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.

scholarly journals Design and Performance Evaluation of a Heat Pump System Utilizing a Permanent Dewatering System

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2273
Author(s):  
Seung-Hoon Park ◽  
Yong-Sung Jang ◽  
Eui-Jong Kim
Keyword(s):  
Energy Source ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Large Scale ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Air Source Heat Pump ◽  
And Performance

The earth provides a vast resource of groundwater from aquifers a few meters beneath the surface. Thus, buildings that use underground space must be equipped with dewatering wells to drain the permeated groundwater to the sewage pipelines to ensure the structural stability of the building. Although the inflowing groundwater temperatures and flow rates are stable enough for groundwater to be used as an energy source, 79% of the permeated groundwater is discarded through the sewers, generating significant sewerage expenses. This study introduced a novel heat exchanger module to utilize the permeated groundwater as an unused energy source using heat pumps, and the performance of the system was evaluated by TRNSYS simulations. First, the sizing of the unit heat exchanger module was proposed according to the mean inflow rate of the permeated groundwater. Second, the heat pump system was configured using multiple modules in the source-side loop. Finally, the performance of the proposed heat pump system was compared with that of a conventional air source heat pump using realistic load and temperature profiles. This preliminary study demonstrated interesting performance results, with a coefficient of performance for heating that was higher than that of a conventional heat pump system by 0.79. The results show the potential utilization of the systems for a construction project requiring large-scale underground spaces, where abundant groundwater is available.

The design of a seasonal heat storage system with a geothermal heat pump for a residential building in Tehran

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Akbar Alidadi Shamsabadi ◽  
Mehdi Jahangiri ◽  
Tayebeh Rezaei ◽  
Rouhollah Yadollahi Farsani ◽  
Ali Seryani ◽  
...  
Keyword(s):  
Heat Pump ◽  
Heating System ◽  
Coefficient Of Performance ◽  
Maximum Temperature ◽  
Software Environment ◽  
Geothermal Heat ◽  
Pump System ◽  
Matlab Software ◽  
Content Type ◽  
Heat Pump System

Purpose In this study, a solar water heating system along with a seasonal thermal energy storage and a heat pump is designed for a villa with an area of 192 m2 in Tehran, the capital of Iran. Design/methodology/approach According to the material and the area of the residential space, the required heating of the building was calculated manually and then the thermodynamic analysis of the system and simulation was done in MATLAB software. Finally, regarding the waste of system, an efficient solar heating system, providing all the required energy to heat the building, was obtained. Findings The surface area of the solar collector is equal to 46 m2, the capacity of the tank is about 2,850 m3, insulation thickness stands at 55 cm and the coefficient of performance in required heat pump is accounted to about 9.02. Also, according to the assessments, the maximum level of received energy by the collector in this system occurs at a maximum temperature of 68ºC. Originality/value To the best of the authors’ knowledge, in the present work, for the first time, using mathematical modeling and analyzing of the first and second laws of thermodynamics, as well as using of computational code in MATLAB software environment, the solar-assisted ground source heat pump system is simulated in a residential unit located in Tehran.

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.

Sustainability Study on GCHP Heating System in Severe Cold Area of China

2013 ◽  
Vol 411-414 ◽  
pp. 3084-3087
Author(s):  
Shu Zhang ◽  
Mao Yu Zheng
Keyword(s):  
Heat Pump ◽  
Thermal Load ◽  
Heating System ◽  
Coefficient Of Performance ◽  
Heating Effect ◽  
Pump System ◽  
Heat Pump System ◽  
Heating Performance ◽  
Long Time ◽  
Cold Area

In this paper, the mathematical models of a GCHP system and a Ground-couple heat pump system with air-soil thermal storage (GCHPASTS) were developed, and the 20-year performances of the two systems were simulated in severe cold area of china, respectively. The results show that the soil temperature declines gradually during the operation of a GCHP system, which leads to the decrease of the coefficient of performance (COP) and the heating effect of the heat pump year after year. On the contrary, the balance of ground thermal load can be realized during the operation of a GCHPASTS system, and the heating performance of heat pump is stable and efficient for long time. So, it can be proved that a GCHP system cant be used for heating alone, while a GCHPASTS system is feasibility.

Research on Composite System of Solar Energy Reclaimed Water Heat Pump and Phase Change Energy Storage

2014 ◽  
Vol 521 ◽  
pp. 56-59
Author(s):  
Hui Xing Li ◽  
Peng Cheng ◽  
Guo Hui Feng ◽  
Ran Zhang
Keyword(s):  
Heat Pump ◽  
Operating Cost ◽  
Reclaimed Water ◽  
Water Source ◽  
Heating System ◽  
Hot Water ◽  
Water Heating ◽  
Pump System ◽  
Heat Pump System ◽  
Important Approach

New energy development and utilization is an important approach to solve the problem of energy shortage,a new type of composite heating system is proposed in this study. It expounds the research ideas, the technical principle and operation plan of the system. Through a comparative analysis of the performance coefficient of composite heating system, reclaimed water source heat pump system and solar hot water heating system, it Comes to the conclusions that the composite heating system can not only reduce the operating cost but also improve the running performance of reclaimed water source heat pump and reduce the heat loss of solar hot water heating system.

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.

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.

Experimental Investigation of Air-Source Heat Pump Heating System With a Novel Thermal Storage Refrigerant-Heated Panel

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Suola Shao ◽  
Huan Zhang ◽  
Shijun You ◽  
Yaran Wang
Keyword(s):  
Heat Pump ◽  
Air Temperature ◽  
Thermal Storage ◽  
Heating System ◽  
Economic Feasibility ◽  
Coefficient Of Performance ◽  
Total Annual Cost ◽  
Condensation Temperature ◽  
Outdoor Air ◽  
Air Source Heat Pump

Abstract In response to the triple crisis of energy–environment–economy (3Es), the air-source heat pump (ASHP) system is considered to be one of the most feasible candidates to upgrade the traditional high emission heating solutions. In this paper, a novel thermal storage refrigerant-heated panel (RHP) is proposed for the ASHP heating system. Experiments were conducted in a climate chamber to test the heating and defrosting performance of the system, the thermal performance of the RHP, the system energy efficiency, and the system economic feasibility. The results show that the heat flux of the RHP is as high as 625.5 W/m2 at a condensation temperature of 40 °C and an outdoor air temperature of −7 °C. Meanwhile, the system is demonstrated to be reliable and competitive with efficient thermal stability in heating conditions and comfortable indoor thermal in defrosting conditions. The coefficient of performance (COP) ranges from 2.2 to 4.0 when the outdoor air temperature changes from −12 °C to 7 °C in the tests. Meanwhile, the initial capital cost and the total annual cost of the proposed system are 430 USD and 203.1 USD, respectively, which is competitive in the distracted heating systems.

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