Simulative Study on Solar-Assisted Air Source Heat Pump System

2013 ◽  
Vol 671-674 ◽  
pp. 2141-2144 ◽  
Author(s):  
Qiang Wang ◽  
Feng Zhen Liu ◽  
Li Jun Hou ◽  
Jian Hua Gao
Keyword(s):  
Heat Pump ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Pump Unit ◽  
Pump System ◽  
Heat Pump System ◽  
Air Source Heat Pump ◽  
Heat Pump Unit ◽  
The Stability

A solar assisted air source heat pump unit is designed. The mathematical model of the unit is established and two hybrid operating conditions of the system are simulated. The simulative studying results shows that in winter the solar assisted air source heat pump unit can make full use of solar energy and the coefficient of performance (COP) of air source heat pump can be improved. In summer the cooling heat of air source heat pump could be recovered to improve the stability of solar hot water collector and the COP of the air source heat pump unit is greatly improved. The performance of solar assisted air source heat pump unit is better than that of with no solar assisted air source heat pump.

Experimental Study of Heating-Cooling Combined Ground Source Heat Pump System with Horizontal Ground Heat Exchanger

2011 ◽  
Vol 374-377 ◽  
pp. 398-404 ◽  
Author(s):  
Ying Ning Hu ◽  
Ban Jun Peng ◽  
Shan Shan Hu ◽  
Jun Lin
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pump ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ground Heat Exchanger ◽  
Pipe Length ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling

A hot-water and air-conditioning (HWAC) combined ground sourse heat pump(GSHP) system with horizontal ground heat exchanger self-designed and actualized was presented in this paper. The heat transfer performance for the heat exchanger of two different pipe arrangements, three layers and four layers, respectively, was compared. It showed that the heat exchange quantity per pipe length for the pipe arrangement of three layers and four layers are 18.0 W/m and 15.0 W/m. The coefficient of performance (COP) of unit and system could remain 4.8 and 4.2 as GSHP system for heating water, and the COP of heating and cooling combination are up to 8.5 and 7.5, respectively. The power consumption of hot-water in a whole year is 9.0 kwh/t. The economy and feasibility analysis on vertical and horizontal ground heat exchanger were made, which showed that the investment cost per heat exchange quantity of horizontal ground heat exchanger is 51.4% lower than that of the vertical ground heat exchanger, but the occupied area of the former is 7 times larger than the latter's.

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.

Simulation Study on Solar Collector - Air Source Heat Pump Combined System for Space Heating in Cold Region

2012 ◽  
Vol 238 ◽  
pp. 478-481
Author(s):  
Zhen Qing Wang ◽  
Yan Chen ◽  
Hai Xia Wang
Keyword(s):  
Heat Pump ◽  
Simulation Study ◽  
Hot Water ◽  
Office Building ◽  
Space Heating ◽  
Combined System ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Air Source Heat Pump

An air source heat pump system (ASHPS) was set up, which provided space heating and cooling, as well as hot water for an office building in Tianjin. Its operating performance in winter was evaluated based on test data. Considering the local abundant solar radiation and the way to provide energy in an office building, a simulation study was carried out on the combsystem of ASHP and flat plate air collector (FPAC). The effects of collector area and its outlet parameters on the heating performance of ASHP were studied, and the favorable operating and matching mode were recommended. The results indicate that ASHPS is a technically viable method in Tianjin in winter, but not economically, and the air-solar combsystem should be taken into account for its massive replacement for conventional energy.

Analysis of Single-Phase Convective Heat Transfer and System COP at Higher Power Levels in Thermoelectric-Based Hydronic Cooling and Heating Device

2009 ◽  
Author(s):  
Michael J. Kazmierczak ◽  
Abhishek Gupta
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Flow Rate ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
System Component ◽  
Pump System ◽  
Heat Pump System ◽  
Higher Power ◽  
Te Modules

Experiments were performed on a heat exchanger equipped with multiple thermoelectric (TE) modules. The TE-HX serves as the basic system component in a simple hydronic modular Peltier heat pump system designed to provide chilled or hot water for domestic use (or supplementary building climate control) of small residences [1]. The present work focuses on the detailed convection analysis inside the TE-HX component when 10 thermoelectric modules are utilized. The local heat transfer coefficient at different points along the channel are measured at steady-state, first, when a continuous heater is installed and then when replaced with 10 TE modules. The experimental heat transfer coefficients obtained are compared with available empirical correlations for “transition” (3000 < ReDh < 7000) turbulent flow inside the channel with fair-to-good results. Next, the resulting coefficient-of-performance of the TE heat pump system is measured with its value depending both on system input power and water flow rate. Testing showed that performance degradation, i.e. reduced COPs, occurred when operated at higher power levels but remains satisfactory for up to 688 Watts with higher flow rate.

The Heating Coefficient Experimental Analysis of Solar Water-Assisted Low Temperature Air Source Heat Pump System

2014 ◽  
Vol 953-954 ◽  
pp. 136-143
Author(s):  
Jin Shun Wu ◽  
Yue Bo Hu ◽  
De Zhi Hu ◽  
Hong Wei Liu
Keyword(s):  
Comparative Analysis ◽  
Low Temperature ◽  
Heat Pump ◽  
Compression Ratio ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Heating Efficiency ◽  
Evaporation Temperature ◽  
Air Source Heat Pump

In winter,Many families use air source heat pump because of the low evaporation temperature of the system, resulting in lower heating efficiency of system. To solve this problem, the low temperature solar assisted hot water was added to the project which is on the basis of air source heat pump, and the system has been tested. After analysis of the collection efficiency of solar collectors at low temperatures and comparative analysis of the temperature cycle, pressure, energy consumption of the low-temperature solar-assisted systems and air source heat pump system, the optimal collector temperature and law of heat pump refrigerant cycle changes of the system were obtained. Theoretically, comparative analysis of low temperature air source heat pumps and solar hot water secondary air source heat pump compression ratio and COP. It gives the key parameters affecting the compression ratio and COP, pointing out ways to improve the heat pump COP. Finally, a key measure to improve the thermal performance of the unit system is proposed, to provide a reference for future practical applications and research. Foreword Air source heat pump in ambient air contains rich low grade solar potential as a source of heat, it has inexhaustible characteristics [1] . The main reason for restricting the use of air source heat pump in northern area of our country is when the outdoor air temperature is low in winter, the outdoor coil frost severe heating efficiency air source heat pump is greatly reduced. Martinez suggested experimental study on the application of solar radiant floor heating systems , solar water temperature is 50-60°C, low efficiency, especially when overcast snow lower system efficiency [2] .In view of the outdoor coil frosting problem, direct expansion solar assisted heat pump water heater system using the proposed by Li Yuwu, from a certain extent alleviated the problem of heat in winter for coil winter fros, improving the heating coefficient and improved the operating characteristics of the unit. However, this system requires the direct absorption of heat in air tube, and the specific heat of air is small, difficult to heat storage, illumination by solar radiation impact, unstable system operation [3]. Based on the above issues, for the low-level office building , the new rural residential , this study presents low temperature solar auxiliary air source heat pump system , the device uses low-temperature solar hot water heat pump system as low , both full use of solar energy , but also eliminates the original system frost problems and improve the efficiency of solar collectors and heat set to improve the evaporation temperature of the evaporator , thereby increasing the compression ratio of the heat pump unit .

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.

Experimental Study on New Sewage Source Heat Pump Unit

2013 ◽  
Vol 316-317 ◽  
pp. 49-52
Author(s):  
Zhi Yi Wang ◽  
Jian Jun Li ◽  
Zu Dong Pan
Keyword(s):  
Heat Pump ◽  
Volume Ratio ◽  
Pump Unit ◽  
Pump System ◽  
Dual Purpose ◽  
Heat Pump System ◽  
Urban Sewage ◽  
Existing Problems ◽  
Heat Pump Unit ◽  
Sewage Source

By the analysis of the current technical conditions and existing problems, some improvements are carried out on the urban sewage source heat pump unit. are as follows: Refrigerants side switch sewage source heat pump system, dual-purpose heat exchange for evaporating and condensing & wastewater can enter the unit directly are of the main features of the improved units. Some important techniques, such as inverter screw compressor and variable compressor inner volume ratio are used to the improved unit at the same time. From the authoritative organization’s test, the improved sewage-source heat pump unit has an excellence performance in the nominal cooling and heating conditions.

SIMULATION ON OPERATION CHARACTERISTICS OF HYBRID GROUND-AIR SOURCE HEAT PUMP SYSTEM WITH NATURAL COLD STORAGE

2014 ◽  
Vol 22 (02) ◽  
pp. 1440004 ◽  
Author(s):  
Z. W. HAN ◽  
X. MENG ◽  
M. LIN ◽  
Y. H. ZHANG ◽  
J. YANG ◽  
...  
Keyword(s):  
Heat Pump ◽  
Cold Storage ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Air Source Heat Pump ◽  
Operational Life ◽  
Vapor Compression Refrigeration Cycle ◽  
Set Up ◽  
Operation Characteristics

To solve the problem of the coefficient of performance (COP) decrease and power crunch in cooling dominated South China associated with the long-term usage of ground-source heat pump system (GSHPS), a hybrid ground-air source heat pump system (HGASHPS) with natural cold storage is presented in this paper. The system consists of a GSHP system and compound air-cooled chillers (CACC), which can be operated according to the vapor compression refrigeration cycle or separate type heat pipe natural cycle. The mathematical models of each part of the system were set up and the conversion conditions between operation modes for the system were determined. The transient simulation for HGASHPS with natural cold storage in Nanjing was carried out. The operation characteristics of the systems in operational life were comparatively analyzed. The simulation results indicated that the HGASHPS with natural cold storage could retain the thermal balance of soil temperature field in one year cycle and increase the COP and reliability of the system.

scholarly journals Air-to-water heat pump assessment: Part 2 – Exergetic and exergoeconomic analyses

2021 ◽  
Vol 327 ◽  
pp. 01010
Author(s):  
Nadezhda Doseva ◽  
Daniela Chakyrova
Keyword(s):  
Heat Pump ◽  
Heat Rate ◽  
Experimental Tests ◽  
Exergetic Efficiency ◽  
Ambient Conditions ◽  
Pump Unit ◽  
Pump System ◽  
Heat Pump System ◽  
Heat Pump Unit ◽  
Exergoeconomic Analysis

This study is part 2 of the investigation on the exergetic and exergoeconomic parameters of an existing system with an air-to-water heat pump unit as a heat source. Part 1 presents the used experimental setup. The main aim of the conducted experimental tests is to develop models of produced heat rate and energetic COP at different ambient conditions. The obtained data is used in Part 2 of the study where the exergetinc and exergoeconomic assessment is carried out. The exergetic and exergoeconomic analysis was performed at dynamically changing ambient parameters. The considered operation modes of the air-to-water heat pump (AWHP) unit and backup heater (BUH) were evaluated based on Seasonal Exergetic Efficiency. For the exergoeconomic analysis, the SPECO method is used. Thus, this paper provides an exhaustive understanding of the exergy and exergoeconomic performance of the considered air-to-water heat pump system.

Experiment Study on Ground Temperature Recovery and Operating Performance of Intermittent Heat Storage in GSHP System

2010 ◽  
Author(s):  
Sufen Li ◽  
Lanhua Dai ◽  
Yan Shang
Keyword(s):  
Soil Temperature ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Heat Storage ◽  
Borehole Wall ◽  
Pump Unit ◽  
Pump System ◽  
Heat Pump System ◽  
Heat Pump Unit ◽  
The Impact

The ground source heat pump system (GSHP) continuous operation will result in heat accumulation of the soil around the underground heat exchangers leading the descend operation performance of heat pump system. Based on experiment of GSHP system in summer season, the temperature distribution of humid soil around the vertical boreholes, the power consumption of the heat pump unit, the water temperature in the inlet and outlet of the underground heat exchangers, the heat release rate of per unit length of the buried pipes in humid soil and the cooling coefficient of performance (COP) for the heat pump unit were acquired during the different intermittent heat storage modes. This study investigated the impact of soil temperature change around the borehole wall on the performance of heat pump operation, the influence of intermittent heat storage on the soil temperature near the borehole wall and the performance of heat pump unit, and the effect of intermittent heat storage process on the recovery rate of soil temperature. The results showed that proper control of the operation and interval time of GSHP can effectively improve the soil temperature field around the underground heat exchangers and enhance the performance of GSHP system, thus achieving high efficiency operation of heat pump units.

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