supply, which is relevant to the ecological state of the environment.

scholarly journals Air-to-Water Heat Pump Operation Analysis

2020 ◽  
Author(s):  
Ljubomir Malić ◽  
◽  
Aleksandra Paunović ◽  
Uroš Milovančević ◽  
Milena Otović
Keyword(s):  
Theoretical Analysis ◽  
Heat Pump ◽  
Mechanical Engineering ◽  
Thermodynamic Cycle ◽  
Coefficient Of Performance ◽  
Reciprocating Compressor ◽  
Heating Season ◽  
Pump Operation ◽  
Operation Analysis

The aim of this paper is a theoretical analysis of the operation of an air-to-water heat pump located in the Labo-ratory for Thermal Science at the Faculty of Mechanical Engineering in Belgrade. This results provide the basis for further experimental analyzes of this installation.The paper gives a comparative overview of the performance of a scroll and reciprocating compressor when pro-pane (R290) is used as a refrigerant. Also, the analysis of the influence of internal subcooling on the thermodynamic cycle is presented. Finally, according to the developed model of the heat pump performances investigation, the change in the average values of Coefficient of Performance (COP) during the average heating season, forthe period 2014 –2018, is shown.

scholarly journals Energy and Exergy Analysis of the Condensate Pump During Internal Leakage from the Marine Steam Propulsion System

Pomorstvo ◽  
2018 ◽  
Vol 32 (2) ◽  
pp. 268-280
Author(s):  
Igor Poljak ◽  
Josip Orović ◽  
Vedran Mrzljak
Keyword(s):  
Exergy Analysis ◽  
Pump Energy ◽  
Propulsion System ◽  
Normal Operation ◽  
Energy Losses ◽  
Load Range ◽  
Condensate Pump ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Exergy Losses

An energy and exergy analysis of the condensate pump from the marine steam propulsion system during the condensate leakage between pump stages is presented in this paper. Measurements from the steam propulsion system during exploitation were necessary for collecting all the data for the condensate pump analysis. Due to condensate leakage inside the pump casing, the producer specified condensate pressures at the pump outlet could not be obtained during the exploitation. Low condensate pressure at the pump inlet and condensate temperature slightly above the atmospheric significantly influences the pump exergy analysis. Increase in pump load resulted in an increase of pump energy and exergy losses and efficiencies. In the observed load range during the leakage, pump energy losses are between 19.88 kW and 24.78 kW, while pump energy efficiencies are between 11.12 % and 41.54 %. Pump exergy losses are slightly higher, while exergy efficiencies are slightly lower when compared to energy losses and efficiencies. During normal operation, without leakage, the pump energy efficiencies are from 5 % to 20 % higher in comparison with pump operation when the leakage occurs.

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