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borehole-heat-exchangers
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Evaluation of a transient borehole heat exchanger model in dynamic simulation of a ground source heat pump system
, Article Energy ; Volume 147 , March , 2018 , Pages 81-93 ; 03605442 (ISSN) ; Abbaspour, M ; Saidi, M. H ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The performance of a vertical ground source heat pump system (GSHPS) largely depends on the fluid temperature leaving the borehole heat exchanger (BHE) that may be affected by the short-term behavior of the BHE. Although considerable research has been carried out to analyze the short-term transient response of the BHEs, few studies have investigated its impact on dynamic simulation of GSHPS. Therefore, this paper presents a numerical approach based on a transient BHE model to evaluate the performance of a residential GSHPS over short and long timescales. The numerical results are compared with the results of EnergyPlus software. It is shown that the proposed model can appropriately predict...
Modeling of a Hybrid Ground Source Heat Pump System with Solar Thermal Collector and Phase Change Materials
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour, Majid (Supervisor) ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
In recent years, ground source heat pumps (GSHPs) have received increasing attention for space heating and cooling, and domestic hot water production due to their high energy performance and low environmental impacts. The most common type of ground heat exchanger used in the GSHP systems is borehole heat exchanger (BHE) that consists of U-shaped tubes placed in the vertical boreholes. In this system, the heat is absorbed from or rejected to the ground by circulation of a fluid through the ground loop. The GSHP systems provide high seasonal performance factors when the ground loads are well balanced over the year. However, most buildings in cold or hot climates have unbalanced loads. When the...
A techno-economic analysis of geothermal ejector cooling system
, Article Energy ; Volume 193 , 15 February , 2020 ; Aligolzadeh, F ; Hakkaki Fard, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Ground-coupled ejector cooling (GCEC) systems have been introduced to solve the air-coupled ejector cooling (ACEC) systems problems. To date, no research study is dedicated to compare the GCEC and the ACEC systems and determine the relative payback period of the GCEC system vs. the ACEC system. Furthermore, almost all the previous studies simulated the GCEC systems by elementary models. Therefore, a comprehensive simulation is conducted to assess the techno-economic performance of a GCEC system. The model consists of the ejector and the borehole heat exchanger submodels. The first section of the results compares the ACEC system and the GCEC system during a cooling season. The seasonal...
A numerical model for transient simulation of borehole heat exchangers
, Article Renewable Energy ; Volume 104 , 2017 , Pages 224-237 ; 09601481 (ISSN) ; Abbaspour, M ; Saidi, M. H ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
A numerical model is developed to simulate the borehole heat exchanger both in the short and long time. In this regard, the computational domain is divided into the inside and outside borehole regions. A two-dimensional finite volume method is implemented in a cylindrical coordinate system for modeling of the outside borehole. Also, a thermal resistance-capacity model is presented for the borehole cross section. This model is extended to take into account the fluid transport through the U-tube and the temperature variation of the borehole components with depth. The governing equations of the two regions are solved iteratively in each time step. The proposed model is verified with the...