scholarly journals Validation of black-box performance models for a water-to-water heat pump operating under steady state and dynamic loads

2019 ◽  
Vol 111 ◽  
pp. 01068
Author(s):  
Elena Fuentes ◽  
Jaume Salom
Keyword(s):  
Steady State ◽  
Heat Pump ◽  
Thermal Power ◽  
Energy Performance ◽  
Heat Pumps ◽  
Black Box ◽  
Coefficient Of Performance ◽  
Performance Models ◽  
Pump Performance ◽  
Transient Phases

The use of simple mathematical models for describing the behaviour of heat pumps is important for assessing the energy performance of this equipment when installed in buildings. However, because of their simplicity, commonly used simple models, may not be able to fully account for the dynamic performance of heat pumps during transient phases. In this study, different performance black box models for an on-off water-to-water heat pump are validated by comparison with laboratory experimental results at steady state and dynamic cycling conditions. The models range from the solution based on the interpolation on the heat pump performance map to the detailed dynamic solution that combines correlations for the quasi-steady state operation and activation functions to model the transient phases. The output temperatures, electrical and thermal power and coefficient of performance from simulations were compared with experimental data from a water-to-water heat pump of 40.5 kW nominal heating capacity operating under cycling conditions. After validation with experiments, annual energy performance simulations of a tertiary building provided with a heat pump were conducted. These simulations quantifying the uncertainty expected when using heat pump performance models in simulation environments for estimating their annual energy performance.

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.

Photovoltaic thermal collector assisted heat pumps using environment-friendly working fluids

2020 ◽  
pp. 095440892094736
Author(s):  
AA Ammar ◽  
K Sopian ◽  
M Mohanraj
Keyword(s):  
Heat Pump ◽  
Energy Performance ◽  
Heat Pumps ◽  
Payback Period ◽  
Photovoltaic System ◽  
Coefficient Of Performance ◽  
Photovoltaic Module ◽  
Pump System ◽  
Heat Pump System ◽  
Thermal Evaporator

In this research, a photovoltaic-thermal collector assisted heat pump has been developed and tested its performance under the tropical climatic conditions of Malaysia. The refrigerants such as, R134a and R1234yf were selected based on its thermodynamic and thermo-physical properties. The temperature of the photovoltaic module was theoretically predicted under the influence of tube diameter, tube spacing and refrigerant mass flow rate. Further, the energy performance of the photovoltaic-thermal evaporator and the heat pump system are investigated experimentally. Finally, the economical feasibility of the photovoltaic-thermal collector evaporator was assessed for the period of 20 years. The results showed that, the tube spacing and diameter of the copper tubes used in the photovoltaic-thermal evaporator/collector using R134a and R1234yf were optimized to 80 mm and 12.7 mm, respectively. It was observed that, during the clear sunny day, the average photovoltaic module temperature was reduced to 30.9 °C under the influence of panel cooling using refrigerant. The output of the panel was enhanced by 21%–44% with increase in solar radiation from 400 W/m2 to 1000 W/m2. The coefficient of performance of the heat pump was varied from 4.8 to 6.84 with an average coefficient of performance of 5.8 during clear sunny days. The life cycle economic analysis indicated that, the photovoltaic-thermal collector evaporator assisted heat pump has a payback period of 3 years, whereas the reference photovoltaic system has a payback period of 8 years.

Wind Evaporator Heat Pumps—Part II: Thermal Performance Results

1992 ◽  
Vol 114 (4) ◽  
pp. 286-290
Author(s):  
J. M. O’Reilly ◽  
P. F. Monaghan
Keyword(s):  
Heat Pump ◽  
Weather Conditions ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Test Facility ◽  
Pump Performance ◽  
Wind Speeds ◽  
Testing Period ◽  
Low Wind Speeds ◽  
Compressor Power

Wind evaporators are alternative evaporators for air source heat pumps which rely on wind-driven or natural convection to move air across the heat transfer surfaces. A fully automatic, computer-controlled test facility which allows side-by-side testing of wind evaporator and conventional heat pumps and monitoring of weather conditions has been designed and built at University College Galway. The aim of this paper is to quantify the advantages of wind evaporators by comparing the performance of a wind evaporator heat pump with that of a conventional heat pump over an extended testing period and by examining the relationship between weather conditions and heat pump performance. In this paper, results are presented in the form of plots of coefficient of performance (COP), compressor power, evaporator and condenser heat transfers and climatic variables against time. In addition, a testing period coefficient of performance has been calculated for each heat pump. The results show that wind speed is the dominant climatic variable affecting wind evaporator heat pump performance, and that frost growth does not significantly reduce this performance. Even at extremely low wind speeds, the COP of the wind evaporator heat pump is not significantly affected. After over 460 hr of testing, the testing period COP of the wind evaporator heat pump shows a 16 percent increase over that of the conventional heat pump. (Refer to Nomenclature in Part I of this paper.)

Cooling and heating rate limits of a reversed reciprocating ericsson cycle at steady state

2000 ◽  
Vol 214 (1) ◽  
pp. 75-85 ◽  
Author(s):  
D A Blank ◽  
C Wu
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Pump ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Optimized Design ◽  
Cooling Mode ◽  
Working Fluids ◽  
Heating And Cooling

The optimal cooling and heating rates for the reversed reciprocating Ericsson cycle with ideal regeneration are determined for heat pump operations. These limiting rates are based on the upper and lower thermal reservoir temperature bounds and are obtained using time and entropy minimization procedures from irreversible thermodynamics. Use is made of time symmetry (a second law constraint) to minimize cycle time. This optimally allocates the thermal capacitances of the cycle and minimizes internal cycle entropy generation. Although primarily a theoretical work, a very practical and extensive parametric study using several environmentally friendly working fluids (neon, nitrogen and helium) is included. This study evaluates the relative contributions of various system parameters to rate-optimized design. The coefficient of performance (COP), and thus the quantity of cooling or heating for a given energy input, is the traditional focus; instead this work aims at the rate of cooling or heating in heat pumps under steady state conditions and using ideal gases as their working substances. The results obtained provide additional criteria for use in the study, design and performance evaluation of employing Ericsson cycles in refrigeration, air conditioning and heat pump applications. They give direct insight into what is required in designing a reversed Ericsson heat pump to achieve maximum heating and cooling rates. The choices of working fluids and pressure ratios were found to be very significant design parameters, together with selection of regenerator and source—sink heat transfer parameters. The parameter most influencing both the heating and cooling mode COPs and the heat transfer rates was found to be the heat conductance of the thermal sink.

scholarly journals Measured performance of exhaust air heat pumps in Finnish apartment buildings

2021 ◽  
Vol 246 ◽  
pp. 06001
Author(s):  
Petri Pylsy ◽  
Jarek Kurnitski
Keyword(s):  
Heat Pump ◽  
Ventilation System ◽  
Measurement Data ◽  
District Heating ◽  
Energy Performance ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Apartment Buildings

The energy efficiency of existing apartment buildings is playing an important role in energy and climate targets. In Finland, mechanical exhaust ventilation system is commonly used in older apartment buildings. Hence, there could be an energy saving potential by an exhaust air heat pump system (EAHP). In this work two cases have been studied. Buildings were built in 1960’s and 1970’s and in renovation equipped with hybrid heating system: district heating and exhaust air heat pump system. Two years measurement data, 2018 and 2019, was collected to evaluate the performance of exhaust air heat pump systems. According to measurement data the monthly coefficient of performance (COP) was calculated as well as seasonal coefficient of performance (SCOP) was defined. The monthly COP values varied from 3,1 to 4,6 and SCOP values were about 3,7. Heating energy cost savings were 23-31 %. Energy performance class before and after EAHP installation was calculated. If at least 50 % of heating energy consumption was covered by EAHP then also energy performance class was improved.

scholarly journals Defrosting of Air-Source Heat Pumps: Effect of Real Temperature Data on Seasonal Energy Performance for Different Locations in Italy

2021 ◽  
Vol 11 (17) ◽  
pp. 8003
Author(s):  
Eugenia Rossi di Rossi di Schio ◽  
Vincenzo Ballerini ◽  
Matteo Dongellini ◽  
Paolo Valdiserri
Keyword(s):  
Heat Pump ◽  
Energy Demand ◽  
Energy Performance ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Weather Data ◽  
Dynamic Simulations ◽  
Weather Stations ◽  
Performance Results ◽  
Real Temperature

In this paper, dynamic simulations of the seasonal coefficient of performance (SCOP) of Air-Source Heat Pumps will be presented by considering three different heat pump systems coupled with the same building located in three different Italian municipalities: S. Benedetto del Tronto (42°58′ North, 13°53′ East), Milan (45°28′ North, 9°10′ East), and Livigno (46°28′ North, 10°8′ East). Dynamic simulations were conducted by employing the software package TRNSYS and by considering real weather data (i.e., outdoor air temperature and humidity as well as solar radiation) referring to the three abovementioned cities for a period of 8 years (2013–2020) and collected from on-site weather stations. Attention has been paid to the modeling of the heat pump defrost cycles in order to evaluate their influence on the unit’s seasonal performance. Results show that, when referring to different years, the thermal energy demand displays huge variations (in some cases it can even double its value), while the effective SCOP is characterized by scarce variability. Sensible variations in SCOP values are achieved for Livigno.

Finite-Time Thermodynamic Performance for a Class of Irreversible Heat Pumps

1997 ◽  
Author(s):  
Chih Wu ◽  
Lingen Chen ◽  
Fengrui Sun
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Pump ◽  
Finite Time ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Heat Leak ◽  
Thermodynamic Performance ◽  
The Relationship

The effect of heat resistance and heat leak on the performance of irreversible heat pumps using a generalized heat transfer law is analyzed in this paper. The relationship between the optimal cooling load and the cop (coefficient of performance) for a steady-state irreversible heat pump is derived.

scholarly journals Selection of Heat Pump Capacity Used at Thermal Power Plants under Electricity Market Operating Conditions

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 226
Author(s):  
Milana Treshcheva ◽  
Irina Anikina ◽  
Vitaly Sergeev ◽  
Sergey Skulkin ◽  
Dmitry Treshchev
Keyword(s):  
Electric Power ◽  
Heat Pump ◽  
Heat Load ◽  
Power Plants ◽  
Thermal Power ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Energy Resources ◽  
Thermal Power Plants ◽  
Maximum Heat

The percentage of heat pumps used in thermal power plants (TPPs) in the fuel and energy balance is extremely low in in most countries. One of the reasons for this is the lack of a systematic approach to selecting and justifying the circuit solutions and equipment capacity. This article aims to develop a new method of calculating the maximum capacity of heat pumps. The method proposed in the article has elements of marginal analysis. It takes into account the limitation of heat pump capacity by break-even operation at electric power market (compensation of fuel expenses, connected with electric power production). In this case, the heat pump’s maximum allowable capacity depends on the electric capacity of TPP, electricity consumption for own needs, specific consumption of conditional fuel for electricity production, a ratio of prices for energy resources, and a conversion factor of heat pump. For TPP based on combined cycle gas turbine (CCGT) CCGT-450 with prices at the Russian energy resources markets at the level of 2019, when operating with the maximum heat load, the allowable heat pump capacity will be about 50 MW, and when operating with the minimum heat load—about 200 MW.

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%.

scholarly journals Factors Shaping A/W Heat Pumps CO₂ Emissions—Evidence from Poland

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1576
Author(s):  
Piotr Jadwiszczak ◽  
Jakub Jurasz ◽  
Bartosz Kaźmierczak ◽  
Elżbieta Niemierka ◽  
Wandong Zheng
Keyword(s):  
Air Quality ◽  
Power System ◽  
Heat Pump ◽  
Heat Pumps ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Conventional Heating ◽  
Additional Stress ◽  
The European Union ◽  
Energy Mix

Heating and cooling sectors contribute to approximately 50% of energy consumption in the European Union. Considering the fact that heating is mostly based on fossil fuels, it is then evident that its decarbonization is one of the crucial tasks for achieving climate change prevention goals. At the same time, electricity sectors across the globe are undergoing a rapid transformation in order to accommodate the growing capacities of non-dispatchable solar and wind generators. One of the proposed solutions to achieve heating sector decarbonization and non-dispatchable generators power system integration is sector coupling, where heat pumps are perceived as a perfect fit. Air source heat pumps enable a rapid improvement in local air quality by replacing conventional heating sources, but at the same time, they put additional stress on the power system. The emissions associated with heat pump operation are a combination of power system energy mix, weather conditions and heat pump technology. Taking the above into consideration, this paper presents an approach to estimate which of the mentioned factors has the highest impact on heat pump emissions. Due to low air quality during the heating season, undergoing a power system transformation (with a relatively low share of renewables) in a case study located in Poland is considered. The results of the conducted analysis revealed that for a scenario where an air-to-water (A/W) heat pump is supposed to cover space and domestic hot water load, its CO2 emissions are shaped by country-specific energy mix (55.2%), heat pump technology (coefficient of performance) (33.9%) and, to a lesser extent, by changing climate (10.9%). The outcome of this paper can be used by policy makers in designing decarbonization strategies and funding distribution.

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