Development and Verification of Simulation Model of Hybrid Ground-coupled Heat Pump Systems with Inclined Boreholes PDF Download

Author: Ping Cui
Publisher:
ISBN:
Category : Heat pumps
Languages : en
Pages : 436

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Author: Simon Rees
Publisher: Woodhead Publishing
ISBN: 0081003226
Category : Technology & Engineering
Languages : en
Pages : 484

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Book Description
Advances in Ground-Source Heat Pump Systems relates the latest information on source heat pumps (GSHPs), the types of heating and/or cooling systems that transfer heat from, or to, the ground, or, less commonly, a body of water. As one of the fastest growing renewable energy technologies, they are amongst the most energy efficient systems for space heating, cooling, and hot water production, with significant potential for a reduction in building carbon emissions. The book provides an authoritative overview of developments in closed loop GSHP systems, surface water, open loop systems, and related thermal energy storage systems, addressing the different technologies and component methods of analysis and optimization, among other subjects. Chapters on building integration and hybrid systems complete the volume. - Provides the geological aspects and building integration covered together in one convenient volume - Includes chapters on hybrid systems - Presents carefully selected chapters that cover areas in which there is significant ongoing research - Addresses geothermal heat pumps in both heating and cooling modes

Author: Scott P. Hackel
Publisher:
ISBN:
Category :
Languages : en
Pages : 264

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Author: Sung Lok Do
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The intent of this study was to improve residential energy efficiency in Texas by developing an improved tool for home builders and code officers to use for evaluating their designs. It was achieved by developing a new ground-coupled heat pump (GCHP) model for residential systems to be used with the DOE-2.1e simulation program. To accomplish this, this study investigated closed-loop ground heat exchanger (GHX) models, including horizontal, surface water, and vertical GHX models. This study selected a case-study house in Texas which has a custom-built GHX using a combination of a horizontal GHX and a surface water GHX. This study developed a custom-built GHX model for the case-study house to calculate the entering water temperatures (EWTs). The custom-built GHX model was then validated using the measured EWT data from the case-study house. The results showed the monthly average EWTs differences between the measured and calculated EWTs were observed to be about 2.2 F during the heating season and about 3.2 F during the cooling season. Therefore, this study concluded the slightly over-estimated EWTs were acceptable considering the other uncertainties of the field conditions. In addition, a vertical GHX DOE-2.1e model was developed by using the DOE-2.1e FUNCTION command. The g-function values approximated in this study was used for the vertical GHX DOE-2.1e model. To develop a new DOE-2.1e GCHP simulation model, this study then incorporated the vertical GHX DOE-2.1e input FUNCTION within an air-source heat pump (ASHP) simulation module by modifying existing DOE-2 calculation algorithms. To evaluate the new DOE-2.1e GCHP model, this study also developed simplified residential ASHP/GCHP base-case models for Houston and Dallas, using DOE-2.1e, eQUEST, IC3, REM/Rate, and EnergyGauge. The DOE-2.1e simulation results were then compared against the other programs to verify the accuracy of the new DOE-2.1e GCHP model. The comparison showed good agreement in the total site energy use within 3.3 MMBtu/yr (5.3%) differences. In addition, the simulation results showed the GCHP system benefits: for the total site energy savings, 9.7% in Houston and 13.1% in Dallas, and for the heating plus cooling energy savings, 27.3% in Houston and 35.3% in Dallas. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152691

Author: Jason Earl Gentry
Publisher:
ISBN: 9781109817140
Category :
Languages : en
Pages : 297

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Findings and conclusions. The predicted HGSHP system simulation matched very well to experimental results when each component was calibrated. From the designers' perspective, the performance of the system simulation with all models relying only on manufacturers' data was quite good and should be acceptable for design purposes.

Author: Ioan Sarbu
Publisher: Academic Press
ISBN: 0128042419
Category : Technology & Engineering
Languages : en
Pages : 217

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Book Description
Ground-Source Heat Pumps presents the theory and some of the most recent advances of GSHPs and their implementation in the heating/cooling system of buildings. The authors explore the thermodynamic cycle with calculation, operation regimes and economic indicators and GHG emissions of a vapor compression heat pump. They go on to examine substitution strategies of non-ecological refrigerants and types of compressors and heat pumps, before delving into the different GSHP systems, as well as their compared economic, energy and environmental performances using classical and optimized adjustment for various operating modes. Surface water heat pumps and ground water heat pumps are covered, and special focus is given to both vertical and horizontal ground-coupled heat pump systems, for which modelling and simulation is discussed, and experimental systems are described. Due to its advanced approach to the subject, this book will be especially valuable for researchers, graduate students and academics, and as reference for engineers and specialists in the varied domains of building services. Explores fundamentals and state-of-the-art research, including ground-coupled heat pump (GCHP) systems. Includes performance assessment and comparison for different types of GSHP, numerical simulation models, practical applications of GSHPs with details on the renewable energy integration, information on refrigerants, and economic analysis.

Author: Eui-Jong Kim
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Ground-source heat pump systems with vertical ground heat exchangers (GHE) are gaining popularity worldwide for their higher coefficients of performance and lower CO2 emissions. However, the higher initial cost of installing the borehole GHEs is a main obstacle to spread the systems. To reduce the required total GHE length and efficiently operate the systems, various systems such as hybrid ones (e.g. solar heat injection) have recently been introduced. Accurate prediction of heat transfer in and around boreholes of such systems is crucial to avoid costly overdesigns or catastrophic failures of undersized systems as it is for typical GCHP systems. However, unlike the traditional sizing methods, it is increasingly required to take into account detailed borehole configuration and transient effects (e.g. short circuit effects between U-tubes). Many of the existing GHE models have been reviewed. Some of these models have serious limitations when it comes to transient heat transfer, particularly in the borehole itself. Accordingly, the objective of this thesis is to develop a model that is capable to accurately predict thermal behaviors of the GHEs. A precise response to input variations even in a short time-step is also expected in the model. The model also has to account for a correct temperature and flux distribution between the U-tubes and inside the borehole that seems to be important in the solar heat injection case. Considering these effects in 3D with a detailed mesh used for describing the borehole configurations is normally time-consuming. This thesis attempts to alleviate the calculation time using state model reduction techniques that use fewer modes for a fast calculation but predict similar results. Domain decomposition is also envisaged to sub-structure the domain and vary the time-step sizes. Since the decomposed domains should be coupled one another spatially as well as temporally, new coupling methods are proposed and validated particularly in the FEM. For the simulation purpose, a hybrid model (HM) is developed that combines a numerical solution, the same one as the 3D-RM but only for the borehole, and well-known analytical ones for a fast calculation. An experimental facility used for validation of the model has been built and is described. A comparison with the experimental results shows that the relatively fast transients occurring in the borehole are well predicted not only for the outlet fluid temperature but also for the grout temperatures at different depths even in very short time-steps. Even though the current version of 3D-RM is experimentally validated, it is still worth optimizing the model in terms of the computational time. Further simulations with the 3D-RM are expected to be carried out to estimate the performance of new hybrid systems and propose its appropriate sizing with correspondent thermal impacts on the ground. Finally, the development of the model 3D-RM can be an initiation to accurately model various types of GHE within an acceptable calculation time.

Author: Sankaranarayanan Padhmanabhan
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Vasile Minea
Publisher: CRC Press
ISBN: 1000564258
Category : Science
Languages : en
Pages : 443

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Book Description
Heating and Cooling with Ground-Source Heat Pumps in Cold and Moderate Climates: Design Principles, Potential Applications and Case Studies focuses on applications and cases studies of ground-source heat pumps in moderate and cold climates. It details technical aspects (such as materials, thermal fluid carriers and pumping, and drilling/trenching technologies), as well as the most common and uncommon application fields for basic system configurations. The principles of system integrations and applications in moderate and cold climates (such as hybrid, solar-assisted, thermo-syphon, foundation, mines, snow melting, district heating and cooling ground-source heat pump systems, etc.) are also presented, each followed by case studies. Based on the author's more than 30 years of technical experience Discusses ground-source heat pump technologies that can be successfully applied in moderate and cold climates Presents several case studies, including successful energy results, as well as the main lessons learned This work is aimed at designers of HVAC systems, as well as geological, mechanical, and chemical engineers implementing environmentally-friendly heating and cooling technologies for buildings.

Author: Chang Chen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Ground source heat pump (GSHP) systems are one of the fastest growing applications of renewable energy in the world with annual increases of 10% over the past decade. GSHPs are potentially more efficient than conventional air-to-air heat pumps as they use the relatively constant temperature of the geothermal energy to provide heating or cooling to conditioned rooms at desired temperature and relative humidity. More importantly, GSHP systems can in fact achieve significant energy savings year round, compared to conventional HVAC systems. A hybrid ground source heat pump (HGSHP) system is designed in this study to heat and cool an office building all the year round. Dynamic models of each component of the heat pump system are developed for simulations of heat transfer between each component of the HGSHP system and for control strategy design and analysis. A detailed multiple-load aggregation algorithm (MLAA) is adapted from the literature to precisely account for and calculate the transient heat conduction in vertical ground heat exchangers with different yearly, monthly, and daily pulses of heat. Feedback PI controllers for heat pump units and On/Off controllers for boiler and cooling tower are designed and utilized to match anticipated building loads and to analyze transient response characteristics of such outputs as water flow rate and air flow rate of heat pumps, return water temperature and supply air temperature of heat pumps, water temperatures of ground loops and heat exchangers, water temperature of boiler or cooling tower, and fuel flow rate of boiler. Control strategies for the HGSHP system in both heating and cooling modes of operation are also introduced to study the system responses. With the usage of On/Off controllers and well-tuned PI controllers, as well as optimal control strategies for heating and cooling operations, the HGSHP system is expected to give better operating performance and efficiency. As a result, noticeable energy savings can be achieved in both heating and cooling modes of operation.