scholarly journals Comparative effects of two injection paths on performance of a heat pump with a sub-cooler injection configuration

2020 ◽  
Vol 15 (3) ◽  
pp. 336-350
Author(s):  
Qiu Tu ◽  
Xiujuan Guo ◽  
Lina Zhang ◽  
Jingjing Shao ◽  
Vladimir Soldo ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Pressure Ratio ◽  
High Energy ◽  
Coefficient Of Performance ◽  
Practical Operation ◽  
Expansion Valve ◽  
Electricity Power ◽  
Operation Control ◽  
Injection Technology

Abstract As one of the most promising and convenient heating service to replace coal-fired boilers and electric heaters due to its high energy efficiency, a heat pump has received more and more attention for the economical application and extensive research. The injection technology can be used to improve the heat pump performance. Currently, the injection ratio and pressure ratio are usually used to characterize the effects of injection styles on its performance. This is not conducive to its practical operation control because of additional cost increase. In this work, the effects of two injection cycles due to two injection paths were characterized with openings of a sub-cooling electronic expansion valve, comparatively tested and analyzed. Test results demonstrate that the heating capacities (Qh), electricity power (EP) and coefficient of performance with the refrigerant injection into compressor (CRI) are more than those with the injection into accumulator (ARI), and the overall effect with the CRI is positive because the Qh improvement outperforms EP increase. For example, the maximum Qh with the CRI at 55, 60 and 85 rps were 8.1%, 7.7% and 18.3% higher than those without the CRI, and 7.3%, 6.7% and 19.0% higher than those with the ARI. The thermodynamic model was used to analyze the experimental results and expound the mechanism of the influence of injection path on the performance of heat pump. This work provides guidance for improving energy efficiency in common areas and enhancing Qh in cold areas.

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 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.

scholarly journals An analytical method for defining the pump`s power optimum of a water-to-water heat pump heating system using COP

2017 ◽  
Vol 21 (5) ◽  
pp. 1999-2010 ◽  
Author(s):  
Jozsef Nyers
Keyword(s):  
Mathematical Method ◽  
Energy Efficiency ◽  
Objective Function ◽  
Heat Pump ◽  
Cold Water ◽  
Optimization Procedure ◽  
Heating System ◽  
Coefficient Of Performance ◽  
Optimum Conditions ◽  
First Derivative

This paper analyzes the energy efficiency of the heat pump and the complete heat pump heating system. Essentially, the maximum of the coefficient of performance of the heat pump and the heat pump heating system are investigated and determined by applying a new analytical optimization procedure. The analyzed physical system consists of the water-to-water heat pump, circulation and well pump. In the analytical optimization procedure the "first derivative equal to zero" mathematical method is applied. The objective function is the coefficient of performance of the heat pump, and the heat pump heating system. By using the analytical optimization procedure and the objective function, as the result, the local and the total energy optimum conditions with respect to the mass flow rate of hot and cold water i. e. the power of circulation or well pump are defined.

Experimental Research on Performance of Heat Pump Using Shower Waste Water as Heat Source

2011 ◽  
Vol 480-481 ◽  
pp. 887-892 ◽  
Author(s):  
Han Dong Wang
Keyword(s):  
Waste Water ◽  
Energy Saving ◽  
Heat Pump ◽  
High Energy ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Small Scale ◽  
Stable Operation ◽  
Water Tank ◽  
Water Heater

As we know, there is plenty of waste hot water produced by families’ shower or Sauna and drained directly into the environment. It causes high energy consumption and heat pollution to the environment. In order to recover the heat of shower waste water to save energy, we developed a small scale shower waste water source heat pump (SWWHP) water heater and carried out experiments on it to study its heating performance. Experiments showed that this heat pump water heater system had advantages such as quick starting, compact structure, no need of hot water tank, stable operation and energy saving, etc. It could be used to supply hot water above 40°C for shower or heating, ventilation and air conditioning (HVAC). Measured data showed that during the whole year, when the temperatures of waste water and city water were 20.1～35°C, 20.1～30°C, respectively, it could supply hot water at volumetric flow rate of 2.5～9.6L/min and temperature of 40.1～51.2°C and its heating coefficient of performance (COPh) varied in the range of 3.06～4.81. It could supply enough shower hot water in the whole year in South China and the energy saving efficiency was obvious. Analysis also showed that the COPh was closely relevant to the ratio of temperature differences of waste water and hot water, i.e., ΔTw/ΔTh. The correlation equation of COPh and ΔTw/ΔTh was obtained by method of data regression and it could be used to evaluate the performance of the SWWHP water heater system with error of ±6%.

scholarly journals An Analytical Comparison Between the Performance of a Hot Water Heat Pump With a Non-Azeotropic Refrigerant Mixture and a Pure Refrigerant

1997 ◽  
Author(s):  
F. J. Smit ◽  
Josua P. Meyer
Keyword(s):  
Heat Pump ◽  
Boiling Point ◽  
Fossil Fuels ◽  
Pressure Ratio ◽  
Heat Pumps ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Refrigerant Mixture ◽  
Compressor Pressure Ratio ◽  
Heating Capacity

The applications of hot water in the industrial, domestic and mining applications are numerous, and these are only a few of the core areas of use. In these applications fossil fuels and electrical resistance systems are usually used to heat water to temperatures near boiling point. The refrigerant R22, that is currently being used in hot water heat pumps, delivers hot water temperatures from 60 °C to 65 °C. This limits the applications of hot water heat pumps. This analytical study uses three comparison methods to investigate and compare the potential of a non-azeotropic refrigerant mixture consisting of R22 and R142b. From the results different advantages of non-azeotropic refrigerant mixtures are evident. Depending on the application, if the results of a non-azeotropic refrigerant mixture are compared with a pure R22 heat pump, an increase in hot water temperatures to above boiling point, an increase in coefficient of performance, an increase in capacity and a decrease in compressor pressure ratio are possible. Unfortunately, not all these advantages are valid for each application. For instance, extremely high hot water temperatures are obtained, whilst the heating capacity is excessively low.

Experimental Study on Solar Assisted Heat-Pump Water Heating System

2012 ◽  
Vol 178-181 ◽  
pp. 151-154
Author(s):  
Yuan De Dai ◽  
Na Yu
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Experimental System ◽  
Heating System ◽  
High Energy ◽  
Efficiency Ratio ◽  
Water Heating ◽  
Collecting Efficiency ◽  
Solar Water Heating System ◽  
Heating Technology

Solar assisted heat-pump water heating system combines the advantages of Solar Utilization Technology and heat pump water heating technology, it is a new water heating system with energy conservation and environmental protection. Under the premise of putting up experimental system, some performance parameters have been tested, such as the heating rate, the heat collecting efficiency of the system and the influence of indoor air temperature on the outlet water temperature and the energy efficiency ratio of the water heating system. The experimental results show that solar assisted heat-pump water heating system has the advantages of high energy efficiency ratio, shorter consuming time than traditional solar water heating system when heating water, and it can be concluded that this new water heating system should be applied in the future.

scholarly journals Life cycle cost analysis of different residential heat pump systems

2020 ◽  
Vol 207 ◽  
pp. 01014
Author(s):  
Nadezhda Doseva ◽  
Daniela Chakyrova
Keyword(s):  
Energy Efficiency ◽  
Life Cycle ◽  
Heat Pump ◽  
Life Cycle Cost ◽  
Residential Buildings ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling

Nowadays, the application of air-source heat pumps for heating and cooling in residential buildings has been increased significantly. The main occasion for this is the accessibility of a heat source for these devices - the external air. Nevertheless, the increase of the energy efficiency of the air source heat pump systems is a difficult design problem because their capacity and performance are a function of the dynamically changing parameters of the outdoor air. Because of that, the main aim of this study is to develop an approach for choosing a structural scheme of an air-to-water heat pump system under specific climatic conditions. The considered systems are monovalent, bivalent-parallel and bivalent-alternative heat pump systems. In the current paper is conducted a dynamic energy modeling of heating and cooling demand of a typical residential building situated in Varna, Bulgaria and applying the bin temperature data. It is assessed the effect of the heat pump capacity over the annual and seasonal energy performance of the heat pump systems. It is established the effect of the bivalent temperature, cut-off temperature and on-off cycles duration on rates of the criteria for techno-economic assessment. The seasonal coefficient of performance (SCOP), seasonal energy efficiency rate (SEER) and life cycle costs (LCC) of the analyzed heat pump systems are adopted as assessment parameters.

Technical and Economic Analysis of Biomass Integrated Gasification Combined Cycle

2010 ◽  
Author(s):  
Sebastian Lepszy ◽  
Tadeusz Chmielniak
Keyword(s):  
Energy Efficiency ◽  
Economic Analysis ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
High Energy ◽  
Combined Cycle ◽  
Electricity Production ◽  
Gas Generator ◽  
Integrated Gasification ◽  
The Impact

Biomass integrated gasification combined cycles (BIGCC) are an interesting solution for electricity production. In relation to other biomass conversion technologies, BIGCC is characterized by relatively high energy efficiency. This article presents models and results of simulations of the gas steam cycles integrated with pressurized gasification using biomass as a feedstock. The model and simulations are preformed with Aspen Plus® computer program. The gas generator model consists of two equilibrium reactors. The use of two reactors led to more precise simulations of the flue gas composition, than the model with one reactor. The systems used for study include high-temperature gas cleaning system and a simple gas turbine. The steam cycle consists of 1-pressure heat recovery steam generator (HRSG) and a condensing steam turbine. The main results of the work are: comparison of energy efficiency for a system with different pressure ratio in a gas turbine, sensitive analysis of the impact of steam temperature and pressure in HRSG on energy efficiency. The economic analysis includes determination of the electricity price in Polish economic conditions.

scholarly journals Energy efficiency for the transcritical compression CO2 cycle with the use of the ejector as the first stage of the compression

2010 ◽  
Vol 31 (4) ◽  
pp. 61-69 ◽  
Author(s):  
Joachim Kozioł ◽  
Wiesław Gazda ◽  
Łukasz Wilżyński
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Single Stage ◽  
Coefficient Of Performance ◽  
Operating Characteristics ◽  
Two Phase

Energy efficiency for the transcritical compression CO2cycle with the use of the ejector as the first stage of the compressionAn analysis of energy efficiency for transcritical compression unit with CO2 (R744) as the refrigerant has been carried out using empirical operating characteristics for the two-phase ejector. The first stage of the refrigerant compression is carried out in the ejector. The criterion adopted for the estimation of energy efficiency for the cycle is the coefficient of performance COP. The analysis is performed for the heat pump and refrigeration systems. The results of COP for the systems with the ejector has been compared with the COPLvalues for the single stage Linde cycle.

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