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 Comparison of Transcritical CO2 and Conventional Refrigerant Heat Pump Water Heaters for Domestic Applications

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 479
Author(s):  
Ignacio Paniagua ◽  
Ángel Álvaro ◽  
Javier Martín ◽  
Celina Fernández ◽  
Rafael Carlier
Keyword(s):  
Heat Pump ◽  
Thermodynamic Cycle ◽  
Heat Pumps ◽  
Design Tool ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ambient Conditions ◽  
Water Heater ◽  
Water Heaters

Although CO 2 as refrigerant is well known for having the lowest global warming potential (GWP), and commercial domestic heat pump water heater systems exist, its long expected wide spread use has not fully unfolded. Indeed, CO 2 poses some technological difficulties with respect to conventional refrigerants, but currently, these difficulties have been largely overcome. Numerous studies show that CO 2 heat pump water heaters can improve the coefficient of performance (COP) of conventional ones in the given conditions. In this study, the performances of transcritical CO 2 and R410A heat pump water heaters were compared for an integrated nearly zero-energy building (NZEB) application. The thermodynamic cycle of two commercial systems were modelled integrating experimental data, and these models were then used to analyse both heat pumps receiving and producing hot water at equal temperatures, operating at the same ambient temperature. Within the range of operation of the system, it is unclear which would achieve the better COP, as it depends critically on the conditions of operation, which in turn depend on the ambient conditions and especially on the actual use of the water. Technology changes on each side of the line of equal performance conditions of operation (EPOC), a useful design tool developed in the study. The transcritical CO 2 is more sensitive to operating conditions, and thus offers greater flexibility to the designer, as it allows improving performance by optimising the global system design.

scholarly journals Seasonal coefficient of performance of air-to-air heat pump and energy performance of a building in Poland

2019 ◽  
Vol 116 ◽  
pp. 00039 ◽  
Author(s):  
Piotr Kowalski ◽  
Paweł Szałański
Keyword(s):  
Heat Pump ◽  
Energy Performance ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Climatic Data ◽  
Heating Season ◽  
Season Length ◽  
Local Climate ◽  
Significant Difference

The article discusses the problem of determining for air heat pumps the seasonal efficiency of energy production necessary to determine the energy performance of a building. On the example of selected Polish cities (Suwalki, Bialystok, Warsaw, Wroclaw, Zielona Gora, Resko, Szczecinek, Koszalin) the influence of climatic conditions on the SCOP of an exemplary air-to-air heat pump and on the result of building energy performance calculations was analysed. SCOPs for each location were determined according to the method of EN 14825. The difference between SCOP for average (A) and colder (C) climates according to EN 14825 was 35.6%. It has been shown that the climate of Polish cities may be similar to both the average climate (A) and the colder climate (C), or they significantly differ from both climates. The most significant difference in SCOP between the analysed cities was obtained for Suwalki and Szczecinek. It was 31.9% and 31.4% for the assumed heating season length as for climate (A) and (C) respectively. For the exemplary building in Suwalki, taking SCOP for the average climate (A) and not based on climatic data of Suwalki gives an error of 39.3% in the calculation of primary energy for heating. For the same locations, the differences in SCOP and EP resulting from the assumption of the heating season length as for the average climate (A) or as for the colder climate (C) were respectively from 2.4% to 3.3% and from -3.4% to -2.2%. In diversified Polish climate, assuming the same SCOP values of air heat pumps regardless of location does not allow for their full comparison with devices whose efficiency does not depend on climatic conditions. The authors suggest that when calculating the energy performance of the building, the SCOP should be always determined on the basis of the local climate and the length of the heating season.

The Norwich Heat Pump

1948 ◽  
Vol 158 (1) ◽  
pp. 22-29 ◽  
Author(s):  
J. A. Sumner
Keyword(s):  
Great Britain ◽  
Heat Pump ◽  
Heat Engine ◽  
Electric Energy ◽  
Large Block ◽  
Coefficient Of Performance ◽  
Heating Season ◽  
Final Temperature ◽  
Financial Saving ◽  
Large Heat

The paper provides the history and constructional details and working results of what is believed to be the first large heat pump used for building heating in Great Britain. This machine was constructed and installed as an experimental machine for heating a large block of municipal buildings in Norwich. A brief explanation indicating the principle upon which the heat pump works is given. Reference is also made to the differences between the reversed heat engine when working as a refrigerator and when working as a heat pump. In the latter case there is a deliberate increase in the final temperature T1, from approximately 85 deg. F. to temperatures which may be of the order of 150–200 deg. F. The unsuitability of the term “coefficient of performance”—normally used as a criterion of refrigerator performance—when used as a coefficient relating to the heat pump is pointed out; and the use of a new, alternative term is suggested. The results are shown of operating the Norwich Heat Pump for two winter heating seasons. When using an unsuitable compressor the heat delivered to the building was found to be 3·45 times greater than the equivalent heat (electric) energy required to operate the machine, averaged over the 1945–6 winter heating season. With a more efficient compressor, installed later in 1946, a still better performance is anticipated. The actual costs of heating the building, with coal-fired boilers and a heat pump respectively, are shown in the form of a table. Conclusions indicated are that the heat pump can show a financial saving, as compared with the use of coal-fired boilers, and that it is practicable to use the heat pump in Great Britain for building heating throughout normal English winters.

scholarly journals OPERATION ANALYSIS OF THE AIR-SOURCE HEAT PUMP USING TRNSYS SIMULATION TOOL

2021 ◽  
Vol 13 (0) ◽  
pp. 1-6
Author(s):  
Gabrielė Daugirdaitė ◽  
Giedrė Streckienė ◽  
Tomas Kropas
Keyword(s):  
Heat Pump ◽  
Real Data ◽  
Cold Season ◽  
Heat Pumps ◽  
Climatic Data ◽  
Pump Operation ◽  
Operation Analysis ◽  
Air Source Heat Pump ◽  
Heating Capacity ◽  
Heating Mode

In order to achieve ambitious goals for energy efficiency and requirements for near zero energy buildings, various technological solutions enabling the use of renewable energy are proposed and applied. One such rapidly spreading technology is heat pumps. However, the use of air-­to-­water heat pumps in countries where the cold season is cold and humid has unfavourable conditions for the operation of this equipment during the heating season. As a result, the performance efficiency of the equipment decreases. This article presents the simulation results of an air-­to-­water heat pump operation in Lithuania using the TRNSYS modelling tool; its nominal heating capacity is 6.55 kW. The model was calibrated using real data obtained at Vilnius Gediminas Technical University when measurements were performed under heat pump freezing conditions. The seasonal performance factor of the heat pump heating mode was determined during the calculation. Parametric analysis of the model was also performed, when sensitivity of the model to the initial climatic data was observed. Comparable results are obtained for Vilnius, Prague and London.

The Experimental Investigation and Theoretical Analysis on Transcritical Carbon Dioxide Heat Pump Cycle

2012 ◽  
Vol 455-456 ◽  
pp. 240-245
Author(s):  
Lu Xiang Zong ◽  
Jian Lin Liu ◽  
Xue Shi ◽  
Ying Bai Xie
Keyword(s):  
Carbon Dioxide ◽  
Experimental Investigation ◽  
Theoretical Analysis ◽  
Heat Pump ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Working Fluids ◽  
Heat Pump System ◽  
Exit Temperature ◽  
Transcritical Carbon Dioxide

The (H)CFC-phase out and the fear for future problems for other synthetic working fluids, because of their known and unknown impact on the environment, have introduced a rising interest in environmentally safe natural working fluids. CO2is one of the few non-toxic and non-flammable working fluids that do not contribute to ozone depletion or global warming, if leaked to the atmosphere. Because the critical temperature of CO2is only 31.1°C, the transcritical cycle can be used to improve the coefficient of performance of the system. The experimental investigation and theoretical analysis on transcritical carbon dioxide heat pump system are carried out in this paper. It points out that there is an optimum operational pressure on transcritical carbon dioxide heat pump cycle, when the outlet temperature of gas cooler is constant, the coefficient of performance increases with increasing evaporating temperature at the same conditions, and the operational efficiency increased with decrease of gas cooler exit temperature. So in order to obtain the optimum performance, the influence of evaporating temperature, gas cooler exit temperature, and the operational pressure should be considered during the designing and operating transcritical carbon dioxide heat pump system.

scholarly journals The Viability of Capacity Control of High Temperature Heat Pump Water Heaters Operating Non-Azeotropic Mixtures

1997 ◽  
Author(s):  
Leon Liebenberg ◽  
Josua P. Meyer
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
Life Cycle Cost ◽  
Coefficient Of Performance ◽  
Capacity Control ◽  
Water Heater ◽  
Pump Operation ◽  
Water Heaters ◽  
Heat Pump Water Heater ◽  
Controlled Systems

A high temperature electrically-operated heat pump water heater is evaluated in terms of the viability of employing capacity control using non-azeotropic refrigerant mixtures (NARMs). The system coefficient of performance (COP) is improved by introducing capacity control, which offers continuous modulation by varying heat pump capacity to match the load. This is accomplished by using a non-azeotropic refrigerant mixture (NARM) and changing the composition (x) of the circulating mixture. The NARM R-22/ R-142b is selected due to the requirement for a high condensing temperature and a wide capacity range. The life-cycle cost effectiveness of this heat pump is compared with that of a conventional heat pump (operating a pure fluid). Computer simulations show that the capacity-controlled heat pump, operating between compositions of 100% R-22 and 70% R-22, shows a 29.6% improvement in energy conversion when compared with a conventional R-22 heat pump water heater. The payback periods of the capacity-controlled systems, are strongly dependent on electricity tariff, additional system cost, and period and duration of heat pump operation.

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.

Performance analysis of photovoltaic-thermal road assisted ground source heat pump system during non-heating season

Solar Energy ◽  
2021 ◽  
Vol 221 ◽  
pp. 10-29
Author(s):  
Bo Xiang ◽  
Yasheng Ji ◽  
Yanping Yuan ◽  
Chao Zeng ◽  
Xiaoling Cao ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Heat Pump ◽  
Ground Source Heat Pump ◽  
Heating Season ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source

scholarly journals Heat Pump Bridge Analysis Using the Modified Energy Transfer Diagram

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 137
Author(s):  
Florian Schlosser ◽  
Heinrich Wiebe ◽  
Timothy G. Walmsley ◽  
Martin J. Atkins ◽  
Michael R. W. Walmsley ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Heat Pump ◽  
Heat Recovery ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Combined Application ◽  
Recovery Potential ◽  
Composite Curve ◽  
And Performance ◽  
The Individual

Heat pumps are the key technology to decarbonise thermal processes by upgrading industrial surplus heat using renewable electricity. Existing insight-based integration methods refer to the idealised Grand Composite Curve requiring the full exploitation of heat recovery potential but leave the question of how to deal with technical or economic limitations unanswered. In this work, a novel Heat Pump Bridge Analysis (HPBA) is introduced for practically targeting technical and economic heat pump potential by applying Coefficient of Performance curves into the Modified Energy Transfer Diagram (METD). Removing cross-Pinch violations and operating heat exchangers at minimum approach temperatures by combined application of Bridge Analysis increases the heat recovery rate and reduce the temperature lift to be pumped at the same time. The insight-based METD allows the individual matching of heat surpluses and deficits of individual streams with the capabilities and performance of different market-available heat pump concepts. For an illustrative example, the presented modifications based on HPBA increase the economically viable share of the technical heat pump potential from 61% to 79%.

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