scholarly journals Quasi-dynamic model of the energy efficiency degradation coefficient for an air-to-water heat pump

2018 ◽  
Vol 44 ◽  
pp. 00139 ◽  
Author(s):  
Krzysztof Piechurski ◽  
Małgorzata Szulgowska-Zgrzywa ◽  
Jan Danielewicz
Keyword(s):  
Energy Efficiency ◽  
Dynamic Model ◽  
Heat Pump ◽  
Measurement Data ◽  
Operating Mode ◽  
Heat Pumps ◽  
Part Load ◽  
Actual Degree ◽  
Degradation Coefficient

Operating in part-load conditions significantly affects the energy efficiency of the air-to-water heat pumps. The currently used method of testing the devices does not provide the necessary data for estimating the degradation of the device’s efficiency in part-load operating mode. The value of the degradation coefficient Cc = 0.9 adopted in accordance with the EN 14825 standard is generally used. However, this value often does not reflect the actual degree of the COP reduction. Hence the new quasi-dynamic model and the calculation approach to the degradation coefficient were proposed. The model reflects the real and overall reduction between the full and part-load COP, not only the energy consumption in the stand-by mode. The estimation was made using the field measurement data of the air-to-water heat pump supplying heat to the low temperature installation. It has been proved that the determination of the main parameter is possible using a relatively small amount of data without losing an accuracy.

scholarly journals The modelling of reverse defrosting cycles of air-to-water heat pumps with TRNSYS

2019 ◽  
Vol 111 ◽  
pp. 01063 ◽  
Author(s):  
Matteo Dongellini ◽  
Agostino Piazzi ◽  
Filippo De Biagi ◽  
Gian Luca Morini
Keyword(s):  
Heat Pump ◽  
Operating Mode ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Performance Data ◽  
Energy Losses ◽  
Heating Season ◽  
Indoor Thermal Comfort ◽  
Reverse Mode ◽  
Heating Capacity

The most widespread defrosting technique adopted by Air-Source Heat Pumps (ASHPs) during the heating season is Reverse Cycle Defrosting (RCD). In this paper a dynamic model of RCD, based on performance data provided by the heat pump manufacturer, designed for TRNSYS and with a core-structure suitable for commercial units, is presented. A defrost cycle is divided in three phases. First, the unit heating capacity is reduced as a linear function of the ice layer thickness (Pre-Defrost phase). Subsequently, the reverse cycle operating mode is modelled on the basis of the performance data given by the manufacturer (Defrost phase) and, finally, the heat pump performances are altered taking into account the higher surface temperature of the external coil after the reverse mode (Post-Defrost phase). Then, the influence of defrosting energy losses on the heat pump seasonal performance factor in sites characterized by different climatic conditions has been assessed. Results point out that the ASHP seasonal efficiency decreases of about 5% taking into account defrost energy losses; in addition, the influence of defrost cycles on the internal air temperature is studied by assessing under which conditions the indoor thermal comfort can be guaranteed even in presence of frequent defrost cycles.

Heat Pumps for Energy Saving of Building Hot Water Supply

2011 ◽  
Vol 347-353 ◽  
pp. 587-590
Author(s):  
Qing Hai Luo ◽  
Zheng Zuo
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Water Supply ◽  
Energy Saving ◽  
Heat Pump ◽  
Heat Pumps ◽  
Hot Water ◽  
Low Energy ◽  
Water Heaters ◽  
Hot Water Supply

This paper analyzes the energy consumption of hot water supply in buildings and the insurmountable shortcoming of low energy efficiency of conventional water heaters, and investigates the progress and problems of developing heat pump water heaters. It is pointed out that developing of heat pump water heaters is one of the efficient approaches to improve the energy efficiency of hot water supply.

Dynamic Model of Compression Refrigeration System with a High Pressure Receiver

2011 ◽  
Vol 130-134 ◽  
pp. 575-579
Author(s):  
Wen Peng Zhai ◽  
Ai Guo Wu ◽  
Yu Wen You
Keyword(s):  
Optimal Control ◽  
Energy Efficiency ◽  
High Pressure ◽  
Energy Consumption ◽  
Dynamic Model ◽  
Control Design ◽  
Building Energy ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Part Load

Vapor compression chiller, the largest proportion of building energy consumption as the design and running characteristics, work at part load for most of the time. To improve the energy efficiency at part load, this thesis details some efforts to develop a dynamic model of a vapor compressor system suitable for optimal control design purpose. It present the model of high pressure liquid receiver which is important for the mass balance of the whole system and make sure it operated in a set-point designed. Additional experiments were also performed to verify the precision of the model.

scholarly journals Assessment on the Efficiency of an Active Solar Thermal Facade: Study of the Effect of Dynamic Parameters and Experimental Analysis When Coupled/Uncoupled to a Heat Pump

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 597
Author(s):  
Peru Elguezabal ◽  
Alex Lopez ◽  
Jesus Maria Blanco ◽  
Jose Antonio Chica
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Poor Performance ◽  
Heat Pumps ◽  
Solar Thermal ◽  
Solar Irradiation ◽  
Active System ◽  
Building Sector ◽  
Improve Energy Efficiency ◽  
The Impact

The building sector presents poor performance in terms of energy efficiency and is looking for effective alternatives aimed at reducing the use of fossil fuels. The facade is a key element able to harness renewable energy as an Active Solar Thermal Facade (ASTF). The main purpose of this study is the assessment of a novel design concept based on a steel sandwich panel technology. The performance of the active system will be first addressed by a parametric study in order to analyze its behavior and secondly, by describing a real case based on an experimental test by connecting the active panels to a heat pump. The study shows the impact of solar irradiation and mass flow on the thermal jump achieved, while ambient and fluid inlet temperatures are the most influencing parameters in the efficiency of the facade. When coupled to the heat pump, results from a measurement campaign demonstrate a remarkable improvement in the performance of the ASTF. The results presented provide significant proof about the benefits of a synergetic combination of both technologies—solar facades and heat pumps—as efficient alternatives for the building sector, aiming to improve energy efficiency as well as reduce their dependence on non-renewable sources.

scholarly journals EXPRESS ESTIMATION OF THE ENERGY EFFICIENCY OF A CENTRIFUGAL PUMP WITHOUT EXPERIMENTAL DETERMINATION OF ITS EXPENSES

2019 ◽  
pp. 46-52
Author(s):  
V. S. Kostyshyn ◽  
P. M. Nykolyn
Keyword(s):  
Energy Efficiency ◽  
Experimental Determination ◽  
Centrifugal Pump ◽  
Operating Mode ◽  
Total Efficiency ◽  
Operating Characteristics ◽  
Hydraulic Machines ◽  
Calculated Load ◽  
Load Angle

Using a mathematical model, created on the basis of the electrohydraulic analogy method, a methodology for express estimation of the energy efficiency of a centrifugal pump was developed. The design load angle for analyzing the efficiency of operating modes of hydraulic machines is determined. The dependence of the power-driven engine shaft and the total efficiency of the centrifugal pump on its calculated load angle is established. The relationship between load angle and speed coefficient, which is a prototype of an electromagnetic load angle which characterizes the synchronous machine operating mode, is determined. It is established the dependence of the main pump head on the calculated load angle and the differential pressure created by the centrifugal pump. The developed methodology makes it possible to avoid significant technical and financial difficulties, since flow meters have a high cost and certain requirements for installation, while manometers are established by the standard requirements of the technological process. The estimated value of the load angle of the centrifugal pump through its catalog parameters is determined. The operating characteristics for the main centrifugal pump of type НМ-7000-210 were calculated and built without experimental determination of its head. Such approach showed a good coincidence of calculated and experimental characteristics. Relative error of energy characteristics does not exceed ten percents.  The proposed methodology can be used for express estimation of the efficiency of energy transformations of the whole electric drive pump unit. Express-analysis is a key to successful management of the energy economy through timely detection of inefficient modes of operation of electric-driven pump units and makes energy research cheaper.

Dutch building code regulates noise limits for outside placed heat pumps

2021 ◽  
Vol 263 (5) ◽  
pp. 1703-1711
Author(s):  
Wim Beentjes ◽  
Theo Campmans
Keyword(s):  
Heat Pump ◽  
Power Level ◽  
Measurement Procedure ◽  
Heat Pumps ◽  
Living Environment ◽  
Design Tool ◽  
Small Companies ◽  
Co Emission ◽  
Selection Of

To reduce CO-emission, Air/Water and Air/Air heat pumps are increasingly used in the Netherlands. Due to several noise complaints, the Dutch government decided that legal regulations were necessary to restrict outside noise. The legislation process consisted of three phases. Determination of noise limits on neighbouring plot boundaries, based on a comparison with existing noise regulations for small companies in a defined quiet living environment. Creation of rules for ground-bound dwellings and for apartments. Determination of the legal noise measurement procedure of installed heat pumps, such as defining working conditions and how to deal with tonality. Developing a design tool for simple situations. This tool calculates the sound attenuations between the heat pump and all relevant receiver positions. The smallest attenuation determines the allowed sound power level of the heat pump. This is key information for appropriate selection of heat pumps. For complex situations, special calculation is still needed.

Study on Principle and Application of Heat Pump Technology

2014 ◽  
Vol 525 ◽  
pp. 607-610 ◽  
Author(s):  
Jian Zhang ◽  
Hui Yu Wang ◽  
Jian Zhang
Keyword(s):  
Heat Pump ◽  
Intelligent Control ◽  
Operating Mode ◽  
Heat Pumps ◽  
Pump System ◽  
Heat Pump System ◽  
Heat Pump Unit ◽  
Temperature Heat ◽  
Potential Basis ◽  
System Operating

This paper studies the low temperature heat source heat pumps to improve the efficiency of the heat pump unit with economic principles and the use of compressed improve the working conditions of the compressor, and to explore the system operating mode. A new test run integrated heat pump system is designed. Heat pump system can be controlled by the intelligent control of the implementing agencies, to improve the economic system, the research of this paper can provide a potential basis for the efficient use of energy heat pump.

Transient Dehumidification Characteristics of a Heat Pump in Cooling Mode

1991 ◽  
Vol 113 (4) ◽  
pp. 264-271
Author(s):  
Srinivas Katipamula ◽  
Dennis L. O’Neal
Keyword(s):  
Relative Humidity ◽  
Heat Pump ◽  
Dew Point ◽  
Cooling Mode ◽  
Part Load ◽  
Start Up ◽  
Hot And Humid Climates ◽  
Indoor Air Flow ◽  
Load Conditions ◽  
Degradation Coefficient

Much of the seasonal cooling operation of the heat pump occurs at part-load conditions when the unit cycles on and off to meet the cooling load. The seasonal efficiency under part-load conditions of the heat pump is typically estimated from a laboratory measurement of the degradation coefficient (CD). Manufacturers are only required to estimate CD at a single test condition where the indoor coil performs sensible cooling only. The effects of transient dehumidification losses are not accounted in estimating the seasonal efficiency. In hot and humid climates, dehumidification performance of a heat pump is as important as the sensible cooling performance. Therefore, a series of tests were designed to quantify the part-load dehumidification characteristics of a three ton residential air-to-air heat pump. The tests include: cycling rates from 0.8 to 10 cycles per hour (cph), percent on-times of 20, 50, and 80 percent, indoor dry-bulb temperature between 22.2°C and 26.7°C, and indoor relative humidity between 20 to 67 percent. The outdoor conditions and the indoor air flow rate were constant for all test runs. All experiments were performed in psychometric chambers under controlled conditions. The dehumidification process started between 60 to 150 seconds after start-up depending on the test conditions. During start-up, the losses in the latent capacity were greater than the losses in the sensible capacity. The dehumidification response increased with indoor dry-bulb temperature at constant relative humidity and decreased with indoor temperature at constant dew-point temperature.

scholarly journals Quasi-dynamic model of the energy efficiency for an air-to-water heat pump

2019 ◽  
Vol 100 ◽  
pp. 00065
Author(s):  
Krzysztof Piechurski ◽  
Małgorzata Szulgowska-Zgrzywa
Keyword(s):  
Energy Efficiency ◽  
Steady State ◽  
Heat Pump ◽  
Dynamic Test ◽  
Heat Pumps ◽  
Dynamic Effects ◽  
Heating Installation ◽  
Reliable Model ◽  
The Impact ◽  
Operational Data

The energy efficiency of air-to-water heat pump operating in an actual heating installation depends on many factors. In order to create a reliable model of the unit, it is necessary to include as many of them as possible. Unfortunately, the most common data provided by heat pump manufacturers are based on tests performed in accordance with the EN 14511 standard [1]. These tests are performed in steady-state conditions and do not provide reliable information on the impact of dynamic effects on the energy efficiency of the device. The solution may be the tests in quasi-dynamic conditions. The article presents the possibility of creating the characteristics of an air-to-water heat pumps based on operational data. The accuracy of the created model has been compared with the characteristics resulting from measurements in steady state conditions. It has been confirmed that dynamic test data, after proper selection, will allow to determine the characteristics of repeatable parameters and this can be an alternative to tests performed in fixed conditions.

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