Experimental Study on Performance Enhancement of Heat Pump With Screw Compressor

2004 ◽  
Author(s):  
Wu Huagen ◽  
Shu Pengcheng ◽  
Zhao Yuanyang ◽  
Xing Ziwen
Keyword(s):  
Heat Pump ◽  
Air Conditioning ◽  
Performance Enhancement ◽  
Coefficient Of Performance ◽  
Screw Compressor ◽  
Alternative Refrigerants ◽  
Air Source Heat Pump ◽  
Central Air Conditioning ◽  
Compressor Performance ◽  
Industrial Refrigeration

The air-source heat pump has been widely used in industrial refrigeration and central air-conditioning applications because of its unique superiority. An important consideration in the design of heat pump is improving its COP (coefficient of performance). In this paper, the results of experimental investigation on the effects of alternative refrigerants (R22, R134a, R404A and R407C) and economizer on the performance of heat pump are presented. The COP of the heat pump used R134a is up to 4.5% higher than R22, but its capacity got a 37.08% decrease. The refrigerant R407C applied in heat pump can improve the capacity up to 7.86% than R22, but its COP shows a decrease up to 5.92%. The refrigerant R404A used in heat pump will result in poor capacity and COP compared to R22. The economizer system used in heat pump will improve the COP, but as the superfeed pressure of the economizer increases, the system COP increases first, and then drops. So there exists an optimal superfeed pressure of the economizer for the best COP. Also, the effect of the economizer on the screw compressor performance is analyzed by recording the P-v indicator diagram.

scholarly journals Modeling and Simulation of Heat Pump Air-Conditioning System using Ecofriendly Refrigerants

2021 ◽  
Vol 9 (VI) ◽  
pp. 1166-1170
Author(s):  
Ajay Landage
Keyword(s):  
Energy Efficiency ◽  
Comparative Analysis ◽  
Physical Properties ◽  
Heat Pump ◽  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Simulation Approach ◽  
Alternative Refrigerants ◽  
Air Conditioning System ◽  
Selection Of

A simulation approach to heat pump systems is proposed in this paper. The evaluation of working fluids is conducted. Moreover, the selected refrigerants are used in the simulation. Subsequently, the system is analyzed in terms of the coefficient of performance (COP) and energy efficiency. Some alternative refrigerants, instead of R22 used R290 refrigerent. It is described the selection of refrigerants adapted to each utilization, based on the thermodynamic and -physical properties, the technological behaviour, costs and use constraints as principal aspects of the environmental protection. Also, it is performed a comparative analysis in function of the total equivalent warming impact (TEWI) for some possible substitutes of refrigerant R22 used in various refrigeration and heat pump systems.

scholarly journals Studying a Hybrid System Based on Solid Oxide Fuel Cell Combined With an Air Source Heat Pump and With a Novel Heat Recovery

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Giulio Vialetto ◽  
Marco Noro ◽  
Masoud Rokni
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Electric Power ◽  
Heat Pump ◽  
Heat Recovery ◽  
Research Work ◽  
Solid Oxide ◽  
Coefficient Of Performance ◽  
Oxide Fuel ◽  
Air Source Heat Pump

In this paper, a new heat recovery for a microcogeneration system based on solid oxide fuel cell and air source heat pump (HP) is presented with the main goal of improving efficiency on energy conversion for a residential building. The novelty of the research work is that exhaust gases after the fuel cell are first used to heat water for heating/domestic water and then mixed with the external air to feed the evaporator of the HP with the aim of increasing energy efficiency of the latter. This system configuration decreases the possibility of freezing of the evaporator as well, which is one of the drawbacks for air source HP in Nordic climates. A parametric analysis of the system is developed by performing simulations varying the external air temperature, air humidity, and fuel cell nominal power. Coefficient of performance (COP) can increase more than 100% when fuel cell electric power is close to its nominal (50 kW), and/or inlet air has a high relative humidity (RH) (close to 100%). Instead, the effect of mixing the exhausted gases with air may be negative (up to −25%) when fuel cell electric power is 20 kW and inlet air has 25% RH. Thermodynamic analysis is carried out to prove energy advantage of such a solution with respect to a traditional one, resulting to be between 39% and 44% in terms of primary energy. The results show that the performance of the air source HP increases considerably during cold season for climates with high RH and for users with high electric power demand.

The Economic Performance of Ground-Source Heat Pumps

2014 ◽  
Vol 919-921 ◽  
pp. 1735-1738 ◽  
Author(s):  
Peng Gong ◽  
Jian Tang
Keyword(s):  
Energy Efficiency ◽  
Total Energy ◽  
Heat Pump ◽  
Air Conditioning ◽  
Ground Source Heat Pump ◽  
Ground Source Heat Pumps ◽  
Heating Systems ◽  
Ground Source ◽  
Groundwater Heat Pump ◽  
Central Air Conditioning

Ground-Source Heat Pump (PSHP) was verified by US Environmental Protection Agency (EPA) as one of the most efficient air conditioning systems on present market. It has a higher efficiency than other heating systems from 50% to 70%, and a higher efficiency than other cooling systems from 30% to 50%. The working principle of PSHP determines its low operating costs. By comparing the total energy efficiency, the existing groundwater heat pump total energy efficiency is the highest, about 115%. The total energy efficiency for soil-source heat pump is up to 100%. But traditional air conditioning is far less than the level. Articles present a research on Ground-Source Heat Pump system and its cost with a scientific and objective principles. Ground-source heat pump is a new central air conditioning system of Low-carbon energy saving. Due to the high technical content, function requirement, and installation difficulty , the average initial investment of ground-source heat pump is much higher than traditional central air conditioning. Taking into account the added costs of heating systems based on traditional central air-conditioning, such as boilers, it will not deviate too much from it.

scholarly journals Frosting Phenomenon and Frost-Free Technology of Outdoor Air Heat Exchanger for an Air-Source Heat Pump System in China: An Analysis and Review

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2642 ◽  
Author(s):  
Yi Zhang ◽  
Guanmin Zhang ◽  
Aiqun Zhang ◽  
Yinhan Jin ◽  
Ruirui Ru ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Operating Cost ◽  
Heating System ◽  
Coefficient Of Performance ◽  
Outdoor Air ◽  
Pump System ◽  
Heat Pump System ◽  
Reduce Operating Cost ◽  
Air Source Heat Pump

Frost layer on the outdoor air heat exchanger surface in an air-source heat pump (ASHP) can decrease the system coefficient of performance (COP). Although the common defrosting and anti-frosting methods can improve the COP, the periodic defrosting not only reduces the system energy efficiency but also deteriorates the indoor environment. To solve these problems, it is necessary to clearly understand the frosting phenomenon and to achieve the system frost-free operation. This paper focused firstly on the analyses of frosting pathways and frosting maps. Followed by summarizing the characteristics of frost-free technologies. And then the performances of two types of frost-free ASHP (FFASHP) systems were reviewed, and the exergy and economic analysis of a FFASHP heating system were carried out. Finally, the existing problems related to the FFASHP technologies were proposed. Results show that the existing frosting maps need to be further improved. The FFASHP systems can not only achieve continuous frost-free operation but reduce operating cost. And the total COP of the FFASHP heating system is approximately 30–64% higher than that of the conventional ASHP system under the same frosting conditions. However, the investment cost of the FFASHP system increases, and its reliability also needs further field test in a wider frosting environment. In the future, combined with a new frosting map, the control strategy for the FFASHP system should be optimized.

scholarly journals The Performance of an ASHP System Using Waste Air to Recover Heat Energy in a Subway System

2019 ◽  
Vol 1 (1) ◽  
pp. 154-163 ◽  
Author(s):  
Konstantinos Ninikas ◽  
Nicholas Hytiris ◽  
Rohinton Emmanuel ◽  
Bjorn Aaen
Keyword(s):  
Heat Pump ◽  
Air Temperature ◽  
Short Communication ◽  
Heat Energy ◽  
Coefficient Of Performance ◽  
Air Source Heat Pump ◽  
Lessons Learnt ◽  
Waste Air ◽  
Subway System

In this short communication, we demonstrate that the performance of a typical air source heat pump (ASHP), exploiting a relatively stable air temperature within a subway environment, is high, even during the peak heating months. After a nine-month operational run, the coefficient of performance is demonstrated to be 3.5. The design and installation difficulties are stated together with the lessons learnt following this trial. The actual energy and carbon savings are discussed.

Analysis of Domestic Hot Water Production Efficiency for Detached Houses

2015 ◽  
Vol 797 ◽  
pp. 185-191
Author(s):  
Arkadiusz Gużda ◽  
Norbert Szmolke
Keyword(s):  
Heat Pump ◽  
Production Efficiency ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Production ◽  
Water Heater ◽  
Domestic Hot Water ◽  
Air Source Heat Pump ◽  
Heat Pump Water Heater ◽  
Detached House

The article compares two means for domestic hot water production (DHW) for a detached house that is using gas boiler with a closed combustion chamber and air source heat pump water heater (ASHPWH). An analysis of domestic hot water production using an air source heat pump was made taking into account coefficient of performance listed according to the new BS EN 16147 standard. The analysis of outlay related to the investment and operating costs was also performed. Ultimately, the more profitable choice for domestic hot water production was made.

Combined Desalination and Refrigeration Systems Driven by Low-Grade Heat

2008 ◽  
Author(s):  
Yongqing Wang ◽  
Noam Lior
Keyword(s):  
Heat Pump ◽  
Gas Turbines ◽  
Air Conditioning ◽  
Saturation Pressure ◽  
Coefficient Of Performance ◽  
Saturated Steam ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Wide Range ◽  
Low Grade Heat

There is often a need for both water desalination and cooling (refrigeration/air-conditioning). The cooling can be used to significantly raise system efficiency by compressor inlet cooling in a dual-purpose power-generation and desalination system using gas turbines, or simply to supply refrigeration or air conditioning beside fresh water. Motivated by the good synergetic potential of energy/exergy utilization through the combination of the LiBr-H2O refrigeration unit, LiBr-H2O heat pump, and low-temperature multi-effect evaporation desalter, two combined refrigeration and water systems, ARHP-MEE (Absorption Refrigeration Heat Pump and Multi-Effect Evaporation desalter) system and ARHP-AHP-MEE (Absorption Refrigeration Heat Pump + Absorption Heat Pump + Multi-Effect Evaporation desalter) system, driven by low-grade heat were configured, modeled and analyzed in detail in the paper. Typically, driving steam with saturation pressure of 0.15–0.35 MPa and correspondingly saturation temperature of 111.4–138.9°C is applicable to run the systems. The main results are: (1) the combined systems have good synergy, with an energy saving rate of 42% in a case study of ARHP-MEE; (2) the refrigeration-heat cogenerated ARHP subsystem is the main reason for the synergy, where the coefficient of performance is around 1.6 and exergy efficiency above 60% when driven by 0.25 MPa saturated steam; (3) at the cost of a more complex configuration, the ARHP-AHP-MEE system has the ability of varying its outputs in very wide range, offering good flexibility on design and operation; (4) the ARHP-MEE system is predicted to have good economics, and its outputs can be varied in a wide range but not independently because their ratio remains almost constant. A parametric analysis was also performed for the ARHP-MEE, further improving the understanding of the system performance.

Economic Analysis of Solar Energy/Air Compound Source Heat Pump System

2011 ◽  
Vol 130-134 ◽  
pp. 1605-1608
Author(s):  
Tao Liu ◽  
Zhi Gang Zhang ◽  
Wei Zhang
Keyword(s):  
Solar Energy ◽  
Economic Analysis ◽  
Heat Pump ◽  
Air Conditioning ◽  
Evaluation Criteria ◽  
System Model ◽  
Pump System ◽  
Heat Pump System ◽  
Heating Systems ◽  
Air Source Heat Pump

The foundation, principle and prior condition and engineering economic Evaluation Criteria of engineering economic analysis are introduced. The economy for a solar energy/air source heat pump system is analyzed. Through a single air-cooled heat pump system, air conditioning in summer + winter heating systems, solar / air source compound heat pump system model analysis and comparison of three systems, integrated initial investment and running costs of both, come to solar / air source compound heat pump system has certain advantages in economical efficiency.

Heating Performance Investigations on Two Applications of a Solar Assisted Air Source Heat Pump System

2011 ◽  
Vol 374-377 ◽  
pp. 284-287 ◽  
Author(s):  
Yu Wang ◽  
Yu Wen You ◽  
Zhi Gang Zhang
Keyword(s):  
Heat Pump ◽  
Solar Collector ◽  
Coefficient Of Performance ◽  
Experimental Investigations ◽  
Pump System ◽  
Heat Pump System ◽  
Heating Performance ◽  
Air Source Heat Pump

A solar assisted air source heat pump (SAASHP) system is proposed to improve heating performance of air source heat pump (ASHP).The proposed system has been applied in two buildings, a series of experimental investigations were conducted in the both applications, it indicated that the SAASHP system gets better heating performance than ASHP system, the coefficient of performance (COP) gets 10% and 65% increase respectively in two applications. It is also concluded that the ratio of solar collector area to construction area significantly affects the improvement of heating performance in SAASHP system. This work may promote further research and more applications of SAASHP system.

scholarly journals Exploratory Research to Improve Energy-Efficiency of a Ground-Coupled Heat Pump Utilizing an Automatic Control Device of Circulation Pump Speed

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5016
Author(s):  
Ioan Sarbu ◽  
Calin Sebarchievici
Keyword(s):  
Energy Efficiency ◽  
Simulation Model ◽  
Heat Pump ◽  
Co2 Emission ◽  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Exploratory Research ◽  
Circulation Pump ◽  
Pump Speed ◽  
Heat Pump Unit

Ground-coupled heat pumps (GCHPs) are an efficient thermal energy production system that can satisfy the gap between heating and air-conditioning. Be that as it may, exploratory research on GCHPs is still lacking. The first objective of this article is to describe a utilitarian energy-efficiency improvement device for a vertical GCHP system that includes a buffer tank (BT) between the heat pump unit and the fan coil units and user supply, utilizing the quantitative regulation of water flow rate with a variable-speed circulation pump. At that point, the investigative estimations are utilized to test the performances of the GCHP system in various operating modes. Fundamental efficiency parameters (coefficient of performance (COP) and CO2 emission) are achieved for one month of running utilizing two control strategies of the GCHP—standard and optimized regulation of the water pump speed—and a benchmarking of these parameters is achieved. Exploratory research has indicated higher efficiency of the system for the flow regulation solution utilizing a BT and programmed control equipment for the circulation pump speed compared with the standard regulation solution (COPsys with 7–8% higher and CO2 emission level 7.5–8% lower). The second objective is to elaborate a simulation model of the necessary heat/cold in heating and air-conditioning periods, utilizing the Transient Systems Simulation (TRNSYS) program. Finally, the simulation, acquired utilizing the TRNSYS program, is analyzed and compared with experimental information, leading to a good agreement and, along these lines, the simulation model is approved.

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